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diff --git a/old/68580-0.txt b/old/68580-0.txt deleted file mode 100644 index e092b2b..0000000 --- a/old/68580-0.txt +++ /dev/null @@ -1,33902 +0,0 @@ -The Project Gutenberg eBook of A handbook of systematic botany, by -Johannes Eugenius Warming - -This eBook is for the use of anyone anywhere in the United States and -most other parts of the world at no cost and with almost no restrictions -whatsoever. You may copy it, give it away or re-use it under the terms -of the Project Gutenberg License included with this eBook or online at -www.gutenberg.org. If you are not located in the United States, you -will have to check the laws of the country where you are located before -using this eBook. - -Title: A handbook of systematic botany - -Author: Johannes Eugenius Warming - -Translator: Michael Cresse Potter - -Contributor: Emil Friedrich Knoblauch - -Release Date: July 21, 2022 [eBook #68580] - -Language: English - -Produced by: Peter Becker, Karin Spence and the Online Distributed - Proofreading Team at https://www.pgdp.net (This file was - produced from images generously made available by The - Internet Archive) - -*** START OF THE PROJECT GUTENBERG EBOOK A HANDBOOK OF SYSTEMATIC -BOTANY *** - - - - - - A HANDBOOK - - OF - - SYSTEMATIC BOTANY - - BY - - DR. E. WARMING - - _Professor of Botany in the University of Copenhagen_ - - WITH A REVISION OF THE FUNGI BY - - DR. E. KNOBLAUCH, - _Karlsruhe_ - - TRANSLATED AND EDITED BY - M. C. POTTER, M.A. F.L.S. - - _Professor of Botany in the University of Durham - College of Science, Newcastle-upon-Tyne - Author of “An Elementary Text-book of Agricultural Botany”_ - - WITH 610 ILLUSTRATIONS - - [Illustration] - - London - SWAN SONNENSCHEIN & CO - NEW YORK: MACMILLAN & CO - 1895 - - - - - BUTLER & TANNER, - THE SELWOOD PRINTING WORKS, - FROME, AND LONDON. - - - - - PREFACE. - - -The present translation of Dr. E. Warming’s _Haandbog i den -Systematiske Botanik_ is taken from the text of the 3rd Danish -Edition (1892), and from Dr. Knoblauch’s German Edition (1890), and -the book has been further enriched by numerous additional notes which -have been kindly sent to me by the author. Dr. Warming’s work has long -been recognised as an original and important contribution to Systematic -Botanical Literature, and I have only to regret that the pressure -of other scientific duties has delayed its presentation to English -readers. Dr. Warming desires me to record his high appreciation of the -careful translation of Dr. Knoblauch, and his obligation to him for a -number of corrections and improvements of which he has made use in the -3rd Danish Edition. In a few instances I have made slight additions -to the text; these, however, appear as footnotes, or are enclosed in -square brackets. - -In the present Edition the Thallophytes have been revised and -rearranged from notes supplied to me by Dr. Knoblauch, to whom I am -indebted for the Classification of the Fungi, according to the more -recent investigations of Brefeld. The Bacteria have been revised by -Dr. Migula, the Florideæ rearranged after Schmitz, and the Taphrinaceæ -after Sadebeck. The main body of the text of the Algæ and Fungi remains -as it was originally written by Dr. Wille and Dr. Rostrup in the Danish -Edition, though in many places considerable alterations and additions -have been made. For the sake of comparison a tabular key to the -Classification adopted in the Danish Edition is given in the Appendix. - -In the Angiosperms I have retained the sequence of orders in the Danish -original, and have not rearranged them according to the systems -more familiar to English students. In any rearrangement much of the -significance of Dr. Warming’s valuable and original observations -would have been lost, and also from a teacher’s point of view I have -found this system of great value. Although at present it may not be -completely satisfactory, yet as an attempt to explain the mutual -relationships, development and retrogression of many of the orders, it -may be considered to have a distinct advantage over the more artificial -systems founded upon Jussieu’s Divisions of Polypetalæ, Gamopetalæ, and -Apetalæ. - -With reference to the principles of the systematic arrangement adopted, -I may here insert the following brief communication from the author -(dated March, 1890), which he has requested me to quote from the -preface of Dr. Knoblauch’s edition:--“Each form which, on comparative -morphological considerations, is clearly less simple, or can be shown -to have arisen by reduction or through abortion of another type having -the same fundamental structure, or in which a further differentiation -and division of labour is found, will be regarded as younger, and as -far as possible, and so far as other considerations will admit, will -be reviewed later than the ‘simpler,’ more complete, or richer forms. -For instance, to serve as an illustration: EPIGYNY and PERIGYNY are -less simple than HYPOGNY; the Epigynous _Sympetalæ_, _Choripetalæ_, -_Monocotyledones_ are, therefore, treated last, the _Hydrocharitaceæ_ -are considered last under the _Helobieæ_, etc. ZYGOMORPHY is younger -than ACTINOMORPHY; the _Scitamineæ_ and _Gynandræ_ therefore follow -after the _Liliifloræ_, the _Scrophulariaceæ_ after the _Solanaceæ_, -_Linaria_ after _Verbascum_, etc. FORMS WITH UNITED LEAVES indicate -younger types than those with free leaves; hence the _Sympetalæ_ -come after the _Choripetalæ_, the _Sileneæ_ after the _Alsineæ_, the -_Malcaceæ_ after the _Sterculiaceæ_ and _Tiliaceæ_, etc. - -“ACYCLIC (spiral-leaved) flowers are older than cyclic -(verticillate-leaved) with a definite number, comparing, of course, -only those with the same fundamental structure. The _Veronica_-type -must be considered as younger, for example, than _Digitalis_ -and _Antirrhinum_, these again as younger than _Scrophularia_; -_Verbascum_, on the contrary, is the least reduced, and therefore -considered as the oldest form. Similarly the one-seeded, nut-fruited -_Ranunculaceæ_ are considered as a later type (with evident abortion) -than the many-seeded, folicular forms of the Order; the _Paronychieæ_ -and _Chenopodiaceæ_ as reduced forms of the _Alsineæ_ type; and the -occurrence of few seeds in an ovary as generally arising through -reduction of the many-seeded forms. The _Cyperaceæ_ are regarded as -a form derived from the _Juncaceæ_ through reduction, and associated -with this, as is so often the case, there is a complication of the -inflorescence; the _Dipsacaceæ_ are again regarded as a form proceeding -from the _Valerianaceæ_ by a similar reduction, and these in their -turn as an offshoot from the _Caprifoliaceæ_, etc. Of course these -principles of systematic arrangement could only be applied very -generally; for teaching purposes they have often required modification.” - -In preparing the translation considerable difficulty has been -experienced in finding a satisfactory rendering of several terms which -have no exact equivalent in English. I may here especially mention the -term Vorblatt (Forblad) which I have translated by the term bracteole, -when it clearly applied to the first leaf (or leaves) on a pedicel; but -in discussing questions of general morphology a term was much needed -to include both vegetative and floral shoots, and for this I have -employed the term “Fore-leaf.” Also, the term “Floral-leaf” has been -adopted as an equivalent of “Hochblatt,” and the term “bract” has been -limited to a leaf subtending a flower. I have followed Dr. E. L. Mark -in translating the word “Anlage” by “Fundament.” - -At the end of the book will be found a short appendix giving an outline -of some of the earlier systems of Classification, with a more complete -account of that of Hooker and Bentham. - -In a book of this character it is almost impossible to avoid some -errors, but it is hoped that these will be comparatively few. In -correcting the proof-sheets I have received invaluable assistance -from Dr. Warming and Dr. Knoblauch, who have kindly read through -every sheet, and to whom I am greatly indebted for many criticisms -and suggestions. I have also to thank Mr. I. H. Burkill for his kind -assistance in looking over the proofs of the Monocotyledons and -Dicotyledons, and Mr. Harold Wager for kindly reading through the -proofs of the Algæ and Fungi. My thanks are also especially due to Mr. -E. L. Danielsen, and I wish to take this opportunity of acknowledging -the very considerable help which I have received from him in -translating from the Original Danish. - M. C. POTTER. -_January, 1895._ - - - - - TABLE OF CONTENTS. - - BEING THE SYSTEM OF CLASSIFICATION ADOPTED IN - THE PRESENT VOLUME. - - (_The Algæ and Fungi rearranged in co-operation with Dr. E. - Knoblauch, the other Divisions as in the 3rd Danish Edition._) - - - PAGE - - DIVISION I. THALLOPHYTA 4 - - A. Sub-Division. Myxomycetes, Slime-Fungi 5 - - B. Sub-Division. Algæ 8 - - Class 1. SYNGENETICÆ 14 - - „ 2. DINOFLAGELLATA 16 - - „ 3. DIATOMEÆ 18 - - „ 4. SCHIZOPHYTA 22 - - Family 1. Schizophyceæ 22 - - „ 2. Bacteria 26 - - Class 5. CONJUGATÆ 41 - - „ 6. CHLOROPHYCEÆ 46 - - Family 1. Protococcoideæ 47 - - „ 2. Confervoideæ 53 - - „ 3. Siphoneæ 59 - - Class 7. CHARACEÆ 64 - - „ 8. PHÆOPHYCEÆ (OLIVE-BROWN SEAWEEDS) 68 - - Family 1. Phæosporeæ 68 - - „ 2. Cyclosporeæ 73 - - Class 9. DICTYOTALES 76 - - „ 10. RHODOPHYCEÆ (RED SEAWEEDS) 77 - - Family 1. Bangioideæ 77 - - „ 2. Florideæ 78 - - C. Sub-Division. Fungi 84 - - Class 1. PHYCOMYCETES 96 - - Sub-Class 1. _Zygomycetes_ 96 - - „ 2. _Oomycetes_ 100 - - Family 1. Entomophthorales 102 - - „ 2. Chytridiales 102 - - „ 3. Mycosiphonales 104 - - Class 2. MESOMYCETES 108 - - Sub-Class 1. _Hemiasci_ 108 - - „ 2. _Hemibasidii_ 109 - - Class 3. MYCOMYCETES (HIGHER FUNGI) 114 - - Sub-Class 1. _Ascomycetes_ 114 - - Series 1. Exoasci 116 - - „ 2. Carpoasci 118 - - Family 1. Gymnoascales 118 - - „ 2. Perisporiales 119 - - „ 3. Pyrenomycetes 125 - - „ 4. Hysteriales 132 - - „ 5. Discomycetes 132 - - „ 6. Helvellales 136 - - Ascolichenes 136 - - Sub-Class 2. _Basidiomycetes_ 144 - - Series 1. Protobasidomycetes 145 - - „ 2. Autobasidiomycetes 157 - - Family 1. Dacryomycetes 159 - - „ 2. Hymenomycetes 159 - - „ 3. Phalloideæ 172 - - „ 4. Gasteromycetes 173 - - Basidiolichenes 176 - - Fungi Imperfecti 176 - - - DIVISION II. MUSCINEÆ (MOSSES) 181 - - Class 1. HEPATICÆ 188 - - Family 1. Marchantieæ 190 - - „ 2. Anthoceroteæ 191 - - „ 3. Jungermannieæ 191 - - Class 2. MUSCI FRONDOSI 192 - - Family 1. Sphagneæ 193 - - „ 2. Schizocarpeæ 195 - - „ 3. Cleistocarpeæ 195 - - „ 4. Stegocarpeæ 195 - - - DIVISION III. PTERIDOPHYTA 198 - - Class 1. FILICINÆ 205 - - Sub-Class 1. _Filices_ 205 - - Family 1. Eusporangiatæ 210 - - „ 2. Leptosporangiatæ 212 - - Sub-Class 2. _Hydropterideæ_ 215 - - Class 2. EQUISETINÆ (HORSETAILS) 221 - - Sub-Class 1. _Isosporous Equisetinæ_ 221 - - „ 2. _Heterosporous Equisetinæ_ 225 - - Class 3. LYCOPODINÆ (CLUB MOSSES) 226 - - Sub-Class 1. _Lycopodieæ_ 226 - - „ 2. _Selaginelleæ_ 228 - - TRANSITION FROM THE CRYPTOGAMS TO THE PHANEROGAMS 234 - - Asexual Generation of the Cormophytes 234 - - Sexual Generation; Fertilisation 243 - - - DIVISION IV. GYMNOSPERMÆ 251 - - Class 1. CYCADEÆ (CYCADS) 252 - - „ 2. CONIFERÆ (PINE-TREES) 255 - - Family 1. Taxoideæ 259 - - „ 2. Pinoideæ 262 - - Class 3. GNETEÆ 270 - - Fossil Gymnosperms 271 - - - DIVISION V. ANGIOSPERMÆ 273 - - Class 1. MONOCOTYLEDONES 274 - - Family 1. Helobieæ 278 - - „ 2. Glumifloræ 283 - - „ 3. Spadicifloræ 297 - - „ 4. Enantioblastæ 308 - - „ 5. Liliifloræ 309 - - „ 6. Scitamineæ 323 - - „ 7. Gynandræ 328 - - Class 2. DICOTYLEDONES 334 - - Sub-Class 1. _Choripetalæ_ 337 - - Family 1. Salicifloræ 337 - - „ 2. Casuarinifloræ 339 - - „ 3. Quercifloræ 340 - - „ 4. Juglandifloræ 349 - - „ 5. Urticifloræ 351 - - „ 6. Polygonifloræ 358 - - „ 7. Curvembryæ 363 - - „ 8. Cactifloræ 375 - - „ 9. Polycarpicæ 377 - - „ 10. Rhœadinæ 393 - - „ 11. Cistifloræ 406 - - „ 12. Gruinales 416 - - „ 13. Columniferæ 421 - - „ 14. Tricoccæ 430 - - „ 15. Terebinthinæ 435 - - „ 16. Aesculinæ 439 - - „ 17. Frangulinæ 443 - - „ 18. Thymelæinæ 448 - - „ 19. Saxifraginæ 451 - - „ 20. Rosifloræ 456 - - „ 21. Leguminosæ 466 - - „ 22. Passiflorinæ 475 - - „ 23. Myrtifloræ 482 - - „ 24. Umbellifloræ 490 - - „ 25. Hysterophyta 498 - - Sub-Class 2. _Sympetalæ_ 504 - - _A. Pentacyclicæ_ 506 - - Family 26. Bicornes 506 - - „ 27. Diospyrinæ 510 - - „ 28. Primulinæ 511 - - _B. Tetracyclicæ_ 514 - - Family 29. Tubifloræ 514 - - „ 30. Personatæ 517 - - „ 31. Nuculiferæ 531 - - „ 32. Contortæ 541 - - „ 33. Rubiales 548 - - „ 34. Dipsacales 556 - - „ 35. Campanulinæ 560 - - „ 36. Aggregatæ 564 - - APPENDIX 574 - - INDEX 593 - - - - - CORRIGENDA. - - - Page 9, line 12 from top, for _Hydrodicton_ read _Hydrodictyon_. - „ 14, lines 1 and 2 from top, for _as in the preceding case_ - read _in this case_. - „ 14, „ 2 and 15 from top, for _zygote_ read _oospore_. - „ 88, line 15 from bottom, for _Periphyses_ read _periphyses_. - „ 124, „ 7 „ „ for _Chæromyces_ read _Choiromyces_. - „ 142, „ 2 „ „ and in Fig. 137, for _Bœomyces_ read - _Bæomyces_. - „ 152, „ 2 „ top, for _Pirus_ read _Pyrus_. - „ 152, „ 5 „ „ for _Crategus_ read _Cratægus_. - „ 216, Fig. 215, for _Salvina_ read _Salvinia_. - „ 306, line 6 from top, for _Pista_ read _Pistia_. - „ 316, „ 26 „ „ after Dracæna insert a comma. - „ 337, „ 13 „ „ for _end_ read _beginning_. - „ 483, „ 11 „ bottom, for _Lagerstrœmia_ read - _Lagerstrœmeria_. - -For ä, ö and ü read æ, œ and ue throughout. - -The following are not officinal in the British Pharmacopœia:--page 316, -_Dracæna_ (Dragon’s-blood), _Smilax glabra_; p. 321, “Orris-root”; -p. 326, species of _Curcuma_, _Alpinia officinarum_; p. 333, -_Orchis_-species (“Salep”). On page 296, par. 4, only Pearl Barley is -offic. in the Brit. Phar. - - - - - CLASSIFICATION OF THE VEGETABLE KINGDOM. - - -The Vegetable Kingdom is arranged in 5 Divisions. - -Division I.--=Thallophyta=, =Stemless Plants=, or those which -are composed of a “thallus,” _i.e._ organs of nourishment which -are not differentiated into root (in the sense in which this term is -used among the higher plants), stem, or leaf. Vascular bundles are -wanting. Conjugation and fertilisation in various ways; among most of -the Fungi only vegetative multiplication. - - In contradistinction to the Thallophytes all other plants are - called “Stem-plants” (“Cormophyta”), because their shoots are - leaf-bearing stems. The name Thallophyta (Stemless-plants) is - to some extent unsuitable, since many of the higher Algæ are - differentiated into stem and leaf. - -The Thallophytes are again separated into 3 sub-divisions, namely: - - Sub-Division =A.=--=Myxomycetes, Slime-Fungi=, with only 1 class. - - Sub-Division =B.=--=Algæ=, with 10 classes: - Class 1. Syngeneticæ. - „ 2. Dinoflagellata, Peridinea. - „ 3. Diatomeæ, Diatoms. - „ 4. Schizophyta, Fission Algæ. - „ 5. Conjugatæ. - „ 6. Chlorophyceæ, Green Algæ. - „ 7. Characeæ, Stone-worts. - „ 8. Phæophyceæ, Brown Algæ. - „ 9. Dictyotales. - „ 10. Rhodophyceæ, Red Algæ. - - Sub-Division =C.=--=Fungi=, with 3 classes: - Class 1. Phycomycetes. - „ 2. Mesomycetes. - „ 3. Mycomycetes, Higher Fungi. - -Division II.--=Bryophyta or Muscineæ, Mosses.= These have -leaf-bearing shoots, but neither true roots nor vascular bundles. The -lowest Mosses have, however, a thallus. Fertilisation is accomplished -by means of self-motile, spirally coiled spermatozoids, through the -agency of water. From the fertilised oosphere a “fruit-body” (capsule) -with unicellular organs of reproduction (spores) is produced. The spore -on germination gives rise to the vegetative system, which bears the -organs of sexual reproduction; and this system is divided into two -stages--the protonema, and the leaf-bearing plant produced on it. - -Alternation of generations: - - I. The protonema and the entire nutritive system which - bears the organs of sexual reproduction. - II. The capsule-like sporangium, with spores. - 2 Classes: 1. Hepaticæ, Liverworts. - 2. Musci, Leafy Mosses. - -Division III.--=Pteridophyta or Vascular Cryptogams=, =Fern-like -Plants= having leaf-bearing shoots, true roots, and vascular bundles -with tracheides and sieve-tubes. Fertilisation as in the Mosses. From -the fertilised oosphere the leaf-bearing shoot arises, which bears -on its leaves the reproductive organs, the spores, in capsule-like -sporangia. From the germination of the spore a small prothallium is -formed, which bears the sexual reproductive organs. - -Alternation of generations: - - I. Prothallium with organs of sexual reproduction. - II. Leaf-bearing shoot with capsule-like sporangia. - 3 Classes: 1. Filicinæ, True Ferns. - 2. Equisetinæ, Horsetails. - 3. Lycopodinæ, Club-mosses. - -Division IV.--=Gymnospermæ.= The vegetative organs are in the -main similar to those in the 3rd Division; special shoots are modified -into flowers for the service of reproduction. From the oosphere, which -is fertilised by means of the pollen-tube, the leaf-bearing plant is -derived; this passes the first period of its life as an embryo in -the seed, and continues its development when the germination of the -seed takes place. The organs corresponding to the spores of the two -preceding Divisions, are called respectively the pollen-grain and -embryo-sac. The pollen-grains are multicellular; i.e. they contain -an indistinct prothallium. In the embryo-sac a prothallium, rich in -reserve material (endosperm), with female organs of reproduction, is -developed BEFORE FERTILISATION. The pollen-grains are carried -by means of the wind to the ovules; these enclose the embryo-sac, and -are situated on the open fruit-leaf (carpel), which has no stigma. - -Alternation of generations: - - I. Prothallium = Endosperm in ovule. - II. Leaf-bearing plant, with flowers which produce the pollen-sac - and ovule. - 3 Classes: 1. Cycadeæ. - 2. Coniferæ. - 3. Gnetaceæ. - -Division V.--=Angiospermæ=. The members of this group are very -similar to those of Division IV. The ovules are, however, encased in -closed fruit-leaves (ovary), which have a special portion (stigma) -adapted for the reception and germination of the pollen-grains. The -pollen-grains are bicellular, but with only a membrane separating -the two nuclei; they are carried to the stigma by animals (chiefly -insects), by the wind, or by some other means. Endosperm is not formed -till AFTER FERTILISATION. Alternation of generations in the main as in -the Gymnosperms, but less distinct; while the sexual generation, the -prothallium, with the organs of fertilisation, is also strongly reduced. - - 2 Classes:[1] 1. Monocotyledones. Embryo with one seed-leaf. - 2. Dicotyledones. Embryo with two seed-leaves. - - For a long time the vegetable kingdom has been divided - into. CRYPTOGAMS (so called because their organs - of reproduction remained for some time undiscovered), and - PHANEROGAMS or Flowering-plants which have evident - sexual organs. - - The first three divisions belong to the Cryptogams, and the - third and fourth divisions to the Phanerogams. This arrangement - has no systematic value, but is very convenient in many ways. - - The Cryptogams are also known as Spore-plants, since they - multiply by unicellular organs (spores), and the Phanerogams in - contradistinction are called Seed-plants (Spermaphyta), since - they multiply by seeds, multicellular bodies, the most important - part of which is the embryo (a plant in its infancy). Mosses, - Ferns, and Gymnosperms are together known as Archegoniatæ, since - they possess in common a female organ of distinct structure, the - Archegonium. - - - - - DIVISION I. - - THALLOPHYTA. - - -The thallus in the simplest forms is unicellular; in the majority, -however, it is built up of many cells, which in a few instances are -exactly similar; but generally there is a division of labour, so -that certain cells undertake certain functions and are constructed -accordingly, while others have different work and corresponding -structure. Vessels or similar high anatomical structures are seldom -formed, and the markings on the cell-wall are with few exceptions very -simple. The Myxomycetes occupy quite an isolated position; their organs -of nourishment are naked masses of protoplasm (plasmodia). - -As regards the external form, the thallus may be entirely without -special prominences (such as branches, members), but when such are -present they are all essentially alike in their origin and growth, -that is, disregarding the hair-structures which may be developed. A -shoot of a Seaweed or of a Lichen, etc., is essentially the same as -any other part of the plant; only among the highest Algæ (Characeæ, -certain Siphoneæ, _Sargassum_, and certain Red Seaweeds) do we find the -same differences between the various external organs of the plant body -as between stem and leaf, so that they must be distinguished by these -names. - -_Roots_ of the same structure and development as in the Seed-plants -are not found, but _organs of attachment_ (rhizoids and haptera) serve -partly the biological functions of the root. - -SYSTEMATIC DIVISION OF THE THALLOPHYTES. To the Thallophytes belong -three sub-divisions--Slime-Fungi, Algæ, and Fungi. Formerly the -Thallophytes were divided into Algæ, Fungi, and Lichens. But this -last group must be placed among the Fungi, since they are really -Fungi, which live symbiotically with Algæ. The _Slime-Fungi_ must be -separated from the true Fungi as a distinct subdivision. The _Algæ_ -possess a colouring substance, which is generally green, brown, or -red, and by means of which they are able to build up organic compounds -from carbonic acid and water. The Bacteria, especially, form an -exception to the Algæ in this respect; like the Fungi and Slime-Fungi -they have as a rule no such colouring material, but must have organic -carbonaceous food; these plants form no starch, and need no light for -their vegetation (most Fungi require light for fructification). The -Myxomycetes, Bacteria, and Fungi derive their nourishment either as -_saprophytes_ from dead animal or vegetable matter, or as _parasites_ -from living animals or plants (hosts), in which they very often cause -disease. - - A remark, however, must be made with regard to this division. - Among the higher plants so much stress is not laid upon the - biological relations as to divide them into “green” and - “non-green”; _Cuscuta_ (Dodder), a parasite, is placed among - the Convolvulaceæ, _Neottia_ and _Corallorhiza_, saprophytes, - belong to the Orchidacere, although they live like Fungi, - yet their relations live as Algæ. In the same manner there - are some colourless parasitic or saprophytic forms among the - Algæ, and stress must be laid upon the fact that not only the - Blue-green Algæ, but also the Bacteria, which cannot assimilate - carbonic-acid, belong to the Algæ group, Schizophyceæ. The - reason for this is that systematic classifications must be based - upon the relationship of form, development, and reproduction, - and from this point of view we must regard the Bacteria as - being the nearer relatives of the Blue-green Algæ. All the - Thallophytes, which are designated Fungi (when the entire - group of Slime-Fungi is left out), form in some measure a - connected series of development which only in the lower forms - (Phycomycetes) is related to the Algæ, and probably through them - has taken its origin from the Algæ; the higher Fungi have then - developed independently from this beginning. The distinction - of colour referred to is therefore not the only one which - separates the Algæ from the Fungi, but it is almost the only - characteristic mark by which we can at once distinguish the two - great sub-divisions of the Thallophytes. - - The first forms of life on earth were probably “Protistæ,” - which had assimilating colour material, or in other words, they - were Algæ because they could assimilate purely inorganic food - substances, and there are some among these which belong to the - simplest forms of all plants. Fungi and Slime-Fungi must have - appeared later, because they are dependent on other plants which - assimilate carbon.[2] - - - _Sub-Division I._--=MYXOMYCETES, SLIME-FUNGI.= - -The Slime-Fungi occupy quite an isolated position in the Vegetable -Kingdom, and are perhaps the most nearly related to the group of -Rhizopods in the Animal Kingdom. They live in and on organic remains, -especially rotten wood or leaves, etc., on the surface of which their -sporangia may be found. - -They are organisms without chlorophyll, and in their vegetative -condition are masses of protoplasm without cell-wall (_plasmodia_). -They multiply by means of _spores_, which in the true Slime-Fungi[3] -are produced in sporangia, but in some others[4] free. The spores -are round cells (Fig. 1 _a_) which in all the true Slime-Fungi are -surrounded by a cell-wall. The wall bursts on germination, and the -contents float out in the water which is necessary for germination. -They move about with swimming and hopping motions like swarmspores -(_e_, _f_), having a cilia at the front end and provided with a -cell-nucleus and a pulsating vacuole. Later on they become a little -less active, and creep about more slowly, while they continue to alter -their form, shooting out arms in various places and drawing them in -again (_g_, _h_, _i_, _k_, _l_, _m_); in this stage they are called -_Myxamœbæ_. - - [Illustration: FIG. 1.--_a-l_ Development of “_Fuligo_” from - spore to Myxamœba; _a-m_ are magnified 300 times; _m_ is a - Myxamœba of _Lycogala epidendron_; _l´_ three Myxamœbæ of - _Physarum album_ about to unite; _o_, a small portion of - plasmodium, magnified 90 times.] - - [Illustration: FIG. 2.--The plasmodium (_a_) of _Stemonitis - fusca_, commencing to form into sporangia (_b_); drawn on July - 9. The dark-brown sporangia were completely formed by the next - morning; _c-e_ shows the development of their external form.] - - [Illustration: FIG. 3.--Four sporangia of _Stemonitis fusca_, - fixed on a branch. _a_ The plasmodium.] - - [Illustration: FIG. 4.--Sporangium of _Arcyria incarnata_. _B_ - closed; _C_ open; _p_ wall of sporangium; _cp_ capilitium.] - -The Myxamœba grows whilst taking up nourishment from the material in -which it lives, and multiplies by division. At a later stage a larger -or smaller number of Myxamœbæ may be seen to coalesce and form large -masses of protoplasm, _plasmodia_, which in the “Flowers of Tan” may -attain the size of the palm of a hand, or even larger, but in most -others are smaller. The plasmodia are independent, cream-like masses of -protoplasm, often containing grains of carbonate of lime and colouring -matter (the latter yellow in the Flowers of Tan). They creep about in -the decaying matter in which they live, by means of amœboid movements, -internal streamings of the protoplasm continually taking place; finally -they creep out to the surface, and very often attach themselves to -other objects, such as Mosses, and form sporangia (Fig. 2). These are -stalked or sessile and are generally cylindrical (Fig. 3), spherical -or pear-shaped (Fig. 4); they rarely attain a larger size than that of -a pin’s head, and are red, brown, white, blue, yellow, etc., with a -very delicate wall. In some genera may be found a “Capillitium” (Fig. 4 -_cp_), or network of branched fine strands between the spores. Flowers -of Tan (_Fuligo septica_) has a fruit-body composed of many sporangia -(an Æthalium), which has the appearance of flat, irregular, brown -cakes, inside the fragile external layer of which a loose powder, the -spores, is found. It generally occurs on heaps of tanners’ bark, and -appears sometimes in hot-beds in which that material is used, and is -destructive by spreading itself over the young plants and choking them. - -All the motile stages may pass into _resting stages_, the small forms -only surrounding themselves with a wall, but the large ones at the -same time divide in addition into polyhedral cells. When favourable -conditions arise, the walls dissolve and the whole appears again as a -naked (free-moving) mass of protoplasm. - -To the genuine Slime-Fungi belong: _Arcyria_, _Trichia_, _Didymium_, -_Physarum_, _Stemonitis_, _Lycogala_, _Fuligo_, _Spumaria_, -_Reticularia_. - -Some genera wanting a sporangium-wall belong to the Slime-Fungi: -_Ceratiomyxa_, whose fruit-body consists of polygonal plates, each -bearing stalked spores; _Dictyostelium_, in which the swarm-stage is -wanting and which has stalked spores. _Plasmodiophora brassicæ_ preys -upon the roots of cabbages and other cruciferous plants, causing large -swellings. _Pl. alni_ causes coral-shaped outgrowths on the roots of -the Alder (_Alnus_). _Phytomyxa leguminosarum_ may be found in small -knobs (tubercles) on the roots of leguminous plants. It is still -uncertain whether it is this Fungus or Bacteria which is the cause of -the formation of these tubercles. - - - _Sub-Division_ II.--=ALGÆ=. - -=Mode of Life.= The Algæ (except most of the Bacteria) are themselves -able to form their organic material by the splitting up of the carbonic -acid contained in the water, or air in some cases, and for this purpose -need light. The majority live in water, fresh or salt, but many are -present on damp soil, stones, bark of trees, etc. - -With the exception of the Bacteria, no saprophytes have actually been -determined to belong to this group, and only very few true parasites -(for instance, _Phyllosiphon arisari_, _Mycoidea_, etc.), but a -good many are found epiphytic or endophytic on other Algæ, or water -plants, and on animals (for instance, certain _Schizophyceæ_ and -_Protococcoideæ_; _Trichophilus welckeri_ in the hairs of _Bradypus_, -the Sloth), and several species in symbiotic relation to various Fungi -(species of Lichen), to Sponges (_e.g. Trentepohlia spongiophila_, -_Struvea delicatula_), and to sundry Infusoria and other lower -animals as Radiolarias, _Hydra_, etc. (the so-called _Zoochlorella_ -and _Zooxantella_, which are perhaps partly stages in development of -various Green and Brown Algæ). - -=Vegetative Organs.= The cells in all the Algæ (excepting certain -reproductive cells) are surrounded by a membrane which (with the -exception of the Bacteria) consists of pure or altered cellulose, -sometimes forming a gelatinous covering, at other times a harder one, -with deposits of chalk or silica formed in it. The cell-nucleus, -which in the Schizophyta is less differentiated, may be one or more -(_e.g. Hydrodictyon_, _Siphoneæ_) in each cell. Excepting in the -majority of the Bacteria, _colour materials_ (of which _chlorophyll_, -or modifications of it, always seems to be found) occur, which either -permeate the whole cytoplasm surrounding the cell-nucleus, as in most -of the coloured Schizophyta, or are contained in certain specially -formed small portions of protoplasm (chromatophores). - -The individual at a certain stage of development consists nearly always -of only one cell; by its division multicellular individuals may arise, -or, if the daughter-cells separate immediately after the division, as -in many of the simplest forms, the individual will, during the whole -course of its existence, consist of only a single cell (unicellular -Algæ). In multicellular individuals the cells may be more or less -firmly connected, and all the cells of the individual may be exactly -alike, or a division of labour may take place, so that certain cells -undertake certain functions, and are constructed accordingly; this -may also occur in parts of the cell in the large unicellular and -multinuclear Algæ (Siphoneæ, p. 62). - -The cells in most of the Algæ belong to the _parenchymatous_ form; -these, however, in the course of their growth, may very often become -somewhat oblong; in many Algæ (particularly Fucoideæ and Florideæ) -occur, moreover, _hyphæ-like threads_, which are very long, often -branched, and are either formed of a single cell, or, more frequently, -of a row of cells, having a well-pronounced apical growth. The -parenchymatous as well as the hyphæ-like cells may, in the higher -Algæ (especially in certain Fucoideæ and Florideæ), be further -differentiated, so that they form well-defined anatomico-physiological -systems of tissue, _i.e._ assimilating, conducting, storing, and -mechanical. - -With regard to _the external form_, the thallus may present no -differentiation, as in many unicellular Algæ, or in multicellular Algæ -of the lower order, which are then either equally developed in all -directions (_e.g. Pleurococcus_, Fig. 47), or form flat cell-plates -(_Merismopedium_) or threads (_Oscillaria_, Fig. 21). The first step -in the way of differentiation appears as a difference between apex and -base (_Rivularia_, _Porphyra_); but the division of labour may proceed -so that differences may arise between vegetative and reproductive cells -(_Œdogonium_, Fig. 54); hairs and organs of attachment (rhizoids and -haptera), which biologically serve as roots, are developed, and even -leaves in certain forms of high order, belonging to different classes -(_e.g. Caulerpa_, Fig. 59; _Characeæ_, Fig. 61; _Sargassum_, Fig. 72; -and many Florideæ). - -=The non-sexual reproduction= takes place _vegetatively_, in many -instances, simply by division into two, and more or less complete -separation of the divisional products (Diatomaceæ, Desmidiaceæ (Fig. -36), many Fission-plants, etc.), or by detached portions of the thallus -(_e.g. Caulerpa_, _Ulva lactuca_, etc.; among many Schizophyceæ, -small filaments known as _hormogonia_ are set free), or _asexually_ by -special reproductive cells (_spores_) set free from the thallus; these -may be either _stationary_ or _motile_. The stationary reproductive -cells (spores) may either be devoid of cell-wall (tetraspores of the -Florideæ), or may possess a cell-wall; in the latter case they may be -formed directly from the vegetative cells, generally by the thickening -of the walls (_akinetes_), or only after a process of re-juvenescence -(_aplanospores_). Aplanospores, as well as akinetes, may either -germinate immediately or may become resting-cells, which germinate only -after a period of rest. - -THE MOTILE ASEXUAL REPRODUCTIVE CELLS are spherical, egg- or -pear-shaped, naked, _swarmspores_ (_zoospores_), which have arisen -in other cells (_zoosporangia_), and propel themselves through the -water by means of cilia; or they are _Phyto-Amœbæ_, which have no -cilia and creep on a substratum by means of pseudopodia. The cilia, -which are formed from the protoplasm (in the Bacteria, however, from -the membrane), are mostly situated at the pointed and colourless end, -which is directed forwards when in motion, and are 1, 2 (Fig. 5 _B_), -4 or more. Both the cilia in the Brown Algæ are attached to one side -(Fig. 65); they are occasionally situated in a circle round the front -end (_Œdogonium_, Fig. 6 _a_, and _Derbesia_), or are very numerous -and situated in pairs distributed over a large part or nearly the -whole of the zoospore (_Vaucheria_). Besides being provided with one -or more nuclei (_Vaucheria_), they may also have a red “eye spot” -and vacuoles, which are sometimes pulsating, _i.e._ they appear and -reappear at certain intervals. The swarmspores move about in the -water in irregular paths, and apparently quite voluntarily, revolving -round their longer axes; but they come to the surface of the water in -great numbers either because of their dependence on light, or driven -by warm currents in the water, or attracted by some passing mass of -food material. The swarmspores germinate, each forming a new plant, -as their movement ceases they surround themselves with a cell-wall, -grow, and then divide; in Fig. 6 _b_, two may be seen in the condition -of germination, and about to attach themselves by means of the front -end, which has been developed into haptera (see also Fig. 5 _B_, lowest -figure). - -=The sexual reproduction= here, probably in all cases, consists in the -coalescence of two masses of protoplasm, that is, in the fusion of -their nuclei. - - [Illustration: FIG. 5.--_Cladophora glomerata. A_ The lower - cells are full of swarmspores, whilst from the upper one the - greater part have escaped through the aperture _m_. _B_ Free and - germinating swarmspores.] - - [Illustration: FIG. 6.--_Œdogonium_: _a_ (free), _b_ germinating - swarmspores.] - - [Illustration: FIG. 7.--_Zanardinia collaris. A_ Male - gametangia (the small-celled) and female gametangia - (large-celled). _C_ Female gamete. _D_ Male gamete. _B E_ - Fertilisation. _F_ Zygote. _G_ Germinating zygote.] - -The simplest and lowest form is termed =conjugation=, or =isogamous= -fertilisation, and is characterized by the fact that the two coalescing -cells (termed gametes) are equal, or almost equal, in shape and size -(the female gamete in the _Cutleriaceæ_, _e.g. Zanardinia collaris_, -Fig. 7, is considerably larger than the male gamete). The cell in -which the _gametes_ are developed is called a _gametaugium_, and the -reproductive cell formed by their union--which generally has a thick -wall and only germinates after a short period of rest--is termed a -_zygote_ or _zygospore_. The conjugation takes place in two ways:-- - -(_a_) In the one way the gametes are motile cells (_planogametes_, -_zoogametes_, Fig. 8), which unite in pairs during their swarming -hither and thither in the water; during this process they lie side by -side (Fig. 8 _d_), generally at first touching at the clear anterior -end, and after a time they coalesce and become a motionless _zygote_, -which surrounds itself with a cell-wall (Fig. 8 _e_). This form of -conjugation is found in _Ulothrix_ (Fig. 8 _d_), _Acetabularia_, and -other Algæ (Figs. 45, 56, 66). - - [Illustration: FIG. 8.--_Ulothrix zonata_: a portion of - a thread with zoospores, of which two are formed in each - cell (zoosporangium), the dark spots upon them are the “red - eye-spots”; 1, 2, 3, 4 depict successive stages in the - development of the zoospores; _b_ a single zoospore, at _v_ the - pulsating vacuole; _c_ portion of a thread with gametes, of which - sixteen are formed in each gametangium; _d_ gametes free and in - conjugation; _e_ conjugation has been effected, and the formed - zygotes are in the resting condition.] - -(_b_) Among other Algæ (_e.g. Diatomaceæ_ and _Conjugatæ_), the -conjugating cells continue to be surrounded by the cell-wall of -the mother-cell (_aplanogametes_ in an _aplanogametangium_); the -aplanogametangia generally grow out into short branches, which lie -close together and touch one another, the wall at the point of contact -is then dissolved (Fig. 39). Through the aperture thus formed, the -aplanogametes unite, as in the first instance, and form a rounded -zygote, which immediately surrounds itself with a cell-wall. Various -modifications occur; compare Figs. 37, 39, 41, 43. - - [Illustration: FIG. 9.--Fertilisation in the Bladder-wrack - (_Fucus vesiculosus_).] - - [Illustration: FIG. 10.--_Sphæroplea annulina._] - -The highest form of the sexual reproduction is the =Egg- or Oogamous= -fertilisation. The two coalescing cells are in the main unlike each -other in form as well as size. The one which is considered as the male, -and is known as the _spermatozoid_ (_antherozoid_), developes as a rule -in large numbers in each mother-cell (_antheridium_); they are often -self-motile (except in the Florideæ, where they are named _spermatia_), -and are many times smaller than the other kind, the female, which -is known as the _egg-cell_, (_oosphere_). The egg-cell is always a -motionless, spherical, primordial cell which can either float about -freely in the water, as in the Fucaceæ (Fig. 9), or is surrounded by -a cell-wall (_oogonium_); generally only one oosphere is to be found -in each oogonium, but several occur in _Sphæroplea_ (Fig. 10). The -result of the spermatozoid coalescing with the egg-cell is, as in this -case, the formation of a oospore, which generally undergoes a period of -rest before germination (the Florideæ are an exception, a fruit-body, -_cystocarp_, being produced as the result of coalescence). - - An example of fertilisation is afforded by the Alga, _Sphæroplea - annulina_ (Fig. 10). The filamentous thallus is formed of - cylindrical cells with many vacuoles (_r_ in _A_); some cells - develope egg-cells (_B_), others spermatozoids (_C_), the latter - in a particularly large number. The egg-cells are spherical, - the spermatozoids of a club- or elongated pear-shape with two - cilia at the front end (_G_; _E_ is however a swarmspore). - The spermatozoids escape from their cells through apertures - in the wall (_o_ in _C_) and enter through similar apertures - (_o_ in _B_) to the egg-cells. The colourless front end of the - spermatozoid is united at first with the “receptive spot” of the - egg-cell (see _F_), and afterwards completely coalesces with - it. The result is the formation of a oospore with wart-like - excrescences (_D_). - -The female (_parthenogenesis_) or male (_androgenesis_) sexual cell -may, sometimes without any preceding fertilisation, form a new -individual (_e.g. Ulothrix zonata_, _Cylindrocapsa_, etc.). - -=Systematic division of the Algæ.= The Algæ are divided into the -following ten classes: - - 1. SYNGENETICÆ; 2. DINOFLAGELLATA, or PERIDINEA; 3. DIATOMACEÆ; - 4. SCHIZOPHYTA, FISSION-ALGÆ; 5. CONJUGATÆ; 6. CHLOROPHYCEÆ, - GREEN-ALGÆ; 7. CHARACEÆ, STONE-WORTS; 8. PHÆOPHYCEÆ; 9. - DICTYOTALES; 10. RHODOPHYCEÆ. - -Among the lowest forms of the Algæ, the Syngeneticæ, the -Dinoflagellata, and the unicellular Volvocaceæ (Chlamydomoneæ), -distinct transitional forms are found approaching the animal kingdom, -which can be grouped as animals or plants according to their method of -taking food or other characteristics. Only an artificial boundary can -therefore be drawn between the animal and vegetable kingdoms. In the -following pages only those forms which possess _chromatophores_, -and have _no mouth_, will be considered as Algæ. - - - Class 1. =Syngeneticæ.= - -The individuals are uni- or multicellular, free-swimming or motionless. -The cells (which in the multicellular forms are loosely connected -together, often only by mucilaginous envelopes) are naked or surrounded -by a mucilaginous cell-wall, in which silica is never embedded. They -contain one cell-nucleus, one or more pulsating vacuoles, and one to -two band- or plate-like chromatophores with a brown or yellow colour, -and sometimes a pyrenoid. - -Reproduction takes place by vegetative division, or asexually by -zoospores, akinetes (or aplanospores?). Sexual reproduction is unknown. -They are all fresh water forms. - - To this class may perhaps be assigned the recently arranged and - very little known orders of _Calcocytaceæ_, _Murracytaceæ_, - _Xanthellaceæ_, and _Dictyochaceæ_, which partly occur in the - free condition in the sea, in the so-called “Plankton,” and - partly symbiotic in various lower marine animals. - -The _Syngeneticæ_ are closely related to certain forms in the -animal kingdom, as the Flagellatæ. - -Order 1. =Chrysomonadinaceæ.= Individuals, uni- or multicellular, -swimming in free condition, naked or surrounded by a mucilaginous -covering. The cells are generally oval or elongated, with 2 (rarely -only 1) cilia, almost of the same length, and generally with a red -“eye-spot” at their base, and with 2 (rarely 1 only) band-shaped -chromatophores. Reproduction by the longitudinal division of the -individual cells either during the swarming, or during a resting stage; -in the multicellular forms also by the liberation of one or more cells, -which in the latter case are connected together. - - A. Unicellular: _Chromulina_, _Cryptoglena_, _Microglena_, - _Nephroselmis_. - - B. Multicellular: _Uroglena_, _Syncrypta_ (Fig. 11), _Synura_. - - [Illustration: FIG. 11.--_Syncrypta volvox_: the multicellular - individual is surrounded by a mucilaginous granular envelope.] - - Among the unicellular Chrysomonadinaceæ are probably classed - some forms which are only stages in the development of the - multicellular, or of other _Syngeneticæ_. - -Order 2. =Chrysopyxaceæ= are unicellular, and differ mainly -from the preceding in being attached either on a slime-thread -(_Stylochrysalis_), or enclosed in an envelope (_Chrysopyxis_, -Fig. 12). They have two cilia, and multiply by longitudinal -(_Chrysopyxis_) or transverse division, and the swarming of one of the -daughter-individuals (zoospore). Division may also take place in a -motionless stage (_palmella-stage_). - - [Illustration: FIG. 12.--_Chrsopyxis bipes_: _m_ envelope, _Ec_ - chromatophore, _cv_ contractile vacuole.] - -Order 3. =Dinobryinaceæ.= The individuals are originally attached, -uni- or multicellular; each individual cell is distinctly contractile, -and fixed at the bottom of a cup-shaped, open envelope. Cilia 2, but -of unequal length. Asexual reproduction by zoospores, which are formed -by straight or oblique longitudinal division of the mother-cell, -during a palmella-stage which is produced in the winter aplanospores. -_Epipyxis_, _Dinobryon_. - -Order 4. =Hydruraceæ.= The individuals are attached, without cilia, -multicellular, branched, and with apical growth. The cells are -spherical, but in the final stage almost spindle-shaped, and embedded -in large masses of mucilage. Asexual reproduction by zoospores which -are tetrahedric, with 1 cilia, and by resting akinetes. _Hydrurus_ is -most common in mountain brooks. - - - Class 2. =Dinoflagellata.= - -The individuals are of a very variable form, but always unicellular, -and floating about in free condition. The cell is _dorsiventral_, -_bilateral_, _asymmetric_ and generally surrounded by a colourless -membrane, which has _no silica_ embedded in it, but is formed of -a substance allied to _cellulose_. The membrane, which externally -is provided with pores and raised borders, easily breaks up into -irregularly-shaped pieces. In the forms which have longitudinal and -cross furrows, _two cilia_ are fixed where these cross each other, and -project through a cleft in the membrane; one of these cilia _projects -freely_ and is directed longitudinally to the front or to the rear, -the other one _stretches crosswise_ and lies close to the cell, often -in a furrow (cross furrow). The chromatophores are coloured brown or -green and may either be two parallel (_Exuviella_), or several radially -placed, discs, which sometimes may coalesce and become a star-shaped -chromatophore. The coloring material (pyrrophyl) consists, in addition -to a modification of chlorophyl, also of _phycopyrrin_ and _peridinin_; -this colour is sometimes more or less masked by the products of -assimilation which consist of yellow, red or colourless oil (?) and -starch. Cell-nucleus one: in _Polydinida_ several nuclei are found; -contractile vacuoles many, which partly open in the cilia-cleft (Fig. -13 _gs_). In some an eye-spot, coloured red by hæmatochrome, is found. -Pyrenoids occur perhaps in _Exuviella_ and _Amphidinium_. - -THE REPRODUCTION takes place as far as is known at present, only -by division. This, in many salt water forms, may take place in the -swarming condition, and, in that case, is always parallel to the -longitudinal axis. The daughter-individuals, each of which retains half -of the original shell, sometimes do not separate at once from each -other, and thus chains (_e.g._ in _Ceratium_) of several connected -individuals may be formed. In others, the division occurs after -the cilia have been thrown off and the cell-contents rounded. The -daughter-cells then adopt entirely new cell-walls. A palmella-stage -(motionless division-stage) sometimes appears to take place, and also -aplanospores (?) with one or two horn-like elongations (_e.g._ in -_Peridinium cinctum_ and _P. tabulatum_); at germination one, or after -division, two or more, new individuals may be formed. - -Sexual reproduction has not been observed with certainty. - -The Dinoflagellata move forward or backward, turning round their -longitudinal axes; in their motion they are influenced by the action -of light. The motion possibly may be produced only by the transverse -cilium, which vibrates rapidly; whilst the longitudinal cilium moves -slowly, and is supposed to serve mainly as a steering apparatus. They -live principally in salt water, but also in fresh. - -Besides the coloured forms, which are able to make their own organic -compounds by the splitting up of the carbonic acid contained in the -water, there are a few colourless forms (_e.g. Gymnodinium spirale_), -or such as do not possess chromatophores (_Polykrikos_); these appear -to live saprophytically, and may be able to absorb solid bodies with -which they come in contact. - -Dinoflagellata occur in the “Plankton” of the open sea, where they form -together with Diatomaceæ the basis for the animal life. It is known -with certainty that some salt water forms (like the _Noctiluca_, -which belongs to the animal kingdom and to which they are perhaps -related) produce light, known as phosphorescence. - - [Illustration: FIG. 13.--_A_ and _B Glenodinium cinctum_. _A_ - seen from the ventral side, _B_ from behind; _fg_ transverse - cilium; _g_ longitudinal cilium; _ch_ chromatophores; _a_ starch; - _n_ cell-nucleus; _v_ vacuole; _oc_ eye-spot; _C Ceratium - tetraceros_ from the ventral side; _r_ the right, _b_ the - posterior horn; _lf_ longitudinal furrow; _gs_ cilium-cleft; _v_ - vacuole; _g_ longitudinal cilium. (_A_ and _B_ mag. 450 times, - _C_ 337 times.)] - - _Dinoflagellata_ (_Peridinea_, _Cilioflagellata_) are allied - through their lowest form (_Exuviella_) to the Syngeneticæ and - especially to the order Chrysomonadinaceæ. They may be divided - into three orders. - -Order 1. =Adinida.= Without transverse or longitudinal furrows, but -enclosed in two shells, and with two parallel chromatophores in each -cell. _Exuviella_, _Prorocentrum_. - -Order 2. =Dinifera.= With tranverse and generally longitudinal furrow. -Many radially-placed, disc-formed chromatophores. The most common -genera are--_Ceratium_ (Fig. 13), _Peridinium_, _Glenodinium_ (Fig. -13), _Gymnodinium_, _Dinophysis_. - -Order 3. =Polydinida.= With several transverse furrows, no -chromatophores, and several cell-nuclei. Only one genus--_Polykrikos_. - - The order _Polydinida_ deviates in a high degree from the - other Dinoflagellata, not only by its many tranverse furrows, - each with its own transverse cilium, and by the absence of - chromatophores, but also in having several cell-nuclei and a - kind of stinging capsule, which otherwise does not occur within - the whole class. It may therefore be questionable whether this - order should really be placed in the vegetable kingdom. - - - Class 3. =Diatomeæ.= - -The individuals--each known as a _frustule_--assume very various -forms and may be unicellular or multicellular, but present no -differentiation; many similar cells may be connected in chains, -embedded in mucilaginous masses, or attached to mucilaginous -stalks. The cells are bilateral or centric, often asymmetrical, -slightly dorsiventral and have no cilia; those living in the free -condition have the power of sliding upon a firm substratum. The cell -contains 1 cell-nucleus and 1–2 plate-shaped or several disc-shaped -chromatophores. The colouring material “_Melinophyl_” contains, in -addition to a modification of chlorophyl, a brown colouring matter, -_diatomin_. 1 or 2 pyrenoids sometimes occur. Starch is wanting and the -first product of assimilation appears to be a kind of oil (?). - - [Illustration: FIG. 14.--_Pinnularia_: _B_, from the edge, shows - the valves fitting together; _A_, a valve.] - - [Illustration: FIG. 15.--Various Diatomaceæ. A _Diatoma vulgare_. - B _Tabellaria flocculosa_. C _Navicula tumida_ (lateral views). - D _Gomphonema constrictum_ (lateral views). E _Navicula - west[=i][=i]_ (lateral views).] - -The cell-walls are _impregnated with silica_ to such a degree that -they are imperishable and are therefore able to contribute in a great -measure to the formation of the earth’s crust. The structure of their -cell-wall is most peculiar and _differs from all other plants_ (except -certain Desmidiaceæ); it does not consist of a single piece but is -made up of two--the “shells”--(compare _Exuviella_ and _Prorocentrum_ -among the Dinoflagellata) which are fitted into each other, one being -a little larger than the other and embracing its edge, like a box with -its lid (Fig. 14 _B_). The two parts which correspond to the bottom -and lid of the box are known as _valves_. Along the central line of -the valves a longitudinal _rib_ may often be found, interrupted at -its centre by a small cleft (perhaps homologous with the cilia-cleft -of the Dinoflagellata), through which the protoplasm is enabled to -communicate with the exterior (Fig. 14 _A_). It is principally by -reason of the valves, which bear numerous fine, transverse ribs, striæ -or warts, etc. (Figs. 14, 15, 17), that the Diatomeæ have become so -well known and employed as test objects in microscopical science. When -the division takes place, the two shells are separated a little from -each other, and after the cell-contents have divided into two masses, -two new shells are formed, one fitting into the larger valve, the -other one into the smaller valve of the original frustule. The latter -cell (frustule) is thus, upon the whole, smaller than the mother-cell, -and as the cells do not increase in size, some frustules are smaller -than the ones from which they are derived, and thus, by repeated -divisions, it follows that smaller and smaller frustules are produced. -This continued diminution in size is, however, compensated for by the -formation, when the cells have been reduced to a certain minimum, of -_auxospores_, 2–3 times larger. These may either be formed _asexually_ -by the protoplasm of a cell increasing, rounding off and surrounding -itself with a new wall (_e.g. Melosira_) or after _conjugation_, -which may take place with various modifications: 1. Two individuals -unite after the secretion of a quantity of mucilage, and the valves -then commence to separate from each other, on the side which the two -individuals turn towards each other. The protoplasmic bodies now -release themselves from their cell-wall, and each rounds off to form an -ellipsoidal mass; these two protoplasmic masses (gametes) coalesce to -form a zygote, the cell-nuclei and chromatophores also fusing together. -The zygote increases in size, and surrounds itself with a firm, smooth, -siliceous wall--the _perizonium_. The auxospores, whichever way they -arise, are not resting stages. The germination of the zygote commences -by the protoplasm withdrawing itself slightly from the cell-wall and -constructing first the larger valve, and later on the smaller one; -finally the membrane of the zygote bursts (_e.g. Himantidium_). 2. -The conjugation occurs in a similar manner, but the protoplasm of the -cells divides transversely before conjugation into two daughter-cells. -Those lying opposite one another conjugate (Fig. 16) and form two -zygotes. The formation of the perizonium, and germination take place -as in the preceding instance (_e.g. Epithemia_). 3. Two cells place -themselves parallel to each other, and each of the two cell-contents, -without coalescing, becomes an auxospore. The formation of the wall -takes place as in the preceding case. This is found in the Naviculeæ, -Cymbelleæ, the Gomphonemeæ (_e.g. Frustulia_, _Cocconema_). - - [Illustration: FIG. 16.--Conjugation of _Cymbella variabilis_. - _A_, The protoplasm in the two cells has divided into two masses; - _B_ these masses coalesce in pairs; the cells (_B C_) enclosed - in a mucilaginous matrix. _C D_ Auxospores and their formation.] - -The Diatomaceæ may be found in salt as well as in fresh water (often -in such masses that the colour of the water or mud becomes yellow or -brown; in the same manner the genera _Chætoceros_, _Rhizosolenia_, -_Coscinodiscus_, and several others, form large slime-masses, -“Plankton” on the surface of the sea), on damp soil and in dust blown -by the wind. They occur as fossils in the recent formations, often -in large deposits (siliceous earth, mountain meal), as in the cement -lime in Jutland, the alluvial deposits beneath Berlin, in clay strata -beneath peat bogs, in guano, etc. These accumulations of fossilized -diatoms are used in the manufacture of dynamite and in various -manufactures. - -The Diatomaceæ appear nearest to, and must be placed as a group -co-ordinate with the Dinoflagellata, as they doubtless may be supposed -to derive their origin from forms resembling _Exuviella_, and to have -lost the cilia. The resemblances to the Desmidiaceæ which are striking -in many respects, can only be conceived as analogies, and cannot be -founded upon homologies, and it is therefore impossible to regard them -as proof of genetic relationship. The family contains only one order. - - [Illustration: FIG. 17.--Various Diatomeæ. _A Synedra radians._ - _B Epithemia turgida_ (from the two different sides). _C Cymbella - cuspidata. D Cocconeis pediculus_ (on the right several - situated on a portion of a plant, on the left a single one more - highly magnified).] - -Order 1. =Diatomaceæ.= This order may be divided into two -sub-orders, viz.-- - -Sub-Order 1. =Placochromaticæ.= The chromatophores are discoid, large, -1 or 2 in each cell; the structure of the valves is bilateral and -always without reticulate markings. The following groups belong to -this sub-order: _Gomphonemeæ_, _Cymbelleæ_, _Amphoreæ_, _Achnantheæ_, -_Cocconeideæ_, _Naviculeæ_, _Amphipleureæ_, _Plagiotropideæ_, -_Amphitropideæ_, _Nitzchieæ_, _Surirayeæ_, and _Eunotieæ_. - -Sub-Order 2. =Coccochromaticæ.= The chromatophores are granular, small -and many in each cell. The structure of the cells is zygomorphic -or centric, often with reticulate markings. The following groups -belong to this sub-order: _Fragilarieæ_, _Meridieæ_, _Tabellarieæ_, -_Licmophoreæ_, _Biddulphieæ_, _Anguliferæ_, _Eupodisceæ_, -_Coscinodisceæ_, and _Melosireæ_. - - - Class 4. =Schizophyta, Fission-Algæ.= - -The individuals are 1--many celled; the thallus consists in many of a -single cell, in others of chains of cells, the cells dividing in only -one definite direction (Figs. 18, 21). In certain Fission-Algæ the -cell-chain branches (Fig. 30) and a difference between the anterior -and the posterior ends of the chain is marked; in some, the cells may -be united into the form of flat plates by the cell-division taking -place in two directions; and in others into somewhat cubical masses, or -rounded lumps of a less decided form, by the divisions taking place in -three directions; or less defined masses may be formed by the divisions -taking place in all possible directions. - -The cell-walls rarely contain cellulose, they often swell considerably -(Figs. 20, 22), and show distinct stratifications, or they are almost -completely changed into a mucilaginous mass in which the protoplasts -are embedded, _e.g._ in _Nostoc_ (Fig. 22), and in the “Zooglœa” stage -of the Bacteria (Fig. 27). Sexual reproduction is wanting. Vegetative -reproduction by division and the separation of the divisional products -by the splitting of the cell-wall or its becoming mucilaginous; among -the Nostocaceæ, Lyngbyaceæ, Scytonemaceæ, etc., “Hormogonia” are found; -in _Chamæsiphon_ and others single reproductive akinetes are formed. -Many Fission-Algæ conclude the growing period by the formation of -resting akinetes or aplanospores. - -The Schizophyta may be divided into 2 families: - -1. SCHIZOPHYCEÆ. - -2. BACTERIA. - - - Family 1. =Schizophyceæ,[5] Blue-Green Algæ.= - -All the Blue-green Algæ are able to assimilate carbon by means of -a colouring material containing chlorophyll (cyanophyll); but the -chlorophyll in this substance is masked by a blue (phycocyan), or red -(phycoerythrin, _e.g._ in _Trichodesmium erythræum_ in the Red Sea) -colouring matter which may be extracted from them in cold water after -death. The colouring matter, in most of them, permeates the whole of -the protoplasm (excepting the cell-nucleus), but in a few (_e.g._ -_Glaucocystis_, _Phragmonema_), slightly developed chromatophores are -to be found. Where the cells are united into filaments (cell-chains) a -differentiation into apex and base (_Rivulariaceæ_) may take place, and -also between ordinary vegetative cells and heterocysts; these latter -cannot divide, and are distinguished from the ordinary vegetative cells -(Fig. 22 _h_) by their larger size, yellow colour, and poverty of -contents. Branching sometimes occurs and is either true or spurious. - - [Illustration: FIG. 18.--_Microcoleus lyngbyanus_: _a_ portion of - a filament, the thick sheath encloses only one cell-chain; in one - place a cell is drawn out by the movement of the cell-chain; _b_ - the cell-chain has divided into two parts (“hormongonia”) which - commence to separate from each other.] - -The cell-chain in the spurious branching divides into two parts, -of which either one or both grow beyond the place of division -(Fig. 18) and often out to both sides (_e.g. Scytonema_), the -divisions however, always take place transversely to the longitudinal -direction of the cell-chain. In the true branching a cell elongates -in the direction transverse to the cell-chain, and the division -then takes place nearly at right angles to the former direction -(_Sirosiphoniaceæ_). - - [Illustration: FIG. 19.--_Cylindrospermum majus_: _a_ resting - akinete with heterocyst; _b-d_ germinating stages of a resting - akinete; _e_ filament with two heterocysts and the formation - of new akinetes; _f_ part of a filament with a heterocyst, and - mature resting akinete.] - -Cilia are wanting, but the filaments are sometimes self-motile (_e.g._ -hormogonia in _Nostoc_) and many partly turn round their axes, partly -slide forward or backward (_Oscillaria_). - -Reproduction takes place by spores and hormogonia in addition to simple -cell-division. Hormogonia are peculiar fragments of a cell-chain -capable of motion, and often exhibit a vigorous motion in the sheath, -until at last they escape and grow into a new individual (Fig. 18). -The spores are reproductive akinetes (_Chamæsiphon_, etc.) or resting -akinetes; these latter arise by the vegetative cells enlarging and -constructing a thick cell-wall (Fig. 19 _e f_). On germination, -this cell-wall bursts and the new cell-chain elongates in the same -longitudinal direction as before (Fig. 19 _b c_). Many (_e.g._ -_Oscillaria_) may however winter in their ordinary vegetative stage. -Aplanospores are wanting. - -The Fission-Algæ are very prevalent in fresh water and on damp soil, -less so in salt water; they also often occur in water which abounds in -decaying matter. Some are found in warm springs with a temperature as -high as 50° C. - -The Family may be divided into 2 sub-families: - -1. HOMOCYSTEÆ (heterocysts are wanting): _Chroococcaceæ_, _Lyngbyaceæ_ -and _Chamœsiphonaceæ_. - -2. HETEROCYSTEÆ (heterocysts present): _Nostocaceæ_, _Rivulariaceæ_, -_Scytonemaceæ_ and _Sirosiphoniaceæ_. - -Order 1. =Chroococcaceæ.= The individuals are 1--many-celled, but all -the cells are uniform, united to form plates or irregular masses, often -surrounded by a mucilaginous cell-wall, but never forming cell-chains. -Multiplication by division and sometimes by resting akinetes, but -reproductive akinetes are wanting. _Chroococcus_, _Aphanocapsa_, -_Glœocapsa_ (Fig. 20), _Cœlosphærium_, _Merismopedium_, _Glaucocystis_, -_Oncobyrsa_, _Polycystis_, _Gomphosphæria_. - - [Illustration: FIG. 20.--_Glœocapsa atrata_: _A_, _B_, _C_, _D_, - _E_ various stages of development.] - - [Illustration: FIG. 21.--_Oscillaria_; =a= terminal, =b= central - portion of a filament.] - -Order 2. =Lyngbyaceæ (Oscillariaceæ).= The cells are discoid (Fig. -21), united to straight or spirally twisted, free filaments, which are -unbranched, or with spurious branching. The ends of the cell-chains -are similar. Heterocysts absent. Reproduction by synakinetes, resting -akinetes are wanting. _Oscillaria_ (Fig. 21), _Spirulina_, _Lyngbya_, -_Microcoleus_, _Symploca_, _Plectonema_. - -Order 3. =Chamæsiphonaceæ.= The individuals are 1--many-celled, -attached, unbranched filaments with differentiation into apex and base, -without heterocysts. Multiplication by reproductive akinetes; resting -akinetes are wanting. _Dermocarpa_, _Clastidium_, _Chamæsiphon_, -_Godlewskia_, _Phragmonema_. - -Order 4. =Nostocaceæ.= The individuals are formed of multicellular, -unbranched filaments, without differentiation into apex and base; -heterocysts present. Reproduction by synakinetes and resting akinetes. - - [Illustration: FIG. 22.--_Nostoc verrucosum. A_ The plant in - its natural size; an irregularly folded jelly-like mass. _B_ One - of the cell-chains enlarged, with its heterocysts (_h_), embedded - in its mucilaginous sheath.] - -Some genera are not mucilaginous, _e.g. Cylindrospermum_ (Fig. 19). -The cell-chains in others, _e.g. Nostoc_, wind in between one another -and are embedded in large structureless jelly-like masses, which may -attain the size of a plum or even larger (Fig. 22); sometimes they are -found floating in the water, sometimes attached to other bodies. Other -genera as follows: _Aphanizomenon_ and _Anabæna_ (in lakes and smaller -pieces of water); _Nodularia_ is partly pelagic. Some occur in the -intercellular spaces of higher plants, thus _Nostoc_-forms are found -in _Anthoceros_, _Blasia_, _Sphagnum_, _Lemna_, and in the roots of -_Cycas_ and _Gunnera_; _Anabæna_ in _Azolla_. - -Order 5. =Rivulariaceæ.= The individuals are multicellular filaments, -with differentiation into apex and base; spurious branching, and a -heterocyst at the base of each filament, reproduction by synakinetes -and resting akinetes, rarely by simple reproductive akinetes. -_Rivularia_, _Glœotrichia_, _Isactis_, _Calothrix_. - -Order 6. =Scytonemaceæ.= The individuals are formed of multicellular -filaments with no longitudinal division; differentiation into apex and -base very slight or altogether absent; branching spurious; heterocysts -present. Reproduction by synakinetes, rarely by resting akinetes and -ordinary reproductive akinetes. _Tolypothrix_, _Scytonema_, _Hassalia_, -_Microchæte_. - -Order 7. =Sirosiphoniaceæ.= The individuals are formed of multicellular -threads with longitudinal divisions; true branching and heterocysts, -and often distinct differentiation into apex and base. Reproduction -by synakinetes, rarely by resting akinetes and ordinary reproductive -akinetes. _Hapalosiphon_, _Stigonema_, _Capsosira_, _Nostocopsis_, -_Mastigocoleus_. - - - Family 2. =Bacteria.=[6] - -The Bacteria (also known as Schizomycetes, and Fission-Fungi) are the -smallest known organisms, and form a parallel group to the Blue-green -Algæ, but separated from these Algæ by the absence of their colouring -material; chlorophyll is only found in a few Bacteria. - -The various forms under which the vegetative condition of the Bacteria -appear, are termed as follows: - -1. GLOBULAR FORMS, COCCI (Figs. 27, 30 _c_): spherical or ellipsoidal, -single cells, which, however, are usually loosely massed together and -generally termed “_Micrococci_.” - -2. ROD-LIKE FORMS: more or less elongated bodies; the shorter forms -have been styled “_Bacterium_” (in the narrower sense of the word), -and the term “_Bacillus_” has been applied to longer forms which are -straight and cylindrical (Figs. 28, 29, 30 _E_). - - [Illustration: FIG. 23.--_Spirillum sanguineum._ Four specimens. - One has two cilia at the same end, the sulphur grains are seen - internally.] - -3. THREAD-LIKE FORMS: unbranched, long, round filaments, resembling -those of _Oscillaria_, are possessed by _Leptothrix_ (very thin, -non-granular filaments; Fig. 30 _A_, the small filaments) and -_Beggiatoa_ (thicker filaments, with strong, refractile grains or drops -of sulphur (Fig. 31); often self-motile). Branched filaments, with -false branching like many _Scytonemaceæ_, are found in _Cladothrix_ -(Fig. 30 _B_, _G_). - -4. SPIRAL FORMS: Rod-like or filamentous bodies, which more or less -strongly resemble a corkscrew with a spiral rising to the left. In -general these are termed _Spirilla_ (Fig. 23); very attenuated spirals, -_Vibriones_ (standing next to Fig. 30 _M_); if the filaments are -slender and flexible with a closely wound spiral, _Spirochætæ_ (Fig. -24). - -5. The MERISMOPEDIUM-FORM, consisting of rounded cells arranged in -one plane, generally in groups of four, and produced by divisions -perpendicular to each other. - -6. The SARCINA-FORM, consisting of roundish cells which are produced -by cellular division in all the three directions of space, united into -globular or ovoid masses (“parcels”) _e.g. Sarcina ventriculi_ (Figs. -25, 26). - - [Illustration: FIG. 24.--_Spirochæte obermeieri_, in active - motion (_b_) and shortly before the termination of the fever - (_c_); a blood corpuscles.] - -All Bacteria are unicellular. In the case of the micrococci this is -self-evident, but in the “rod,” “thread,” and “spiral” Bacteria, very -often numerous cells remain united together and their individual -elements can only be recognised by the use of special reagents. - - [Illustration: FIG. 25.--_Sarcina ventriculi._ One surface only - is generally seen. Those cells which are drawn with double - contour are seen with the correct focus, and more distinctly than - those cells lying deeper drawn with single contour.] - - [Illustration: FIG. 26.--_Sarcina minuta_: _a-d_ successive - stages of one individual (from 4–10 p.m.); _f_ an individual of - 32 cells.] - -The condition termed “Zooglœa,” which reminds us of _Nostoc_, is -produced by the cells becoming strongly mucilaginous. A number of -individuals in active division are found embedded in a mass of -mucilage, which either contains only one, or sometimes more, of the -above-named forms. The individuals may eventually swarm out and -continue their development in an isolated condition. Such mucilaginous -masses occur especially upon moist vegetables (potatoes, etc.), on the -surface of fluids with decaying raw or cooked materials, etc. The -mucilaginous envelope is thrown into folds when the Bacteria, with -their mucilaginous cell-walls, multiply so rapidly that there is no -more room on the surface of the fluid. - -The cells of the Bacteria are constructed like other plant-cells in -so far as their diminutive size has allowed us to observe them. The -cell-wall only exceptionally shows the reactions of cellulose (in -_Sarcina_, _Leuconostoc_; also in a Vinegar-bacterium, _Bacterium -xylinum_); a mucilaginous external layer is always present. The body -of the cell mostly appears to be an uniform or finely granulated -protoplasm. Very few species (_e.g. Bacillus virens_) contain -chlorophyll; others are coloured red (purple sulphur Bacteria); the -majority are colourless. _Bacillus amylobacter_ shows a reaction -of a starch-like material when treated with iodine before the -spore-formation. Some Bacteria contain sulphur (see p. 37). The body, -which has been described as a _cell-nucleus_, is still of a doubtful -nature. - -Artificial colourings with aniline dyes (especially methyl-violet, -gentian-violet, methylene-blue, fuchsin, Bismarck-brown and Vesuvin) -play an important part in the investigations of Bacteria. - -MOVEMENT. Many Bacteria are self-motile; the long filaments of -_Beggiatoa_ exhibit movements resembling those of _Oscillaria_. In many -motile forms the presence of cilia or flagella has been proved by the -use of stains; many forms have one, others several cilia attached at -one or both ends (Fig. 23) or distributed irregularly over the whole -body; the cilia are apparently elongations of the mucilaginous covering -and not, as in the other Algæ of the protoplasm. In _Spirochæte_ the -movement is produced by the flexibility of the cell itself. Generally -speaking, the motion resembles that of swarm-cells (_i.e._ rotation -round the long axis and movement in irregular paths); but either end -has an equal power of proceeding forwards. - - The swarming motion must not be confounded with the hopping - motion of the very minute particles under the microscope - (Brownian movement). - -VEGETATIVE REPRODUCTION takes place by continued transverse division; -hence the name “Fission-Fungi” or “Fission-Algæ,” has been applied to -the Bacteria. - -SPORES. The spores are probably developed in two ways. In the -ENDOSPOROUS species (Figs. 28, 29), the spore arises as a new cell -inside the mother-cell. The spores are strongly refractile, smaller -than the mother-cell, and may be compared to the aplanospores of other -Algæ. In addition to these there are the ARTHROSPOROUS species in -which the cells, just as in _Nostoc_ and other Blue-green Algæ, assume -the properties of spores without previously undergoing an endogenous -new construction, and are able to germinate and form new vegetative -generations (Fig. 27). The formation of spores very often commences -when the vegetative development begins to be restricted. - - [Illustration: FIG. 27.--_Leuconostoc mesenterioides_: _a_ - a zooglœa, natural size; _b_ cross section of zooglœa; _c_ - filaments with spores; _d_ mature spores; _e-i_ successive stages - of germination; in _e_ portions of the ruptured spore-wall are - seen on the external side of the mucilaginous covering. (_b-i_ - magnified 520.)] - -The spores germinate as in _Nostoc_ by the bursting of the external -layer of the cell-wall, either by a transverse or longitudinal cleft, -but always in the same way, in the same species (Fig. 28, example of -transverse cleft). - -DISTRIBUTION. Bacteria and their germs capable of development, are -found everywhere, in the air (dust), in surface water, and in the -superficial layers of the soil. The number varies very much in -accordance with the nature of the place, season, etc. They enter, -together with air and food, into healthy animals and occur always in -their alimentary tract. - -GROWTH AND REPRODUCTION depend upon the conditions of temperature. -There is a certain minimum, optimum and maximum for each species; for -instance (in degrees Centigrade)-- - - Minim. Opt. Maxim. - _Bacillus subtilis_ + 6 c. 30 + 50 - _B. anthracis_ 15 20–25 43 - _Spirillum choleræ asiaticæ_ 8 37 40 (but grows - only feebly - if under - 16°). - _Bacterium tuberculosis_ 28 37–38 42 - - [Illustration: FIG. 28.--_Bacillus megaterium_: _a_ outline of a - living, vegetative cell-rod; _b_ a living, motile, pair of rods; - _p_ a similar 4-celled rod after the effects of iodine alcohol; - _c_ a 5-celled rod in the first stages of spore-formation; _d-f_ - successive stages of spore-formation in one and the same pair - of rods (in the course of an afternoon); _r_ a rod with mature - spores; _g^1–g^3_ three stages of a 5-celled rod, with spores - sown in nutritive solution; _h^1–h^2_, _i_, _k_, _l_ stages of - germination; _m_ a rod in the act of transverse division, grown - out from a spore which had been sown eight hours previously. - (After de Bary; _a_ mag. 250, the other figures 600 times).] - - [Illustration: FIG. 29.--_Bacillus amylobacter._ Motile rods, - partly cylindrical and without spores, partly swollen into - various special shapes and with spore-formation in the swelling. - _s_ Mature spore, with thick mucilaginous envelope. (After de - Bary; mag. 600 times, with the exception of _s_, which is more - highly magnified.)] - -The functions of life cease on a slight excess of the maximum or -minimum temperature, numbness setting in when either of these limits -is passed. _Crenothrix_-threads provided with mucilaginous envelopes -may, according to Zopf, sustain a temperature of-10°. Some Bacteria are -said to be able to resist the exposure to as low a temperature as-110° -for a short time. It is not known at what degree of cold the death of -the Bacteria occurs: the greatest degree of heat which the vegetative -cells can withstand is about the same as that for other vegetative -plant-cells, namely, about 50–60° C. Certain Bacteria, _e.g. B. -thermophilus_, grow and thrive vigorously at 70° C. Many spores, on the -contrary, are able to bear far higher temperatures (in several species -a temperature for some duration of above 100°, those of _Bacillus -subtilis_, for instance, can withstand for hours a temperature of 100° -in nutrient solutions; the spores remain capable of development after -exposure to a dry heat of 123° C.). - -The _Desiccation_ of the air, if prolonged, kills many forms when in -the vegetative condition. The spores however can bear a much longer -period of dryness, some even several years. - -OXYGEN. Some species cannot live without a supply of free oxygen -(_Aerobic_), _e.g._ the Vinegar-bacteria, the Hay-bacilli, the -Anthrax-bacilli, the Cholera-_Microspira_. Other species again thrive -vigorously without supply of free oxygen, and are even checked in their -development by the admission of air (_Anaerobic_), _e.g._ the butyric -acid Bacterium (_Clostridium butyricium_ = _Bacillus amylobacter_). -A distinction may be drawn between obligate and facultative aerobics -and obligate and facultative anaerobics. Several Bacteria, producing -fermentation, may grow without the aid of oxygen when they are living -in a solution in which they can produce fermentation; but, if this is -not the case, they can only grow when a supply of oxygen is available. -A great number of the pathogenic Bacteria belong to the facultative -anaerobics. - -A luminous Bacterium (_Bacillus phosphorescens_) which in the presence -of a supply of oxygen gives a bluish-white light, has been found in -sea-water. Phosphorescent Bacteria have frequently been observed -upon decaying sea-fish, as well as on the flesh of other animals; by -transferring the Bacteria from cod fish to beef, etc., the latter may -be made luminous. - -_Organic carbon compounds_ are indispensable for all Bacteria, (except, -as it appears, for the nitrifying organisms), as they can only obtain -the necessary supplies of _carbon_ from this source. The supplies -of _nitrogen_, which also they cannot do without, can be obtained -equally as well from organic compounds as from inorganic salts, such as -saltpetre or ammonia-compounds. The various “ash-constituents” are also -essential for their nourishment. - -While Moulds and Yeast-Fungi grow best in an acid substratum, the -_Bacteria_, on the other hand, generally thrive _best_ in a _neutral_ -or slightly _alkaline_ one. - -In _sterilization_, _disinfection_, and _antisepsis_, means are -employed by which the Bacteria are killed, or checked in their -development, for instance, by heat (ignition, cooking, hot vapours, -hot air, etc.), or poisons (acids, corrosive sublimate). The process -of preserving articles of food, in which they are boiled and then -hermetically sealed, aims at destroying the Bacteria, or the spores of -those which already may be present in them, and excluding all others. - -As the Bacteria are unable to assimilate carbon from the carbonic -acid of the air, but must obtain it from the carbon-compounds already -in existence in the organic world, they are either _saprophytes_ -or _parasites_. Some are exclusively either the one or the other, -_obligate_ saprophytes or parasites. But there are transitional -forms among them, some of which are at ordinary times saprophytes, -but may, when occasion offers, complete their development wholly or -partly as parasites--_facultative parasites_; others are generally -parasitic, but may also pass certain stages of development as -saprophytes--_facultative saprophytes_. - -All chlorophyll-free organisms act in a transforming and disturbing -manner on the organic compounds from which they obtain their -nourishment, and while they themselves grow and multiply, they produce, -each after its kind, compounds of a less degree of complexity, _i.e._ -they produce _fermentation_, _putrefaction_, sometimes the formation of -_poisons_, and in living beings often _disease_. - -Those organisms which produce fermentation are called _ferments_; -this word, however, is also employed for similar transformations in -purely chemical materials (inorganic ferments or enzymes). Many organic -(“living”) ferments, among which are Yeast-cells and Bacteria, give -off during their development certain inorganic and soluble ferments -(enzymes) which may produce other transformations without themselves -being changed. Different organisms may produce in the same substratum -different kinds of transformation; alcoholic fermentation may for -instance be produced by different species of Fungi, but in different -proportions, and the same species produces in different substrata, -different transformations (_e.g._ the Vinegar-bacteria oxydize diluted -alcohol to vinegar, and eventually to carbonic acid and water). - - In the study of Bacteria it is absolutely necessary to sterilize - the vessels employed in cultivation, the apparatus, and nutrient - solutions, _i.e._ to free them from Bacteria germs and - also to preserve the cultures from the intrusion of any foreign - germs (“pure-cultures”). A firm, transparent, nutritive medium - is frequently employed. This may be prepared by adding to - the nutrient solutions (broth) either gelatine, or--when the - Bacteria are to be cultivated at blood-heat--serum of sheep’s or - calf’s blood, agar-agar or carragen; serum alone may in itself - serve as a nutrient medium. The so-called “plate-cultures” are - frequently employed, _i.e._ the germs are isolated by - shaking them with the melted liquid nutrient gelatine, which - is then spread on a glass plate and allowed to coagulate; when - later on the individual germs grow into colonies, these remain - separate in the solid substratum and it is easy to pursue - their further development. Similar plate-cultures may also be - cultivated in test-tubes and on microscopic slides. The slides - and glass plates must be placed in “moist chambers” free from - Bacteria. By sowing a few cells (if possible one) using a fine - platinum wire, pure cultures for further investigation may be - obtained. - - In order to prove the relationship between pathogenic Bacteria - and certain diseases, the experimental production of pathogenic - Bacteria by the inoculation of Bacteria from pure cultures into - healthy animals, is very important. - -It has not so far been possible to establish a _classification_ -of the Bacteria, as the life-history of many species, has not yet -been sufficiently investigated.[7] The opinions of botanists are at -variance, in many cases, about the forms of growth of a particular -kind. Some species are pleomorphic (many-formed) while others possess -only one form. - -The following Bacteria are =Saprophytes=:-- - -_Cladothrix dichotoma_ is common in stagnant and running water which is -impregnated with organic matter; the cell-chains have false branching. -According to Zopf, _Leptothrix ochracea_ is one of the forms of this -species which, in water containing ferrous iron (_e.g._ as FeCO_{3}), -regularly embeds ferric-oxide in its sheath by means of the activity -of the protoplasm. _Leptothrix ochracea_ and other Iron-bacteria, -according to Winogradsky (1888), do not continue their growth in water -free from protoxide of iron; while they multiply enormously in water -which contains this salt of iron. The large masses of ochre-coloured -slime, found in meadows, bogs, and lakes, are probably due to the -activity of the Iron-bacteria. - - [Illustration: FIG. 30.--_Cladothrix dichotoma._] - -Those forms which, according to Zopf’s views, represent the forms -of development of _Cladothrix dichotoma_ are placed together in -Fig. 30. A represents a group of plants, seventy times magnified, -attached to a Vaucheria. The largest one is branched like a tree, with -branches of ordinary form; a specimen with spirally twisted branches -is seen to the right of the figure, at the lower part some small -_Leptothrix_-like forms. _B_ shows the manner of branching and an -incipient _Coccus_-formation. _C_ a _Coccus_-mass whose exit from the -sheath has been observed. _D_ the same mass as _C_ after the course of -a day, the Cocci having turned into _rods_. _E_ a group of Cocci in -which some have developed into shorter or longer rods. _F_ one of these -rods before and after treatment with picric acid, which causes the -chain-like structure to become apparent. _G_ a portion of a plant with -conspicuous sheath, two lateral branches are being formed. _H_ part of -a plant, whose cells have divided and form Cocci. The original form -of the cells in which the Cocci are embedded may still be recognised. -I. _Leptothrix_-filaments with conspicuous mucilaginous sheath, from -which a series of rods is about to emerge; the rod near the bottom -is dead, and has remained lying in the sheath. _K_ part of a plant -which is forming Cocci, those at the top are in the zooglœa-stage, at -the base they are elongating to form rods and _Leptothrix_-filaments. -_L_ a portion of a branched _Cladothrix_, which divides into motile -_Bacillus_-forms; the rays at the free ends indicate the currents -which the cilia produce in the water. _M_ a spirally-twisted, swarming -filament, before and after division into halves. _N_ part of a -tree-like zooglœa with Cocci and short rods.--All of these spirilla, -zooglœa, etc., which Zopf has connected with _Clad. dichotoma_, are -according to Winogradsky, independent organisms. - -_Micrococcus ureæ_ produces _urinal fermentation_ (transformation of -urinal matter into ammonium carbonate); aerobic; round cells generally -united to form bent chains or a zooglœa.--Several other kinds of -Bacteria have the same action as this one: in damp soil containing -ammonia-compounds, _saltpetre-formations_ are produced by _M. -nitrificans_ and several different kinds of Bacteria. - -_Micrococcus prodigiosus_ is found on articles of food containing -starch; “bleeding bread” is caused by this Bacterium, which has the -power of forming a red pigment; it also occurs in milk, and produces -lactic acid. - -_Leuconostoc mesenterioides_ is the frog-spawn Bacterium (Fig. 27) -which is found in sugar manufactories, and has the power of producing -a viscous fermentation in saccharine solutions which have been derived -from plants, _e.g._ in beetroot-sugar manufactories, where large -accumulations of mucilage are formed at the expense of the sugar, with -an evolution of carbonic acid. The cell-rows, resembling somewhat a -pearl necklace, have thick mucilaginous cell-walls, and form white -“Nostoc”-lumps. The mucilage eventually deliquesces and the cells -separate from each other; arthrospores?--Similar viscous deteriorations -occur in beer and wine, which may then be drawn out into long, string -like filaments--“ropiness.” - -_Bacterium aceti_, the Vinegar-bacterium, oxidizes alcohol into -acetic acid (acetous-fermentation) and forms a greyish covering of -Bacteria (“Vinegar-mother”) on the surface of the liquid; the acetic -acid formed, becomes by continued oxidization by _B. aceti_, again -transformed into carbonic acid and water. Aerobic; short cylindrical -cells, often united into chains, or to form a zooglœa; sometimes also -rod-and spindle-shaped. The Vinegar-bacteria and other kinds with -ball- or rod-forms sometimes become swollen, spindle-shaped, or oval -links; they are supposed to be diseased forms[8] (“Involution-forms”). - -_Bacillus lacticus_ (_Bacterium acidi lactici_, Zopf) is always found -in milk which has stood for some time, and in sour foods (cabbage, -cucumbers, etc.); it turns the milk sour by producing lactic acid -fermentation in the sugar contained in the milk; the lactic acid -formed, eventually causes the coagulation of the casein. It resembles -the Vinegar-bacteria, occurring as small cylindrical cells, rarely in -short rows; not self-motile.--Several other Bacteria appear to act in -the same way, some occurring in the mouth of human beings; some of -these Bacteria give to butter its taste and flavour. - -The _kefir-grains_ which are added to milk for the preparation of -kefir, contain in large numbers a Bacterium (_Dispora caucasica_) in -the zooglœa-form, a Yeast-fungus, and _Bacillus lacticus_. Kefir is a -somewhat alcoholic sour milk, rich in carbonic acid; it is a beverage -manufactured by the inhabitants of the Caucasus, from the milk of cows, -goats, or sheep, and is sometimes used as a medicine. In the production -of kefir, lactic acid fermentation takes place in one part of the sugar -contained in the milk, and alcoholic fermentation in another part, and -the casein which had become curdled is partially liquefied (peptonised) -by an enzyme of a Zooglœa-bacterium. - -_Bacillus amylobacter_ (_Bacillus butyricus_), the -Butyric-acid-bacterium (Fig. 29), is a very common anaerobic which -produces fermentation in sugar and lactic-acid salts, and whose -principal product is _butyric acid_. It destroys articles of -food and (together with other species) plays a part in the butyric -acid fermentation which is necessary in the making of cheese; it is -very active wherever portions of plants are decaying, in destroying -the cellulose in the cell-walls of herbaceous plants, and is thus -useful in the preparation of flax and hemp. The cells are self-motile, -generally cylindrical, sometimes united into short rows; endosporous; -the spore-forming cells swell, assume very different forms, and show -granulose reaction. The germ-tube grows out in the direction of the -long axis of the spore. - -_Bacillus subtilis_, the Hay-bacillus, is developed in all decoctions -of hay; a slender, aerobic, self-motile Bacillus; endosporous -(aplanospores); the spore-wall ruptures transversely on germination. - -_Crenothrix kuehniana_ occurs in the springs of many baths, in wells, in -water or drain-pipes. - - [Illustration: FIG. 31.--_Beggiatoa alba_: _a_ from a fluid - containing abundance of sulphuretted hydrogen; _b_ after lying 24 - hours in a solution devoid of sulphuretted hydrogen; _c_ after - lying an additional 48 hours in a solution devoid of sulphuretted - hydrogen, by this means the transverse walls and vacuoles have - become visible.] - -_Beggiatoa_ (parallel with the Blue-green Alga _Oscillaria_). Long -filaments formed of cylindrical cells which are attached by one -of the ends, but which are nearly always free when observed. The -filaments, like those of _Oscillaria_, describe conical figures in -their revolutions, the free filaments slide upwards and parallel with -one another; sheaths are wanting; strongly refractive sulphur drops -are found in the interior. The Beggiatoas are the most prevalent -_Sulphur-bacteria_. They occur, very commonly in large numbers, -wherever plant or animal remains are decaying in water in which -sulphuretted hydrogen is being formed; thus, for example, _B. alba_ -(Fig. 31) occurs frequently as a white covering or slimy film on mud -containing organic remains. ~_B. mirabilis_ is remarkable for its -size and its strong peristaltic movements.~ The Sulphur-bacteria -oxidize the sulphuretted hydrogen, and accumulate sulphur in the -shape of small granules of soft amorphic sulphur, which in the living -cell never passes over into the crystalline state. They next oxidize -this sulphur into sulphuric acid, which is immediately rendered -neutral by absorbed salts of calcium, and is given off in the form -of a sulphate, thus CaCO_{3} is principally changed into CaSO_{4}. -In the absence of sulphur the nutritive processes are suspended, and -consequently death occurs either sooner or later. The Sulphur-bacteria -may exist and multiply in a fluid which only contains traces of -organic matter, in which organisms devoid of chlorophyll are not able -to exist. The Beggiatoas very frequently form white, bulky masses -in sulphur wells and in salt water, the traces of organic material -which the sulphur water contains proving sufficient for them. ~The -cellulose-fermentation, to which the sulphur wells in all probability -owe their origin, mainly procures them suitable conditions for -existence. The CaCO_{3} and H_{2}S, formed during the cellulose -fermentation by the reduction of CaSO_{4} is again changed into -CaSO_{4} and CO_{2} by the Sulphur-bacteria (Winogradsky, 1887).--Other -Sulphur-bacteria, the so-called purple Sulphur-bacteria, _e.g._ -_B. roseo-persicina_, _Spirillum sanguineum_ (Fig. 23), _Bacterium -sulfuratum_, etc., have their protoplasm mixed with a red colouring -matter (bacterio-purpurin) which, like chlorophyll, has the power, -in the presence of light, of giving off oxygen (as proved by T. W. -Englemann, 1888, in oxygen-sensitive Bacteria). The three purple -Sulphur-bacteria mentioned, are, according to Winogradsky, not -pleomorphic kinds but embrace numerous species.~ - -Many _Spirilli_ (_Spirillum tenue_, _S. undula_, _S. plicatile_, and -others) are found prevalent in decaying liquids. - -Bacteria (especially Bacilli) are the cause of many substances emitting -a foul odour, and of various changes in milk. - -=Parasitic Bacteria= live in other living organisms; but the relation -between “host” and parasite may vary in considerable degree. Some -parasites do no injury to their host, others produce dangerous -contagious diseases; some choose only a special kind as host, others -again live equally well in many different ones. There are further -specific and individual differences with regard to the _predisposition_ -of the host, and every individual has not the same receptivity at all -times. - -THE HARMLESS PARASITES OF HUMAN BEINGS. Several of the above mentioned -saprophytes may also occur in the alimentary canal of human beings; -_e.g._, the Hay-bacillus, the Butyric-acid-bacillus, etc.; but the -gastric juice prevents the development of others, at all events in -their vegetative condition. _Sarcina ventriculi_, “packet-bacterium,” -is only known to occur in the stomach and intestines of human beings, -and makes its appearance in certain diseases of the stomach (dilation -of the stomach, etc.) in great numbers, without, however, being the -cause of the disease. It occurs in somewhat cubical masses of roundish -cells (Fig. 25). - -LESS DANGEROUS PARASITES. In the mouth, especially between and on -the teeth, a great many Bacteria are to be found (more than fifty -species are known), _e.g. Leptothrix buccalis_ (long, brittle, -very thin filaments which are united into bundles), Micrococci in -large lumps, _Spirochæte cohnii_, etc. Some of them are known to be -injurious, as they contribute in various ways to the decay of the -teeth (_caries dentium_); a _Micrococcus_, for instance, forms lactic -acid in materials containing sugar and starch, and the acid dissolves -the lime salts in the external layers of the teeth: those parts of -the teeth thus deprived of lime are attacked by other Bacteria, and -become dissolved. Inflammation in the tissues at the root of a tooth, -is probably produced by septic materials which have been formed by -Bacteria in the root-canal. - -DANGEROUS PARASITES. In a large number of the infectious diseases of -human beings and animals, it has been possible to prove that parasitic -Bacteria have been the cause of the disease. Various pathogenic -Bacteria of this nature, belonging to the coccus, rod, and spiral -Bacteria groups, are mentioned in the following:-- - -=Pathogenic Micrococci.= _Staphylococcus pyogenes aureus_ produces -abscesses of various natures (boils, suppurative processes in internal -organs). The same effects are produced by-- - -_Streptococcus pyogenes_, which is the most frequent cause of malignant -puerperal fever; it is perhaps identical with-- - -_Streptococcus erysipelatis_, which is the cause of erysipelas in human -beings. - -_Diplococcus pneumoniæ_ (A. Fränkel) is the cause of pneumonia, and of -the epidemic cerebro-spinal meningitis. - -_Gonococcus_ (Neisser) is the cause of gonorrhea and inflammation of -the eyes. - -=Pathogenic Rod-Bacteria.= _Bacterium choleræ gallinarum_, an aerobic, -facultative parasite which produces fowl-cholera among poultry; it is -easily cultivated on various substrata as a saprophyte. The disease -may be conveyed both through wounds and by food, and may also be -communicated to mammals. - -_Bacillus anthracis_, the _Anthrax bacillus_ (Fig. 32), chiefly attacks -mammals, especially herbivorous animals (house mice, guinea-pigs, -rabbits, sheep, cattle), in a less degree omnivorous animals (including -human beings), and in a still less degree the Carnivores. Aerobic. -Cylindrical cells, 3–4 times as long as broad, united into long -rod-like bodies, which may elongate into long, bent, and twisted -filaments. Not self-motile. Endosporous. Germination takes place -without the throwing off of any spore-membrane (compare Hay-bacillus p. -37 which resembles it). Contagion may take place both by introduction -into wounds, and from the mucous membrane of the intestines or lungs, -both by vegetative cells and by spores; in intestinal anthrax, however, -only by spores. The Bacillus multiplies as soon as it has entered the -blood, and the anthrax disease commences. The Bacilli not only give off -poison, but also deprive the blood of its oxygen. Vegetative cells only -occur in living animals. This species is a _facultative parasite_ which -in the first stage is a saprophyte, and only in this condition forms -spores. - - [Illustration: FIG. 32.--_Anthrax bacillus_ (_Bacillus - anthracis_) with red (_b_) and white (_a_) blood-corpuscles.] - - [Illustration: FIG. 33.--_Anthrax bacillus._ The formation of the - spores; magnified 450 times.] - -_Bacillus tuberculosis_ produces tuberculosis in human beings, also -in domestic animals (_perlsucht_). It is a distinct parasite, but may -also live saprophytically. It is rod-formed, often slightly bent, and -is recognised principally by its action with stains (when stained with -an alkaline solution of methyl-blue or carbolic fuchsin, it retains the -colour for a long time even in solutions of mineral acids, in contrast -with the majority of well-known Bacteria): it probably forms spores -which are able to resist heat, dryness, etc. - - _Bacillus lepræ_ produces leprosy; _Bacillus mallei_ produces - glanders; _Bacillus tetani_, tetanus (the tetanus bacillus - is very common in soil; anaerobic); _Bacillus diphtheriæ_, - diphtheria; _Bacillus typhosus_, typhoid fever, etc. - -=Pathogenic Spiral Bacteria.= _Spirochæte obermeieri_ (Fig. 24) -produces intermittent fever (febris recurrens); it makes its appearance -in the blood during the attacks of fever, but it is not to be found -during intervals when there is no fever. Obligate parasite. - -_Spirillum choleræ asiaticæ_ (_Microspira comma_) without doubt -produces Asiatic cholera; an exceedingly motile spirillum, which is -also found in short, bent rods (known as the “Comma-bacillus”), it -lives in the intestines of those attacked by the disease, and gives off -a strong poison which enters the body. It is easily cultivated as a -saprophyte. - -A great many circumstances seem to show that a number of other -infectious diseases (syphilis, small-pox, scarlet-fever, measles, -yellow-fever, etc.) owe their origin to parasitic Bacteria, but this -has not been proved with certainty in all cases. - -It has been possible by means of special cultivations (ample supply of -oxygen, high temperature, antiseptic materials) to produce from the -parasitic Bacteria described above (_e.g._ the fowl-cholera and the -anthrax Bacteria) _physiological varieties_ which are distinct from -those appearing in nature and possess a less degree of “virulence,” -_i.e._ produce fever and less dangerous symptoms in those animals -which are inoculated with them. The production of such physiological -varieties has come to be of great practical importance from the fact -that they are used as vaccines, _i.e._ these harmless species produce -in the animals inoculated with them _immunity_ from the malignant -infectious Bacteria from which they were derived. This immunity is -effected by the change of the products of one or more of the Bacteria, -but we do not yet know anything about the way in which they act on -the animal organism. The white blood corpuscles, according to the -Metschnikoff, play the part of “Phagocytes” by absorbing and destroying -the less virulent Bacteria which have entered the blood, and by so -doing they are gradually enabled to overcome those of a more virulent -nature. - - [Illustration: FIG. 34.--_a_ and _b_ The same blood-cell of a - Frog: _a_ in the act of engulfing an anthrax-bacillus; _b_ after - an interval of a few minutes when the bacillus has been absorbed.] - - - Class 5. =Conjugatæ.= - -The Algæ belonging to this class have chlorophyll, and pyrenoids -round which starch is formed. The cells divide only in one direction, -they live solitarily, or united to form filaments which generally -float freely (seldom attached). Swarm-cells are wanting. _The -fertilisation is isogamous (conjugation) and takes place by means -of aplanogametes._ The zygote, after a period of rest, produces, -immediately on germination, one or more new vegetative individuals; -sometimes akinetes or aplanospores are formed in addition. They only -occur in fresh or slightly brackish water. - -Order 1. =Desmidiaceæ.= The cells generally present markings on the -outer wall, and are mostly divided into two symmetrical halves by a -constriction in the middle, or there is at least a symmetrical division -of the protoplasmic cell-contents. The cell-wall consists nearly -always of two layers, the one overlapping the other (Fig. 35 _C_). The -cells either live solitarily or are united into unbranched filaments. -The mass of protoplasm formed by the fusion of the two conjugating -cells becomes the zygote, which on germination produces one (or after -division 2, 4 or 8) new vegetative individual. The chromatophores are -either star-, plate-, or band-shaped, and regularly arranged round the -long axis of the cell. - - [Illustration: FIG. 35.--A Cell of _Gymnozyga brebissonii_, - external view showing the distribution of the pores. _B A_ - portion of the membrane of _Staurastrum bicorne_ with pores - containing protoplasmic projections. _C_ Cell-wall of _Hyalotheca - mucosa_ during cell-division: the central part, being already - formed, shows the connection with the divisional wall.] - -The Desmidiaceæ are not able to swim independently, many species, -however, show movements of different kinds by rising and sliding -forward on the substratum. These movements, which are partly dependent -upon, and partly independent of light and the force of gravitation, are -connected with the protrusion of a mucilaginous stalk. The mucilage, -which sometimes surrounds the whole individual, may acquire a prismatic -structure, it is secreted by the protoplasmic threads which project -through certain pores definitely situated in the walls (Fig. 35 -_A_, _B_). - -VEGETATIVE MULTIPLICATION takes places by division. A good example of -this is found in _Cosmarium botrytis_ (Fig. 36 _A-D_). The nucleus -and chromatophores divide, and simultaneously the central indentation -becomes deeper, the outer wall is then ruptured making a circular -aperture through which the inner wall protrudes forming a short, -cylindrical canal between the two halves to which it is attached (Fig. -36 _C_). After elongation the canal is divided by a central transverse -wall, which commences as a ring round its inner surface and gradually -forms a complete septum. The dividing wall gradually splits, and the -two individuals separate from each other, each one having an old and -a new half. The two daughter-cells bulge out, receive a supply of -contents from the parent-cells, and gradually attain their mature size -and development (Fig. 36 _B-D_). Exceptions to this occur in some forms. - - [Illustration: FIG. 36.--_Cosmarium botrytis. A-D_ Different - stages of cell-division.] - - [Illustration: FIG. 37.--_Cosmarium meneghinii_: _a-c_ same - individual seen from the side, from the end, and from the edge; - _d-f_ stages of conjugation; _g-i_ germination of the zygote.] - -CONJUGATION takes place in the simplest way in _Mesotænium_, where -the two conjugating cells unite by a short tube (conjugation-canal), -which is not developed at any particular point. The aplanogametes -merge together after the dissolution of the dividing wall, like two -drops of water, almost without any trace of preceding contraction, so -that the cell-wall of the zygote generally lies in close contact with -the conjugating cells. The conjugating cells in the others lie either -transversely (_e.g. Cosmarium_, Fig. 37 _d_; _Staurastrum_, etc.), -or parallel to one another (_e.g. Penium_, _Closterium_, etc.), and -emit a short conjugation-canal (Fig. 37 _d_) from the centre of that -side of each cell which is turned towards the other one. These canals -touch, become spherical, and on the absorption of the dividing wall -the aplanogametes coalesce in the swollen conjugation-canal (Fig. -37 _e_), which is often surrounded by a mucilaginous envelope. The -zygote, which is often spherical, is surrounded by a thick cell-wall, -consisting of three layers; the outermost of these sometimes bears -thorn-like projections, which in some species are simple (Fig. 37 -_f_), in others branched or variously marked; in some, however, it -remains always smooth (_e.g._ _Tetmemorus_, _Desmidium_). Deviation -from this mode of conjugation may occur within certain genera (_e.g._ -_Closterium_, _Penium_). Upon germination the contents of the zygote -emerge, surrounded by the innermost layers of the wall (Fig. 37 _g_, -_h_) and generally divide into two parts which develop into two new -individuals, placed transversely to each other (Fig. 37 _i_); these may -have a somewhat more simple marking than is generally possessed by the -species. - - [Illustration: FIG. 38.--Desmidiaceæ. _A Closterium - moniliferum_; _B Penium crassiusculum_; _C Micrasterias - truncata_ (front and end view); _D Euastrum elegans_; _E_ - _Staurastrum muticum_ (end view).] - - The most frequent genera are:-- - - _A._ Solitary cells: MESOTÆNIUM, PENIUM (Fig. 38 _B_), - CYLINDROCYSTIS, EUASTRUM (Fig. 38 _D_), MICRASTERIAS (Fig. 38 - _C_), COSMARIUM (Fig. 36, 37), XANTHIDIUM, STAURASTRUM (Fig. 38 - _E_), PLEUROTÆNIUM, DOCIDIUM, TETMEMORUS, CLOSTERIUM (Fig. 38 - _A_), SPIROTÆNIA. - - _B._ Cells united into filaments: SPHÆROZOSMA, DESMIDIUM, - HYALOTHECA, GYMNOZYGA, ANCYLONEMA, GONATOZYGON. - -Order 2. =Zygnemaceæ.= Cell-wall without markings. The cells are -cylindrical, not constricted in the centre, and (generally) united into -simple, unbranched filaments. The whole contents of the conjugating -cells take part in the formation of the zygote, which on germination -grows out directly into a new filament. - -_Spirogyra_ is easily recognised by its spiral chlorophyll band; -_Zygnema_ has two star-like chromatophores in each cell (Fig. 40); -both these genera are very common Algæ in ponds and ditches. - - [Illustration: FIG. 39.--_Spirogyra longata. A_ At the - commencement of conjugation, the conjugation-canals begin - to protrude at _a_ and touch one another at _b_; the spiral - chlorophyll band and cell-nuclei (_k_) are shown. _B_ A more - advanced stage of conjugation; _a_, _a’_ the rounded female and - male aplanogametes: in _b’_ the male aplanogamete is going over - to and uniting with the female aplanogamete (_b_).] - - [Illustration: FIG. 40.--A cell of _Zygnema_. _S_ Pyrenoid.] - - [Illustration: FIG. 41.--_Zygnema insigne_, with zygote.] - - [Illustration: FIG. 42.--Germinating zygote of _Spirogyra - jugalis_: the young plant is still unicellular; the end which is - still in the wall of the zygote is elongated and root-like; the - chromatophore divides and forms the spiral band.] - -The conjugation among the Zygnemaceæ takes place in the following -manner: the cells of two filaments, lying side by side, or two cells, -the one being situated above the other in the same filament (Fig. 41), -push out small protuberances opposite each other (Fig. 39 _A_, _a_, -_b_); these finally meet, and the dividing wall is absorbed so that a -tube is formed connecting one cell with the other; the protoplasmic -contents round off, and the whole of these contents of one of the -cells glides through the conjugation-tube and coalesces with that of -the other (Fig. 39 _B_), the aggregate mass then rounds off, surrounds -itself with a cell-wall, and becomes a zygote. A distinct difference -may be found between the cells in the two filaments, those in the one -whose protoplasmic contents pass over being cylindrical, while those -of the recipient one are more barrel-shaped, and of a larger diameter. -The former may be regarded as a male, the latter as a female plant. -The zygote germinates after a period of rest, and grows out into a new -filament (Fig. 42). - -Order 3. =Mesocarpaceæ.= The cell-walls are glabrous, unconstricted -in the centre, and united into simple unbranched filaments. The -chromatophore consists of an axial chlorophyll-plate, with several -pyrenoids. The zygote is formed by the coalescence of two cells (Fig. -43) (sometimes three or four), but the whole protoplasmic contents of -the cells do not take part in this process, a portion always remaining -behind; the aplanogametes coalesce in the conjugation-canal. The -zygote thus formed appears incapable of germination until after 3–5 -divisions. Of the cells so formed, only one is fertile, the sterile -cells, according to Pringsheim, constituting a rudimentary sporocarp. -The germinating cells grow out into a new filament. In this order, -conjugation has been observed between two cells of the same filament. -The Mesocarpaceæ thrive best in water which contains lime. - - [Illustration: FIG. 43.--Mougeotia calcarea. Cells showing - various modes of conjugation: at _m_ tripartition; _pg_ - quadripartition; _s_ quinquipartilion of the zygote.] - - - Class 6. =Chlorophyceæ (Green Algæ).= - -These Algæ are coloured green by chlorophyll, seldom in combination -with other colouring matter, and then especially with red. The product -of assimilation is frequently starch, which generally accumulates round -certain specially formed portions of protoplasm termed pyrenoids. -The thallus is uni- or multicellular; in the higher forms (certain -Siphoneæ) the organs of vegetation attain differentiation into stem -and leaf. The asexual reproduction takes place in various ways; the -sexual reproduction is effected by conjugation of motile gametes, or -by oogamous fertilisation. The swarm-cells (zoospores, gametes, and -spermatozoids) are constructed symetrically, and have true protoplasmic -cilia, these generally being attached to the front end of the -swarm-cells. Most of these Algæ live in water (fresh or salt); some are -found upon damp soil, stones, or tree-stems, and some live enclosed in -other plants. - -The Class is divided into three families:-- - -1. PROTOCOCCOIDEÆ: Volvocaceæ, Tetrasporaceæ, Chlorosphæraceæ, -Pleurococcaceæ, Protococcaceæ, Hydrodictyaceæ. - -2. CONFERVOIDEÆ: Ulvaceæ, Ulothricaceæ, Chætophoraceæ, Mycoideaceæ, -Cylindrocapsaceæ, Œdogoniaceæ, Coleochætaceæ, Cladophoraceæ, -Gomontiaceæ, Sphæropleaceæ. - -3. SIPHONEÆ: Botrydiaceæ, Bryopsidaceæ, Derbesiaceæ, Vaucheriaceæ, -Phyllosiphonaceæ, Caulerpaceæ, Codiaceæ, Valoniaceæ, Dasycladaceæ. - - - Family 1. =Protococcoideæ.= - -The Algæ which belong to this group are uni- or multicellular with -the cells more or less firmly connected, sometimes in a definite, -sometimes in an indefinite form (Fig. 47). Colonies are formed either -by division or by small unicellular individuals becoming united in a -definite manner; the colonies formed in this latter way are termed -_Cœnobia_. Apical cells and branching are absent. Multiplication -by division; asexual reproduction by zoospores, rarely by akinetes. -Sexual reproduction may be wanting, or it takes place by isogamous, -rarely by oogamous fertilisation. - -Some are attached by means of a stalk to other objects (_Characium_, -Fig. 49), others occur as “Endophytes” in the tissues of certain Mosses -or Phanerogams, _e.g. Chlorochytrium lemnæ_, in _Lemna trisulca_; -_Endosphæra_, in the leaves of _Potamogeton_, _Mentha aquatica_, -and _Peplis portula_; _Phyllobium_, in the leaves of _Lysimachia -nummularia_, _Ajuga_, _Chlora_, and species of Grasses; _Scotinosphæra_ -in the leaves of _Hypnum_ and _Lemna trisulca_; the majority, however, -live free in water and in damp places. Many species which were formerly -considered to belong to this family have been proved to be higher Algæ -in stages of development. - -Order 1. =Volvocaceæ.= The individuals in this order are either -uni- or multicellular, and during the essential part of their life are -free-swimming organisms. They are generally encased in a mucilaginous -envelope, through which 2–6 cilia project from every cell. The -vegetative reproduction takes place by the division of all, or a few, -of the cells of the individual; in some a palmella-stage is found in -addition. The sexual reproduction takes place by isogamous or oogamous -fertilisation. - - The Volvocaceæ may be considered to include the original forms - of the Chlorophyceæ, because, among other reasons, the motile - stage is here the most prominent; they also form the connecting - link between the animal Flagellata, and forms intermediate to - the _Syngeneticæ_ may perhaps be found amongst them. Three - series of green Algæ may be supposed to have taken their origin - from the Volvocaceæ: CONJUGATEÆ (_Desmidiaceæ_) which have lost - the swarming stage, but whose conjugation is the nearest to the - fertilisation in _Chlamydomonas pulvisculus_: the PROTOCOCCACEÆ - in which the vegetative divisions have disappeared, while the - swarming stage continues to be present, though of shorter - duration; and TETRASPORACEÆ, in which the vegetative divisions - are more prominent, whilst the swarming stage is less so. - -A. UNICELLULAR INDIVIDUALS. The principle genera are: _Chlamydomonas_, -_Sphærella_, _Phacotus_.--_Sphærella nivalis_ is the Alga which -produces the phenomenon of “Red Snow,” well known on high mountains and -on ice and snow fields in the polar regions. The red colouring matter -which appears in this and other green Algæ, especially in the resting -cells, is produced by the alteration of the chlorophyll. - -_Phacotus lenticularis_ has an outer covering incrusted with lime, -which, at death, or after division, opens out into two halves. -Species may be found among _Chlamydomonas_, in which conjugation -takes place between gametes of similar size without cell-wall, but -in _C. pulvisculus_ conjugation takes place between male and female -aplanogametes which are surrounded by a mucilaginous envelope. - - [Illustration: FIG. 44--_Gonium pectorale._] - - [Illustration: FIG. 45.--_Pandorina morum._] - -B. MULTICELLULAR INDIVIDUALS. The most important genera are _Gonium_, -_Stephanosphæra_, _Pandorina_, _Eudorina_, _Volvox_.--_Gonium_ has 4 -or 16 cells arranged in a definite pattern in a flat plate (Fig. 44). -_Pandorina_ (Fig. 45), has 16 cells arranged in a sphere (Fig. 45 _A_). -The vegetative reproduction takes place in this way: each cell, after -having rounded off, and after the withdrawal of the cilia, divides -itself into 16 new ones (Fig. 45 _B_), each forming a new individual, -which soon grows to the size of the mother-individual. It was in this -Alga that the conjugation of self-motile gametes was first discovered -by Pringsheim, 1869. When conjugation is about to take place, each -cell divides into sixteen, as in vegetative reproduction, but the 16 -× 16 cells all separate from one another (Fig. 45 _C_, female gametes, -and _D_, male gametes), and swarm solitarily in the water. The male -are, most frequently, smaller than the female, but otherwise they are -exactly alike; they are more or less pear-shaped, with a colourless -anterior end, 2 cilia, a red “eye-spot,” etc. After swarming for some -time they approach each other, two and two, generally a large and a -smaller one, and come into contact at their colourless end; in a few -moments they coalesce and become one cell (Fig. 45 _E_, _F_), this has -at first a large colourless anterior end, 4 cilia, and 2 “eye-spots” -(Fig. 45 _G_), but these soon disappear and the cell becomes uniformly -dark-green and spherical, and surrounds itself with a thick cell-wall, -losing at the same time its power of motion: the zygote (Fig. 45 _H_) -is formed, and becomes later on a deep red colour. On the germination -of the zygote, the protoplasmic cell-contents burst open the wall (Fig. -45 _J_), and emerge as a large swarmspore (Fig. 45 _K_) which divides -into 16 cells, and the first small individual is formed (Fig. 45 _L_, -_M_). - -_Eudorina_ is like _Pandorina_ in structure, but stands somewhat -higher, since the contrast between the conjugating sexual cells is -greater, the female one being a motionless oosphere. - - [Illustration: FIG. 46.--_Volvox globator_, sexual individual: - _a_ antheridia which have formed spermatozoids; _b_ oogonia.] - -The highest stage of development is found in _Volvox_ (Fig. 46). The -cells are here arranged on the circumference of a sphere, and enclose -a cavity filled with mucilage. The number of these cells may vary from -200–22,000, of which the majority are vegetative and not reproductive, -but some become large, motionless oospheres (Fig. 46 _b_); others, -which may appear as solitary individuals, divide and form disc-shaped -masses of from 8–256 small spermatozoids (Fig. 46 _a_). After the -oosphere has been fertilised by these, the oospore surrounds itself by -a thick, sometimes thorny cell-wall, and on germination becomes a new -individual of few cells. A few cells conspicuous by their larger size -may be found (1–9, but generally 8) in certain individuals, and these -provide the vegetative reproduction, each forming by division a new -individual. - -Order 2. =Tetrasporaceæ= reproduce both by vegetative divisions and -swarmspores, some have also gamete-conjugation. The principal genera -are: _Tetraspora_, _Apiocystis_, _Dactylococcus_, _Dictyosphærium_, -_Chlorangium_. - -Order 3. =Chlorosphæraceæ.= _Chlorosphæra._ - -Order 4. =Pleurococcaceæ.= In this order the swarm-stages and sexual -reproduction are entirely absent. Vegetative reproduction by division. -The principal genera are: _Pleurococcus_ (Fig. 47), _Scenedesmus_ -(Fig. 48), _Raphidium_, _Oocystis_, _Schizochlamys_, _Crucigenia_, -_Selenastrum_.--_Pleurococcus vulgaris_ (Fig. 47) is one of the -most common Algæ throughout the world, occurring as green coverings -on tree-stems, and damp walls, and it is one of the most common -lichen-gonidia. - - [Illustration: FIG. 47.--_Pleurococcus vulgaris._] - - [Illustration: FIG. 48.--_Scenedesmus quadricauda._] - -Order 5. =Protococcaceæ.= The cells are motionless, free or affixed -on a stalk (_e.g. Characium_, Fig. 49), either separate or loosely -bound to one another; they never form multicellular individuals. -Multiplication by division is nearly always wanting. Reproduction -takes place by swarmspores, which have 1 or 2 cilia, and sexual -reproduction in some by gamete-conjugation. The principal genera are: -_Chlorococcum_, _Chlorochytrium_, _Chlorocystis_, _Scotinosphæra_, -_Endosphæra_, _Phyllobium_, _Characium_, _Ophiocytium_, _Sciadium_. - - [Illustration: FIG. 49.--_Characium strictum._ - _A_ The cell-contents have divided into many swarmspores. - _B_ Swarmspores escaping.] - -Order 6. =Hydrodictyaceæ.= The individuals are unicellular but -several unite after the zoospore-stage into definitely formed families -(cœnobia). Ordinary vegetative division is wanting, but asexual -reproduction takes place by zoospores (or by motionless cells without -cilia), which unite and form a family similar to the mother-family, -inside the mother-cell, or in a mucilaginous envelope. Where sexual -reproduction is found it takes place by gamete-conjugation. The -principal genera are: _Pediastrum_ (Fig. 50), _Cœlastrum_, -_Hydrodictyon_ (Fig. 51). - - [Illustration: FIG. 5O.--_Pediastrum asperum._] - - [Illustration: FIG. 51.--_Hydrodictyou reticulatum. A_ A cell - where the zoospores are on the point of arranging themselves to - form a net. _B_ A cell with gametes swarming out.] - -The cœnobium of _Hydrodictyon reticulatum_ (Water-net) is formed of -a large number of cells which are cylindrical, and attached to one -another by the ends (Fig. 51). The asexual reproduction takes place by -zoospores, which are formed in large numbers (7,000–20,000) in each -mother-cell, within which they move about for a time, and then come -to rest and arrange themselves into a new net (Fig. 51 _A_) which is -set free by the dissolution of the wall of the mother-cell, grows, -and becomes a new cœnobium. The sexual reproduction takes place by -gamete-conjugation. The gametes are formed in the same manner as the -zoospores, but in larger numbers (30,000–100,000), and swarm out of the -mother-cell (Fig. 51 _B_). The zygote forms, on germination, 2–5 large -zoospores, each with one or two cilia, these generally swarm about -for a time, and after a period of rest become irregular thorny bodies -(polyhedra); their contents again divide into zoospores, the thorny -external coating of the polyhedra is cast off, and the zoospores, -surrounded by the dilated internal coating, unite to form a small -family, which produces several others in the manner described. - - - Family 2. =Confervoideæ.= - -The individuals are always multicellular, the cells firmly bound -together and united into unbranched or branched filaments, expansions, -or masses of cells which grow by intercallary divisions or have -apical growth. In the first seven orders the cells are uninuclear, -but the cells of the remaining three orders contain several nuclei. -Asexual reproduction by zoospores, akinetes or aplanospores. Sexual -reproduction by isogamous or oogamous fertilisation. - - The Confervoideæ, through the Ulvaceæ, are connected with the - Tetrasporaceæ, and from the _Coleochætaceæ_, which is the most - highly developed order, there are the best reasons for supposing - that the Mosses have taken their origin. The _Cladophoraceæ_ - show the nearest approach to the _Siphoneæ_. - -Order 1. =Ulvaceæ.= The thallus consists of one or two layers of -parenchymatous cells, connected together to form either a flat membrane -(_Monostroma_, _Ulva_) or a hollow tube (_Enteromorpha_), and may be -either simple, lobed, or branched. Reproduction takes place by detached -portions of the thallus; or asexually by zoospores or akinetes. -Gamete-conjugation is known to take place in some members of this -order, the zygote germinating without any resting-stage. The majority -are found in salt or brackish water. - - [Illustration: FIG. 52.--_Ulothrix zonata_: a portion of a - filament with zoospores, which are formed two in each cell - (zoosporangium); the dark spots are the red “eye-spots”; 1, - 2, 3, 4, denote successive stages in the development of the - zoospores; _b_ a single zoospore, _v_ the pulsating vacuole; - _c_ portion of a filament with gametes, sixteen are produced in - each gametangium; _d_ free gametes, solitary or in the act of - conjugation; _e_ the conjugation is completed, and the formed - zygote has assumed the resting-stage.] - -Order 2. =Ulothricaceæ.= The thallus consists normally of a simple -unbranched filament (sometimes a small expansion consisting of one -layer of cells is formed, as in _Schizomeris_ and _Prasiola_ which -were formerly described as separate genera). Asexual reproduction -takes place by means of zoospores (with 1, 2, or 4 cilia), akinetes -or aplanospores; the last named may germinate immediately, or only -after a period of rest. Sexual reproduction takes place by the -conjugation of gametes of about the same size, each having two cilia -(Fig. 52 _d_). The zygote of _Ulothrix_, on germination, produces a -brood of zoospores which swarm for a time and then elongate to become -_Ulothrix_-filaments (alternation of generations). The gametes may also -germinate without conjugation in the same manner as the zoospores. -The principal genera are: _Ulothrix_, _Hormidium_, _Conferva_, -_Microspora_.--_Ulothrix zonata_ is very common in running fresh water. -Nearly all the species of _Hormidium_ occur on damp soil, tree-stems -and stones. - -Order 3. =Chætophoraceæ.= The thallus consists of a single, branched, -erect or creeping filament of cells, often surrounded by mucilage. -The cells have only one nucleus. Asexual reproduction by zoospores -with 2 or 4 cilia, by akinetes, or aplanospores. In many, conjugation -between gametes with 2 cilia may be found. They approach on one side, -Ulothricaceæ, and on the other, Mycoideaceæ. The principal genera -are: _Stigeoclonium_, _Draparnaldia_, _Chætophora_, _Entoderma_, -_Aphanochæte_, _Herposteiron_, _Phæothamnion_, _Chlorotylium_, -_Trichophilus_, _Gongrosira_, _Trentepohlia_. Most of the species of -_Trentepohlia_ are coloured red by the presence of a red colouring -material, which occurs in addition to the chlorophyll. They are aerial -Algæ which live on stones (_T. jolithus_, “violet stone,” so named -on account of its violet-like odour in rainy weather), on bark and -old wood (_T. umbrina_), or on damp rocks (_T. aurea_). _Trichophilus -welckeri_ lives in the hair of Bradypus. - -Order 4. =Mycoideaceæ.= The thallus is discoid, consisting of one or -more cell-layers, and is always attached. Asexual reproduction by -zoospores with 2 or 4 cilia. Sexual reproduction in some species by the -conjugation of gametes with 2 cilia. This order forms the connecting -link between _Chætophoraceæ_ and _Coleochætaceæ_. The species occur in -fresh water (_Chætopeltis_) as well as in salt (_Pringsheimia_), on the -carapace of tortoises (_Dermatophyton_ = _Epiclemmydia_), or endophytic -between the cuticle and the epidermal cells of the leaves of tropical -plants, destroying the leaf-tissue (_Mycoidea_). - -Order 5. =Cylindrocapsaceæ.= The thallus consists of a simple (rarely, -in parts, formed of many rows) unbranched filament, attached in the -young condition, which has short cells with a single nucleus, and is -enveloped in a thick envelope with a laminated structure. Asexual -reproduction by zoospores with 2 cilia, which are formed 1, 2, or 4 in -each vegetative cell. The antheridia are produced by a single cell, -or a group of cells, in a filament, dividing several times without -increasing in size. Two egg-shaped spermatozoids, each with 2 cilia -(Fig. 53 _D_), are formed in each antheridium, and escape through -an aperture in the side; in the first stages they are enclosed in a -bladder-like membrane (Fig. 53 _B_, _C_). Other cells of the filament -swell out and form oogonia (Fig. 53 _A_), which resemble those of -_Œdogonium_. After fertilisation, the oospore surrounds itself with a -thick wall, and assumes a reddish colour. The germination is unknown. -The unfertilised oospheres remain green, divide often into 2–4 -daughter-cells, and grow into new filaments. - - [Illustration: FIG. 53.--_Cylindrocopsa involuta. A_ Oogonium - with oosphere (_o_) surrounded by spermatozoids (_s_). _B_ Two - antheridia, each with two spermatozoids. _C_ Spermatozoids - surrounded by their bladder-like membrane. _D_ Free spermatozoid.] - -This order, which only includes one genus, _Cylindrocapsa_, forms the -connecting link between _Ulothricaceæ_ and _Œdogoniaceæ_. The few -species (4) occur only in fresh water. - -Order 6. =Œdogoniaceæ.= The thallus consists of branched (_Bulbochæte_) -or unbranched (_Œdogonium_) filaments, attached in the early stages. -The cells may be longer or shorter, and have one nucleus. Asexual -reproduction by zoospores, which have a chaplet of cilia round the base -of the colourless end (Fig. 6 _a_). Sexual reproduction takes place by -oogamous fertilisation. On the germination of the oospore, 4 zoospores -are formed (Fig. 54 _F_). They occur only in fresh or slightly brackish -water. The division of the cells takes place in quite a peculiar and -unusual manner. At the upper end of the cell which is about to divide, -a ring-shaped thickening of soft cellulose is formed transversely round -the wall; the cell-nucleus of the mother-cell and the protoplasm then -divide by a transverse wall into two portions of similar size, and the -cell-wall bursts transversely along the central line of the thickened -ring. The cell-wall thus divides into two parts--the upper one short, -the “cap,” and the lower one much longer, the “sheath.” The portions -of the original cell-wall now separate from each other, the cellulose -ring extending, and supplying an additional length of cell-wall between -them. The cap and sheath will project a little in front of the piece -thus inserted. The dividing wall between the two new cells is formed -near to the uppermost edge of the sheath, and gradually becomes thicker -and firmer. The inserted piece of wall forms the larger part of the -wall of the upper cell: the remainder is formed by the cap. This mode -of division is repeated exactly in the same way, and new caps are -formed close below the first one, one for every division. - - [Illustration: FIG. 54.--_A Œdogonium ciliatum. A_ Female - plant with three oogonia (_og_) and dwarf-males (_m_). _B_ An - oogonium with spermatozoid (_z_) seen entering the oosphere - (_o_) having passed through an aperture near the summit of the - oogonium; _m_ dwarf-male. _C_ Ripe oospore. _D Œdogonium - gemelliparum. F_ Portion of a male filament from which - spermatozoids (_z_) are emerging. _E_ Portion of filament of - _Bulbochæte_; the upper oogonium still encloses the oospore, in - the central one the oospore is escaping while the lower one is - empty. _F_ Four zoospores developed from an oospore. _G_ Zoospore - germinating.] - -Fertilisation takes place in the following way. The oogonium is a -large ellipsoidal, swollen cell (_og_, in Fig. 54 _A_), whose contents -are rounded off into an oosphere with a colourless receptive-spot -(see _B_); an aperture is formed in the wall of the oogonium, through -which the spermatozoids are enabled to enter (_B_). The spermatozoids -are produced either directly, as in _D_ (in pairs), in basal cells -of the filament, or indirectly. In the latter case a swarmspore -(_androspore_) is formed which comes to rest, attaches itself to an -oogonium, germinates, and gives rise to a filament of a very few -cells--_dwarf-male_ (_A_, _B_, _m_). The spermatozoids are formed in -the upper cell of the dwarf-male (_m_), and are set free by the summit -of the antheridium lifting off like a lid. On the germination of the -oospore (_C_), which takes place in the following spring, 4 zoospores -are produced (_F_) (_i.e._ the sexual generation); these swarm about -for a time, and ultimately grow into new filaments. - - [Illustration: FIG. 55.--_Coleochæte pulvinata. A_ A portion - of a thallus with organs of reproduction; _a_ oogonium before, - _b_ after fertilisation; _c_ an antheridium, closed; _d_ open, - with emerging spermatozoid. _B_ Ripe oogonium, with envelope. _C_ - Germination of the oospore. _D_ Zoospore. _E_ Spermatozoid.] - -Order 7. =Coleochætaceæ.= The thallus is always attached, and of a -disc- or cushion-shape, formed by the dichotomous branching of filaments -of cells united in a pseudo-parenchymatous manner. Each cell has only -one nucleus. Asexual reproduction by zoospores with 2 cilia (Fig. 55 -_D_), which may arise in all the cells. Sexual reproduction by oogamous -fertilisation. The spermatozoids resemble the swarmspores, but are -smaller (_E_), and originate singly (in the species figured) in small -conical cells (_c_, _d_ in _A_). The oogonia are developed at the -extremities of certain branches: they are bottle-shaped cells with very -long and thin necks (_trichogyne_), open at the end (_a_ in _A_); at -the base of each oogonium is a spherical oosphere. The spermatozoids -reach the oosphere through the trichogyne, or through an aperture in -the wall when the trichogyne is absent, and fertilisation having taken -place, the oogonium becomes surrounded by a cell-layer (envelope), -which grows out from the cells near its base (_b_ in _A_), and in this -way a kind of fruit is formed (_B_) (_spermocarp_, _cystocarp_). - -The oospore, next spring, divides and forms a parenchymatous tissue -(homologous with the Moss-sporophyte); this bursts open the envelope -(_C_), and a zoospore (homologous with the spores of the Moss-capsule) -arises in each of the cells, and produces a new _Coleochæte_. We have -then, in this case, a still more distinct alternation of generations -than in _Œdogonium_. Only one genus, _Coleochæte_, is known, but it -contains several species, all living in fresh water. - -Order 8. =Cladophoraceæ.= This order is probably derived from the -Ulothricaceæ. The thallus consists of a single, unbranched or branched -filament, generally with an apical cell. The cells have each 2 or more -nuclei. Asexual reproduction by zoospores with 2 or 4 cilia, and by -akinetes. Conjugation of gametes with 2 cilia is found in some genera. -They occur in salt as well as in fresh water. The principal genera are: -_Urospora_, _Chætomorpha_, _Rhizoclonium_, _Cladophora_; of the last -named genus the species _C. lanosa_ and _C. rupestris_ are common in -salt water; _C. fracta_ and _C. glomerata_ in fresh water. - -Order 9. =Gomontiaceæ.= _Gomontia polyrrhiza_, the only species -hitherto known, is found on old calcareous shells of certain salt water -Molluscs. - -Order 10. =Sphæropleaceæ.= The thallus consists of free, unbranched -filaments, with very elongated multinuclear cells. The vegetative -cells form no zoospores. Sexual reproduction by oogamous fertilisation -(see page 13, Fig. 10 _B_). The oospore has a thick wall (Fig. 10 -_D_) studded with warts, and assumes a colour resembling red lead. It -germinates only in the following spring, and produces 1–8 zoospores, -each with 2 cilia (Fig. 10 _E_), which grow into new filaments. Only -one species, _Sphæroplea annulina_, is known. - - - Family 3. Siphoneæ. - -The thallus has apical growth, and in the vegetative condition consists -generally of one single (in the Valoniaceæ most frequently of more) -multinuclear cell, which may be much branched, and whose separate parts -in the higher forms (_e.g. Bryopsis_, Fig. 57; _Caulerpa_, Fig. -59, etc.) may be differentiated to perform the various physiological -functions (as root, stem and leaf). Vegetative multiplication by -detached portions of the thallus (gemmæ); asexual reproduction -by zoospores, akinetes, or aplanospores. Sexual reproduction by -gamete-conjugation, rarely by oogamous fertilisation. The zygote or -oospore germinates as a rule without any resting-stage. - - [Illustration: FIG. 56.--_Botrydium granulatum_: _a_ an entire - plant forming swarmspores; _b_ swamspores; _c_ an individual with - gametangia; _d_, gamete; _e_, _f_, _g_ conjugation; _h_ zygote - seen from above; _i_ the same in a lateral view.] - -Most of the Siphoneæ occur in salt water or on damp soil. Many (_e.g._ -_Dasycladaceæ_) are very much incrusted with lime, and occur, in the -fossilized condition, in the deposits from the Cretaceous period to -the present time. The Siphoneæ are connected by their lowest forms -(_Botrydiaceæ_ or _Valonia_) with the Protococcaceæ, but show also, -through the Valoniaceæ, points of relationship to the _Cladophoraceæ_. - -Order 1. =Botrydiaceæ.= The thallus in the vegetative condition -is unicellular, club-shaped, with a small single (_Codiolum_) or -repeatedly dichotomously branched system of colourless rhizoids -(_Botrydium_, Fig. 56 _a_), by which it is attached to objects immersed -in salt water (_Codiolum_) or to damp clay soil (_Botrydium_). Asexual -reproduction by zoospores with one (_Botrydium_) or two cilia, and by -aplanospores. The sexual reproduction is only known in _Botrydium_, and -takes place in the following manner: in the part of the thallus which -is above ground and in an active vegetative condition, several round -cells (Fig. 56 _c_) are formed, which may be green or red according as -they grow under water, or exposed to the strong light of the sun. These -cells must be considered as “gametangia” as they produce many gametes -(_d_) provided with two cilia. The zygote (_h_, _i_) formed by the -conjugation (_e_, _f_, _g_) may either germinate immediately, or become -a thick-walled resting-cell of an irregular, angular form. - - Order 2. =Bryopsidaceæ.= The thallus in the vegetative condition - is unicellular, and consists at the lower extremity of branched - rhizoids, while the upper portion is prolonged into a stem-like - structure of unlimited growth, producing, acropetally, branches - and leaf-like structures. The latter have limited growth, - and are separated by a cross wall from the stem, and become - gametangia, or drop off. The gametes have two cilia, and are of - two kinds: the female, which are green and large and the male, - which are of brownish colour and smaller. Zoospores or any other - method of asexual reproduction are unknown. Only one genus, - _Bryopsis_, living in salt water. - - [Illustration: FIG. 57.--_Bryopsis plumosa_. A the plant, natural - size. B A portion (enlarged) which shows the growing point (v), - and the leaves derived from it in acropetal succession.] - - Order 3. =Derbesiaceæ.= Only one genus, _Derbesia_, living in - saltwater. The zoospores, which are formed in a few lateral, - swollen zoosporangia, possess one nucleus which has arisen - through the coalescence of several, and they resemble the - zoospores of _Œdogonium_ by having a circle of cilia attached at - the base of the colourless spot. - -Order 4. =Vaucheriaceæ.= The thallus consists, in the vegetative -condition, of a single irregularly or dichotomously branched cell, -without differentiation into stem or leaf; root-like organs of -attachment may however occur. Asexual reproduction by zoospores, which -are formed singly in the extremity of a branch cut off by a transverse -wall. They contain many nuclei, and bear small cilia situated in -pairs, which give the appearance of a fine “pile” covering the whole -or a great part of the surface. Akinetes, aplanospores, and phytoamœbæ -(naked masses of protoplasm, without cilia, which creep like an amœba -on a substratum) may occur under certain conditions. - -The sexual reproductive organs are formed on short lateral branches, -and are separated from the vegetative cell (Fig. 58 _A_) by cell-walls. -Numerous spermatozoids, each with two cilia, are developed in the -coiled antheridium (_A_, _b_). The oogonium is a thick, egg-shaped, -often oblique cell, with its protoplasm rounded into an oosphere, -which has a hyaline “receptive-spot” (_A_, _a_) immediately beneath -the aperture formed in the wall of the oogonium. A slimy mass, which -serves to receive the spermatozoids, is formed in some species in this -aperture. The spermatozoids when liberated swim towards and enter -the oosphere, which then immediately surrounds itself with a thick -cell-wall. The mature oospore (_B_) contains a large quantity of oil. -At germination the outer cell-wall bursts and a new plant is formed. -There is only one genus, _Vaucheria_, with species living in salt as -well as in fresh water and on damp soil. - - [Illustration: FIG. 58.--_Vaucheria sessilis_. _A_ Fertilisation; - _b_ the antheridia; _a_ the oogonia; _a_ the receptive spot. _B_ - Oospore.] - -Order 5. =Phyllosiphonaceæ= are parasites in the leaves and stalks of -Flowering-plants. - -Order 6. =Caulerpaceæ.= The thallus has distinct differentiation into -root, stem and leaf-like members (Fig. 59); it is unicellular. Within -the cell, strong, branched threads of cellulose extend from one side -to the other serving as stays to support the thallus. Reproduction -takes place by detached portions of the thallus; no other modes of -reproduction are known. This order may most approximately be classed -with the _Bryopsidaceæ_. The genus _Caulerpa_ consists of more than -seventy species which inhabit the tropical seas. - -Order 7. =Codiaceæ.= The thallus has various forms, but without -distinct differentiation in stem- or leaf-structures, sometimes (_e.g._ -_Halimeda_) it is very much incrusted with lime. In the early stages -it is unicellular (later, often multicellular), very much branched, -with the branches, at any rate partly, so united or grown in amongst -one another (Fig. 60) that an apparently parenchymatous cellular -body is formed. Akinetes or aplanospores are wanting; zoospores (or -gametes?) may be developed in some species, however, in special swollen -sporangia. Fertilisation similar to that in _Bryopsis_ occurs perhaps -in _Codium_. They are all salt water forms. - -Order 8. =Valoniaceæ.= The thallus is generally multicellular, without -differentation into stem- or leaf-structures, but the cells are -sometimes united together and form a leaf-like reticulate expansion -(_e.g. Anadyomene_). Zoospores are known in some, and they are then -formed directly in the vegetative cells. In others (_e.g. Valonia_), -a mass of protoplasm, which maybe separated through the damaging of -a cell, can surround itself with a cell-wall, and grow into a new -plant. No other modes of reproduction are known. The most important -genera are: _Valonia_, _Siphonocladus_, _Chamædoris_, _Struvea_, -_Microdictyon_, _Anadyomene_. They are all salt water forms. - - [Illustration: FIG. 59.--_Caulerpa prolifera_ (natural size).] - - As already pointed out, the _Valoniaceæ_ occupy a somewhat - central position among the Siphoneæ, and present points - of similarity and contrast with the _Botrydiaceæ_ and the - _Bryopsidaceæ_ through _Valonia_, with the _Dasycladaceæ_ - through _Chamædoris_, and also with the _Cladophoraceæ_ through - _Siphonocladus_, and _Struvea_. - -Order 9. =Dasycladaceæ.= The thallus consists of an axile longitudinal -cell, destitute of transverse walls, attached at the base by root-like -organs of attachment, and producing acropetally whorls of united, -single or branched, leaf-like structures with limited growth. Asexual -reproduction is wanting. Sexual reproduction by conjugation of gametes -which arise in separate, fertile leaves, either directly or from -aplanospores, which develope into gametangia. The principal genera are: -_Acetabularia_, _Dasycladus_, _Neomeris_, _Cymopolia_. All marine. - - [Illustration: FIG. 60.--_Halimeda opuntia._ Plant (natural - size). _B_ Part of a longitudinal section.] - -The curiously shaped _Acetabularia mediterranea_ grows gregariously -on limestone rocks, and shells of mussels in the Mediterranean; it -resembles a minute umbrella with a small stem, sometimes as much as -nine centimetres in height, and a shade which may be more than one -centimetre in diameter. The cell-membrane is thick, and incrusted -with carbonate and oxalate of lime. Only the lower, root-like part of -the thallus, which penetrates the calcareous substratum survives the -winter, and may grow up into a new plant. The sterile leaves, which -drop off early, are dichotomously branched and formed of cylindrical -cells separated from each other by cross-walls, but they are not grown -together. The shade is formed by a circle of 70–100 club-shaped rays -(fertile leaves) grown together, in each ray 40–80 aplanospores are -formed, which become liberated at the breaking of the shade, and later -on are changed to gametangia (compare _Botrydium_) which open by a -lid and allow a large number of egg-shaped gametes with two cilia to -escape. Gametes from various gametangia conjugate with one another; the -product of the conjugation swarms about for some time, rounds off, and -then surrounds itself with a cell-wall. The zygote germinates after -a period of rest and then produces a sexual plant. The aplanospores -(gametangia) thus represent the sexual generation. - - - Class 7. =Characeæ.= - -The thallus has a stem with nodes and internodes; and whorls of leaves, -on which may be developed the antheridia and oogonia, are borne at -the nodes. Vegetative reproduction by bulbils and accessory shoots. -Zoospores are wanting. The antheridia are spherical, and contain a -number of filaments in which the spirally coiled spermatozoids, each -with two cilia, are formed. The oogonium is situated terminally, and -is at first naked, but becomes later on surrounded by an investment, -and forms after fertilisation the so-called “fruit.” The oospore, after -a period of rest, germinates by producing a “proembryo,” from which -the young sexual plant arises as a lateral branch. The Characeæ are -distinguished by the structure of their vegetative system as well as by -the spirally-coiled spermatozoids, and stand as an isolated group among -the Thallophytes, of which, however, the Siphoneæ appear to be their -nearest relations. They were formerly, but wrongly, placed near the -Mosses. The class contains only one order, the Characeæ. - -Order 1. =Characeæ.= Algæ with a peculiar odour, often incrusted with -lime, and of a brittle nature. They generally grow gregariously in -large masses at the bottom of fresh and brackish water, and are from a -few inches to more than a foot in height. The stem has long internodes -which in _Nitella_ are formed of one cylindrical cell; in _Chara_ of -a similar cell, but closely surrounded by a cortical layer of smaller -ones. The protoplasm in contact with the cell-wall exhibits in a -well-marked degree the movement of rotation (cyclosis), carrying the -chlorophyll corpuscles along with it. The internodes are separated -from each other by a layer of small cells (nodal cells) from which the -leaves are produced. The leaves are borne in whorls of from 5–12 which -regularly alternate with one another as in the higher verticillate -plants; a branch is borne in the axil of the first formed leaf of each -whorl (Fig. 61 _A_, _n_). - - [Illustration: FIG. 61.--_Chara fragilis. A_ Portion of a - plant, natural size. _B_ Portion of a leaf _b_, with leaflets - β′-β′′; _a_ antheridium; _c_ oogonium. _C_ A shield.--_Nitella - flexilis. D_ Filament from antheridium with spermatozoids. _E_ - Free spermatozoids.] - -The leaves are constructed in the same manner as the stem; they are -divided into a series of joints, but have only a limited power of -growth; their terminal cell, too, is not enclosed by a cortex. Leaflets -are borne at their nodes. The growth of the stem is unlimited, and -proceeds by means of an apical cell (Fig. 62 _s_). The apical cell -divides into a segment-cell and a new apical cell. The segment-cell -then divides by a transverse wall into two cells, one lying above the -other; the lower one, without any further division, becomes one of the -long, cylindrical, internodal cells (Fig. 62 _in_), and the upper one -(Fig. 62 _n_) divides by vertical walls to form the nodal cells. The -cortical cells (Fig. 62 _r_) which surround the long internodal cells -of _Chara_, are derived from the divisions of the nodal cells; the -cells covering the upper portion of an internodal cell being derived -from the node immediately above it, and those in the lower part of the -internode from the node below it. - - [Illustration: FIG. 62.--_Chara fragilis_: _s_ apical cell; _n_, - _n_ nodal cells; _in_ internodal cells; _bl_, _bl_ leaves; _r_, - _r_ the cortical cells.] - - [Illustration: FIG. 63.--Oogonium of _Chara_: _k_ “crown”; _u_ - receptive spot; _s_ spermatozoids.] - -The organs of reproduction are very conspicuous by their colour -and form. They are always situated on the leaves, the plants being -very frequently monœcious. The antheridia (Fig. 61 _B_, _a_) are -modified leaflets or the terminal cell of a leaf; they are spherical -and become red when mature. Their wall consists of 8 “shields,” -_i.e._ of plate-like cells, 4 of which cover the upper half, and are -triangular; the 4 round the lower half, to which the stalk of the -antheridia is attached, being quadrilateral, with sides of unequal -length. The shields (Fig. 61 _C_) have dentated edges, with the teeth -fitting into one another, and their faces ornamented with ridges. From -the centre of the internal face of each shield (_C_) a cylindrical -cell, the _manubrium_, projects nearly as far as the centre of the -antheridium; at the inner end of each of the manubria a spherical -cell, the _capitulum_, is situated. Each capitulum bears six secondary -capitula, from each of which four long coiled filaments (_C_, _D_) -project into the cavity of the antheridium. These filaments are divided -by transverse walls into from 100–200 discoid cells, in each of which -a biciliated, coiled spermatozoid is developed (_D_, _E_) from the -nucleus. The spermatozoids escape from their mother-cell and are set -free by the shields separating from one other. - -The female organ of reproduction (Fig. 61 _B_, 63) is a small modified -shoot, whose apical cell functions as an oogonium, its protoplasm -forming the oosphere, which has a colourless receptive-spot at the -summit (Fig. 63 _u_). The oogonium is situated on a nodal cell, from -which 5 cells grow out in a circle and coil round the oogonium, -covering it with a close investment. These cells divide once or twice -at the top, so that 5 or 10 small cells are cut off, which project -above the oogonium and form the so-called “crown” (Fig. 63 _k_). The -crown either drops off at fertilisation, or its cells separate to form -a central canal for the passage of the spermatozoids. The wall of the -oosphere[9] above the receptive spot becomes mucilaginous, and allows -the spermatozoid to fuse with the oosphere. The oospore, on germination -(Fig. 64 _sp_), becomes a small filamentous plant of limited growth -(Fig. 64 _i_, _d_, _q_, _pl_)--the proembryo--and from this, as a -lateral outgrowth, the sexual generation is produced. - -The order is divided into two sub-orders:-- - -A. NITELLEÆ. The crown consists of 10 cells; cortex absent: _Nitella_, -_Tolypella_. - -B. CHAREÆ. The crown consists of 5 cells; cortex present: -_Tolypellopsis_, _Lamprothamnus_, _Lychnothamnus_, _Chara_. - -_Chara crinita_ is parthenogenetic; in large districts of Europe -only female plants are found, yet oospheres are formed capable of -germination. - - [Illustration: FIG. 64.--_Chara fragilis._ Germinating oospore - (_sp_); _i_, _d_, _g_, _pl_, form together the proembryo rhizoids - (_w′_) are formed at _d_; _w′_ the so-called tap-root; at _g_ are - the first leaves of the sexual plant, which appears as a lateral - bud.] - -About 40 species of fossilized _Chara_, determined by their carpogonia, -are known in the geological formations from the Trias up to the present -day. - - - Class 8. =Phæophyceæ (Olive-Brown Seaweeds).= - -The Phæophyceæ are Algæ, with chromatophores in which the chlorophyll -is masked by a brown colour (phycophæin). The product of assimilation -is a carbohydrate (fucosan), _never true starch_. In the highest -forms (_Fucaceæ_), the thallus presents differentiation into stem, -leaf, and root-like structures. The asexual reproduction takes place -by means of zoospores. The sexual reproduction is effected by the -coalescence of motile gametes, or by oogamous fertilisation. The -swarm-cells are _monosymmetric_, each moved by two cilia which are true -protoplasmic structures, and generally _attached laterally_ (Fig. 65). -The Phæophyceæ are almost entirely saltwater forms; a few species of -_Lithoderma_ live in fresh water. - -The class is divided into two families:-- - -1. PHÆOSPOREÆ: 1 Sub-Family, Zoogonicæ; 2 Sub-Family, Acinetæ. - -2. CYCLOSPOREÆ: Fucaceæ. - - - Family 1. =Phæosporeæ.= - -The family consists of multicellular plants, whose cells are firmly -united together to form a thallus; this, in the simplest cases, may be -a branched filament of cells (_Ectocarpus_), or, in the highest, may -resemble a stem with leaves (_Laminariaceæ_), while all transitional -forms may be found between these two. The thallus grows by intercalary -divisions (_e.g. Ectocarpus_), or by an apical cell (_e.g._ -_Sphacelaria_); pseudo-parenchymatous tissue may sometimes be formed by -cells, which were originally distinct, becoming united together. The -size of the thallus varies; in some species it is quite small--almost -microscopical,--while in the largest it is many metres in length. - -The vegetative cells in the lower forms are nearly uniform, but in -those which are more highly developed (_Laminariaceæ_ and _Fucaceæ_), -they are sometimes so highly differentiated that mechanical, -assimilating, storing and conducting systems may be found; the last -named systems are formed of long cells with perforated, transverse -walls, which bear a strong resemblance to the sieve-tubes in the higher -plants. - - [Illustration: FIG. 65.--Swarmspore of _Cutleria multifida_.] - -The colouring matter in the living cells (“phæophyl”) contains -chlorophyll; but this is concealed by a brown (“phycophæin”), and a -yellow (“phycoxanthin”) colouring material, and hence all these Algæ -are a lighter or darker _yellow-brown_. Starch is not formed. Asexual -reproduction takes place, (1) by zoospores which arise in unilocular -zoosporangia, and are monosymmetric, with two cilia attached laterally -at the base of the colourless anterior end (Fig. 65), the longer -one being directed forwards and the shorter backwards; or (2) by -aplanospores (?). - - [Illustration: FIG. 66.--_Ectocarpus siliculosus_. _I a-f_ A - female gamete in the various stages of coming to rest. _II_ A - motionless female gamete surrounded by male gametes. _III a-e_ - Stages in the coalescence of male and female gametes.] - - [Illustration: FIG. 67.--_Zanardinia collaris_. _A_ Male - gametangia (the smaller celled) and female gametangia (the - larger celled). _C_ Female gamete. _D_ Male gamete. _B_, _E_ - Fertilisation. _F_ Zygote. _G_ Germinating zygote.] - -Sexual reproduction has only been discovered in a few cases, and takes -place by means of gametes (oogamous fertilisation perhaps occurs in the -Tilopteridæ). The gametes have the same structure as the zoospores, -and arise in multilocular gametangia; these, like the zoosporangia, -are outgrowths from the external surface, or arise as modifications -from it. The conjugating gametes may be similar (_e.g. Ectocarpus -pusillus_), or there may be a more or less pronounced difference of -sex, an indication of which is found in _Ectocarpus siliculosus_ (Fig. -66). When the gametes in this species have swarmed for a time, some, -which are generally larger, are seen to attach themselves by one of the -cilia, which by degrees is shortened to form a kind of stalk (compare -the upper gamete in Fig. 66 _II_); these are the female gametes, which -now become surrounded by a number of males endeavouring to conjugate -with them, but only one succeeds in effecting fertilisation. The -protoplasm of the two gametes coalesces (Fig. 66 _III_), and a zygote -(_e_) is formed. The male gametes which do not conjugate may germinate, -but the plants derived from them are much weaker than those produced -by the zygotes. Strongly pronounced sexual differences are found in -the Cutleriaceæ, in which order the male and female gametes arise in -separate gametangia (Fig. 67 _A_). The male gametes (Fig. 67 _D_) are -much smaller than the female gamete (Fig. 67 _C_); the latter, after -swarming for a short time, withdraws the cilia, and is then ready to -become fertilised (Fig. 67 _B_, _E_), thus we have here a distinct -transition to the oogamous fertilisation which is found in the Fucaceæ. -Alternation of generations is rarely found. - -1. Sub-Family. =Zoogonicæ.= - -Reproduction by means of gametes and zoospores. - -Order 1. =Ectocarpaceæ.= The thallus consists of single or branched -filaments with intercalary growth, extending vertically from a -horizontal, branched filament or a disc, but sometimes it is reduced to -this basal portion only. Zoosporangia and gametangia (for fertilisation -see Fig. 66) are either outgrowths or arise by the transformation of -one or several of the ordinary cells. The most common genera are: -_Ectocarpus_ and _Pylaiella_. - -Order 2. =Choristocarpaceæ.= _Choristocarpus_, _Discosporangium_. - -Order 3. =Sphacelariaceæ.= The thallus consists of small, -parenchymatous, more or less ramified shoots, presenting a feather-like -appearance. In the shoots, which grow by means of an apical cell (Fig. -68 _S_), a cortical layer, surrounding a row of central cells, is -present. Sporangia and gametangia are outgrowths from the main stem or -its branches. _Sphacelaria_, _Chætopteris_ are common forms. - - [Illustration: FIG. 68.--Apex of the thallus of _Chætopteris - plumosa_. _S_ Apical cell.] - -Order 4. =Encoeliaceæ.= _Punctaria_, _Asperococcus_, _Phyllitis fascia_. - -Order 5. =Striariaceæ.= _Striaria_, _Phlœospora_. - -Order 6. =Dictyosiphonaceæ.= _Dictyosiphon._ - -Order 7. =Desmarestiaceæ.= _Desmarestia aculeata_ is common. - -Order 8. =Myriotrichiaceæ.= _Myriotrichia._ - -Order 9. =Elachistaceæ.= _Elachista fucicola_ is a common epiphyte on -species of _Fucus_. - -Order 10. =Chordariaceæ.= The shoot-systems are often surrounded -by mucilage. _Chordaria_; _Leathesia difformis_ occurs as rounded, -brown-green masses of the size of a nut, generally attached to other -Seaweeds. - -Order 11. =Stilophoraceæ.= _Stilophora rhizodes_ is common. - -Order 12. =Spermatochnaceæ.= _Spermatochnus paradoxus_ is common. - -Order 13. =Sporochnaceæ.= _Sporochnus._ - -Order 14. =Ralfsiaceæ.= _Ralfsia verrucosa_ is common as a red-brown -incrustation on stones and rocks at the water’s edge. - -Order 15. =Lithodermataceæ.= Some species of the genus _Lithoderma_ -occur in fresh water. - - [Illustration: FIG. 69.--_Laminaria digitata_ (much reduced in - size).] - -Order 16. =Laminariaceæ.= The thallus is more or less leathery, and -has generally a root-like lower part (Fig. 69) which serves to attach -it, and a stalk or stem-like part, terminated by a large leaf-like -expansion. Meristematic cells are situated at the base of the leaf, -and from these the new leaves are derived. The older leaf thus pushed -away by the intercalary formation of the younger ones, soon withers -(Fig. 69). Gametes are wanting. Zoosporangia are developed from -the lower part of a simple, few-celled sporangiophore, which is an -outgrowth from a surface-cell and has a large club-formed apical cell. -The sporangia are aggregated into closely packed sori, which cover -the lower part of the terminal leaf, or occur on special, smaller, -lateral, fertile fronds (_Alaria_). Most of the species belonging to -this order live in seas of moderate or cold temperature and occur -in the most northern regions that have yet been explored, forming -their organs of reproduction during the cold and darkness of the -arctic night. _Laminaria_ is destitute of a midrib and has only one -terminal leaf. _L. digitata_ has a broad leaf, which, by the violence -of the waves, is torn into a number of palmate strips (Fig. 69). _L. -saccharina_ has a small, undivided leaf. _Alaria_ has a midrib and -special fertile fronds. _A. esculenta_ occurs plentifully on the west -coast of Norway and on the shores of Great Britain. _Chorda filum_, a -common seaweed, is thick, unbranched, and attains a length of several -metres, without any strong demarcation between stalk and leaf. Some -attain quite a gigantic size, _e.g. Macrocystis pyrifera_, whose -thallus is said sometimes to be more than 300 metres in length. The -_Lessonia_-species, like the above, form submarine forests of seaweed -on the south and south-west coasts of South America, the Cape, and -other localities in the Southern Hemisphere. - - USES. The large Laminarias, where they occur in great numbers, - are, like the Fuci, used for various purposes, for example, in - the production of iodine and soda, and as an article of food - (_Laminaria saccharina_, _Alaria esculenta_, etc.). _Laminaria - saccharina_ contains a large quantity of sugar (mannit) and is - in some districts used in the preparation of a kind of syrup; - in surgical operations it is employed for the distension of - apertures and passages, as for instance the ear-passage. It - is by reason of the anatomical peculiarities and structure of - the cell-walls, that they are employed for this purpose. The - cell-walls are divided into two layers, an inner one which - has very little power of swelling, and an outer one, well - developed and almost gelatinous--the so-called “intercellular - substance”--which shrivels up when dried, but can absorb water - and swell to about five times its size. The stalks of _Laminaria - clustoni_ are officinal. - -Order 17. =Cutleriaceæ.= The thallus is formed by the union of the -originally free, band-shaped shoots. The growth is intercalary. Sexual -reproduction by the conjugation of male and female gametes. An asexual -generation of different appearance, which produces zoospores, arises -from the germination of the zygote. _Cutleria_, _Zanardinia_. - -Sub-Family 2. =Acinetæ.= - -Branched, simple cell-rows with intercalary growth. The organs -of reproduction are partly uni-and partly multicellular; in the -unicellular ones a cell without cilia is formed, which may be destitute -of a cell-wall, but has one nucleus (oosphere?), or which has a -cell-wall and contains several (generally four) nuclei (aplanospores?); -in the multicellular, monosymmetric swarm-cells with two cilia -(spermatozoids?) are formed. The fertilisation has not been observed. - -Order 1. =Tilopteridaceæ.= _Haplospora_, _Tilopteris_. - - - Family 2. =Cyclosporeæ.= - -The individuals are multicellular, with growth by an apical cell. The -thallus--often bilateral--is differentiated into a root-like structure -(attachment-disc), and stem, sometimes also into leaves (_Sargassum_). -Sometimes a differentiation occurs into various tissue-systems, viz. an -external assimilating tissue, a storing tissue, a mechanical tissue -of thickened, longitudinal, parenchymatous, strengthening cells, and -a conducting tissue of sieve-cells, or of short sieve-tubes with -perforated walls. Colouring material, as in Phæosporeæ. Vegetative -reproduction can only take place by means of detached portions of the -thallus (_Sargassum_), which are kept floating by means of bladders -(Fig. 70 _A_, _a_, Fig. 72). Zoospores are wanting. - -The sexual reproduction takes place by oogamous fertilisation. The -oogonia and antheridia are formed inside special organs (conceptacles), -and are surrounded by paraphyses. The conceptacles (Fig. 70 _B_, -Fig. 71 _b_) are small, pear-shaped or spherical depressions, -produced by a special ingrowth of the surface cells of the thallus, -and their mouths (_ostioles_) project like small warts; they are -either situated near the end of the ordinary branches of the thallus -(_Fucus serratus_, Fig. 71 _a_) which may be swollen on this account -(_Fucus vesiculosus_, Fig. 70 _A_, _b_), or on special short branches -(_Ascophyllum_, _Sargassum_). The vertical section of a conceptacle is -seen in Fig. 70 _B_ (see also Fig. 71 _b_) where, in addition to the -paraphyses, oogonia only are seen (_F. vesiculosus_ is diœcious--male -plant, yellow-brown; female plant, olive-brown); but in some -species antheridia, together with oogonia, are produced in the same -conceptacle. The oogonia are large, almost spherical cells, situated on -a short stalk, in each of which are formed from 1–8 (in _Fucus_, 8; in -_Ascophyllum_, 4; in _Halidrys_, 1; in _Pelvetia_, 2) rounded, immotile -oospheres. The wall of the oogonium ruptures, and the oospheres, -still enclosed in the inner membrane, are ejected through the mouth -of the conceptacle, and float about in the water, being finally set -free by the bursting of the inner membrane. The antheridia are oblong -cells (Fig. 70 _C_, _a_), many of which are produced on the same -branched antheridiophore (Fig. 70 _C_); the numerous spermatozoids are -provided with 2 cilia and are very small (Fig. 70 _D_, two antheridia -surrounded by spermatozoids, one being open). The spermatozoids, still -enclosed by the inner membrane of the antheridium, are similarly -set free, and fertilisation takes place in the water, numerous -spermatozoids collecting round the oosphere (Fig. 70 _E_), which is -many times larger, and by their own motion causing it to rotate. After -fertilisation, the oospore surrounds itself with a cell-wall and -germinates immediately, attaching itself (Fig. 70 _F_) to some object, -and by cell-division grows into a new plant. - - [Illustration: FIG. 70.--_Fucus vesiculosus. A_ Portion of - thallus with swimming bladders (_a_) and conceptacles (_b_). _B_ - Section of a female conceptacle; _h_ the mouth; _p_ the inner - cavity; _s_ oogonia. _C_ Antheridiophore; _a_ antheridium; _p_ - sterile cells. _D_ Antheridia out of which the spermatozoids are - escaping. _E_ Fertilisation. _F_ Germinating oospore.] - - [Illustration: FIG. 71.--_Fucus serratus_. _a_ Portion of a male - plant which has been exposed to the action of the open air for - some time; small orange-yellow masses, formed by the antheridia, - are seen outside the mouths of the male conceptacles (nat. size). - _b_ Cross section through the end of a branch of a female plant, - showing the female conceptacles (× 4).] - - [Illustration: FIG. 72.--_Sargassum bacciferum_. A portion of the - thallus, natural size.] - -Order 1. =Fucaceæ.= The following species are common on our coasts: -_Fucus vesiculosus_ (Fig. 70) has a thallus with an entire margin, -and with bladders arranged in pairs; _F. serratus_ (Fig. 71) without -bladders, but with serrated margin; _Ascophyllum nodosum_ has -strap-like shoots, which here and there are swollen to form bladders; -_Halidrys siliquosa_ has its swimming bladders divided by transverse -walls; _Himanthalia lorea_, which is found on the west coast of Norway, -and the south coast of England, has a small perennial, button-shaped -part, from the centre of which proceeds the long and sparsely branched, -strap-like, annual shoot, which bears the conceptacles. The Gulf-weed -(_Sargassum bacciferum_, Fig. 72) is well known historically from the -voyage of Columbus; it is met with in large, floating, detached masses -in all oceans, and is found most abundantly in the Atlantic, off the -Canary Islands and the Azores, and towards the Bermudas. The stalked, -spherical air-bladders are the characteristic feature of this genus. -The thallus is more highly developed than in _Fucus_, and there is a -contrast between the stem and leaf-like parts. The portions which are -found floating are always barren, only those attached are fertile. - - USES. The Fucaceæ, like the Laminariaceæ, are used as manure - (the best kinds being _Fucus vesiculosus_ and _Ascophyllum - nodosum_), for burning to produce kelp, and as food for domestic - animals (_Ascophyllum nodosum_ is especially used for this - purpose). - - - Class 9. =Dictyotales.= - -The plants in this class are multicellular, and brown, with apical -growth, new cells being derived either from a flat apical cell, or from -a border of apical cells. The thallus is flat, leaf- or strap-shaped, -attached by haptera, which are either found only at the base, or -on the whole of the lower expansion of the thallus. The cells are -differentiated into the following systems of tissues: an external, -small-celled layer of assimilating cells, generally one cell in -thickness, and an internal, large-celled layer of one or only a few -cells in thickness, forming the mechanical and conducting tissues. -All the reproductive cells are motionless. Asexual reproduction by -naked, motionless spores (tetraspores) which are formed 1–4 in each -tetrasporangium, the latter being outgrowths from the surface cells -of special, sexless individuals. Zoospores are wanting. The sexual -organs are of two kinds, oogonia and antheridia, which are formed from -the surface cells, either on the same or different individuals. The -oogonia are spherical or oval, and are generally placed close together; -each contains one oosphere, which on maturity is ejected into the -surrounding water, and is then naked and motionless. The antheridia -are formed of longitudinal cells, united in groups, whose contents -by repeated divisions--transverse and longitudinal--are divided into -a large number of small, colourless, motionless spermatia--round or -elongated--which are set free by the dissolution of the wall of the -antheridium. The process of fertilisation has not yet been observed. - -The Dictyotales, in having tetraspores and spermatia, deviate -considerably from the Phæophyceæ, but may be classed near to the -Tilopteridæ, in which there are asexual spores with 4 cell-nuclei, -which may be considered as an indication of the formation of -tetraspores. - - Order 1. =Dictyotaceæ.= _Dictyota dichotoma_ which has a thin, - regularly dichotomously divided thallus, occurs on the coasts of - the British Isles. _Padina_ is found on the south coast. - - - Class 10. =Rhodophyceæ (Red Seaweeds).= - -The plants comprised in this class are multicellular; they are -simple or branched filaments, or expansions consisting of 1 to -several layers of cells; the thallus may be differentiated (as -in many _Florideæ_), to resemble stem, root, and leaf. The cells -contain a distinctly differentiated nucleus (sometimes several), -and distinct chromatophores, coloured by rhodophyll. The chlorophyll -of the chromatophores is generally masked by a red colouring matter -(phycoerythrin), which may be extracted in cold, fresh water; or rarely -by phycocyan. Pyrenoids occur in some. Starch is never formed in the -chromatophores themselves, but a modification--Florideæ starch--may -be found in the colourless protoplasm. Asexual reproduction by motile -or motionless spores (tetraspores) which are devoid of cilia and of -cell-wall. Swarmspores are never found. - -Sexual reproduction is wanting, or takes place by the coalescence of -a spermatium and a more or less developed female cell. The spermatia -are naked masses of protoplasm, devoid of cilia and chromatophores. -The female cell (carpogonium) is enclosed by a cell-wall, and after -fertilisation forms a number of spores, either with or without -cell-walls (carpospores), which grow into new individuals. - -The Rhodophyceæ may be divided into two families: - - 1. BANGIOIDEÆ. - 2. FLORIDEÆ. - - - Family 1. =Bangioideæ.= - -The thallus consists of a branched or unbranched cell-filament, formed -of a single row or of many rows of cells, or of an expansion, one or -two layers of cells in thickness, but without conspicuous pores for the -intercommunication of the cells. The growth of the thallus is chiefly -intercalary. The star-like chromatophores contain chlorophyll and are -coloured blue-green with phycocyan, or reddish with phycoerythrin; -all these colouring matters are occasionally found in the same cell -(_Bangia_-species). Asexual reproduction by tetraspores, without cilia, -but capable of amœboid movements. - -Sexual reproduction is wanting, or takes place by the coalescence of a -spermatium with a carpogonium, which is only slightly differentiated -from the vegetative cells, and is devoid of a trichogyne. The -carpospores are destitute of cell-wall and arise directly by the -division of the fertilised oosphere. The Bangioideæ occur chiefly in -salt water. - - Order 1. =Goniotrichaceæ.=--The thallus consists of a - branched cell-filament without rhizoids. Tetraspores are - formed directly from the entire contents of the mother-cell, - without any preceding division. Fertilisation unknown. - _Asterocystis_, _Goniotrichum_. - - The _Goniotrichaceæ_, through the blue-green _Asterocystis_, - are allied to the Myxophyceæ, and through _Goniotrichum_ to the - _Porphyraceæ_. - - Order 2. =Porphyraceæ.=--The thallus is formed of an expansion - consisting of a layer of 1–2 cells, which, at the base, are - attached to the substratum by means of a special form of haptera - (_Porphyra_, _Diploderma_); or of unbranched (very rarely - slightly branched) filaments, attached at the base by haptera - (_Bangia_): or it extends from a prostrate cell-disc (various - species of _Erythrotrichia_). Tetraspores are formed after one - or more divisions of the mother-cell, either from the whole or - only a part of its contents; they possess amœboid movements, - or have a jerky, sliding-forward motion. The antheridia have - the same appearance as the vegetative cells, but divide several - times, and several spermatia are formed, either simultaneously - from the whole contents (_Porphyra_, _Bangia_), or the spermatia - are successively formed from a part of the contents of the - antheridium (_Erythrotrichia_). The carpogonium is without a - trichogyne, but the oosphere has a colourless spot which may - sometimes rise a little above the surface of the thallus, and - may be considered as an early stage in the development of the - trichogyne. The spermatia form a canal through the membrane of - the carpogonium, and their contents coalesce with the oosphere - at its colourless spot. The fertilised oosphere divides on - germination into a number of carpospores, which are set free as - naked, motionless masses of protoplasm, which grow and give rise - to new individuals (alternation of generations). - - - Family 2. =Florideæ.= - -The thallus has one or more apical cells, grows principally by apical -growth, and may be differentiated into root, stem, and leaf. The -chromatophores vary in form, but have a red or brownish colour, due -to chlorophyll and phycoerythrin. Asexual reproduction by motionless -tetraspores, which generally arise by the division into four of the -contents of the tetrasporangium. The carpogonium has a trichogyne, -and the carpospores, which are formed indirectly from the fertilised -oosphere, possess a cell-wall. - - [Illustration: FIG. 73.--_Callithamnion elegans_: _a_ a plant - with tetraspores (× 20); _b_ apex of a branch with tetraspores(× - 250).] - - [Illustration: FIG. 74.--_Polysiphonia variegata_: _a_ a portion - of a male plant with antheridia; _b_ spermatia; _c_ transverse - section of thallus.] - -The thallus may assume very different forms. In the simplest species -it is filamentous and formed of single, branched rows of cells -(_Callithamnion_, etc., Fig. 73). _Ceramium_ has a filamentous thallus, -generally dichotomously forked (Fig. 75), or sometimes pinnately -branched, which, at the nodes, or throughout its entire length, is -covered by a layer of small cortical cells. _Polysiphonia_ (Fig. -74) has a filamentous, much branched thallus, made up of a central -cylindrical cell, surrounded by a layer of other cells, cortical cells, -which in length and position correspond to the central ones. In many of -the Red Algæ the vegetative organs are differentiated into stems and -leaves, the former having, as in _Chara_, unlimited growth in length, -whilst the latter soon attain their full development. _Chondrus_ -has a fleshy, gelatinous thallus, without nodes; it is repeatedly -forked into flat branches of varying thickness. _Furcellaria_ has a -forked thallus with thick branches and without nodes. The thallus of -_Delesseria_ (Fig. 76) consists of branches, often bearing leaf-like -structures, with a midrib and lateral ribs springing from it. These -ribs persist through the winter, and at the commencement of the -succeeding period of vegetation the lateral ribs become the starting -points for new leaves. In _Corallina_ the thallus is pinnately -branched, and divided into nodes and internodes. The name has been -given to this genus from the fact that the thallus is incrusted with -carbonate of lime to such a degree that it becomes very hard, and the -whole plant adopts a coral-like appearance. Other genera which are -similarly incrusted, and have a leaf-like or even crustaceous thallus -(such as _Melobesia_, _Lithothamnion_), are included in this family. - -In some instances the cells of the thallus may be found -_differentiated_ into more or less well defined tissues, so that it -is possible to find special assimilating, mechanical, and conducting -tissues, the last named in some cases having the double function of -conducting and of serving as a reservoir in which starch is found as -a reserve material. The cells of the Florideæ, which are formed by the -division of a mother-cell into two daughter-cells of unequal size, have -always larger or smaller pits in the cell-walls, and the thin cell-wall -separating two pits from each other is perforated by a number of small -holes. These pits are particularly developed in the conducting tissues, -but sieve-tubes are very rarely to be found. - - [Illustration: FIG. 75.--_Ceramium diaphanum_ (nat. size).] - - [Illustration: FIG. 76.--_Delesseria sanguinea_ (about ⅓).] - -_Tetraspores_ may be wanting (_e.g. Lemanea_) or may often arise on -special, non-sexual individuals. In some (_e.g. Batrachospermum_) -only one tetraspore is formed in each tetrasporangium, but the number -is generally four, which may be formed tetrahedrally (Fig. 73) or by -divisional walls perpendicular to each other, or even in a single row. -The tetrasporangia in some species are free (Fig. 73), but in the -majority they are embedded in the thallus. - - [Illustration: FIG. 77.--_A Lejolisia mediterranea_: _r_ - haptera; _s_ longitudinal section through a cystocarp; _p_ the - empty space left by the liberated spore (_t_). _B-E Nemalion - multifidum_: _a_ antheridia; _b_ procarpium with trichogyne, to - which two spermatia are adhering.] - -The sexual reproduction (discovered by Thuret and Bornet, 1867) -differs in the essential points from that of all other plants, and -approaches most nearly to the sexual reproduction of the _Bangioideæ_. -The sexual cells are developed from the terminal cells (never nodal -cells) of the branched cell-filaments, which constitute the thallus. -The mother-cells of the spermatia (_spermatangia_) are generally -arranged in a group, in the so-called _antheridia_ (Figs. 74, 77 _A_, -_a_). On becoming ripe the membrane of the spermatangium ruptures -and the _spermatia_ emerge as spherical or ovoid, naked (a little -later they may possess a cell-wall) masses of protoplasm which are -not endowed with the power of motion, and hence are carried passively -by the current of the water in which they may happen to be, to the -female cell. This latter is analogous with the oogonium of the Green -Algæ. The female reproductive organ is termed the _procarpium_, and -consists of two parts, a lower swollen portion--the _carpogonium_ -(Fig. 77 _b_ in _A_ and _B_)--which contains the cell-nucleus, and an -upper filamentous prolongation--the _trichogyne_ (Fig. 77 _B_)--which -is homologous with the colourless receptive spot of the oosphere of -the Green Algæ, and the _Porphyraceæ_. In the sexual reproduction -of the majority of the Florideæ, a very important part is played by -certain special cells, rich in cell-contents--the _auxiliary cells_. -These are either dispersed in the interior of the thallus, or are -arranged together in pairs with the cell-filament which bears the -carpogonium, and are generally united with this to form an independent -multicellular _procarpium_. The spermatia attach themselves firmly to -the trichogyne and surround themselves with a cell-wall. The dividing -wall at the point of contact is perforated, and the nucleus of the -spermatium probably travels through the trichogyne to the swollen part -of the procarpium--the _carpogonium_--and fuses with its nucleus. After -fertilisation the trichogyne withers (Fig. 77 _C_), but the lower -portion of the procarpium, constituting the _fertilised oosphere_, -grows out and forms in various ways, first a tuft of spore-forming -filaments known as _gonimoblasts_, and finally the _carpospores_. These -latter form a new asexual generation (compare the germination of the -oospore of _Œdogonium_ and _Coleochæte_). - -The gonimoblasts may arise in three ways:-- - - 1. In the _Nemalionales_, branched filaments grow out from the - oosphere and form an upright, compressed or expanded tuft of - spore-forming filaments. - - 2. In the _Cryptonemiales_, several branched or unbranched - filaments (_ooblastema-filaments_) grow out from the oosphere, - and conjugate in various ways with the auxiliary cells. The - gonimoblasts are then formed from the single cells produced by - the conjugation. - - 3. In the _Gigartinales_ and _Rhodymeniales_ the oosphere - conjugates with an auxiliary cell by means of a short - ooblastema-filament, and from this auxiliary cell a gonimoblast - is produced. - - The motionless _carpospores_, which sometimes in the early - stages are naked, and afterwards invested with a cell-wall, are - developed from the terminal cells (and perhaps also from some - of the other cells) of the branches of the gonimoblast. The - gonimoblasts constitute sharply defined parts of the plant in - which the carpospores arise. These parts are called _cystocarps_ - and are either naked (Fig. 77 _E_), or surrounded by a covering - (pericarp or involucre, Fig. 77 _A_) formed in different - ways. On this account the Florideæ were formerly divided into - GYMNOSPOREÆ (_Batrachospermum_, _Nemalion_, _Ceramium_, etc.) - and ANGIOSPOREÆ (_Farcellaria_, _Lejolisia_, _Delesseria_, - _Melobesia_, etc.). - -The Florideæ are divided into four sub-families:-- - - Sub-Family 1. =Nemalionales.= The fertilised oosphere produces - directly the gonimoblast. - - Order 1. =Lemaneaceæ.= Algæ of brownish colour and living in - fresh water. They lack tetraspores, and the very sparingly - branched fertile filaments, composed of many rows of cells, grow - out from a proembryo, which consists of a single row of cells - bearing branches. _Lemanea fluviatilis_, often found on rocks - and stones in quickly flowing streams. - - Order 2. =Helminthocladiaceæ.= Tetraspores are generally wanting - (_e.g._ in _Nemalion_) or arise one in each tetrasporangium - (_e.g. Batrachospermum_) and it is only in _Liagora_ - that four cruciate tetraspores are formed. _Chantransia - corymbifera_ consists of simple, branched cell-rows, and is - an independent species. Several other _Chantransia-forms_, - living in fresh water, are “proembryos” of species of the genus - _Batrachospermum_. The germinating carpospore grows out into - filaments and forms a so-called proembryo which, if not shaded, - attains only a small size, but when growing in shady situations - presents a much greater development. These highly developed - proembryos have been described as species of _Chantransia_. - The proembryo can reproduce by division, or by tetraspores - which are developed singly in the sporangia; in _B. vagum_ and - _B. sporulans_ which do not possess fully developed female - reproductive organs, the proembryos serve almost entirely to - reproduce the species. The young _Batrachospermum_-plant arises - from the end of an upright filament of the proembryo. The - proembryo is generally persistent, and continually produces new - _Batrachospermums_. These latter bear the sexual reproductive - organs and also whorls of branches: the central row of cells - is enclosed by cells growing from the base of the whorls of - branches, and from these cortical cells secondary proembryos - are developed. In this alternation of shoots there is really - no alternation of generations, since the proembryo and the - shoots with the sexual reproductive organs are parts of the same - thallus. - - Several species of _Batrachospermum_ have a bluish green or - verdigris colour. _Nemalion multifidum_ has a brown-red thallus, - slightly branched, which is attached to rocks near the water’s - edge. - - Order 3. =Chætangiaceæ.= _Galaxaura_ has a thallus thickly - incrusted with lime. - - Order 4. =Gelidiaceæ.= _Naccaria, Gelidium._ - - Sub-Family 2. =Gigartinales.= The fertilised auxiliary cell - grows towards the thallus, to produce the gonimoblasts. - Procarpia generally present. - - Order 5. =Acrotylaceæ.= _Acrotylus._ - - Order 6. =Gigartinaceæ.= _Gigartina_, _Phyllophora_, - _Ahnfeltia_; _Chondrus crispus_, with dark red, dichotomously - branched thallus, is common on the coasts of Scandinavia and - Great Britain. - - Order 7. =Rhodophyllidaceæ.= _Rhodophyllis_, _Euthora_; - _Cystoclonium purpurascens_ is common, and sometimes the ends of - its branches may be modified into tendril-like haptera. - - Sub-Family 3. =Rhodymeniales.= The fertilised auxiliary cell - forms the gonimoblast on the side away from the thallus. - Procarpia are abundantly produced. - - Order 8. =Sphærococcaceæ.= _Gracilaria._ - - Order 9. =Rhodymeniaceæ.= _Rhodymenia palmata_ is a common - species. _Lomentaria_, _Chylocladia_, _Plocamium_. - - Order 10. =Delesseriaceæ.= _Delesseria sanguinea_; _D. alata_ - and _D. sinuosa_ are handsome forms which are not uncommon. - - Order 11. =Bonnemaisoniaceæ.= _Bonnemaisonia._ - - Order 12. =Rhodomelaceæ.= _Rhodomela_, _Odonthalia_; - _Polysiphonia_, of which many species are to be found on the - coasts of Great Britain, has a filamentous, richly branched - thallus consisting of a central row of cells surrounded by a - varying number of cortical cells of similar size--the so-called - “siphons.” - - Order 13. =Ceramiaceæ.= Pretty Algæ, often branched - dichotomously, or unilaterally pinnate. _Spermothamnion, - Griffithsia, Callithamnion, Ceramium, Ptilota._ - - Sub-Family 4. =Cryptonemiales.= The cells formed by the - coalescence of the auxiliary cells and the ooblastema-filaments, - produce the gonimoblasts. The _carpogonium-filaments_ and - the auxiliary cells are scattered singly in the thallus. - - Order 14. =Gloiosiphoniaceæ.= _Gloiopeltis._ - - Order 15. =Grateloupiaceæ.= _Halymenia, Cryptonemia._ - - Order 16. =Dumontiaceæ.= _Dumontia, Dudresnaya._ - - Order 17. =Nemastomaceæ.= _Furcellaria_, which has - dichotomously branched, round shoots, is common on the coasts of - Great Britain. - - Order 18. =Rhizophyllidaceæ.= _Polyides, Rhizophyllis._ - - Order 19. =Squamariaceæ.= The Algæ belonging to this order - form crust-like coverings on stones, mussel-shells, and on - other Algæ, but are not themselves incrustated: _Petrocelis_, - _Cruoria_, _Peyssonellia_. - - Order 20. =Corallinaceæ.= Partly crustaceous, partly erect, - branched Algæ, thickly incrusted with lime, so that a few - species (_Lithothamnia_, also called _Nullipora_) occur in - fossilized condition from Jurassic to Tertiary periods. - _Melobesia, Lithophyllum, Lithothamnion, Corallina._ - -USES. “Carragen” is the thallus of _Chondrus crispus_ (Irish Moss) -and _Gigartina mamillosa_. It is a common article of food on the -coasts of Ireland, and swells to a jelly when cooked. It is officinal. -_Rhodymenia palmata_ is generally eaten as food in Ireland and in some -places on the west coast of Norway; it is also used as food for sheep -and hence is termed “Sheep-seaweed.” Agar-Agar is the jelly obtained -from species of _Gelidium_ and _Gigartina_ growing in China and Japan. - - - - - Sub-Division III. =FUNGI.= - - -=Mode of Life.= The Fungi have no chlorophyll, and are thus unable in -any stage of their existence to assimilate carbon; they must therefore -live as _saprophytes_ or _parasites_. There is, however, no strong line -of demarcation between these; many Fungi commence as true parasites, -but only attain their full development upon or in dead plants or -animals (_Rhytisma_, _Empusa_). Many saprophytes may occasionally -appear as parasites, and are then designated “_facultative parasites_” -(_Nectria cinnabarina_, _Lophodermium pinastri_), in contradistinction -to those which only appear as parasites, “_obligate parasites_” -(Mildew, Brand-and Rust-Fungi, _Cordyceps_). - -The parasites which live on the surface of the host-plant are termed -_epiphytic_ (Mildew, _Fusicladium_); and those living in its tissues -are termed _endophytic_ (_Ustilago_, _Peronospora_). _Epizoic_ -(_Oidium tonsurans_, _Laboulbenia_) and _endozoic_ Fungi (_Cordyceps_, -_Entomophthora_), are distinguished, in the same manner, as those -which live on the surface or in the interior of animals. The Fungi -designated _pathogenic_ are especially those which produce disease in -human beings and in animals. - -Most of the diseases of plants are attributed to the parasitic Fungi. -These force their way into the host-plant by piercing the outer wall -of the epidermis, as in the Potato-disease; or by growing in through -the stomata, _e.g._ the summer generations of the Rust of Wheat; or -they can only penetrate through a wound, _e.g. Nectria_. Some effect -an entrance into the host-plant by the secretion of a poisonous matter -or ferment, which softens and destroys the cell-walls (_Sclerotinia_). -Some Yeast and Mould Fungi secrete ferments (enzymes), which, for -example, convert cane-sugar into a sugar capable of fermentation. - -The relation of the parasitic Fungus to the host-plant is mainly of two -kinds. In the one case, the cell-contents are destroyed, the protoplasm -is killed, and the cellular tissue becomes discoloured and dies -(_Peronospora_, _Armillaria mellea_, _Polyporus_); in the other case, -the parasite has an irritating effect on the cellular tissue, whereby -the affected organ grows more rapidly and becomes larger than normal, -producing _hypertrophy_. Such malformations are termed _Fungi-galls_ -(Mycocecidia); in this manner “witches’ brooms” are produced by -_Æcidium_, “pocket-plum” by _Taphrina_, and other deformities by -_Exobasidium_ and _Cystopus candidus_. This hypertrophy may either be -produced by a vigorous cell-multiplication, which is most frequently -the case, or by the enlargement of the individual cells (_Synchytrium_, -_Calyptospora_). The relation between host and Fungus among the Lichens -is of a very peculiar nature, termed “_symbiosis_.” - -=Vegetative Organs.= The vegetative parts of a Fungus are termed its -_mycelium_.[10] This is formed of a mass of long, cylindrical, branched -cells resembling threads (and hence termed _hyphæ_), which have a -continued apical growth. The mycelium, in its early development, shows -a well-marked difference between the two main groups of true Fungi: -in the _Phycomycetes_, or Algal Fungi, the mycelium has no transverse -walls, and is therefore unicellular, while in the _Mesomycetes_ and -_Mycomycetes_ it is provided with dividing walls, which gradually arise -during growth, in the youngest hyphæ; intercalary transverse walls -may also be formed at a later period. In the hyphæ of some of the -Higher Fungi (_Hymenomycetes_), connections may be formed between two -contiguous cells of the same hypha, by a protuberance growing out from -an upper cell just above the transverse wall, and forming a junction -with the cell below. These are known as _clamp-connections_; they -appear to be of use in affording communication between the two cells. - -The hyphæ of Fungi, where they come in contact with one another, -often grow together, so that =H=-formed combinations (fusions) are -produced, which give rise to very compact felted tissue. When the -hyphæ are not only closely interwoven, but also united and provided -with many transverse walls, the mycelium assumes the appearance of a -tissue with isodiametric cells, and is then termed _pseudo-parenchyma_. -The hyphæ-walls are sometimes very much thickened, and composed of -several layers, and the external layers, by the absorption of water, -may often swell very much and become mucilaginous. In some instances -the walls are colourless, in others coloured, the most frequent colour -being brown. The cell-contents may also be coloured, and in that case -are generally yellow; this colour is chiefly connected with the fat -(oil) which may be found in abundance in the Fungi, whilst starch is -invariably absent in all the true Fungi. - -The mycelium assumes many different forms; sometimes it appears as a -thread-like, cobwebby, loose tissue, less frequently as firm strands, -thin or thick membranes, horn-like plates or tuber-like bodies. The -_thread-like_ mycelium may, in the parasitic Fungi, be intercellular -or intracellular, according as it only extends into the interstices -between the cells or enters into the cells proper. In the first case -there are generally found haustoria, or organs of suction (_e.g._ among -the _Peronosporaceæ_; _Taphrina_, on the contrary, has no haustoria); -but haustoria are also found among the epiphytic Fungi (_e.g._ -Erysiphaceæ). Intracellular mycelia are found in the Rust-Fungi, -in _Claviceps purpurea_, _Entomophthora_, etc. In spite of its -delicate structure, this mycelium may live a long time, owing to the -circumstance that it continues to grow peripherally, while the older -parts gradually die off (“fairy rings”). - -_String-like_ mycelia may be found, for example, in _Phallus_, -_Coprinus_, and are formed of hyphæ, which run more or less parallel -to each other. _Membrane-like_ mycelia are chiefly to be found in -Fungi growing on tree-stems (Polyporaceæ and Agaricaceæ); they may -have a thickness varying from that of the finest tissue-paper to that -of thick leather, and may extend for several feet. The peculiar horny -or leather-like strands and plates which, for instance, appear in -_Armillaria mellea_, are known as _Rhizomorpha_; they may attain a -length of more than fifty feet. The _tuber-like_ mycelia or _sclerotia_ -play the part of resting mycelia, since a store of nourishment is -accumulated in them, and after a period of rest they develope organs of -reproduction. The sclerotia are hard, spherical, or irregular bodies, -from the size of a cabbage seed to that of a hand, internally white -or greyish, with a brown or black, pseudo-parenchymatous, external -layer. Sclerotia only occur in the higher Fungi, and are found both in -saprophytes, _e.g. Coprinus_, and in parasites, _e.g. Claviceps_ -(Ergot), _Sclerotinia_. - -=Reproduction.= SEXUAL REPRODUCTION is found only among the lower Fungi -which stand near to the Algæ, the Algal-Fungi, and takes place by the -same two methods as in the Algæ, namely by _conjugation_ and by the -_fertilisation_ of the egg-cell in the oogonium. - -The majority of Fungi have only ASEXUAL reproduction. The -most important methods of this kind of reproduction are the -_sporangio-fructification_ and the _conidio-fructification_. - -In the SPORANGIO-FRUCTIFICATION the _spores_ (endospores) _arise -inside_ a mother-cell, the sporangium (Fig. 80). Spores without a -cell-wall, which move in water by means of cilia and hence are known -as _swarmspores_ or _zoospores_, are found among the Oomycetes, the -sporangia in which these are produced being called swarm-sporangia or -zoosporangia (Figs. 86, 87, 91, 94). - -In the CONIDIO-FRUCTIFICATION the _conidia_ (exospores) arise on -special hyphæ (conidiophores), or directly from the mycelium. When -conidiophores are present, the conidia are developed upon them -terminally or laterally, either in a basipetal succession (in -many Fungi, for example in _Penicillium_, Fig. 111, _Erysiphe_, -_Cystopus_), or acropetally (in which method the chains of conidia -are often branched; examples, _Pleospora vulgaris_, _Hormodendron -cladosporioides_). All conidia are at first unicellular, sometimes -at a later stage they become two-celled or multicellular through the -formation of partition-walls (_Piptocephalis_). The conidia with thick, -brown cell-walls, and contents rich in fats (_resting conidia_), can -withstand unfavourable external conditions for a much longer period -than conidia with thin walls and poor in contents. - -The SPORANGIA arise either from the ordinary cells of the mycelium -(_Protomyces_), or are borne on special hyphæ. They are generally -spherical (_Mucor_, Fig. 80; Saprolegniaceæ), egg-, pear-, or -club-shaped (Ascomycetes), more rarely they are cylindrical or -spindle-shaped. While among the Phycomycetes the size, form, and -number of spores are indefinite in each species, in the Ascomycetes the -sporangia (_asci_) have a definite size, form, and number of spores. -The spores of the Ascomycetes are known as ascospores. - -The sporangio-fructification is found under three main forms. - -1. FREE SPORANGIOPHORES which are either single (_Mucor_, Fig. 78), or -branched (_Thamnidium_). - -2. SPORANGIAL-LAYERS. These are produced by a number of sessile or -shortly-stalked sporangia, being formed close together like a palisade -(_Taphrina_, Fig. 105). - -3. SPORANGIOCARPS. These consist usually of many sporangia enclosed in -a covering, they are found only in the Carpoasci, and are also known as -_ascocarps_. The parts of an ascocarp are the _covering_ (_peridium_), -and the _hymenium_, which is in contact with the inner wall of the -peridium, and is generally made up of asci, and sterile, slender -hyphæ. The latter either penetrate between the asci and are branched -and multicellular (_paraphyses_, Figs. 103 _d_, 123, 125, 129), or -clothe those parts of the inner wall which bear no asci (_periphyses_; -among many peronocarpic Ascomycetes, _e.g. Chætomium_, _Sordaria_, -_Stictosphæra hoffmanni_). The ascocarps are produced directly from -the mycelium, or from a _stroma_, that is a vegetative body of various -forms, in which they may be embedded (Figs. 116 _B_, _C_). - -Among the conidio-fructifications there are, in the same way, three -divisions. - -1. FREE CONIDIOPHORES (Fig. 109). The form of the conidiophores, -the shape, and number of its spores are various. In the most highly -developed Fungi, the Basidiomycetes, there are, however, special more -highly developed conidiophores, the _basidia_, which have a definite -form and spores of a definite shape and number. The conidia borne on -basidia are called _basidiospores_. - -2. CONIDIAL-LAYERS. (_a_) The SIMPLEST case of this is found when -the conidiophores arise directly from the mycelium, parallel to -one another, and form a flat body (_e.g. Exobasidium vaccinii_, -_Hypochnus_; among the Phycomycetes, _Empusa muscæ_ and _Cystopus_). -(_b_) In a HIGHER form the conidial-layers are thick, felted threads -(_stroma_) inserted between the mycelium and the _hymenium_ (_i.e._ -the region of the conidiophores). Examples are found in a section -of the Pyrenomycetes (Fig. 122). (_c_) The HIGHEST form has the -_basidial-layer_, that is a conidial-layer with more highly developed -conidiophores (basidia). The basidial-layer, with stroma, and the -hymenium (region of the basidia), forms the basidio-fructification, -which is branched in the Clavariaceæ, and hat-shaped in other -Hymenomycetes (in these groups the hymenium is confined to the lower -side of the pileus). - -The hymenium of the conidial-layer and basidial-layer is composed -entirely of conidiophores, or of conidiophores and sterile hyphæ -(_paraphyses_) which are probably always unicellular. Paraphyses are -found in _Entomophthora radicans_, and in certain Basidiomycetes -(_e.g. Corticium_). - -3. CONIDIOCARPS (_pycnidia_). A special covering surrounds the -conidia-forming elements. The inner side of this covering (_peridium_) -bears the hymenium, _i.e._ those elements from which the conidia are -abstricted. The conidiocarps arise either immediately from the hyphæ -or from a _stroma_ in which they are generally embedded. Conidiocarps -are entirely wanting in the Phycomycetes. On the other hand they are -found among the Ascomycetes and Basidiomycetes, and in the latter group -the conidiocarps contain more highly differentiated conidiophores -(basidia) and are known as _basidiocarps_. Conidiocarps with simple -conidiophores, are found only among the Basidiomycetes, in the -Uredinaceæ, and in _Craterocolla cerasi_. In the Ascomycetes (Figs. -120 _d_, _e_; 117 _a_, _b_; 123 _a_; 124 _b_) the conidiocarps are -visible, as points, to the naked eye, while the basidiocarps of the -Basidiomycetes (Figs. 170, 171, 173–176, 178–180) vary from the size of -a pea to that of a child’s head. The “spermogonia” of the Ascomycetes -and Lichenes, are conidiocarps with small conidia (_microconidia_) -which germinate sometimes more slowly than other conidia, and formerly -were erroneously considered as male reproductive cells, and called -spermatia. - -The conidia of the Fungi are not primitive structures. The comparison -of the sporangia and conidia among the Zygomycetes, and among the -species of the genus _Peronospora_ shows, that the conidia are aberrant -formations, and that they have arisen through the degeneration of the -sporangium, which, by the reduction of its spores to one, has itself -become a spore. - - In the genera _Thamnidium_ and _Chætocladium_ the gradual - diminution of the sporangia, and the reduction of the number - of spores can be distinctly followed. In _Thamnidium_ the - number of spores is often reduced to one, which is _free_ in - the sporangium. In _Chætocladium_ however the sporangia are - typically _one-spored_, the spore is always united with the - sporangium, and the two become a single body, the so-called - _conidium_, which is in reality a closed sporangium. How - close is the connection between the sporangia and conidia of - _Thamnidium_ and _Chætocladium_, is seen from the fact that, - in the conidial stage of _Chætocladium_ the same whorl-form of - branching appears as in the sporangial stages of _Thamnidium - chætocladioides_, and also, that the conidia of _Ch. - fresenianum_ throw off the former sporangium-wall (exosporium), - while _Ch. jonesii_ germinates without shedding its exosporium. - The Phycomycetes have doubtless sprung from Water-Algæ and - inherit the sporangia from them. On this supposition, as the - Phycomycetes assumed a terrestrial mode of life, the sporangia - would become adapted to the distribution of the spores by - means of the air, the sporangia would become small, contain - dust-like spores, and would eventually become closed-sporangia, - _i.e._ conidia. The conidia are a terrestrial method for the - multiplication of Fungi. In the Hemiasci and the Ascomycetes the - sporangia are still preserved, but in every instance they are - adapted to terrestrial spore-distribution, their spores being - set free on the destruction of the sporangium-wall (generally - shot out) and distributed through the air. For further examples - of spore-distribution see below, p. 91–93. - -The reproduction of Fungi is accomplished not only by spores -and conidia, but also sometimes by _chlamydospores_. These are -fundaments[11] of sporangiophores and conidiophores, which have -taken on a resting condition in the form of a spore, and are able -to germinate and produce carpophores. In the formation of the -chlamydospores the hyphæ accumulate reserve materials at the expense -of the neighbouring cells; in the undivided hyphæ of the Phycomycetes -transverse walls are formed, and finally the chlamydospores are set -free by the decay of the empty cells connecting them with the mycelium. -One must distinguish between _oidia_ and _true chlamydospores_. The -former are more simple, the latter are a somewhat more differentiated -form of carpophore fundaments, which serve for propagation in the same -manner as spores. In _Chlamydomucor racemosus_ the chlamydospores -grow out into the air and form differentiated carpophores. In -the Autobasidiomycetes they only germinate vegetatively, and -not with the formation of fructifications. From _Chlamydomucor_ -up to the Autobasidiomycetes the successive development of the -fructification, which is interrupted by the formation of the -chlamydospores, degenerates more and more. Among certain Ustilagineæ -the chlamydospores (brand-spores) no longer germinate with the -production of fructifications. In the Uredinaceæ, only one of the three -chlamydospore-forms has the property of producing fructifications -on germination; the other forms only germinate vegetatively, like -ordinary spores, and in the same manner as the chlamydospores of -the Autobasidiomycetes. In the Hemibasidii, and the Uredinaceæ, in -_Protomyces_, the chlamydospores are the chief means of reproduction. -They are found also among the Ascomycetes. - -The sporangia and the conidia of the Fungi have their common origin -in the sporangia of the Phycomycetes. The asci (and the Ascomycetes -which are characterised by these bodies) are descended from the -sporangia-forming, lower Fungi; the basidia (and the Basidiomycetes) -from those which bear conidia. _The sporangia of the Phycomycetes are -the primitive form and the starting point for all the reproductive -forms of the Fungi._ The chlamydospores appear besides in all -classes of Fungi as supplementary forms of reproduction, and are of -no importance in determining relationships. Although the expression -“fruit” must essentially be applied to true Phanerogams, yet, through -usage, the term “_fruit-forms_,” is employed to designate the forms -or means of reproduction of Fungi, and the organs of reproduction -are known as _organs of fructification_, the sporangiophores -and conidiophores as _fruit-bearers_ (_carpophores_), and the -sporangiocarps, conidiocarps, and basidiocarps as “_fruit-bodies_.” - - The majority of Fungi have more than one method of reproduction, - often on various hosts (Uredinaceæ). Species with one, two, - or more than two methods of reproduction are spoken of as - having monomorphic, dimorphic, or pleomorphic fructification. - Monomorphic, _e.g._ the Tuberaceæ; dimorphic, _Mucor_, - _Piptocephalis_, Saprolegniaceæ, _Penicillium crustaceum_; - pleomorphic, _Puccinia graminis_, _Capnodium salicinum_ (in the - last species there are five methods of reproduction: yeast-like - conidia, free conidiophores, conidiocarps with small and large - conidia, and ascocarps). - -=The liberation and distribution of the spores and conidia.= The spores -and conidia, on account of their small size and lightness, are spread -far and wide by currents in the air, but in addition to this method, -insects and other animals frequently assist in disseminating them. The -liberation of the conidia is occasionally effected by the complete -shrinking away of the conidiophore, but more frequently by abstriction -from the conidiophores, either by their gradually tapering to a point, -or by the dissolution of a cross-wall (generally of a mucilaginous -nature). The individual links of conidia-chains are detached from -one another in the same way, or often by means of small, intercalary -cells, which are formed at the base of the individual links, and -becoming slimy, dissolve upon the maturity of the spores. Special -contrivances for ejecting the spores and conidia may often be found. -In _Peronospora_ the cylindrical fruit-hyphæ in the dry condition -become strap-shaped and also twisted. These are very hygroscopic, -and the changes of form take place so suddenly, that the spores are -violently detached and shot away. In _Empusa_ a peculiar squirting -mechanism may be found (Fig. 85). Each club-shaped hypha which projects -from the body of the fly, bears a conidium at its apex; a vacuole, -which grows gradually larger, is formed in the slimy contents of the -hypha, and the pressure thereby eventually becomes so great that the -hypha bursts at its apex, and the conidium is shot into the air. By -a similar mechanism, the spores of many of the Agaricaceæ are cast -away from the parent-plants. In the case of _Pilobolus_ (Fig. 84) -the entire sporangium is thrown for some distance into the air by a -similar contrivance, the basal region of the sporangium having, by -the absorption of water, been transformed into a slimy layer which -is readily detached. _Sphærobolus_, a Gasteromycete, has a small, -spherical fruit-body (basidiocarp), the covering of which, when ripe, -suddenly bursts, and the basidiospores contained in it are forcibly -ejected. - -_The spores which are enclosed in asci_ are, in some instances, set -free from the mother-cell (ascus) prior to their complete development -(_Elaphomyces_, _Eurotium_). In the case of the majority of the -Pyrenomycetes and Truffles, the asci swell by the absorption of water -into a slimy mass, which gradually disappears, so that the spores lie -free in the fruit-body; they either remain there till the fruit-body -decays, as in those which have no aperture (Perisporiaceæ, Tuberaceæ), -or the slimy mass, by its growth, is forced out through the aperture of -the sporocarp, taking the spores with it (_Nectria_). The ejection of -the spores by mechanical means takes place in a number of Ascomycetes, -and should many spores be simultaneously ejected, a dust-cloud may be -seen with the naked eye to arise in the air from the fruit-body. This -is the case in the larger species of _Peziza_, _Helvella_, _Rhytisma_, -when suddenly exposed to a damp current of air. A distinction is -drawn between a simultaneous ejection of all the spores contained -in the ascus, and an ejection at intervals (successive), when only -one spore at a time is thrown out. The first of these methods is the -most frequent, and is brought about by the ascus being lined with a -layer of protoplasm, which absorbs water to such a degree that the -elastic walls are extended at times to double their original size. The -spores are forced up against the free end of the ascus, a circular -rupture is made at this point, and the elastic walls contract, so -that the fluid with the spores is ejected. Special means may in some -instances be found to keep the spores together, and compel their -simultaneous ejection. Thus, a tough slime may surround all the -spores (_Saccobolus_), or a chain-apparatus, similarly formed of tough -slime; or there may be a hooked appendage from each end of the spores -which hooks into the appendage of the next spore (_Sordaria_). The -paraphyses occurring between the asci in many Ascomycetes, also play a -part in the distribution of the spores, by reason of the pressure they -exercise. The asci in some of the Pyrenomycetes, which are provided -with jar-shaped fruit-bodies, elongate to such an extent that, without -becoming detached from their bases, they reach the mouth of the -fruit-body one at a time, burst and disperse their spores, and so make -room for those succeeding. An ejection of the spores at intervals from -the ascus is rarer. It takes place, for instance, in _Pleospora_, whose -asci have a double wall. The external wall, by absorption of water, -at last becomes ruptured, and the internal and more elastic membrane -forces itself out in the course of a few seconds to one of two or three -times greater length and thickness, so that one spore after another is -forcibly ejected from a narrow aperture at the end of the ascus. - -=Germination of spores= (conidia and chlamydospores). In many spores -may be found one or more _germ-pores_, _i.e._ thinner places, either -in the inner membrane (uredospores, _Sordaria_) or in the external -membrane (teleutospores in Rust-Fungi), through which the germination -takes place. Generally this does not occur till the spores have been -set free: in some Ascomycetes germination commences inside the ascus -(_Taphrina_, _Sclerotinia_). The different ways in which the spores -germinate may be classified into three groups. - -I. THE ORDINARY GERMINATION occurs by the spore emitting a germ-tube, -which immediately developes into a mycelium. In spores with a double -wall it is only the inner membrane which forms the germ-tube. In -swarmspores a single wall is formed after the withdrawal of the cilia, -and this, by direct elongation, becomes the germ-tube. The protoplasm -accumulated in the spore enters the hypha, which, in pure water, can -only grow as long as the reserve nourishment lasts. - -=2.= GERMINATION WITH PROMYCELIUM differs only by the circumstance that -the hypha developed from the germ-tube has a very limited growth, and -hence it does not immediately develope into a mycelium, but produces -conidia (Rust-and Brand-Fungi). This promycelium must only be regarded -as an advanced development of a conidiophore or basidium. - -=3.= THE YEAST-FORMATION of conidia consists in the production of -outgrowths, very much constricted at their bases, from one or more -places. Each of the conidia formed in this manner may again germinate -in the same way. When sufficient nourishment is present, a branched -chain of such conidia is formed, and these are finally detached -from one another. Yeast-like buddings from the conidia are produced -in various Fungi, _e.g. Ascoidea_, _Protomyces_, Ustilagineæ, -Ascomycetes, Tremellaceæ, etc. In the Ustilagineæ these conidia are -an important element in the development. The budding conidia of -_Exobasidium_ forms a “mould” on the nutritive solution. The yeast-like -conidia are not to be confounded with the “Mucor-yeast” (comp. -Mucoraceæ). For _Saccharomyces_ see Appendix to the Fungi, page 176. - -In a compound spore (_i.e._ when a mass of spores are associated -together) each spore germinates on its own account. There are -sometimes, however, certain among them which do not germinate, but -yield their contents to those which do. - -The _length of time_ for which conidia can retain their power of -germination is shortest (being only a few weeks) in those having -thin walls and containing a large supply of water (Peronosporaceæ, -Uredinaceæ). In many spores a resting period is absolutely necessary -before they are able to germinate (resting spores). It has been -observed in some spores and conidia, that the faculty of germinating -may be preserved for several years if the conditions necessary for -germination remain absent (Ustilagineæ, _Eurotium_, _Penicillium_). - -The optimum, minimum and maximum temperatures required for the -germination of the spores has been decided in the case of a good many -Fungi. A large portion of the most common Fungi have their optimum at -20°C., minimum at 1–2°C, maximum at 40°C. In the case of pathogenic -Fungi the optimum is adapted to the temperature of the blood. Fungi -living in manure, whose spores are often adapted to germinate in -the alimentary canals of warm-blooded animals, have an optimum -corresponding to the temperature of these animals, but with a little -margin. - -=Systematic Division.=--The lowest class of the Fungi is that of the -PHYCOMYCETES, which have an unicellular mycelium, sexual and asexual -reproduction, and have doubtless sprung from sporangia-bearing, lower -Green Algæ. From the Phycomycetes (and certainly from the Zygomycetes) -spring two well defined branches, each with numerous distinct species; -to the one branch belong the HEMIASCI and the ASCOMYCETES, to the other -the HEMIBASIDII and the BASIDIOMYCETES. Ascomycetes and Basidiomycetes -may be united under the title of MYCOMYCETES or HIGHER FUNGI. The -Hemiasci and the Hemibasidii constitute the class of MESOMYCETES. -The Hemiasci are an intermediate form between Zygomycetes and -Ascomycetes; the Hemibasidii a similar group between the Zygomycetes -and Basidiomycetes. Mesomycetes and Mycomycetes have only asexual -reproduction; sexual reproduction is wanting. Their mycelium is -multicellular. - -Up to the present time about 39,000 species have been described. - -Review of the divisions of the Fungi:-- - - Class I.--=Phycomycetes (Algal-Fungi).= - - Sub-Class 1. =Zygomycetes.= - Sub-Class 2. =Oomycetes.= - Family 1. ENTOMOPHTHORALES. - Family 2. CHYTRIDIALES. - Family 3. MYCOSIPHONALES. - - Class II. =Mesomycetes.= - - Sub-Class 1. =Hemiasci.= - Sub-Class 2. =Hemibasidii (Brand-Fungi).= - - Class III.--=Mycomycetes (Higher Fungi).= - - Sub-Class 1. =Ascomycetes.= - Series 1. =Exoasci.= - Series 2. =Carpoasci.= - Family 1. GYMNOASCALES. } - Family 2. PERISPORIALES. } Angiocarpic Exoasci. - Family 3. PYRENOMYCETES. } - Family 4. HYSTERIALES. } Hemiangiocarpic Exoasci. - Family 5. DISCOMYCETES.} - Family 6. HELVELLALES. Gymnocarpic (?) Exoasci. - - Additional: ASCOLICHENES. Lichen-forming Ascomycetes. - - Sub-Class 2. =Basidiomycetes.= - Series 1.--Protobasidiomycetes. Partly gymnocarpic, partly - angiocarpic. - Series 2. Autobasidiomycetes. - Family 1. DACRYOMYCETES. Gymnocarpic. - Family 2. HYMENOMYCETES. Partly gymnocarpic, partly - hemiangiocarpic. - Family 3. PHALLOIDEÆ. Hemiangiocarpic. - Family 4. GASTEROMYCETES. Angiocarpic. - - Additional: BASIDIOLICHENES. Lichen-forming Basidiomycetes. - - Additional to the Fungi: FUNGI IMPERFECTI. Incompletely known - (_Saccharomyces_, _Oidium_-forms, etc.). - - - Class 1. =Phycomycetes (Algal-Fungi).=[12] - -This group resembles _Vaucheria_ and the other Siphoneæ among the -Algæ. - -ORGANS OF NUTRITION. The mycelium is formed of a single cell, often -thread-like and abundantly branched (Fig. 78). Vegetative propagation -by chlamydospores and oidia. Asexual reproduction by endospores -(sometimes _swarmspores_) and conidia. Sexual reproduction by -conjugation of two hyphæ as in the Conjugatæ, or by fertilisation of an -egg-cell in an oogonium. On this account the class of the Phycomycetes -is divided into two sub-classes: ZYGOMYCETES and OOMYCETES. - - - Sub-Class I. =Zygomycetes.= - -Sexual reproduction takes place by zygospores, which function as -resting-spores, and arise in consequence of _conjugation_ (Fig. 81); in -the majority of species these are rarely found, and only under special -conditions. The most common method of reproduction is by endospores, by -acrogenous conidia, by chlamydospores, or by oidia. _Swarmspores are -wanting._ Parasites and saprophytes (order 6 and 7). The zygospores are -generally produced when the formation of sporangia has ceased; _e.g._ -by the suppression of the sporangial-hyphæ (_Mucor mucedo_), or by -the diminution of oxygen; _Pilobolus crystallinus_ forms zygospores, -when the sporangia are infected with saprophytic _Piptocephalis_ or -_Pleotrachelus_. - -=A.= Asexual reproduction only by sporangia. - -Order 1. =Mucoraceæ.= The spherical sporangia contain many spores. -The zygospore is formed between two unicellular branches (gametes). - -The unicellular mycelium (Fig. 78) of the Mucoraceæ branches -abundantly, and lives, generally, as a saprophyte on all sorts of -dead organic remains. Some of these Fungi are known to be capable of -producing _alcoholic fermentation_, in common with the Saccharomyces. -This applies especially to _Chlamydomucor racemosus_ (_Mucor -racemosus_), when grown in a saccharine solution, and deprived of -oxygen; the mycelium, under such conditions, becomes divided by -transverse walls into a large number of small cells. Many of these -swell out into spherical or club-shaped cells, and when detached from -one another become chlamydospores, which abstrict new cells of similar -nature (Fig. 79). These chlamydospores were formerly erroneously -termed “mucor-yeast,” but they must not be confounded with the -yeast-conidia (page 94). They are shortened hyphæ, and are not conidia -of definite size, shape, and point of budding. Oidia are also found in -_Chlamydomucor_. - - [Illustration: FIG. 78.--_Mucor mucedo._ A mycelium which has - sprung from one spore, whose position is marked by the *: _a_, - _b_, _c_ are three sporangia in different stages of development; - _a_ is the youngest one, as yet only a short, thick, erect - branch; _b_ is commencing to form a sporangium which is larger in - _c_, but not yet separated from its stalk.] - -The Mucoraceæ, in addition to the chlamydospores and oidia, have a more -normal and ordinary method of reproduction; viz., by _spores_ which -are formed without any sexual act. _Mucor_ has round sporangia; from -the mycelium one or more long branches, sometimes several centimetres -in length, grow vertically into the air; the apex swells (Figs. 78, -80) into a sphere which soon becomes separated from its stalk by a -transverse wall; in the interior of this sphere (sporangium) a number -of spores are formed which eventually are set free by the rupture of -the wall. The transverse wall protrudes into the sporangium and forms -the well-known columella (Fig. 80 _d_, _e_). The formation of spores -takes place in various ways among the different genera. - - [Illustration: FIG. 79.--Chlamydospores of _Chlamydomucor - racemosus_ (× 375 times.)] - - [Illustration: FIG. 80.--_Mucor mucedo_: _a_ a spore commencing - to germinate (× 300 times); _b_ a germinating spore which has - formed a germ-tube from each end (× 300 times); _c_ the apex of - a young sporangium before the formation of spores has commenced; - the stalk is protruded in the sporangium in the form of a column: - on the wall of the sporangium is found a very fine incrustation - of lime in the form of thorn-like projections; _d_ a sporangium - in which the formation of spores has commenced; _e_ a sporangium, - the wall of which is ruptured, leaving a remnant attached to the - base of the columella as a small collar. A few spores are seen - still adhering to the columella.] - -SEXUAL REPRODUCTION by conjugation takes place in the following -manner. The ends of two hyphæ meet (Fig. 81) and become more or less -club-shaped; the ends of each of these are cut off by a cell-wall, and -two new small cells (Fig. 81 _A_) are thus formed, these coalesce and -give rise to a new cell which becomes the very thick-walled zygote -(zygospore), and germinates after period of rest, producing a new -hypha, which bears a sporangium (Fig. 81 _E_). - -_Mucor mucedo_, Pin-mould, resembles somewhat in appearance -_Penicillium crustaceum_ and is found growing upon various organic -materials (bread, jam, dung, etc.). - -_Pilobolus_ (Figs. 83, 84) grows on manure. Its sporangium (Fig. 84 -_a″_) is formed during the night and by a peculiar mechanism (page 92) -is shot away from the plant in the course of the day. This generally -takes place in the summer, between eight and ten a.m. The sporangium is -shot away to a height which may be 300 times greater than that of the -plant itself, and by its stickiness it becomes attached to portions of -plants, etc., which are in the vicinity. If these are eaten by animals, -the spores pass into the alimentary canal and are later on, sometimes -even in a germinating condition, passed out with the excrement, in -which they form new mycelia. - -_Phycomyces nitens_ (“Oil-mould”) is the largest of the Mould Fungi; -its sporangiophores may attain the height of 10–30 c.m. - -Order 2. =Rhizopaceæ.= _Rhizopus nigricans_ (_Mucor stolonifer_) which -lives on decaying fruits containing sugar, on bread, etc., has, at the -base of the sporangiophores, tufts of rhizoids, _i.e._ hyphæ, which -function as organs of attachment. From these, “runners” are produced -which in a similar manner develope sporangiophores and rhizoids. - - [Illustration: FIGS. 81, 82.--_Mucor mucedo_: _A-C_ stages in the - formation of the zygote; D zygote; E germination of zygote: the - exospore has burst, and the endospore grown into a hypha bearing - a sporangium.] - -Order 3. =Thamnidiaceæ.= On the same sporangiophore, in addition to -a large, terminal, many-spored sporangium, many smaller, lateral -sporangia are formed with a few spores. Thamnidium. - -=B.= Asexual reproduction by sporangia and conidia. - -Order 4. =Choanephoraceæ.= _Choanephora_ with creeping endophytic -mycelium, and perpendicular sporangiophores. - -Order 5. =Mortierellaceæ.= _Mortierella polycephala_ produces on the -same mycelium conidia and sporangiophores. _M. rostafinskii_ has a long -stalked sporangiophore, which is surrounded at its base by a covering -of numerous felted hyphæ. - - [Illustration: FIG. 83.--_Pilobolus._ Mycelium (_a_, _a_), with a - sporangiophore (_A_) and the fundament of another (_B_).] - - [Illustration: FIG. 84.--_Pilobolus._ Sporangium (_a″_) with - stalk (_a-c_), which is covered by many small drops of water - pressed out by turgescence.] - -=C.= Asexual reproduction only by conidia. - -Order 6. =Chætocladiaceæ.= The conidia are abstricted singly and -acrogenously. _Chætocladium_ is a parasite on the larger Mucoraceæ. - -Order 7. =Piptocephalidaceæ.= The conidia are formed acrogenously and -in a series, by transverse divisions. The zygospore arises at the -summit of the conjugating hyphæ, which are curved so as to resemble a -pair of tongs. _Piptocephalis_ and _Syncephalis_ live parasitically on -the larger Mucoraceæ. - - - Sub-Class 2. =Oomycetes.= - -Sexual reproduction is oogamous with the formation of brown, -thick-walled _oospores_ which germinate after a period of rest. -Asexual reproduction by conidia and _swarmspores_. Parasites, seldom -saprophytes. - -The oospores are large spores which are formed from the egg-cell -(oosphere) of the _oogonium_ (oosporangium, Fig. 89, 95). A branch of -the mycelium attaches itself to the oogonium and forms at its apex -the so-called “_antheridium_” (pollinodium[13]): this sends one or -more slender prolongations (fertilising tubes) through the wall of the -oogonium to the egg-cell. - - [Illustration: FIG. 85.--_Empusa muscæ_ (Fly-mould). I. A fly - killed by the fungus, surrounded by a white layer of conidia. II. - The conidiophores (_t_) projecting from the body of the fly. Some - of the conidia, a few of which have developed secondary conidia, - are attached to the hairs (mag. 80 times). III. A perfect hypha. - IV. A hypha in the act of ejecting a conidium (_c_), enveloped - in a sticky slime (_g_). V. A conidium which has developed a - secondary conidium (_sc_). VI. A branched hypha produced by - cultivation. VII. A secondary conidium which has produced a small - mycelium (_m_). VIII. A conidium germinating on the fly’s body. - IX. Mycelium. X. Conidia germinating like yeast in the fatty - tissue of the fly. (III.-VII. and IX. magnified 300 times; VIII. - and X. magnified 500 times.)] - - A fertilisation, a passage of the contents of the antheridium - to the egg-cell, has as yet only been observed in _Pythium_; - in _Phytophthora_ only one small mass of protoplasm passes - through the fertilising tube to the egg-cell; in _Peronospora_ - and the Saprolegniaceæ no protoplasm can be observed to pass - through the fertilising tube, so that in these instances - _parthenogenesis_ takes place; _Saprolegnia thuretii_, etc., - have generally even no antheridia, but nevertheless form normal - oospores. Fertilisation of the egg-cell by means of self-motile - _spermatozoids_ is only found in _Monoblepharis sphærica_. - -=A.= Asexual reproduction by conidia only. - - - Family 1. =Entomophthorales.= - -The mycelium is richly branched. The family is a transitional step to -the conidia-bearing Zygomycetes, since the oospores of many members of -this family arise, and are formed, like zygospores. - -Order 1. =Entomophthoraceæ.= Mycelium abundantly developed. This -most frequently lives parasitically in living insects, causing their -death. The conidiophores forming the conidial-layer project from the -skin, and abstrict a proportionately large conidium which is ejected -with considerable force, and by this means transferred to other -insects. These become infected by the entrance of the germ-tube into -their bodies. The spherical, brown resting-spores develope inside the -bodies of insects and germinate by emitting a germ-tube. - - GENERA: _Empusa_ has a good many species which are parasitic - on flies, moths, grasshoppers, plant-lice. The conidia emit a - germ-tube which pierces the skin of the insect; a number of - secondary conidia are then produced inside its body, by division - or by gemmation similar to that taking place in yeast, each - of which grows and becomes a long unbranched hypha, and these - eventually fill up the body of the animal, causing distension - and death. Each of these hyphæ projects through the skin, - and abstricts a conidium, which is ejected by a squirting - contrivance. The best known species is _E. muscæ_ (Fig. 85), - which makes its appearance epidemically towards autumn on the - common house-fly, and shows itself by the dead flies which are - found on the windows and walls attached by their probosces, - distended wings, and legs. They have swollen abdomen, broad - white belts of hyphæ between the abdominal rings, and are - surrounded by a circle of whitish dust formed by the ejected - conidia.--_Entomophthora_ sends out, at definite places, from - the mycelium hidden in the insect’s body, bundles of hyphæ, - which serve the purpose of holding fast the dead insects, the - ramifications attaching themselves to the substratum: the - conidiophores are branched, the conidia are ejected by the - divisional walls between the hyphæ and the conidia dividing into - two layers, those which terminate the hyphæ suddenly expanding - and throwing the conidia into the air. _E. radicans_ makes its - appearance epidemically on caterpillars. - -=B.= Asexual reproduction by zoospores or conidia. - - - Family 2. =Chytridiales.= - -In this family the mycelium is very sparsely developed or is -wanting. The entire plant consists principally or entirely of a -single zoosporangium whose zoospores have generally one cilium. The -resting-spores arise either directly from the zoosporangium, which, -instead of forming zoospores, surrounds itself by a thick cell-wall; or -they are formed by the conjugation of two cells (in which case they are -spoken of as oospores). Microscopic Fungi, parasitic on water plants -(especially Algæ) or small aquatic animals, seldom on land plants. - -Order 1. =Olpidiaceæ.= Without mycelium. Swarmspores and -resting-spores. - - In the _Olpidieæ_, the swarmspores, probably, most frequently - form themselves into a plasmodium (naked mass of protoplasm) - which may become a single zoosporangium or a resting sporangium. - _Olpidium trifolii_ occurs in _Trifolium repens_.--In the - _Synchytrieæ_ the plasmodium emerging from the swarmspores - breaks up either at once, or after a period of rest, into - smaller plasmodia, each of which will become a zoosporangium. - _Synchytrium anemones_ is found on _Anemone nemorosa_; _S. - mercurialis_ on _Mercurialis perennis_; _S. aureum_ on many - plants, particularly _Lysimachia nummularia_. - - [Illustration: FIG. 86.--_Chytridium lagenula._ Zoosporangium _a_ - before, _b_ after the liberation of the swarmspores.] - - [Illustration: FIG. 87.--_Obelidium mucronatum_: _m_ mycelium; - _s_ swarmspores.] - -Order 2. =Rhizidiaceæ.= Mycelium present. Zoospores and -resting-spores. - - _Chytridium_ (Fig. 86). _Obelidium_ (Fig. 87) is bicellular; the - one cell is the mycelium, the other the zoosporangium; found - on insects. The species of _Cladochytrium_ are intercellular - parasites on marsh plants. _Physoderma._ - -Order 3. =Zygochytriaceæ.= Mycelium present. Zoospores and oospores. -The latter are the product of the conjugation of two cells (Fig. 88). - - _Polyphagus euglenæ_ on _Euglena viridis_. _Urophlyctis pulposa_ - on species of _Chenopodium_. - - - Family 3. =Mycosiphonales.= - -The mycelium is bladder-like or branched. Zoospores. Sexual -reproduction by oospores, which are produced in oogonia. The latter are -fertilised, in some forms, by the antheridium. - - Order 1. =Ancylistaceæ.= The entire bladder-like mycelium - is used for the construction of zoosporangia, oogonia, or - antheridia. _Lagenedium_ is parasitic on _Spirogyra_, etc. - -Order 2. =Peronosporaceæ.= Almost entirely _parasites_. The -unicellular, often very long and abundantly branched mycelium lives -in the intercellular spaces of living plants, especially in the -green portions, and these are more or less destroyed and deformed in -consequence. Special small branches (_suction-organs_, “_haustoria_”) -are pushed into the cells in order to abstract nourishment from them. -Both oospores and conidia germinate either immediately, or they -develope into sporangia with swarmspores, having always two cilia. Only -one oospore is formed in each oogonium; its contents (Fig. 89) divide -into a centrally placed egg-cell and the “periplasm” surrounding it; -this is of a paler colour and on the maturity of the oospore forms its -thick, brown, external covering. - - [Illustration: FIG. 88.--_Polyphagus euglenæ. A_ with smooth, - _B_ with thorny oospores; _m_ and _f_ the two conjugating cells.] - - [Illustration: FIG. 89.--_Peronospora alsinearum._ Mycelium with - egg-cell and antheridium.] - - [Illustration: FIG. 90.--_Phytophthora infestans_ (strongly - magnified). Cross section through a small portion of a - Potato-leaf (the under side turned upwards): _a_ the mycelium; _b - b_ two conidiophores projecting through a stoma; _c_ conidia; _e_ - the spongy tissue of the leaf; _g_ the epidermis.] - -_The Potato-fungus_ (_Phytophthora infestans_) is of great interest. -Its thallus winters in the Potato-tuber; other organs for passing the -winter, such as oospores, are not known. When the tuber germinates, the -Fungus-hyphæ penetrate the young shoot and keep pace with the aerial -growth and development of the plant. The conidiophores emerge through -the stomata, especially on the under side of the leaves; they branch -like a tree (Fig. 90), and appear to the naked eye as a fine mould on -the surface of the plant. The disease soon makes itself known by the -brown colouring of those parts of the plant which are attacked, and by -their withering. An ovoid conidium arises at first by the formation of -a dividing wall at the apex of each branch of the conidiophore (Fig. 90 -_c c_), and immediately underneath it another is formed, which pushes -the first to one side, and so on. These conidia sometimes germinate -directly, and form a mycelium, but most frequently their protoplasm -divides into many small masses, each of which becomes a pear-shaped -zoospore provided with two cilia (Fig. 91). Water is required for -their germination, and when the ripe conidia are placed in a drop of -water the swarm-cells are formed in the course of about five hours. -They swarm about in rain and dewdrops in the Potato-fields, and are -carried with the water to the Potato-plants and to the tubers in -the soil. The wind also very easily conveys the conidia to healthy -Potato-fields and infects them. The enormous quantity of conidia and -swarm-cells that may be formed in the course of a summer explains the -rapid spreading of the disease; and the preceding makes it clear why -wet summers are favourable to its existence. When the swarm-cells -germinate, they round off, and then surround themselves with a -cell-wall which grows out into the germ-tube, and _pierces through the -epidermis_ of the host-plant (Fig. 92). Having entered the host, a new -mycelium is formed. The potato disease, since 1845, has been rampant in -Europe; it has, no doubt, been introduced from America, which, it must -be remembered, is the home of the Potato-plant. - - [Illustration: FIG. 91.--_Phytophthora infestans_: _a-c_ conidia - detached; in _c_ the swarm-cells are leaving the mother-cell; _d_ - two free-swimming swarm-cells.] - - [Illustration: FIG. 92.--_Phytophthora infestans._ Cross section - through a portion of a Potato-stalk. Two germinating conidia - (_a_, _b_) piercing the epidermis, and the mycelium penetrating - the cells.] - - The conidia exhibit various characters which are employed for - the separation of the genera. _Pythium_ is the most simple - form. The contents of the terminally-formed conidia emerge as - a spherical mass and divide into swarmspores. _P. de Baryanum_ - lives in the seedlings of many different Flowering-plants, - which it completely destroys.--_Phytophthora_ is distinguished - by the circumstance that the sparsely-branched conidiophores - bear, sympodially, chains of conidia. Besides the Potato-fungus - (see above), _Ph. fagi_ belongs to this group; it developes - oospores very abundantly, and does great harm to seedlings of - the Beech, Sycamore, and Pine trees.--_Peronospora_ generally - has conidiophores which are repeatedly forked, and bear a - conidium on each of the most extreme ramifications. Many do - great harm to their host-plants. _P. viticola_, on Vines, and - _P. nivea_, on umbelliferous plants, have swarmspores, which are - absent in the following species of this genus: _P. sparsa_, on - Roses; _P. gangliformis_, on composites; _P. alsinearum_, on - Stitchwort; _P. parasitica_, on cruciferous plants; _P. viciæ_, - on Vetches and Peas; _P. schachtii_, on Beets; _P. violacea_, - on the flowers of _Scabiosa_; _P. radii_, on the ray-florets of - _Matricaria_.--_Cystopus_ (_Albugo_) has the conidia developed - in chains, which form a cohesive white layer underneath the - epidermis of the host-plant. _Cystopus candidus_, on cruciferous - plants, especially Shepherd’s Purse and _Brassica_; the - germination commences on the cotyledons, and from this point the - mycelium developes together with the host-plant; _C. cubicus_, - on the leaves of Compositæ. - - [Illustration: FIG. 93.--A fly overgrown with _Saprolegnia_.] - - [Illustration: FIG. 94.--Formation of swarmspores in a - _Saprolegnia_: a germinating swarmspores.] - -Order 3. =Saprolegniaceæ=, _Water-Fungi_ which live as saprophytes on -organic remains lying in water, for instance, on dead flies (Fig. 93), -worms, remains of plants; but they may also make their appearance on -living animals, being frequently found, for example, on the young trout -in rearing establishments. - - [Illustration: FIG. 95.--Oogonium with two antheridia, _Achlya - racemosa_.] - -The thallus is a single, long and branched cell. It has one portion -which serves as root, and lives in the substratum, where it ramifies -abundantly for the purpose of absorbing nourishment; and another -portion projecting freely in the water, and sending out hyphæ on all -sides (Fig. 93). The asexual reproduction takes place by swarmspores -(Fig. 94), which are developed in large sporangia; these swarmspores -generally possess two cilia, and on germination grow into new plants. -The entire protoplasm in the oogonium is formed into one or more -oospheres, without any surrounding “periplasm.” The oospheres may not -be fertilised (p. 100), and then develope parthenogenetically. - - Genera: _Saprolegnia_, whose swarmspores disperse immediately - after having left the sporangium. _S. ferax_ is the - cause of a disease in fish (“Salmon disease”) and in the - crayfish.--_Achlya_, whose swarmspores accumulate in a hollow - ball before the mouth of the sporangium.--_Leptomitus_ has - strongly indented hyphæ, causing a “linked” appearance. - _L. lacteus_ is frequent in the waste matter from sugar - factories.--_Monoblepharis_ deviates from the others by the - greater development of its fertilising process; the oosphere, - situated in an open oogonium, becoming fertilised by self-motile - spermatozoids, which are provided with a cilium at the posterior - end. - - - Class 2. =Mesomycetes.= - -The Mesomycetes are intermediate forms between the Phycomycetes and -the Higher Fungi. In the vegetative organs, and in the multicellular -hyphæ, they resemble the Higher Fungi; the methods of reproduction, -however, show the characters of the Phycomycetes, namely sporangia -and conidiophores of varying size and with varying number of spores; -definite and typically formed asci and basidia are not present. Sexual -reproduction is wanting. The HEMIASCI are transitional between the -Phycomycetes and the Ascomycetes, the HEMIBASIDII (Brand-Fungi) form -the transition to the Basidiomycetes. - - - Sub-Class 1. =Hemiasci.= - -The Hemiasci are Fungi with _sporangia_ which, _although resembling -asci_, yet have _not_, however, _a definite form and a definite number -of spores_. Besides endospores, conidia, chlamydospores and oidia are -found. - - Order 1. =Ascoideaceæ.= _Ascoidea rubescens_ forms irregular, - reddish-brown masses in the sap issuing from felled Beeches. It - has _free sporangia_, which resemble asci in their structure, in - the development and ejection, and in the definite shape and size - of the spores. The formation of the sporangia takes place when - the nutriment is nearly exhausted, and resembles that of the - conidia, since they are developed from the end of a hypha which - enlarges, and the swelling becomes separated by a transverse - wall. Within the sporangia numerous spores of a cap-like form - are developed, which are set free through an opening at the - apex. Sporangia are formed successively at the apex of the - same hypha, the second commencing to develope as the first is - dehiscing. Conidia and sporangia are not formed simultaneously; - the former may be considered as closed sporangia. - - Order 2. =Protomycetaceæ.= _Protomyces pachydermus_ causes - hard swellings on the stems and leaf-stalks of the Cichorieæ - (_Taraxacum_, etc.). These swellings consist of _chlamydospores_ - (resting-spores), which germinate and become free, ascus-like - sporangia, with numerous small spores. In nutritive solutions - the chlamydospores form conidia with yeast-like buddings. _P. - macrosporus_ on _Ægopodium_, and other Umbelliferæ. - - Order 3. =Thelebolaceæ.= _Thelebolus stercoreus_, is found - on the dung of deer, hares, and rabbits, and has _closed - sporangia_, which resemble asci in their shape and regular - construction, and in the ejection of spores. The covering - encloses only one sporangium, even where the sporangia arise - close together. - -This order, by reason of the covering of the sporangia, forms the -transition from the Hemiasci to the Carpoasci, while the two first -supply an intermediate step to the Exoasci. - - - Sub-Class 2. =Hemibasidii, Brand-Fungi.= - -The Brand-Fungi (also known as USTILAGINEÆ) are Fungi with -_basidia-like conidiophores_, which, however, have not yet advanced -to a definite form or number of conidia. They are true parasites, -whose mycelium spreads itself in the intercellular spaces of Flowering -plants. The mycelium is colourless, quickly perishable, has transverse -walls at some distance from each other (Fig. 96), and sends out -haustoria into the cells of the host-plant. - - [Illustration: FIG. 96.--_Entyloma ranunculi._ 1. Cross section - of a portion of a leaf of _Ficaria_ permeated by the mycelium; a - bundle of hyphæ with conidia emerging from a stoma; in one of the - cells are found four brand-spores. 2. A brand-spore developed in - the middle of a hypha.] - -It most frequently happens that the germ-tube enters the host-plant at -its most tender age, that is, during the germination of the seed; the -mycelium then wanders about in the tissues of the shoot during its -growth, until it reaches that part of the plant where the spores are to -be formed. The spore-formation takes place in the same way in all those -species whose brand-spores are developed in the floral parts of the -host-plant. Many Brand-Fungi have, however, a more local occurrence, -and the mycelium is restricted to a smaller area of the leaf or stem. -Those organs of the host-plant in which the brand-spores are developed -often become strongly hypertrophied. In perennial plants the mycelium -winters very often in the rhizome. - - [Illustration: FIG. 97.--_Doassansia alismatis._ 1. A fruit-body, - formed by a covering of oblong hyphæ, which encloses a mass - of brand-spores, and is embedded in the leaf-tissue of the - host-plant; 20 times natural size. 2. A germinating brand-spore, - 500 times natural size. 3. Three connected resting-spores, 400 - times natural size. 4. Two conidia grown together, 600 times - natural size.] - -The brand-spores are the winter resting-spores of the Brand-Fungi. -They arise in the tissues of the host-plant, which is often destroyed, -and become free through the rupture of the epidermis; they are -thick-walled, generally brown or violet, and very often possess warts, -spines, or reticulate markings. Fruit-bodies, that is enclosed organs -of reproduction, are found in few genera (_Sphacelotheca_, _Graphiola_; -_Doassansia_, Fig. 97). In _Tolyposporium_, _Tuburcinia_, _Thecaphora_ -(Fig. 102), etc., the brand-spores are united into a _ball of spores_. -On germination the brand-spores behave as _chlamydospores_, namely, -as the fundament of conidiophores, by emitting a short germ-tube, -_i.e._ a conidiophore (“promycelium”). The USTILAGINACEÆ (Fig. 99, 2) -have a short _transversely divided_ conidiophore, with _laterally_ -developed conidia (comp. the basidia of the Protobasidiomycetes). -The conidiophores of the TILLETIACEÆ are undivided (unicellular -promycelia), and bear the conidia terminally, and so resemble the -basidia of the Autobasidiomycetes. - - [Illustration: FIG. 98.--_Tuburcinia._ 1. _T. trientalis._ Hyphæ, - some of which bear conidia at the apex, forcing themselves out - between the epidermal cells on the under side of the leaf; 320 - times natural size. 2. _T. trientalis._ A ball of spores in which - some of the individual brand-spores are about to germinate; 520 - times natural size. 3. _T. primulicola_: various forms of conidia - (500 times natural size).] - - In _Tilletia_, _Entyloma_, _Neovossia_, _Tuburcinia_, the - brand-spores germinate and form basidia-like conidiophores with - spindle-shaped conidia; their mycelium, on the other hand, - produces later only single, sickle-shaped conidia, so that - two kinds of conidia are found, as in a few Basidiomycetes. - In some species, _e.g. Ustilago hordei_, the brand-spores - only germinate vegetatively and form a mycelium. In nutritive - solutions (solutions of dung, etc.) where they live as - _saprophytes_, the brand-spores of many species emit germ-tubes, - and on these, _yeast-like conidia_ are produced by repeated - budding, which grow into mycelia only when the nutritive - solution is exhausted. These conidia have not the power of - producing alcoholic fermentation. The very numerous conidia, - which are found in the dung of herbivorous animals, are probably - the yeast-conidia of Brand-Fungi. The brand-spores, which are - eaten by animals with the grain and hay, pass into the dung - and without doubt give rise to a very rich multiplication of - yeast-conidia. - - [Illustration: FIG. 99.--_Ustilago._ 1. Formation of - brand-spores. 2. Germinating brand-spore of _U. perennans_. - 3. Germinating brand-spore of _U. cardui_ (after Brefeld). 4. - _U. filiformis. a_ A brand-spore with developed basidium; - _b_ another, with a conidium; _c_ with two conidia; _d_ with - two conidia placed diametrically opposite to each other; _e_, - detached conidia which are growing into hyphæ.] - - [Illustration: FIG. 100.--_Tilletia tritici_: _a_ an ear of - Wheat in which all the grains are attacked by Stinkbrand; - _b_ a blighted corn surrounded by the chaff; _c_ a blighted - corn grown together with a stamen; _d_ the same cut across; - _e_ a brand-spore; _f_, _g_, _h_ germinating brand-spores; - _i_ germinating conidia; _j_ the mycelium; _k_-_k_ - brand-spore-forming mycelium-threads. (_c-h_ magnified 400 times; - _i-k_ 300 times.)] - - The conidia (also called “sporidia”) of many species unite - generally into an H-form (Figs. 97, 4; 100 h; 101, 4). This - union in pairs does not, however, take place with a view to - germination, there is no fusion of nuclei, and therefore in this - “fusion” there is no sexual act. - - Order 1. =Ustilaginaceæ.= Conidiophores with transverse walls - and lateral conidia.--_Ustilago_ (Fig. 99) generally developes - its spores in the floral organs of its host-plant, the ovary or - anthers, where they arise from hyphæ, and form a slimy mass - which when mature becomes a black dust. - - To this order belong _U. avenæ_, parasitic on Oats, _U. hordei_ - and _U. nuda_ (_U. jenseni_), on Barley; these are the usual - cause of “Smut” on cereals. _U. hypodytes_ on straw of _Elymus_ - and _Agropyrum_. _U. filiformis_ in the leaves of _Glyceria_. - _U. caricis_ transforms the fruits of various species of - _Carex_ into black, dusty balls. _U. violacea_ developes its - violet spore-powder in the anthers of the Caryophyllaceæ. - _U. tragopogonis_, transforms entire inflorescences of - _Tragopogon_ into a black-violet mass. Among the largest are _U. - grandis_, which causes the large swollen nodes in the stem of - _Phragmites_, and the Maize Blight, _U. maydis_, which produces - outgrowths about the size of a hand on the spadix of the Maize. - - Order 2. =Tilletiaceæ.= Conidiophores undivided, generally - several conidia arise at their apices.--_Tilletia tritici_, - the _Stinkbrand on Wheat_ (Fig. 100). The mycelium lives in - Wheat-plants, producing its spores in the ovary after the whole - interior of this body has been destroyed by the mycelium, with - the exception of the external layer of the wall of the ovary, - which remains essentially unaltered and encloses the closely - packed, firm mass of spores (Fig. 100 _d_). The grains of Wheat - thus attacked are shorter and thicker than the sound ones, - and the ears show the presence of this Fungus by their erect - position, and the wide separation of the chaff (Fig. 100 _a_). - The unpleasant odour of the ovary prior to the ripening of the - spores, has given the name “Stinkbrand,” and, in like manner, - its hardness when it encloses the ripe spores, is the reason - of its being also called “Stonebrand.” On account of this - hardness, the diseased grains are readily harvested together - with the healthy ones, which become infected by the spores at - the threshing. _T. lævis_ (_T. fœtens_) also occurs on Wheat and - has smooth brand-spores. - - [Illustration: FIG. 101.--_Urocystis._ 1, _U. covalloides_. - A spore-ball, magnified 450 times. 2–4, _U. anemones_: 2–3, - brand-spores which are about to germinate (magnified 450 times). - 4, Conidia, the two in a state of fusion, a third with vacuoles - and division-wall, magnified 500 times.] - - _Entyloma_ (Fig. 96), a genus with numerous species, which - appear in spots on the leaves of the host-plant, and - _Tuburcinia_ (Fig. 98), which makes its appearance on the - Primulaceæ, produce white conidia-spots on the surface of the - host-plant. The first-named has single spores, the latter has - its spores closely massed together.--_Urocystis_ (Fig. 101) - has its spores surrounded by a number of small and lighter - coloured barren spores. _U. occulta_, Rye-stem Blight, forms - its spores in long streaks in the stems and leaves of the Rye, - and does considerable damage. _U. cepulæ_ on Onions. _U. violæ_ - forms large dark-violet swellings in the leaf-stalk and stems - of Violets.--_Thecaphora_ (Fig. 102) appears in seedlings of - _Convolvulus_ and _Astragalus_. - - As a means of protection against the Smut-Fungi which make their - appearance on the different cereals, a submersion of the grains - in a solution of blue vitriol (½%) for twelve hours, or better - still, submerging for five minutes in water heated to 53–55° _C_ - (Jensen’s method) is employed. - - [Illustration: FIG. 102.--_Thecaphora._ 1, _T. convolvuli_, a - ball of spores, one of the brand-spores has emitted a septate - branched conidiophore (× 520). 2, _T. affinis_, a ball of spores - (× 520).] - - - Class 3. =Mycomycetes, Higher Fungi.= - -The MYCOMYCETES are not entirely aquatic in habit; they have hyphæ with -_transverse walls_, but _no sexual reproductive organs_. The asexual -reproduction takes place in very different ways; by endospores (in -asci), conidia, basidiospores, chlamydospores, and oidia. Swarmspores -are never found. - -Two chief methods of reproduction may be distinguished, and hence the -class may be divided into two large sub-classes:--the ASCOMYCETES (with -asci), and the BASIDIOMYCETES (with basidia). - - - Sub-Class 1. =Ascomycetes.= - -The main characteristic which distinguishes the Ascomycetes is the -_ascus_; a name given to a sporangium of a definite shape and size, -and containing a definite number of spores. The shape is generally -club-like or spherical, the number of spores 8 (in some 2, 4, 16 or -more), see Figs. 103, 105, 108, 110, 113, 116, 120, 121, 123, 129. - -In the lowest forms, the EXOASCI, the ascus springs directly from the -mycelium without the formation of a fruit-body (_i.e._ ascocarp). -In the higher forms, which contain many species, the CARPOASCI, the -asci are united and form ascocarps which may be more or less enclosed -(angiocarpic, hemiangiocarpic, and probably gymnocarpic). - - [Illustration: FIG. 103.--Endogenous formation of spores in - _Peziza confluens_. In the youngest asci there is only one - nucleus (_b_, _e_); this divides into two (_f_); and the division - is repeated so that there are 4 nuclei in _c_ and 8 in _g_. These - surround themselves with protoplasm and a cell-wall (_h_, _i_). - The protoplasm of the mother-cell is not entirely used up.] - -The hyphæ of the _Mycelium_ in some remain free, in others they are -felted together and form thick strands or flat, cushion-like bodies -(compare in particular the stromata of the Pyrenomycetes). Some species -form _sclerotia_ (Figs. 116, 128). - -Asexual reproduction by means of _conidia_ is known in many species -as the principal means of reproduction, and the one which affords -the most rapid means of distribution. The conidia may be produced on -conidiophores (Fig. 109), in conidial-layers (Fig. 122), and often in -conidiocarps (pycnidia, Figs. 120 _d_, _e_; 123 _a_; 124 _b._). These -last occur partly as the so-called “spermogonia” (that is, pycnidia -with microconidia). The conidiophores never approach the basidia. - - In many species the ascospores germinate and form conidia - immediately (_Nectria cinnabarina_, _Sclerotinia_, _Taphrina_, - etc.), sometimes while they are still in the ascus and before - their ejection (_Taphrina_, Fig. 105 _a_). In many instances - the conidia by means of continued budding can, for a longer - or shorter time, produce yeast-conidia, _e.g. Taphrina_. In - many other cases the conidia arise from the germ-tubes of the - ascospores, or at any part of the mycelium. The unripe asci - of _Taphrina_, when placed in water, develop conidia at their - apices. The _Sclerotinia_-species produce numerous conidia - whose germination has never been observed. The formation of - conidia and asci sometimes takes place on the same fruit-body. - In _Heterosphæria patella_ the conidia and asci are developed - successively in the same fruit-body; in the ascocarps of - _Dermatea frangula_ and _Sclerotinia sclerotiorum_ the formation - of conidia may take place. The ascocarps frequently arise - from the conidial-layers (_Nectria cinnabarina_, etc.). This - relationship of the two forms of reproduction to each other - may be explained by considering that both have descended - phylogenetically from sporangia. - -Sometimes _chlamydospores_ and _oidia_ also appear in the Ascomycetes; -on germination, however, they do not, as in _Protomyces_, form -sporangia, and on this account cannot be distinctly distinguished from -conidia. - -The asci are morphologically the highest form of reproduction and -are always found at the close of the development of these Fungi; the -accessory forms of reproduction are first developed, but a well-defined -alternation of generations does not occur. - - In the Ascomycetes there are more than 11,000 described species, - which can be classed as follows:-- - - Series 1. EXOASCI. Only one order. - „ 2. CARPOASCI. - Family 1. _Gymnoascales_, } - „ 2. _Perisporiales_, } Angiocarpic Carpoasci. - „ 3. _Pyrenomycetes_, } - „ 4. _Hysteriales_, } Hemiangiocarpic Carpoasci. - „ 5. _Discomycetes_,} - „ 6. _Helvellales_, Gymnocarpic (?) Carpoasci. - Additional _Ascolichenes_: Lichen-forming Ascomycetes. - - - Series 1. =Exoasci.= - -Ascomycetes with FREE ASCI; sometimes also conidia, chlamydospores and -oidia. One order. - -Order. =Taphrinaceæ.= Of the genera belonging to this order, -_Taphrina_, _Endomyces_, and _Ascocorticium_, the first is most -important. - - _Endomyces decipiens_ is a parasite in the fruit-body of - _Armillaria mellea_; _E. magnusii_ lives in the gelatinous, - fermenting exudations of Oak-trees; _Ascocorticium albidum_ - is found under the bark of the Fir-tree. _Endomyces_ has - chlamydospores and oidia. - -The species of _Taphrina_ are parasites, whose free asci may be found -in great numbers, generally closely pressed together, on the parts of -plants which they have attacked. The asci are developed directly from -the ascogenous cells of a fertile, generally sub-cuticular, hypha, -which arises from the sterile mycelium. The latter arises from the -germinating ascospore, and may hibernate in the tissues of its host, -particularly in the winter buds, and then with the commencement of -the next period of vegetation it continues its growth side by side -with that of its host. The hyphæ ramify in the intercellular spaces or -beneath the cuticle, but have no haustoria. The ascospores (Fig. 105 -_A_) and unripe asci may produce conidia. - - [Illustration: FIG. 104.--_Taphrina_ (_Exoascus_) _pruni_. - Yeast-like budding of a germinating spore (× 600).] - - [Illustration: FIG. 105.--_Taphrina betulina_: _a_ ascus filled - with conidia; _b_ germinating spores (× 600).] - - Very remarkable appearances, and swellings of the attacked - tissues, are produced when the mycelium is perennial; for - example, the “Witches’-brooms” and “Pockets.” The hard, hollow, - stoneless plums, known as “Pocket” or “Bladder” Plums, are - produced by considerable changes in the tissues of the fruit; - these are caused particularly by _T. pruni_ on several species - of _Prunus_. The “Witches’-brooms,” on the contrary, are - deformations of entire twigs or branches, and often attain - a very large size. They occur on _Alnus incana_, caused by - _T. epiphylla_; on _Carpinus betulus_, by _T. carpini_; on - Cherry-trees, by _T. cerasi_; on Plum-trees, by _T. insititiæ_; - on Birches, by _T. turgida_ and _T. betulina_. _T. deformans_ - attacks the leaves of the Peach, and causes them to curl. - - When a perennial mycelium is wanting, the infection is confined - as a rule to white or yellow spots on the leaves, _e.g._ the - commonest, _T. sadebeckii_, on _Alnus glutinosa_, and _T. aurea_ - on species of _Populus_. _T. alni incanæ_ (Fig. 106) causes - considerable hypertrophies on the pistillate catkins of the - Alder, which may be compared to the “pockets” of _Prunus_. - - [Illustration: FIG. 106.--_Taphrina alni incanæ_ on the Alder - (nat. size).] - - - Series 2. =Carpoasci.= - -The Carpoasci are Ascomycetes, whose asci are enclosed in fruit-bodies, -_i.e. ascocarps_. The accessory means of reproduction are free -conidiophores (Fig. 109), conidial-layers (Fig. 122), conidiocarps -(Fig. 120 _D_, _E_, etc.), chlamydospores and oidia. - -For the different methods of distributing the ascospores, see p. 92. - -Of the six families of the Carpoasci, the first three--_Gymnoascales_, -_Perisporiales_, and _Pyrenomycetes_--are ANGIOCARPIC (that is, -the ascocarp remains closed throughout its existence, and does not -dehisce when ripe); the fourth and fifth families (_Hysteriales_ and -_Discomycetes_), on the other hand, are HEMIANGIOCARPIC (the ascocarp, -here also called an _apothecium_, is closed in the early stages, -but opens at the commencement of ripening and exposes a hymenium of -crowded asci); the family of _Helvellales_ has probably GYMNOCARPIC (or -hemiangiocarpic) fruit-bodies. - - - Family 1. =Gymnoascales.= - -The ascocarps are surrounded by a _spongy and incomplete envelope_. One -order, poor in species. - - Order =Gymnoascaceæ=.--The ascocarps are borne sometimes - solitarily, or sometimes coiled together. _Gymnoascus reessii_ - forms small bodies about 1 mm. in diameter on old horse-dung, - which at first are white and afterwards orange-red.--_Ctenomyces - serratus_ lives on the old feathers in birds’ nests. - - - Family 2. =Perisporiales.= - -The ascocarps are surrounded by a _complete envelope_ without any -opening: the fruit-bodies are cleistocarpic; the spores are only -liberated after the disintegration of the fruit-bodies. Paraphyses -are wanting. The two first orders have in addition the means of -reproduction by conidia. - -Order 1. =Erysiphaceæ, Mildews.= The Fungi belonging to this order are -epiphytic parasites, whose mycelium, somewhat resembling a cobweb, may -be seen on the leaves and other green portions of plants (see Figs. -107, 108). The hyphæ ramify in all directions upon the surface of their -host, and emit haustoria which penetrate the epidermal cells, and -thus derive the necessary nutriment. The Mildew-Fungi thus belong to -the obligate parasites, and during their growth dwarf and destroy the -portions of their host on which they live. The reproduction takes place -in the first instance by abstriction of conidio-chains from the end of -special branches (Fig. 108 _c_, a hypha is seen in the act of detaching -a conidium). The conidia may germinate immediately, and thus quickly -reproduce their species. When present in large numbers they appear as -a white meal covering the surface of the plant on which the fungus is -found. Later on appear the dark brown, spheroid ascocarps (Fig. 108 -_a_) which, although small, are generally just visible to the naked eye -as black specks. - - [Illustration: FIG. 107.--_Erysiphe cichoracearum_: _a_ - mycelium-threads; _b_ sterile hypha (“pollinodium”); _c_ fertile - hypha (ascogone or archicarp); _d_ and _e_ young ascocarps.] - -A characteristic feature of the Mildew-Fungi is the thin, -pseudo-parenchymatous covering of the ascocarp, enclosing _one_ -(_Podosphæra_ and _Sphærotheca_; compare _Thelebolus_ among the -Hemiasci) or _a few_ asci (Fig. 108 _c_), which do not form -any hymenium, but are irregularly placed. The cells of the -ascocarp-envelope are often prolonged into hair-like appendages. -The ascocarps are developed from the mycelium at places where two -hyphæ cross each other (Fig. 107). At these places two short and -erect hyphæ are produced side by side. The one from the lower hypha -(Fig. 107 _c_) assumes an ellipsoidal shape, and is known as the -_archicarp_ or _ascogone_, while the other (“_pollinodium_”) arches -over the ascogone. From the latter one ascus may be at once developed -(_Sphærotheca_, etc.), or after its division several asci may be -produced, each developed from one division. The sterile hypha (termed -“pollinodium,” since it was formerly, but erroneously, supposed to -fertilise the ascogone) produces a number of branches, and forms the -pseudo-parenchymatous envelope of one cell in thickness, enclosing the -asci. - - [Illustration: FIG. 108.--_Erysiphe communis._ A small portion - of a leaf with this Fungus growing upon it (considerably - magnified). The hyphæ b and d do not belong to this Fungus, but - are reproductive organs of a pyrenomycetous Fungus parasitic upon - it (_Cicinnobolus_).] - -Many plants, both cultivated and wild, are attacked by various species -of Mildew. A common means of prevention against their attacks is to -dust the diseased parts with sulphur. - - [Illustration: FIG. 109.--_Eurotium glaucum_: α portion of - mycelium lying horizontally; β vertically-placed conidiophore; - the mycelium gives rise to another branch near α; the conidia are - abstricted from short flask-shaped cells; _b_ a ripe conidium; - _c_, _d_ germinating conidia; _e_ spirally-twisted hypha, - commencement of an ascocarp; _f_ a stage later; _g_ still later, - the hypha at the base of the coil has given off branches which - are applied to it; _h_, _i_ sections of young ascocarps.] - - _Sphærotheca pannosa_ occurs on the leaves of Roses, and on the - fruit of Peaches and Apricots. _S. castagnei_ on _Humulus_, - _Cucumis_, etc.--_Erysiphe tuckeri_ grows on the leaves and - fruit of the Vine; it spins its hyphæ over the bunches of - grapes, curtails their growth, and causes them to burst, and - to become decayed and rotten (Grape-disease). The Fungus was - first noticed in England in 1845, and later was found in - all countries where grapes are grown. It is only known in - the conidial form (“Oidium tuckeri”). Many other species of - _Erysiphe_ are found on herbaceous plants.--_Microsphæra_ has - appendages which are repeatedly forked at their extremities. - _M. grossulariæ_ on _Ribes grossularia_.--_Uncinula_ has - appendages with spirally-coiled extremities; on _Salix_ and - _Acer_.--_Phyllactinia_ has a circle of bristle-like appendages - with dilated bases. _P. guttata_ on _Corylus_, _Fraxinus_, - _Fagus_, etc. - -Order 2. =Perisporiaceæ=, Moulds and Mildews. A group of Fungi -widely distributed and found in all situations. Usually they have a -well-developed surface mycelium, and small, round, seldom conspicuous -ascocarps, containing ovoid, pulley-like spores. They are partly -saprophytic, partly parasitic, in the latter condition having a brown -mycelium. - - [Illustration: FIG. 110.--_Eurotium glaucum_: _a_ longitudinal - section of a half-ripe ascocarp, bounded externally by a - well-defined layer of cells, enclosing asci in various stages of - development; _b_ a semi-ripe, _c_ an almost ripe ascus; _d_ and - _e_ spores seen from the edge and side; _f_ germinating spore - twenty-two hours after been sown in plum juice.] - -_Eurotium glaucum_ (= _E. herbariorum_, Figs. 109, 110) and _E. repens_ -live on dead organic matter, preserved fruits, etc. The conidial forms -of both species are known as “Moulds” (Fig. 109), and formerly were -described under the name “_Aspergillus glaucus_.” The conidia for some -time remain attached to each other in chains (Fig. 109 _a_); they are -abstricted from sterigmata arranged radially on the spherical, swollen -end of the conidiophore. The small yellow or brownish ascocarps are -frequently found in herbaria, especially when the specimens have -been insufficiently dried. _Aspergillus fumigatus_ and others are -pathogenic, causing mycosis in warm-blooded animals. - - [Illustration: FIG. 111.--_Penicillium crustaceum_: _a_ conidia - (× 300); _b_ germination of conidia; _c_ small portion of - mycelium, produced from a conidium at *, with five conidiophores; - _d_ young conidiophore (× 630), a flask-shaped cell is - abstricting a conidium; _e_ the same conidiophore after 9–10 - hours.] - - [Illustration: FIG. 112.--_Penicillium crustaceum_: _a_ two - spirally-coiled hyphæ arise from the mycelium, from one of - which (archicarp) the asci are produced; _b_ a further step in - the development of the ascocarp; the branching archicarp is - surrounded by sterile hyphæ; _c_ section of young ascocarp; - the larger hyphæ in the centre are the ascogenous hyphæ; these - are enclosed by a pseudo-parenchyma of sterile hyphæ (× 300); - _d_ series of ripe asci with spores; _e_ four ascopores seen - laterally; _f_ germinating ascospores (× 800).] - -_Penicillium crustaceum_ (_P. glaucum_, Figs. 111, 112) is an -exceedingly common “Mould.” Its mycelium appears very frequently on -any organic matter which is permitted to remain untouched, and soon -covers it with a dense mass of blue-green conidiophores. These branch -at their summits and bear flask-shaped cells from which the conidia -are abstricted. The ascocarps which, both in size and colour, resemble -grains of sand, have only been obtained in luxuriant cultivation with a -limited supply of oxygen. - - _Capnodium salicinum_ (_Fumago salicina_, _Cladosporium - fumago_), a common Mildew, forms dark overgrowths on the leaves - and branches of various shrubs (Poplars, Elms, Willows) and on - Hops. The conidia appear in various forms, as on conidiophores, - in conidiocarps with large multicellular conidia, and in - conidiocarps with small unicellular conidia; in nutritive - solutions yeast-like conidia are also developed.--_Apiosporium - pinophilum_ produces mildew on the leaves of _Abies alba_ and - _Picea excelsa_. (The conidial-forms were formerly described as - “_Antennaria pinophila_”). - -Order 3. =Tuberaceæ, Truffles.= The Fungi belonging to this order -are entirely subterranean. The mycelium is filamentous, and partly -parasitic upon the roots of plants, especially trees, in its -neighbourhood; it is then known as _Mycorhiza_. The fruit-body is -relatively large, in some cases about the size of a hen’s egg. -Internally it is traversed by a number of winding passages (Fig. 113 -_a_), the walls of which are coated with the asci. The asci (_b_) -contain only a small number of spores, and these are set free by the -putrefaction of the fruit-body. Conidia are unknown. - - [Illustration: FIG. 113.--_Tuber melanosporum_: _a_ fruit-body - (nat. size), a portion having been removed to show the internal - structure; _b_ an ascus with ascospores.] - - _Tuber melanosporum_, _T. brumale_, _T. æstivum_, and other - species are edible. _Terfezia leonis_ and _Choiromyces - mæandriformis_ are also edible. The Truffles are always found in - woods and under trees, and disappear when these are destroyed. - France and Italy produce the best and the largest number of - Truffles, which are hunted by specially trained dogs and pigs. - - In _Elaphomyces_ (Stag-Truffle) the fruit-body has a corky - external layer, and is inedible. Some of the species are found - in this country. _E. granulatus_ is parasitic on the roots of - the Fir. - - - Family 3. =Pyrenomycetes.= - -In this family the hymenium is enclosed in small fruit-bodies, -_perithecia_ (Fig. 120 _b_), which appear to the naked eye as small -dots. In shape they resemble a globe or a flask with a narrow mouth, -through which the spores are ejected (peronocarpic ascocarps). -Different kinds of reproduction--conidia, pycnidia (chiefly with -microconidia), chlamydospores, and perithecia--are found in the same -species. The various stages in the life-history of these Fungi are so -dissimilar, that formally they were considered to be different genera. -Ergot furnishes a very good example. - - [Illustration: FIG. 114.--A small portion of an ovary attacked - with _Claviceps purpurea_ (_Sphacelia_).] - - [Illustration: FIG. 115.--An ovary with the conidial stage of - _Claviceps purpurea_ (_Sphacelia_).] - -This family may be subdivided into 3 sub-families. - - - Sub-Family 1. =Hypocreales.= - -The perithecia are _pale, fleshy, brightly coloured_, and generally -aggregated on a stroma. Conidia and chlamydospores occur very -frequently. Only one order. - -Order. =Hypocreaceæ.= In this order the majority are parasites upon -Flowering-plants (_Nectria_, _Polystigma_, _Epichloë_, _Claviceps_); -but some are parasites upon Fungi (_Hypomyces_, _Melanospora_), or upon -insects (_Cordyceps_). - - [Illustration: FIG. 116.--_Claviceps purpurea. A_ Sclerotium - with stromata (_cl_) (× by 2). _B_ Stroma divided longitudinally - to show the perithecia (_cp_). _C_ A perithecium with the - surrounding hyphæ (_hy_). _D_ An ascus ruptured, with the eight - filamentous ascospores emerging.] - -The most important member of this order is the ERGOT (_Claviceps -purpurea_, Figs. 114, 115, 116). This Fungus is found in the flowers of -many species of Grasses, especially the Rye, attacking and destroying -the ovaries. In the FIRST or CONIDIAL STAGE of the attack, the ovaries -are found covered with a white, irregularly folded mycelium (Fig. 114 -_m_, Fig. 115), formed of numerous hyphæ woven together and penetrating -the wall of the ovary. From these a number of hyphæ (Fig. 114 _a_) -project into the air and abstrict from their apices the conidia (_b_) -which serve as reproductive organs. The mycelium also secretes a -sticky, stinking fluid (honey-dew) in which the conidia are embedded -in great numbers. The honey-dew exudes from the bases of the glumes, -and is greedily sought by flies, which thus carry the conidia to -other ovaries. In this manner fresh ears are infected, which might -escape were the conidia only distributed by the wind. This stage -formerly was regarded as an independent Fungus, known as _Sphacelia -segetum_ (Fig. 115). On germination, the conidia produce either a new -mycelium (Fig. 114 _d_, _c_), or new conidia. The SECOND or SCLEROTIUM -STAGE is the one in which the Fungus passes the winter. The mycelium -penetrates deeper and deeper into the attacked ovaries, their tissues -are destroyed and replaced by the hyphæ, which gradually become more -and more felted together. A firm, pseudo-parenchymatous mass of hyphæ -is thus formed at the base of the loosely-woven _Sphacelia_, which is -in part transformed into the hard sclerotium, and the remainder thrown -off. A dark, hard, poisonous body, longer than the natural grain, -is thus formed; these bodies are known as Ergots, and were formerly -considered to be a distinct species,--_Sclerotium clavus_ (“Secale -cornutum,” Ergot, Fig. 116 _A_, _c_). The THIRD STAGE, described as -_Claviceps purpurea_, is developed in the following spring from the -germinating sclerotium, which produces dark-red stromata with short -stalks. In the stroma numerous perithecia with asci and ascospores are -produced. The latter may infect young flowers of the cereals, in which -the disease is then developed as before. - - [Illustration: FIG. 117.--_Nectria cinnabarina_: _a_ branch of - _Acer pseudoplatanus_, with conidial-layers and perithecia (nat. - size); _b_ a conidial-layer (_Tuberculoria vulgaris_); _c_, a - mass of perithecia. (_b_ and _c_ × 8.)] - - Several species of the genus _Nectria_, with blood-red - perithecia, are found as dangerous parasites, especially _N. - ditissima_, which causes “Canker” in the Beech, Ash, and Apple, - etc.; _N. cucurbitula_, which appears on Pine-trees, and _N. - cinnabarina_ (Fig. 117), whose conidial form was formerly named - _Tubercularia vulgaris_.--_Polystigma rubrum_ forms shining - red spots on the green leaves of _Prunus_-species.--_Epichloë - typhina_ is parasitic on the sheaths of Grasses, on which it - first forms a white conidial-layer, later on a yellow layer of - perithecia.--_Cordyceps_ (Chrysalis Fungus, Figs. 118, 119) - lives in and destroys insects, and after compassing their death - produces the club-formed, generally yellow, stromata, one part - of which bears conidia (_Isaria_) and another perithecia. _C. - militaris_ (Fig. 118) on the chrysalides and caterpillars of - moths, is the most common. - - The so-called _Botrytis bassiana_, which produces the disease - known by the name of “Muscardine,” in silkworms, is probably a - conidial form belonging to _Cordyceps_. - - [Illustration: FIG. 118.--_Cordyceps militaris._ I Stromata with - conidiophores (_Isaria farinosa_). II A larva, with stromata, - bearing perithecia. III A spore.] - - [Illustration: FIG. 119.--_Cordyceps robertii_ on the larva of - _Hepialus virescens_: _a_ stalk of stroma; _b_ perithecia.] - - - Sub-Family 2. =Sphæriales.= - -To this sub-family belong the majority of the Pyrenomycetes. The -perithecia are of a _firm consistence_ (tough, leathery, woody or -carbonaceous), and of a _dark_ colour. Their _covering_ is _quite -distinct from the stroma_ when this structure is present. The -stromata are sometimes very large, and may be either cushion-like, -crustaceous, upright and club-like, or branched bodies. In general, -small, inconspicuous Fungi, living on dead vegetable matter, sometimes -parasites. Free conidiophores and conidiocarps are known in many -species, and in several, chlamydospore-like forms of reproduction. -Orders 3–18 constitute the Sphæriaceæ of older systematists. - - [Illustration: FIG. 120.--_Strickeria obducens_: _a_ a portion - of an Ash-branch with the bark partly thrown off; on the wood - are numerous black perithecia (× 20); _b_ longitudinal section - through a perithecium; _c_ a spore; _d_ longitudinal section - through a pycnidium whose ascospores are being ejected; _e_ - portion of the same, with hyphæ and spores.] - -Order 1. =Sordariaceæ.=--Fungi living on dung with fragile perithecia, -either aerial or buried in the substratum. The dark brown or black -spores have either a mucilaginous envelope (_Sordaria_, etc.) or -mucilaginous appendages (_Podospora_), by means of which their -expulsion and distribution are promoted. - -Order 2. =Chætomiaceæ.= Perithecia fragile, free, bearing on the summit -a tuft of hairs. _Chætomium_, on decaying vegetable matter. - -Orders 3–7. _Perithecia scattered or aggregated, situated from the -commencement on the surface of the substratum. Stroma wanting._ - -Order 3. =Trichosphæriaceæ.= _Trichosphæria parasitica_ (Fig. 121), -on _Abies alba_; _Herpotrichia nigra_ on _Picea excelsa_ and _Pinus -montana_. - - [Illustration: FIG. 121.--_Trichosphæria parasitica_: _a_ a - twig of _Abies alba_, with epiphytic mycelium; _b_ a leaf with - mycelium and sporangia (magnified); _c_ a sporangium (× 60); _d_ - an ascus with spores (× 550).] - -Order 4. =Melanommaceæ.= _Rosellinia quercina_ lives in the roots of -1–3-year-old Oaks, and destroys the plants. - -Order 5. =Ceratostomaceæ.= - -Order 6. =Amphisphæriaceæ.= _Strickeria obducens_ (Fig. 120) has -brick-like spores, and lives aggregated on the hard branches of -_Fraxinus_. - -Order 7. =Lophiostomaceæ.= - -Order 8. =Cucurbitariaceæ.= Perithecia tufted, _at first embedded, then -breaking through_, often situated upon an indistinct _stroma_. - -Orders 9–13. _The perithecia remain embedded, and are only liberated -by the casting off of the covering layers of the substratum. Stroma -wanting._ - -Order 9. =Sphærellaceæ.= The species of _Sphærella_ have colourless, -bicellular spores. They live upon the leaves of many plants, and -develope spherical perithecia upon the fallen leaves. - -Order 10. =Pleosporaceæ.= The conidial-forms of _Pleospora herbarum_ -and _P. vulgaris_ form a black covering on various plants, known as -“smuts.”--_Venturia ditricha_ occurs on the underside of dry Birch -leaves, and perhaps to this belongs the conidial-form, _Fusicladium -pirinum_, which causes the “Rust spots” on Apples and Pears. - -Order 11. =Massariaceæ.= - -Order 12. =Clypeosphæriaceæ.= - -Order 13. =Gnomoniaceæ.= Perithecia, with peak-like aperture. _Gnomonia -erythrostoma_ in the leaves of _Prunus avium_, which turn brown and do -not fall in autumn. - -Orders 14–18. _Stroma generally well developed. The perithecia -are embedded in the stroma, but when this is rudimentary, in the -substratum._ - -Order 14. =Valsaceæ.= _Valsa._ - -Order 15. =Diatrypaceæ.= _Diatrype._ - -Order 16. =Melanconidaceæ.= - -Order 17. =Melogrammataceæ.= - -Order 18. =Xylariaceæ.= This order is the most highly developed of the -Sphæriales. The _stroma_ arises on the _surface of the substratum_, -which is generally dead or decorticated wood; it is well-developed, -crustaceous, hemispherical or upright. In the younger conditions -it is covered with a layer of conidia, and later on it bears the -_perithecia_, arranged in a layer immediately _beneath its surface_. -The ascospores are of a dark colour. Often also there are free -conidiophores. - - [Illustration: FIG. 122.--_Xylaria hypoxylon_ (nat. size) on a - tree stump: _a_ younger, _b_ an older stroma, both of which, with - the exception of the black lower portion, are covered with white - conidia; _n_, spot where the perithecia are developed; _c_ an - old stroma with upper part fallen off; _d_, _e_ large branched - stromata; _k_ conidia.] - - _Hypoxylon_ and _Ustulina_ have a cushion-like - or crustaceous stroma.--_Xylaria_ has a club-shaped - or branched stroma, often several centimetres high. _X. - hypoxylon_ (Fig. 122) and _X. polymorpha_ occur on old - tree stumps.--_Poronia_ grows on old horse dung, and has a - conical stroma. - - - Sub-Family 3. =Dothideales.= - -The _perithecia_ are always embedded in a _black stroma_, and are _not -distinctly separated_ from it. The accessory forms of reproduction are: -conidiophores, conidiocarps, and yeast-like conidia. The majority are -parasites. One order. - - Order =Dothideaceæ=. _Phyllachora graminis_ produces scab-like - patches on the leaves of the Grasses.--_Scirrhia rimosa_ grows - on the leaf-sheathes of _Phragmites_.--_Rhopographus pteridis_ - on _Pteridium aquilinum_. - - - Family 4. =Hysteriales.= - -This family, like the following, has hemiangiocarpic ascocarps -(_apothecia_). These are closed in the early stages, but when ripe -_open_ in a _valvular manner_ by a _longitudinal fissure_; they -are black, oblong, and often twisted. Some species are parasites, -especially upon the Coniferæ. - - [Illustration: FIG. 123.--_Lophodermium (Hypoderma) - nervisequium_: _a_ two leaves of _Abies alba_ seen from above - with pycnidia; _b_ a leaf seen from the underside with apothecia; - _c_ an ascus with ascospores. (× 500.)] - - [Illustration: FIG. 124.--Three leaves of the Red-pine with - _Lophodermium macrosporum_: _a_ under side of the leaves with - apothecia; _b_ a leaf from upper side with pycnidia. (× about 2.)] - - [Illustration: FIG. 125.--_Lophodermium pinastri_: _a_ leaves of - _Pinus sylvestris_ with apothecia (nat. size); _b_ two paraphyses - and an ascus with filamentous spores.] - -Order 1. =Hysteriaceæ.= _Hysterium pulicare_ upon the ruptured bark of -many trees. - -Order 2. =Hypodermaceæ.= The species of _Lophodermium_ live upon the -leaves of Conifers, and are the cause of their falling off (_blight_). -_L. pinastri_ (Fig. 125), on the leaves of _Pinus_ and _Picea_; the -leaves become red-brown and fall off; at first conidiocarps are formed, -and later apothecia; _L. nervisequium_ (Fig. 123), on _Abies alba_; -_L. macrosporum_ (Fig. 124), on _Picea excelsa_; _L. brachysporum_, on -_Pinus strobus_. - -Order 3. =Dichænaceæ.= - -Order 4. =Acrospermaceæ.= - - - Family 5. =Discomycetes.= - -The ascocarps (_apothecia_) are at first closed, and _only open_ at -the time of their ripening, not valvularly, but more or less like a -_saucer_ or _cup_, so that the hymenium lies exposed on their upper -surface. In the first three sub-families, and generally also in the -fourth, the apothecia are formed inside the substratum. The apothecia -are, in contrast to the Pyrenomycetes, light and brightly coloured, -and their size varies very much, and may be several centimetres in -diameter. Paraphyses are often present between the asci; they often -contain colouring matter, and give to the disc its characteristic -colour. The tissue on which the asci are borne is known as the -_hypothecium_. The shape and colour of the spores is not so varied as -in the Pyrenomycetes. The accessory forms of reproduction are conidia -(sometimes of two forms), chlamydospores, and oidia. The family is -divided into 5 sub-families. - - - Sub-Family 1. =Phacidiales.= - -The apothecia are developed in the interior of the substratum, which -they break through, and in general dehisce apically. The envelope is -tough and black. Hypothecium inconspicuous; hymenium flat. - - Order 1. =Euphacidiaceæ.= _Phacidium abietinum_, on the leaves - of _Abies alba_.--_Rhytisma_; the pycnidia are found in the - summer on the green leaves, while the apothecia are developed - on the fallen leaves and dehisce in the following spring. _R. - acerinum_ causes black spots on the leaves of the Sycamore, and - _R. salicinum_ on Willows. - - Order 2. =Pseudophacidiaceæ.= - - - Sub-Family 2. =Stictidales.= - -The apothecia when ripe break through the substratum which forms a -border round them. Hymenium generally saucer-shaped. - - Order 1. =Stictidaceæ.= _Stictis._ - - Order 2. =Ostropaceæ.= _Ostropa._ - - - Sub-Family 3. =Tryblidiales.= - -The apothecia are embedded in the substratum in the early stages, and -then are raised high above it. Hypothecium thick. Hymenium cup-shaped. - - Order 1. =Tryblidiaceæ.= _Tryblidium._ - - Order 2. =Heterosphæriaceæ.= _Heterosphæria patella_ - on the dead stalks of Umbellifers. - - - Sub-Family 4. =Dermateales.= - -The apothecia in the early stages are embedded in the substratum and -then break through it, or are from the first situated on the surface of -the substratum. Hypothecium thick. - - Order 1. =Cenangiaceæ.= _Cenangium._ - - Order 2. =Dermateaceæ.= _Dermatea._ - - Order 3. =Patellariaceæ.= _Patellea_, - _Biatorella_, _Patellaria_. - - Order 4. =Caliciaceæ.= _Calicium_, _Coniocybe_, etc., on the - bark of trees. - - Order 5. =Arthoniaceæ.= _Arthonia_ on the bark of several trees. - _Celidium stictarum_ on the apothecia of _Sticta pulmonaria_. - - Order 6. =Bulgariaceæ.= Apothecia gelatinous under moist - conditions, and horny when dried.--_Calloria fusarioides_; the - red apothecia break out in the spring on the dried stalks of - _Urtica dioica_; a gelatinous reproductive form of the Fungus is - found before the apothecia, which consists of oidia (formerly - described as “_Dacryomyces urticæ_”).--_Bulgaria inquinans_ on - the living or fallen trucks of Oaks and Beeches. - - [Illustration: FIG. 126.--_Botrytis cinerea_: _a_ slightly - magnified; _b_ more highly magnified; _c_ germinating conidium.] - - [Illustration: FIG. 127.--_Sclerotinia fuckeliania_: _a_ - sclerotium with conidiophores; _b_ with apothecia; _c_ section - through sclerotium and apothecium; _d_ ascus with eight - ascospores. (× 390.)] - - - Sub-Family 5. =Pezizales.= - -_The apothecia are developed on the surface of the substratum and -are waxy or fleshy_; at the commencement closed, and covered with a -saucer- or cup-shaped, seldom flat, hymenium. The _hypothecium_ is -generally well developed. This sub-family is the richest in species of -the Discomycetes and contains forms of very different habit. They grow -upon dead wood, upon the ground, and upon dung. A few are parasites. - -Order 1. =Helotiaceæ.= Apothecia with waxy envelope of colourless, -or yellowish prosenchymatous cells.--~_Chlorosplenium æruginosum_ -is found on decaying wood (particularly Oak and Birch), to which it -gives a green colour. _Sclerotinia_ has sclerotia which are developed -upon the host-plant and from which, after a period of rest, the long, -brown-stalked apothecia arise. _S. ciborioides_ (_S. trifoliorum_, -Fig. 128) is parasitic on Clover; _S. sclerotiorum_, on _Daucus_-roots, -_Phaseolus_, etc.; _S. baccarum_, on the berries of _Vaccinium -myrtillus_; “_Botrytis cinerea_” is a common parasite and is probably -the conidial form of _S. fuckeliania_ (Fig. 127).--_Helotium herbarum_ -lives on dry plant stems.--_Dasyscypha willkommii_ (Fig. 129) produces -Larch-canker on the bark of the Larch.~ - - [Illustration: FIG. 128.--_Sclerotinia ciborioides_: _a_ - sclerotium with three apothecia slightly magnified; _b_ ascus - with eight ascospores; _c_ germinating ascospore.] - - [Illustration: FIG. 129.--_Dasyscypha willkommii_: _a_ portion of - bark of _Larix decidua_ with sessile, cup-shaped apothecia (nat. - size); _b_ two paraphyses on either side of an ascus with eight - ascospores.] - - Order 2. =Mollisiaceæ.= _Mollisia cinerea_, principally on - decaying wood. - -Order 3. =Pezizaceæ.= This order contains the largest and -morphologically the highest forms of the _Discomycetes_. Apothecia -fleshy, and in the later conditions generally saucer-shaped. - - _Peziza_, with sessile apothecia, growing on the ground; - _P. cochleata_ is brown, and coiled like a snail-shell; _P. - coccinea_ is scarlet; _P. aurantia_ occurs as an orange-coloured - expansion on the ground. - - Order 4. =Ascobolaceæ.= Apothecia fleshy; in the later stages - flat or convex. The asci are, comparatively speaking, large, - and often contain a great number of spores which escape by the - casting off of a lid on the summit of the ascus. Generally - living on dung.--_Ascobolus furfuraceus_, etc. - - - Family 6. =Helvellales.= - -These Fungi have the appearance of clubs, bells, or mushrooms, -consisting of an upright _stalk_ bearing a _large and fleshy_ head, on -the _exterior surface_ of which the _hymenium_ is spread. The ascocarps -are probably gymnocarpic from the beginning, and on this account -these plants are placed in a separate family. The development of the -ascocarps is unknown. The _Morchella_ (Morell) grows on the ground; -some species are edible. 1 order. - - Order. =Helvellaceæ.= _Spathulea_ is yellow and club-shaped, - and forms “fairy rings” in woods.--_Geoglossum_ (Earth-tongue) - projects above the ground as a black tongue, or as a - club-shaped body. Several species are found in meadows and - on heaths.--_Helvella_ has a stalk, bearing an irregularly - folded head, on the external surface of which is the - hypothecium.--_Morchella_ (Morell, Fig. 130), the stalk bears on - its summit the conical or spherical head, the external surface - of which is reticulate and bears the asci.--_Mitrula. Verpa._ - - [Illustration: FIG. 130.--_Morchella esculenta_: _a_ an entire - specimen, about one half natural size; _b_ longitudinal section - through the head.] - - - APPENDIX TO THE ASCOMYCETES: - - - Family 7. =Ascolichenes (Lichen-forming Ascomycetes).= - -The Lichens were formerly classed among the Thallophyta as a group -quite distinct from the Algæ and Fungi. Investigations during the last -twenty-five years, however, have conclusively proved that the Lichens -are Fungi which reproduce in the same manner as the Ascomycetes, or, -more rarely, the Basidiomycetes, and have entered into a peculiar -_symbiotic relation with Algæ_, especially the Cyanophyceæ and -Protococcoideæ, with which they associate, and without which they -would be unable to exist. The Fungus forms the largest portion of the -Lichen, enclosing the Alga with which it may be said to be commensal. -The Fungus especially produces reproductive bodies and absorbs the -inorganic nourishment through the rhizoids, whilst the Alga supplies -it with the organic materials. In consequence of this the Lichens, in -contradistinction to other Fungi, need light for the development of -their nutritive organs, and are therefore, in any case internally, of -a more or less greenish colour. The form and condition of the thallus -is unusual among the Fungi, and they can grow upon rocks and in other -places where no dead organic matter, such as would be required by other -Fungi, is obtainable. - - [Illustration: FIG. 131.--Transverse section through the thallus - of _Sticta fuliginosa_ (× 500): _r-r_ rhizoid-strands, which - arise from the under side; _g-g_ gonidial layer; _m_ medullary - layer; _o_ upper, _u_ lower cortex.] - -Two cellular forms are therefore to be found in each Lichen: - -1. The cells which belong to the Fungus. These are generally septate, -branched _hyphæ_ without any trace of chlorophyll. In the thallus of -the majority of Lichens there may be found a medullary layer (Fig. -131 _m_) of loosely-woven hyphæ, between which there are large air -chambers; and an _external layer_ (cortex) (Fig. 131 _o_, _u_) formed -of closely-woven hyphæ without any intercellular spaces. In some -Lichens (Collemaceæ) the hyphæ wind about in the thallus, being equally -distributed throughout, without forming any decided strata. These -Lichens moreover become gelatinous when exposed to moisture (Fig. 132), -on account of the swelling of the walls of the Algæ. The hyphæ contain -protoplasm with drops of oil, but never starch; their walls easily -swell when exposed to damp after having been dried, and in some (_e.g._ -_Cetraria islandica_) they become gelatinous when cooked. Certain -strata of hyphæ become blue on treatment with iodine alone, from which -it is inferred that the wall is allied, in its chemical nature, to -starch. - -2. The enclosed Algæ, termed “gonidia.” Some belonging to the -Cyanophyceæ, Protococcoideæ, (especially _Pleurococcus_) and -Chroococcaceæ, are spherical and are found isolated, or in irregular -_groups_ of cells (Fig. 131 _g_); some belonging to _Nostoc_ (Fig. 132 -_g_), Lyngbyaceæ, etc., are placed in cell-rows. Each Lichen, as a -rule, has only one definite Algal-form for its gonidium. - -The gonidia either lie together in a certain stratum between the -cortex and the medullary layer (Fig. 131 _g_), or are scattered -irregularly throughout the entire thallus (Fig. 132). The thallus is -in the first instance termed “heteromerous,” in the second instance, -“homoiomerous.” The Fungal-hyphæ embrace the gonidia and apply -themselves closely to, or even penetrate them, and hence it has been -difficult to decide whether the one cellular form does or does not -develop from the other (Figs. 134, 135). - - This theory regarding the symbiosis of Fungi and Algæ to form - a Lichen is termed the Schwendenerian theory, after the first - scientist who advanced it with any weight. It had been already - indicated by De Bary, and further arguments in its support have - at a later time been adduced by Bornet, Stahl, Treub, Frank, - Bonnier, Alfr. Möller and others. - - [Illustration: FIG. 132.--_Collema microphyllum._ Transverse - section through the thallus; _g Nostoc_-chains; _h_ hyphæ.] - - [Illustration: FIG. 133.--_Ephebe pubescens._ The apex of a - branch of the thallus with two lateral branches (_s_): _h_ its - hyphæ; _g_ the apical gonidium of the main branch.] - - [Illustration: FIG. 134.--_Nostoc lichenoides_, which is attached - by a germinating thread (_h_) of _Collema glaucescens_.] - - [Illustration: FIG. 135.--_A_ Germinating spore of _Physcia - parietina_ with _Protococcus viridis_. _B Synalissa symphorea_ - with _Glæocapsa_. _C Cladonia furcata_ with _Protococcus_.] - -The thallus of the Lichen appears mainly under three forms:-- - -1. The CRUSTACEOUS, which adheres firmly to the substratum (bark, -stone) throughout its entire surface, without being raised into any -free patches or lobes. It has, in many instances, no definite outline, -and hyphal-branches from it often penetrate deeply into the substratum. -It grows at the circumference and sometimes dies away in the centre -(Figs. 138, 139, 140). - -2. The FOLIACEOUS. This also lies flat upon the substratum, but is not -firmly attached to and has a definite outline. It grows at the margin, -and raises itself a little by free outgrowths and lobes (Fig. 141). The -rhizoid-strands spring out from its whitish under surface (Fig. 131, -_r_). - - [Illustration: FIG. 136.--Portion of a hymenium: _d_ a thin - stratum on which the asci (_s_) are situated.] - - [Illustration: FIG. 137.--Spores of, _a Cladonia_, _Lecanora_ - and _Pertusaria_; _b Bæomyces_; _c Sphinctrina_; _d_, _e_, - _f_ various species of _Parmelia_; _g_, _h Verrucaria_ in its - younger and older condition; _i_, _k_ species of _Leptogium_.] - -3. The FRUTICOSE, which is attached to its substratum at a small point -from which it projects freely, either erect or pendulous. It is more -or less tufted, in the form of a bush (Figs. 142, 143). These three -thallus-forms gradually pass over by many intermediate forms into one -another. - - [Illustration: FIG. 138.--_Lecanora subfusca_: _a_ the bark on - which it is situated; _l_ the thallus; _s_ the ascocarp; _s’_ an - ascocarp.] - - [Illustration: FIG. 139.--_Graphis_ (two species).] - - [Illustration: FIG. 140.--_Pertusaria communis._] - -The Lichens, like other Ascomycetes, have very variously constructed -ascospores (Fig. 137), which are enclosed in asci (Fig. 136), usually -surrounded by paraphyses attached together. Furthermore they possess -pycnidia (Fig. 141) containing numerous microconidia. These were -formerly considered as organs of fructification, and were termed -“spermatia,” and the pycnidia, “spermogonia.” Alfr. Möller proved, -in 1887, that the microconidia are able to germinate and produce a -mycelium with new conidia, just as in other Ascomycetes. - -VEGETATIVE REPRODUCTION takes place by _soredia_, which to the naked -eye appear as whitish powder on the surface of the thallus. They are -small round bodies, formed by one or a group of gonidia, which are -surrounded by a mass of felted hyphæ. After the rupture of the cortex -they are set free, and readily carried by the wind to other places, -where under favourable circumstances they establish a new thallus. - - [Illustration: FIG. 141.--_A_ A portion of the thallus of - _Parmelia parietina_ with ascocarps (_a_) and pycnidia (_b_). _B_ - A portion of the thallus of _Cetraria islandica_ with pycnidia - at the end of small lobes. _C_ A lobe with pycnidia and ejected - microconidia. (Magnified).] - -GEOGRAPHICAL DISTRIBUTION. The Lichens are the most hardy plants, and -are the first to appear on hitherto bare rocks which they gradually -disintegrate, and hence prepare the way for the growth of other plants. -They are to be found from the Polar regions to the Equator; from the -highest snow-free mountain-peaks down to the level of the sea; on the -stems of trees; on rocks, soil, some even on inundated places; on -stones in woodland streams, and on beaches; but they are never found -upon rotten organic remains. Some grow gregariously in enormous masses, -and form wide-stretching carpets, _e.g._ Reindeer Moss (_Cladonia -rangiferina_), species of _Cetraria_ and other fruticose Lichens. - -USES. On account of the cell-wall being composed of Lichenstarch -(Lichenin), the Iceland-Lichen and Manna-Lichen (_Lecanora esculenta_) -are used as food; the latter grows on stones, in the deserts of Asia -and North Africa, and is often torn loose in large masses and carried -away by the wind. The Reindeer-Lichen is not only the principal food of -the reindeer, but it is also used in the manufacture of Danish brandy. -_Cetraria islandica_ (Lichen islandicus) is OFFICINAL. Colouring -materials (lacmus, orseille, persio) are made from several species, -especially from _Roccella tinctoria_ (from the rocky coasts of the -Mediterranean). _Parmelia saxatilis_ and particularly _Lecanora -tartarea_ are used for colouring purposes in the Northern countries. - -About 2,000 species of Lichens have been described. If we disregard the -Basidiolichenes, which will be considered on page 176, the remaining -Lichens (Ascolichenes) may be divided into the two following orders -according to the structure of the fruit-bodies:-- - -Order 1. =Pyrenolichenes.= The ascocarps (apothecia) are spherical or -flask-shaped, as in the Pyrenomycetes, more rarely linear (_Graphis_). - - According to the nature of the thallus, these Lichens may be - divided into:-- - - _a._ Thallus homoiomerous, but not gelatinous, branching - according to the mode of growth of the Algæ: _Ephebe_ (Fig. - 133), with Algæ of the genus _Stigonema_. - - _b._ Thallus homoiomerous, gelatinous: _Lichina_. - - _c._ Thallus heteromerous, crustaceous: _Verrucaria_, - _Pyrenula_; _Graphis_ (Fig. 139), which may be considered as - Hysteriaceæ with gonidia; several species of _Graphis_ are - common on bark. - - _d._ Thallus heteromerous, foliaceous: _Endocarpon_. - - _e._ Thallus heteromerous, fruticose: _Sphærophorus_. - -Order 2. =Discolichenes.= These, as in the Discomycetes, have open -apothecia, which, as a rule, are cupular, more rarely hemispherical -(_Cladonia_). - - According to the nature of the thallus, these Lichens may be - divided into:-- - - _a._ Thallus homoiomerous, but not gelatinous, branching - according to the mode of growth of the Algæ: _Cœnogonium_. - - _b._ Thallus homoiomerous, gelatinous: _Collema_ (Fig. 132), - with Algæ of the genus _Nostoc_; _Leptogium_. - - _c._ Thallus heteromerous, crustaceous: _Pertusaria_ (Fig. - 140), _Lecidea_, with apothecia open from the beginning; - _Lecanora_, with apothecia, which in the beginning are closed, - later on open, but with a rim formed by the thallus (Fig. 138); - _Bæomyces_, whose apothecia are borne on a stem formed by the - thallus. - - _d._ Thallus heteromerous, foliaceous: _Parmelia_ (_P. - saxatilis_; _P. parietina_, Wall-Lichen, Fig. 141, is yellow, - very frequent on tree-stems, stone-walls, tiles); _Physcia_ (_P. - ciliaris_, frequent on tree-stems); _Sticta_ (_S. pulmonacea_, - Lung-Lichen, on tree-stems); _Peltigera_, especially on the Moss - among trees; _Umbilicaria_, on rocks. - - _e._ Thallus heteromerous, fruticose: _Cetraria_ (_C. - islandica_), “Iceland Moss,” with an olive-brown, flat, - furrowed, fringed thallus, on heaths; _C. nivalis_, white, in - the Polar regions; _Evernia_, _Ramalina_, _Usnea_ (_U. barbata_, - Beard-Lichen, Fig. 143); _Roccella_, _Stereocaulon_, _Cladonia_, - of which the genus _C. rangiferina_, Reindeer-Moss (Fig. 142) is - important; _Cladonia_ has two kinds of thallus, one scaly and - leaf-like, the other erect, which bears the apothecia and may be - fruticose (Fig. 142), or cupular (Fig. 144); they grow in soil - in forests and on heaths. - - [Illustration: FIG. 142.--_Cladonia rangiferina_: _s_ ascocarp.] - - [Illustration: FIG. 143.--_Usnea barbata_: _s_ ascocarp. - (Slightly magnified.)] - - [Illustration: FIG. 144.--_Cladonia pyxidata._] - - - Sub-Class 2. =Basidiomycetes.= - -This sub-class embraces the most highly developed Fungi, with large -“fruit-bodies,” which in ordinary language we shortly term Funguses, -Toadstools, or Mushrooms. - -They have no sporangia, but reproduce only by means of basidiospores, -conidia, chlamydospores and oidia. The chief characteristic of this -sub-class is the _basidium_ (Fig. 145), _i.e._ the conidiophore, which -has a distinctive form, and bears a definite number (generally 4) of -characteristically shaped conidia (basidiospores, Fig. 145 _c_, _d_, -_e_). - - [Illustration: FIG. 145.--Development of spores in _Corticium_.] - -The summit of each basidium is produced generally into four conical -points (_sterigmata_, Fig. 145 _b_), from each of which a basidiospore -is abstricted. The basidia may be classified into three principal -groups, each of which accompanies a distinctive conidiophore: 1, -the long, filamentous, _transversely divided_ basidia, with lateral -sterigmata and spores, found in the Uredinaceæ (Figs. 146 _D_, 153), -Auriculariaceæ (Fig. 160 _B_), and Pilacraceæ; 2, the spherical, -_longitudinally divided_ basidia of the Tremellaceæ (Figs. 160 _C d_; -161 iii. iv.); and 3, the ovoid, or cylindrical, _undivided_ basidia of -the Autobasidiomycetes (Figs. 145, 163, etc.); the two last have apical -sterigmata and spores. - - The first two groups are the septate basidia (_protobasidia_), - of the _Protobasidiomycetes_; while the unseptate basidia - (autobasidia) of the _Autobasidiomycetes_ are the third group. - On the formation of the basidiospores, the nucleus of the - basidium divides into four nuclei, each of which is transferred - to a spore. - -In addition to the basidia, _simple conidiophores_ are also found. -In the Protobasidiomycetes, the simple conidia are very generally -found as accessory methods of reproduction in conjunction with the -basidiospores; but less frequently in the Autobasidiomycetes, _e.g._ -among the Dacryomycetes, Tomentellaceæ, _Heterobasidion annosum_. - - The simple conidiophores vary in size, and in the number and - shape of the conidia; they, however, resemble the basidia, - and are doubtless an early stage in the development of the - definitely formed basidia. - -Finally, well-defined _chlamydospores_, formed in various ways, appear -in the Basidiomycetes as supplementary reproductive bodies (compare p. -90). Among the Protobasidiomycetes, chlamydospores are at present only -found among the Uredinaceæ, but in various forms; in the majority of -families of the Autobasidiomycetes _oidia_ frequently occur (Fig. 162), -but genuine chlamydospores seldom. - -In the same species several of the known forms of reproduction may be -distinguished. - -The _mycelium_ is generally composed of white, branched strands, -consisting of numerous felted hyphæ; in some, sclerotia are found.--The -great majority are saprophytes; some (particularly all the Uredinaceæ), -are parasites. - - - DIVISIONS OF THE BASIDIOMYCETES. - - Series 1. PROTOBASIDIOMYCETES: partly gymnocarpic, partly - angiocarpic. - „ 2. AUTOBASIDIOMYCETES. - Family 1. DACRYOMYCETES: gymnocarpic. - „ 2. HYMENOMYCETES: partly gymnocarpic, partly - hemiangiocarpic. - „ 3. PHALLOIDEÆ: hemiangiocarpic. - „ 4. GASTEROMYCETES: angiocarpic. - Appended. BASIDIOLICHENES: Lichen-forming basidiomycetes. - - - Series I. =Protobasidiomycetes.= - -To this series belong the lowest of the Basidiomycetes. The _basidia_ -appear in two principal forms (1 and 2 on page 144) and are _divided_ -into four cells, either transversely or longitudinally, each division -forming a sterigma which abstricts a basidiospore. The first three -orders, Uredinaceæ, Auriculariaceæ, and Tremellaceæ have _gymnocarpic_ -fruit-bodies, while those of the Pilacraceæ, on the contrary, are -_angiocarpic_. - -Order 1. =Uredinaceæ (Rusts).= All the Rust-Fungi are parasites, their -mycelium living in the interior of the stems and leaves of their -hosts, causing red, brown, or black spots--hence their name--and -malformations, sometimes of considerable size. - -The Rust-Fungi are gymnocarpic and destitute of a hymenium; for these -reasons they are regarded as the simplest order of the Basidiomycetes. -They are entirely parasitic, and their filamentous, branched mycelium -ramifies in the intercellular spaces of its host, and often protrudes -haustoria into the cells. The mycelium is perennial should it enter a -woody tissue; it may also hibernate in the rhizomes of perennial herbs -and permeate the shoots springing from them, but in the majority of -the Rust-Fungi the mycelium has a very limited growth. The chief means -of reproduction of the Rust-Fungi are the _chlamydospores_, which in -the more highly developed species occur in three forms, namely, the -teleuto-, æcidio-, and uredo-spores. The spores, in the host, are -formed immediately beneath its epidermis, which is ruptured on the -ripening of the spores, with the production of “rust,” brown, red, or -black spots. Those chlamydospores which produce basidia are termed -_teleutospores_. The spore on germination produces a _transversely -divided basidium_, “promycelium,” on which basidiospores, “sporidia,” -generally four in number, are produced on lateral sterigmata. This -basidio-fructification is _gymnocarpic_; the basidia neither form a -hymenium nor a fruit-body (only _Cronartium_ and _Gymnosporangium_ have -a slight indication of a basidio-fructification). - -Many Rust-Fungi, in addition to basidiospores, have small, _unicellular -conidia_, “spermatia,” which are borne in conidiocarps, “_spermogonia_.” - -The ~TELEUTOSPORES~ (_Winter-spores_) may be either unicellular or -multicellular; in the majority of cases they are enclosed in a hard -outer cell-wall, the exospore, which in some cases is very strongly -developed; they have also a long or short stalk, the remains of the -spore-bearing hypha. Each cell of the teleutospore has _one germ-pore_ -(a thin portion of the wall, for the protrusion of the germ-tube; -in _Phragmidium_ and _Gymnosporangium_ there are, however, several -germ-pores). The colour of the teleutospores is generally much darker -than that of the uredospores, and it is by these that the majority of -the Rust-Fungi _hibernate_. - - In _Gymnosporangium_, two kinds of teleutospores are found - (distinguished by their size and thickness of exospore). In many - species of _Puccinia_, the form of the teleutospores varies - very much, so that in the same layer spores have been observed - with the characteristic form of other, allied genera.--The - teleutospores of _Endophyllum_ resemble æcidiospores, since they - are united in chains, whose cells are easily separated, and are - produced in the interior of a “peridium.” The multicellular - teleutospores of _Coleosporium_ function as basidia, and from - each cell immediately produce basidiospores.--The teleutospores - of _Coleosporium_ and _Chrysomyxa_, differ from other - teleutospores in the absence of exospore and germ-pore. - -The ÆCIDOSPORES (_Spring-spores_) are produced in chains which are -generally enclosed in an _envelope_ of hyphæ, the _peridium_; the -_peridium_ enclosing the spores being termed the _æcidium_. The -æcidiospores are unicellular, and generally of an orange colour; they -are often separated by intermediate cells which wither and so assist -in the distribution of the spores. The exospore is made up of minute, -radially arranged rods. _Generally germination_ proceeds _immediately_, -the æcidiospore producing a germ-tube, which developes into a mycelium -bearing either uredo- or teleutospores. - - The æcidia of many Rust-Fungi were formerly considered as - distinct genera. The æcidia of _Phragmidium_, _Triphragmium_, - and _Melampsora_, in which the _peridium is wanting_, were in - part considered as _Cæoma_. The æcidia with fimbriate edge, - or those of _Gymnosporangium_ with longitudinal lattice-like - splits, were considered as “_Rœstelia_” (Lattice-Rust); large, - sac-shaped æcidia on the Coniferæ were known as _Peridermium_. - -The ~UREDOSPORES~ (_Summer-spores_) are unicellular and arise singly, -seldom in chains (_Coleosporium_). Their colourless, warty exospore -bears, _in the equatorial plane_, 2–8 _germ-pores_. In the majority, -_germination_ proceeds _immediately_, and a mycelium is produced which -at first gives rise to uredospores and afterwards to teleutospores. - - The uredospore-formations of _Melampsorella_ and _Cronartium_ - are enclosed in an _envelope_, and hence resemble - æcidia.--Between the uredospores sterile, unicellular hyphæ - (paraphyses) may be found. - -The _spermogonia_ are spherical or pear-shaped _conidiocarps_, -generally embedded in the substratum, and are produced before the -æcidia, before or simultaneously with the uredospores, or before the -teleutospores. The conidia, as far as observations go, do not generally -germinate under ordinary conditions. - -Among the Rust-Fungi some species are found which only form -basidiospores and teleutospores (_Puccinia malvacearum_, _Chrysomyxa -abietis_). Other species have in addition uredospores; others -spermogonia and uredospores; others spermogonia and æcidia; others -spermogonia, uredospores and æcidia. Those species in which all the -methods of reproduction are not developed must not be considered as -incomplete forms. - -As a rule the mycelium, which is produced from the basidiospores, -developes æcidia; in the species, however, without æcidia, it -developes the uredo-form, and when the uredospores are also absent, -the teleutospore-form. It has been established in some species -of _Puccinia_ and _Uromyces_ that the formation of æcidia can be -suppressed, and it is not a necessary part of the cycle of development -of the species. - - The majority of Rust-Fungi hibernate in the teleutospore-form. - Many species are able to hibernate in the uredospore-form - (_Coleosporium senecionis_). Others pass the winter in the - æcidio-form, and develope æcidia on new hosts (_Uromyces pisi_, - on _Euphorbia cyparissias_; _Phragmidium subcorticium_, on - _Rosa_; _Æcidium elatinum_, on _Abies alba_). In _Chrysomyxa - abietis_, the mycelium, developed from the basidiospores, - survives the winter. - -Among the Rust-Fungi, with several forms of reproduction, there are -about sixty whose development can only be completed by an _alternation -of hosts_, that is, on one host only uredo-and teleutospores -are produced, while the further development of the germinating -basidiospores, and the formation of the æcidia and spermogonia from its -mycelium, can only take place on a second quite distinct and definite -host (_heterœcious_ or _metoxenous_ Fungi). Those Fungi which have all -their forms of reproduction on the same host are termed _autœcious_ or -_autoxenous_. It is not, however, always necessary that the heterœcious -Rust-Fungi should regularly change their hosts; for example, _Puccinia -graminis_ can hibernate in the uredo-form on the wild Grasses, and in -the spring can distribute itself again in the same form. - - As a consequence of the alternation of hosts the various forms - of development were considered as independent genera (_Uredo_, - _Æcidium_, _Rœstelia_, _Cæoma_, _Peridermium_), until De Bary - and Oersted established, about the same time (1865), the mutual - connection of some forms, and paved the way for the right - conception of these Fungi. - - [Illustration: FIG. 146.--_Puccinia graminis_.] - -As an example of one of the most highly developed species, _Puccinia -graminis_, the “Rust of Wheat,” holds a prominent position. Its -uredospores and teleutospores are produced (Fig. 146) on Grasses -(on cereals, especially Wheat, Rye, Oats, and many wild Grasses), -while the æcidia and spermogonia are confined to the Berberidaceæ. -The teleutospores, developed on the Grasses, hibernate on the dried -portions of their host, and in the succeeding year each of the -two cells of the teleutospore may develop a _basidium_ with four -basidiospores (Fig. 146 _D_, _c_). The basidiospores are distributed by -the wind, germinate quickly, and only proceed to further development on -_Berberis_ or _Mahonia_. The germ-tube _bores through the epidermis_ of -the Barberry-leaf, and forms a mycelium in its interior, its presence -being indicated by reddish-yellow spots on the leaf. After 6–10 days -the flask-shaped _spermogonia_ appear (Fig. 147 _B_; _C_, _a_; conidia -in Fig. 147 _D_) and a few days later the cup-shaped _æcidia_ (Fig. -147 _A_; _C_, _c_, _d_, _e_). The former are generally on the _upper_, -and the latter on the _under side_ of the leaf. The orange-coloured -æcidiospores scatter like dust, and germinate only on Grasses; the -germination takes place in about two days when placed on any green -part of a Grass. The germ-tube enters the Grass-leaf through a stoma; -a mycelium is developed in the leaf, giving rise to a small, oval, -rust-coloured spot (Fig. 146 _A_); in about 6–9 days the epidermis is -ruptured over the red spot, and numerous reddish-yellow _uredospores_, -formed on the mycelium, are set free. The uredospores (Fig. 146 _B_) -are scattered by the wind, and can germinate should they fall on the -green portions of other Grasses: they then emit 2–4 germ-tubes through -the equatorially-placed germ-pores. The germ-tubes enter a leaf through -a stoma, a new mycelium is then developed, and in about eight days -a fresh production of uredospores takes place, which germinate as -before. The uredospore-mycelium very soon produces, in addition, the -brown _teleutospores_, which give a brown colour to the rust-coloured -spots, the familiar uredospores on the cereals being quite suppressed -towards the close of the summer (Fig. 146 _C, D_). The “Rust of Wheat” -hibernates on some wild Grasses in the uredospore-form. - - [Illustration: FIG. 147.--_Æcidium berberidis_. _A_ Portion of - lower surface of leaf of Barberry, with cluster-cups (æcidia). - _B_ A small portion of leaf, with spermogonia, from above. _C_ - Transverse section of leaf on the upper side, in the palisade - parenchyma are three spermogonia (_a b_); on the lower side an - unripe æcidium (_c d_) and two ripe æcidia (_d, e, f_); _f_ chain - of æcidiospores. _D_ Hyphæ, forming conidia.] - - GENERA. _Puccinia_ (Fig. 146, 147) has bicellular teleutospores, - each having a germ-pore, and the æcidia when present have an - indented peridium; some species, as exceptions, have 1–3-celled - teleutospores. Many species are HETERŒCIOUS, for example, _P. - graminis_, described above; _P. rubigo_, which also infests - various Grasses, but whose æcidia appear on _Anchusa_; the - masses of teleutospores are small; they contain paraphyses, and - are for a long time covered by the epidermis. _P. coronata_, on - Oats and Rye Grass; its æcidia on _Rhamnus_; the teleutospores - are surmounted by a crown--“coronate processes.” _P. - phragmitis_, on Reeds; æcidia on species of _Rumex_ and _Rheum_. - _P. moliniæ_, on _Molinia cœrulea_; the æcidia on Orchids. - _P. poarum_, on Meadow-Grass; æcidia on _Tussilago_. Various - Puccinias growing on species of _Carex_ have their æcidia on - _Urtica_, _Lysimachia_, _Cirsium_, _Pedicularis_, etc.--Of - those AUTŒCIOUS species, which have all their generations on the - same host, may be noted:--_P. galii_, _P. menthæ_, _P. violæ_, - _P. epilobii_, _P. asparagi_, which grow on the hosts from - which they have taken their specific names.--As representative - of a group which have spermogonia, uredo-and teleutospores on - the same host, but on different individuals, _P. suaveolens_, - on the Field-Thistle, may be mentioned. The spermogonia have - a strong odour.--A peculiar group (_Leptopuccinia_) has only - teleutospores, which germinate immediately, and whilst still - attached to their living host. To this group belong _P. - arenariæ_, on a number of Caryophyllaceæ; and _P. malvacearum_, - on various Malvaceæ, introduced in 1873 from South America to - Europe, where it soon proved very destructive to Hollyhocks. - - _Uromyces_ (Fig. 149) differs only from _Puccinia_ in always - having unicellular teleutospores. Among this genus both - heterœcious and autœcious species are found. To the first - group belong _U. pisi_, whose æcidia are found on _Euphorbia - cyparissias_, and _U. dactylidis_, whose æcidia appear on - _Ranunculus_; to the second group belong _U. betæ_, _U. - phaseoli_, _U. trifolii_. - - _Triphragmium_ has teleutospores with three cells (one below and - two above), on _Spiræa ulmaria_. - - _Phragmidium_ (Fig. 150) has teleutospores consisting of a - row of cells (3–10) arranged in a straight line; the upper - cell has one germ-pore and the others four germ-pores placed - equatorially. Both this and the preceding genus have large, - irregular æcidia without peridia, but often with bent, club-like - paraphyses (150 _b_ and _c_); they are all autœcious, and are - only found on the Rosaceæ. - - [Illustration: FIG. 148.--_Gymnosporangium sabinæ_. A small - portion of the epidermis of a Pear-leaf (_a_) pierced at _b_ by - the germinating basidiospore (_c_).] - - [Illustration: FIG. 149.--_Uromyces genisteæ_; _a_ uredospore; - _b_ teleutospore.] - - _Endophyllum_ (see above, under teleutospores, p. 147) on - species of _Sempervivum_. - - _Gymnosporangium_ (Figs. 152, 154) has bicellular teleutospores - collected in large, gelatinous masses formed by the swelling of - the long spore-stalks; in each cell 2–4 germ-pores are found. - Uredospores are wanting. All the species are heterœcious; the - teleutospores appear on _Juniperus_, the æcidia (_Rœstelia_) - on the Pomaceæ. _G. sabinæ_, on _Juniperus sabina_, _J. - virginiana_, etc., has the æcidia (“_Rœstelia cancellata_”) - on _Pyrus communis_ (Figs. 152, 148); _G. juniperinum_, on - _Juniperus communis_ with “_Rœstelia cornuta_” (Fig. 154 _a_) - on _Sorbus aucuparia_, _Aria nivea_ (_S. aria_) and _Malus - communis_; _G. clavariæforme_ on _Juniperus communis_, the - æcidium belonging to it (“_Rœstelia lacerata_”) on _Cratægus - oxyacantha_. - - _Melampsora_ has prismatic teleutospores placed parallel to each - other and forming a crustaceous layer; in many species they - are divided longitudinally into several cells (Fig. 151). The - æcidia, without peridium, belonged to the old genus _Cæoma_. - _M. caprearum_, on Willows, has the æcidia (_Cæoma euonymi_) on - _Euonymus_. _M. hartigii_, on Osiers; the æcidium on _Ribes_. - _M. mixta_, on _Salix repens_ and Orchids. _M. pinitorqua_, - on leaves of the Aspen, æcidia on Pine branches (Pine shoot - fungus); _M. populina_ on _Populus monilifera_ and _nigra_; _M. - betulina_ (Fig. 153), on Birch leaves; _M. padi_ (Fig. 151), - on leaves of _Prunus padus_, developes teleutospores in the - epidermal cells; _M. lini_ is the cause of injury to the Flax; - _M. agrimoniæ_. - - [Illustration: FIG. 150.--_Phragmidium gracile_: _a_ an - uredospore; _b_ and _c_ two paraphyses; _d_ a young teleutospore; - _e_ a teleutospore with a basidium and two basidiospores (_s_); - _f_ two series of æcidiospores (_Ph. rosæ_).] - - _Calyptospora gœppertiana_; teleutospores on _Vaccinium vitis - idæa_; spermogonia and æcidia on _Abies alba_ (Firneedle-Rust). - - _Coleosporium_ (Fig. 155) forms its uredospores in - reddish-yellow chains; for the teleutospores, see page 147. - _C. senecionis_, on the Groundsel; its æcidium (_Peridermium - wolffii_) on Pine-leaves (Fig. 155 a). Other species on - _Sonchus_, _Petasites_, _Campanula_, _Rhinanthaceæ_. - - _Chrysomyxa_ (Fig. 156) has bright red, branched - teleutospore-chains; each spore developes a 4-celled basidium. - _C. ledi_, on _Ledum palustre_; its æcidia on the leaves of the - Fir. _C. abietis_ (Fig. 156), without uredo-and æcidiospores; - teleutospores on the leaves of the Fir. In the first summer, - yellow bands are formed on the leaves, and in the following - spring the red cushions of spores. - - [Illustration: FIG. 151.--_Melampsora padi_: _a_ and _b_ - uredospores; _c-f_ teleutospores, seen from different sides.] - - [Illustration: FIG. 152.--Pear-leaf, seen from the under side, - with “_Rœstelia cancellata_”: in different ages (_a_ youngest, - _d_ oldest).] - - [Illustration: FIG. 153.--_Melampsora betulina_: _a_ uredospores; - _b_ three contiguous teleutospores, one of which has developed a - basidium with three basidiospores. (× 400.)] - - [Illustration: FIG. 154.--_Gymnosporanginum juniperinum_: _a_ - a small leaf with three clusters of æcidia (nat. size); _b_ - three conidia; _c_ two æcidiospores on one of which are seen the - germ-pores; _d_ a portion of the wall of an æcidium; _e_, _f_ two - teleutospores.] - - [Illustration: FIG. 155.--_Coleosporium senecionis_: _a_ - Pine-leaves with æcidia (_Peridermium wolffii_) nat. size; _b_ - an æcidiospore; _c_ a germinating æcidiospore; _d_ a chain of - uredospores; _e_ a chain of teleutospores of which the terminal - one has germinated and produced a basidiospore (_s_).] - - _Cronartium_ (Figs. 157, 159) has unicellular teleutospores - united in numbers to form erect threads or columns; the - uredospores are enclosed in a “peridium”; _C. ribicola_ (Fig. - 157), on leaves of Ribes (especially Black Currants); its - æcidia (_Peridermium strobi_, or _P. klebahni_) on the stems - and branches of _Pinus strobus_ (Fig. 159), on which it causes - great damage; _C. asclepiadeum_, on _Vincetoxicum officinale_; - its æcidia (_Peridermium cornui_) on the stems and branches of - _Pinus silvestris_. - - [Illustration: FIG. 156.--_Chrysomyxa abietis_: _a_ leaf of the - Fir, with 5 clusters of basidiospores (× 4); _b_ branched rows of - teleutospores springing from the mycelium (_m_).] - - [Illustration: FIG. 157.--_Cronartium ribicola_: _a_ mass - of uredospores (× 50); _b_ an uredospore; _c_ a column of - teleutospores (× 60); _d_ a small portion of the same more highly - magnified, with a basidium and two basidiospores (_s_).] - - To the Fungi of which the æcidium is known, whilst the remaining - forms are still undetermined, but which are without doubt - heterœcious, belong _Æcidium elatinum_, which produces the - enormous “witches’ brooms” and barrel-shaped swellings on stems - and branches of _Abies alba_; and _Æcidium strobilinum_ (Fig. - 158), which attacks Fir-cones, causing all the scales to become - covered with clusters of æcidia opening by a lid. _Hemileia - vastatrix_ destroyed the coffee plantations in Asia. - - [Illustration: FIG. 158.--_Æcidium strobilinum_: _a_ scale of - cone of _Picea excelsa_, with numerous æcidia; _b_ æcidiospores - arranged in a series; _c_ a cell of the peridium.] - -Order 2. =Auriculariaceæ.= The _long, transversely divided_ basidia -bear laterally 4 _long sterigmata_ with basidiospores (Fig. 160 _B_) -and are united to form an _hymenium_ on the surface of the fruit-body. -Parasites or saprophytes. - - _Auricularia sambucina_ (_Auricula judæ_), Judas’-ear, has large - fruit-bodies, which may attain the size of several inches, - resembling an ear or a mussel shell. In the moist condition they - are flesh-coloured, tough and gelatinous, but when dried, become - hard, grey and wrinkled; the exterior is covered with short - hairs; while the internal surface bears the hymenium. Habitat: - stems and branches of old Elder-trees (_Sambucus_). - -Order 3. =Tremellaceæ.= The _round, pear-shaped, longitudinally divided -basidia_ bear 4 _elongated sterigmata_, situated apically, and 4 -basidiospores (Fig. 160 _C_, _D_), and are united into the _hymenium_ -on the surface of the fruit-body. The fruit-bodies are frequently -gelatinous and quivering; similar fruit-bodies are also found in the -Dacryomycetaceæ and Hydnaceæ. Simple conidiophores, which appear not -infrequently in the basidiocarps, before the basidia, are known in many -species. Saprophytes. - - [Illustration: FIG. 159.--_Peridermium strobi_: æcidia of - _Cronartium ribicola_ (nat. size).] - - [Illustration: FIG. 160.--_B Auricularia sambucina_: _a-d_ - basidia in various stages of development; _e_ a sterigma - bearing a spore.--_C Tremella lutescens_: _a-d_ basidia seen - from various sides (_b_ from above) and in various stages of - development; _e_ sterigma with basidiospore (× 400). _D Exidia - glandulosa_: _a-c_ various stages in the development of a - basidium; _d_ sterigma with basidiospore (× 350).] - - _Exidia_ has kidney-shaped, oblong basidiospores, and small, - hook-like conidia; _E. glandulosa_, _E. albida_, etc., on - wood.--_Craterocolla_ has conidiocarps; _C. cerasi_ on - Cherry-wood.--_Sebacina incrustans_; the yellow, fleshy, or - cartilaginous fruit-bodies are found in autumn covering the - ground in moist woods.--_Tremella_ has round basidiospores; - _T. mesenterica_ has irregularly-folded, quivering, orange - fruit-bodies, about one inch in breadth; _T. lutescens_ (Fig. - 161) has orange-yellow conidial-and yellow basidial-layers; _T. - frondosa_ has fruit-bodies upwards of a foot in breadth. - -Order 4. =Pilacraceæ.= The _transversely divided basidia_ have _no -sterigmata_, but sessile basidiospores, and fill up the cavity of a -_closed_ (_angiocarpic_) _fruit-body_ as a gleba without a regular -arrangement (hymenium wanting). - - _Pilacre fagi_ on the old stems of the Copper-Beech; _P. - petersii_, on dried branches of the Hornbeam, has stalked, - capitate fruit-bodies. - - [Illustration: FIG. 161.--_Tremella lutescens_: I and II - fruit-bodies (nat. size); III vertical section through a - fruit-body; _b_ basidia; _c_ conidia; IV-VI basidia; VII - basidiospore with a second spore; VIII a basidiospore with - yeast-like budding (cultivated); IX a conidiophore. (III-IX about - 400.)] - - - Series 2. =Autobasidiomycetes.= - -This second and larger part of the Basidiomycetes is characterised -by its more highly differentiated, _undivided_, club-shaped, or -cylindrical basidia, which generally bear 4 (seldom 2, 6, 8) -apically-placed sterigmata and basidiospores (Fig. 145). The -fruit-bodies are partly _gymnocarpic_ (in the first 3 orders and in -some Agaricaceæ), partly _hemiangiocarpic_ (in orders 3–6 of the -Hymenomycetes and in the Phalloideæ, the fruit-bodies in these orders -are in the young conditions more or less angiocarpic, but later on -generally open below and bear the hymenium on the under surface of the -fruit-body), partly also _angiocarpic_ (in the Gasteromycetes). - - [Illustration: FIG. 162.--_Dacryomyces deliquescens_: I - fruit-body (nat. size); II vertical section through the hymenium; - III germinating basidiospore; IV a portion of mycelium with - conidia; V a germinating conidium; VI and VII chains of oidia - more or less strongly magnified; VIII basidiospore of _D. - longisporus_; IX germinating basidiospore of _D. ovisporus_; - X and XI _Calocera viscosa_; X fruit-body (nat. size); XI - basidia with basidiospores (highly magnified); XII _Dacryomitra - glossoides_ (nat. size).] - - - Family 1. =Dacryomycetes.= - -The _long, club-shaped basidia_ bear _two tapering sterigmata_, which -develope remarkably large basidiospores (Fig. 162 II, XI) and form -_gymnocarpic_ fruit-bodies with hymenium. 1 order: - -Order 1. =Dacryomycetaceæ.= This order comprises 4 genera of which the -first two develope the hymenium on the whole surface of the fruit-body, -but the two last only on its apex. - - _Dacryomyces_: the folded, gelatinous, _Tremella_-like - fruit-bodies break out in winter on dried wood (hedges) in - the form of red or yellow drops. _D. deliquescens_ is very - common (Fig. 121). The following genera have cartilaginous - fruit-bodies.--_Calocera_ (Fig. 162), with club-like, simple, - or branched, _Clavaria_-like, fruit-bodies; the orange coloured - fruit-bodies of _C. viscosa_ grow aggregated together on the - wood of Conifers.--_Guepinia_ resembles a _Peziza_, and has - the hymenium only on the hollow upper surface.--_Dacryomitra_ - resembles a _Mitrula_ (Fig. 162). - - - Family 2. =Hymenomycetes.= - -This family is very rich in species (more than 8000 have been -described), and to it belong all the “Mushrooms” and “Toadstools.” -The _fruit-bodies_ present very various forms; they are generally -fleshy, very perishable, seldom leathery or corky, in the last case -often perennial. The _basidia_ are more or less _cylindrical_ and bear -_generally_ 4 (seldom 2, 6 or 8) _sterigmata and basidiospores_. The -hymenium in the fully-formed fruit-bodies lies free on the surface: in -orders 1 and 2 and a portion of order 6 it is from the commencement -exposed, fruit-bodies _gymnocarpic_; orders 3–6 have _hemiangiocarpic_ -fruit-bodies (p. 157). In the first order the basidia (or the -hymenium) are developed immediately from the mycelium (Fig. 163); the -fruit-bodies of orders 2 and 3 present a higher grade of development, -and have between the mycelium and hymenium a special hyphal-tissue, -a _stroma_, which is crustaceous, club-like, or coralloid, etc., -and in general bears the hymenium on the largest part of the free, -smooth surface. In the forms most highly developed (orders 4–6) a -new tissue--the _hymenophore_--is introduced between the stroma and -hymenium, which appears on the under side of the fruit-body in the -form of warts, projections, tubes, folds or lamellæ (Figs. 166, 167, -174 _bc_). _Paraphyses_ are frequently found in the hymenium, among -the basidia. In the Hymenomycetes few examples of _conidia_ can be -recognised at first. More frequently _chlamydospores_ are found, -particularly _oidia_. The _mycelium_ is richly branched, generally -colourless, often perennial; it lives in humus or decaying wood, and is -seldom parasitic. The hyphæ generally have clamp-connections and unite, -sometimes, to form a rhizomorpha (Fig. 177) or sclerotia with coloured, -pseudo-parenchymatous covering. - - [Illustration: FIG. 163.--_Exobasidium vaccinii._ I - Hypertrophied stem of _Vaccinium vitis idæa_; II leaf with - gall-like swelling; III section of II; IV transverse section: _m_ - mycelium between the parenchymatous cells; _p_ hypodermal cells; - _e_ epidermis with basidia in various stages of development; V - epidermis with germinating spores; VI and VII spores germinating - in water (IV-VII × 620).] - -Order 1. =Tomentellaceæ.= To this order belong the simplest of the -Hymenomycetes. The basidia (Fig. 145) arise free and irregularly -from the mycelium; a _hymenium_ is _entirely absent_ or _very -slightly formed_ (in _Corticium_ it attains its highest development); -_fruit-bodies_ are _also wanting_.--In general they form flaky, -membranous or leathery coverings on bark and wood. Some are parasites. - - _Hypochnus_ without conidia.--_Tomentella_ with conidiophores; - growing on wood or earth.--_Exobasidium vaccinii_ (Fig. 163), - a parasite on _Vaccinium_, _Andromeda_, _Arctostaphylos_, and - _Rhododendron_, forms flaky-powdery, white or red coverings and - may cause hypertrophy of the parts attacked. _E. warmingii_ is - parasitic on _Saxifraga_; _E. lauri_ causes outgrowths on the - stem of _Laurus canariensis_ as long as a finger, which formerly - were regarded as aerial roots.--_Corticium_ forms membranous - to leathery layers or crusts; _C. quercinum_ on wood and bark, - particularly Oak, is flesh-coloured; _C. cæruleum_ has a blue - hymenium; _C. giganteum_ on the bark of fallen Pine-trees. - -Order 2. =Clavariaceæ.= The hymenium is situated on a stroma, and -either completely _covers the smooth surface_ of the more or less -fleshy _gymnocarpic fruit-body_, or is confined to a tolerably well -defined _upper portion_ of it (_Typhula_). Paraphyses absent. The -vertical, white, yellow, or red fruit-bodies are roundish or club-like, -undivided or richly branched (Fig. 125). Generally on the ground in -woods, seldom on tree-stems, etc. - - [Illustration: FIG. 164.--_Clavaria coralloides_ (nat. size).] - - GENERA: _Clavaria_, generally large Fungi with thick, round - branches. _C. botrytis_ has a very thick, tubercular stem with - numerous short, flesh-coloured branches: it has an agreeable - taste. _C. coralloides_ has a brittle, richly-branched - fruit-body (Fig. 164); basidia with two large spores. _C. - pistillaris_ consists of a single, undivided club of a - yellowish-white colour.--_Sparassis_ has compressed, leaf-like, - curled branches; _S. crispa_ has fruit-bodies as large as - a white cabbage-head, with an agreeable taste.--_Typhula_ - and _Pistillaria_ are small Fungi with filamentous stalks, - terminating in a small club. The fruit-bodies of the former - often arise from a small, spheroid sclerotium; the latter is - distinguished by the basidia bearing only two spores. - -Order 3. =Thelephoraceæ.= The hymenium is placed on a stroma and -_covers the smooth surface_ of the leathery _hemiangiocarpic -fruit-body_, generally _on its under side_. The edge of the stroma, -which bounds the hymenium, is sometimes especially developed -(_Stereum_). Saprophytes. - - GENERA: _Thelephora_. The fruit-bodies in this genus are brown, - very irregularly shaped, and often lobed. The spores too are - brown, but in the other genera colourless. The species are found - growing on barren soil. _T. laciniata_ (Fig. 165) has imbricate, - semicircular, dark-brown pileus, which is jagged at the edge - and upper surface. The fruit-bodies are very often raised above - the ground, and although this species is not a parasite, yet - it destroys young seedlings by growing above and smothering - them.--_Stereum_ has a stiffer fruit-body, with a distinct, - fibrous, intermediate layer. It grows on bark and wood, - projecting like a series of imbricate brackets. _S. hirsutum_ - is yellow; its free edge is provided with a number of stiff - hairs, the upper surface being divided into a number of zones. - _S. purpureum_ has a red-violet hymenium which distinguishes - it from the previous species.--_Cyphella_ has a membranous - cup- or bell-shaped fruit-body, often borne on a stalk, the - concave surface being covered with the hymenium. They are small, - white Fungi, growing on Moss and dead stems.--_Solenia_ is - closely related to _Cyphella_; its fruit-bodies are smaller and - hairy; they are found clustered together forming a crust-like - covering on dead wood.--_Craterellus_ has a large, funnel-shaped - fruit-body, the hymenium covering the external surface. - _C. cornucopioides_ is shaped like a trumpet or a “horn of - plenty.” It is dark-grey, several inches in height, and grows - gregariously on the ground in forests. It is distinguished by - the basidia bearing only two sterigmata. - - [Illustration: FIG. 165.--_Thelephora laciniata_ (nat. size).] - -Order 4. =Hydnaceæ.= The fruit-body is most frequently fleshy, and -varies considerably in shape, the simplest forms being resupinate,[14] -the higher ones umbrella-like. The _hymenophore_ is found on the -free or downward-turned surface, and always takes the _form of soft -emergences_ hanging vertically downwards. The emergencies may be -thorn-, awl-, or wart-like. The species are found growing on the soil -and on dead wood. - - GENERA: _Hydnum_ has subulate, distinct emergences. _H. - repandum_ is yellow, the stalk being placed in the centre of the - pileus. It is an edible species, and often forms “fairy rings” - in woods. _H. auriscalpium_ (Fig. 166) is dark-brown, with stalk - placed at the edge of the pileus. It grows on old Fir-cones. _H. - erinaceus_ grows on old tree-trunks. The fruit-body is yellow - and very large--as big as a human head--with emergences as much - as an inch in length.--_Irpex_ has a leathery fruit-body, partly - resupinate, partly with free, projecting edge; the under side - bears tooth-like emergences which are arranged in rows, and - _Irpex_ thus forms a transition to the Agaricaceæ.--_Phlebia_ - is entirely resupinate, with radially-arranged folds on the free - side, and pectinate border. - - [Illustration: FIG. 166.--_Hydnum auriscalpium_, upon a Fir-cone, - in different stages of development.] - -Order 5. =Polyporaceæ (Pore-Fungi).= An order very rich in species -(about 2000 species are described). The fruit-body is of very -different forms--resupinate, projecting like a bracket, hoof-like, or -umbrella-shaped. In some it is fleshy and edible, in others leathery or -corky, persisting for several years. The hymenophore is situated on the -under side of the fruit-body, and consists of wide or narrow _tubes_ or -_pores_, whose inner surface is clothed with the hymenium (Fig. 167). -In some fruit-bodies large cavities are to be found, which have arisen -as interstices between the labyrinthine curved and reticulate folds. -Chlamydospores are known in some species. Conidia occur very rarely. -Many species work considerable damage: some as parasites on trees, -others by destroying timber. - - [Illustration: FIG. 167.--_Polyporus igniarius._ Section through - the under side of the Fungus: _h-h_ is hyphal-tissue between the - tubes, formed by irregularly felted hyphæ, many of which are seen - cut across; _s_ is the hymenium which covers the walls of the - tubes, and from which the basidia with the spores protrude.] - - GENERA. _Polyporus_ (Pore-Fungus). The tubes are narrow, - accurately fitted together, and forming a thick layer on the - under side of the fruit-body, appearing as a number of fine - holes. The fruit-body most frequently resembles a bracket, or - is hoof-shaped, with one side growing from a tree-trunk; it - is very often perennial, and a new layer of tubes arises in - each succeeding period of vegetation. Strata, corresponding - to the periodically interrupted growth, are thus formed in - storeys one above the other, and are visible on the upper - surface of the fruit-body, as well as in the interior, as a - series of concentric belts, sometimes as many as half a score - or more in number. _P. fomentarius_ (Touchwood) attacks - trees, especially the Beech. The spores germinate on wounds - from broken branches, and the hyphæ, following the course of - the medullary rays, find their way into the interior of the - tree, from whence the mycelium spreads upwards, downwards, and - peripherally, so that the wood becomes rotten (“white-rot”) and - thick felts of mycelium are formed in radial and tangential - directions. A dark line, caused by the youngest parts of the - hyphæ containing a brown juice, marks the boundary between - the rotten and the unattacked parts of the stem (Fig. 168); - at places where the mycelium extends to the bark, the cambium - becomes destroyed and further growth is arrested, so that - longitudinal furrows arise on the stem. It is at these places, - too, that the hoof-shaped, ash-coloured fruit-bodies are - developed, which may attain a circumference of upwards of 7 - feet. The interior of the fruit-body consists of a dried-up, - loosely felted, red-brown mass of hyphæ, which has been used for - tinder and as a styptic (“Fungus chirurgorum”). _P. igniarius_ - has a harder, dark-brown, more rounded fruit-body; it grows in - a similar manner, but especially attacks Oaks, Poplars, and - Plum-trees, the wood of which becomes rotten, and is called - touchwood. _P. pini_ (_Trametes pini_), (Fig. 170), a parasite - on the stems of _Pinus_, causes a kind of “red-rot” in the - stem. _P. sulphureus_ has a soft, cheesy, yellow fruit-body; - it produces “rot” in Oaks and Apple-trees. _P. officinalis_, - Larch-fungus (“Fungus Laricis” in Pharmocopœia), grows on - Larch-trees in the south-east of Europe. _P. versicolor_ has - thin, semicircular fruit-bodies, with zones of various colours - on the upper side; it is one of the most frequent species on - tree-stems. _P. frondosus_ grows on soil in woods, and consists - of numerous aggregated fruit-bodies, which become very large - and fleshy. This species is edible. _P. perennis_ also grows on - the soil in woods; it is very leathery, with central stalk, and - has concentric zones on the upper surface of the fruit-body. - _P. vaporarius_ destroys the wood of living Pines (_Pinus - silvestris_) and Firs (_Picea excelsa_), causing it to become - red-brown; in timber this Fungus causes “red-strip” followed by - a “dry-rot.” _P. squamosus_ destroys many Walnut-trees, and is - also very destructive to Limes and Elms. _P. fulvus_ causes a - “white-rot” in _Abies alba_. - - [Illustration: FIG. 168.--Section of stem of a Beech attacked by - _P. fomentarius_: _a_ non-attacked parts of the stem; _b_ the - furrows where the mycelium has reached the bark, and where the - thick mycelium-strands reach the exterior (⅙th of the nat. size).] - - [Illustration: FIG. 169.--Base of a Fir-tree, with a number of - fruit-bodies of _Heterobasidion annosum_ just beneath the surface - of the soil, indicated by the dotted line (¼th nat. size).] - - [Illustration: FIG. 170.--A fully developed fruit-body of - _Polyporus pini_ (_Trametes pini_), lateral view (nat. size).] - - _Heterobasidion annosum_ (_Polyporus annosus_, _Trametes - radiciperda_, Fig. 169) is characterized by its - _Aspergillus_-like conidiophores. It is a parasite on the - Pine, Fir, Birch, Beech, etc., and is the chief cause of a - root-disease (red-rot) in Pines and Firs; the fruit-bodies - develope a large number of basidiospores; they may be very large - and are found just beneath the surface of the soil (on living or - dead roots), and exposed to the air (on felled stems and roots, - in Scandinavia). - - _Ptychogaster_ has cushion-like fruit-bodies, which consist - chiefly of chlamydospore-chains, formed of ellipsoidal spores, - which alternate with short hyphæ having transverse septa and - clamp-connections. The hymenial portion is limited to a small - group of tubes. _Pt. albus_ (_Oligorus ustilaginoides_) grows - on stumps of Conifers and forms irregular cushions, at first - white and later on brown, which consist almost entirely of - chlamydospores. - - _Boletus_ (Fig. 171) has a fleshy fruit-body resembling a common - Mushroom, with central stalk. The layer of tubes is easily - detached from the pileus, and the tubes are easily separable - from one another. They grow on the ground in woods. Edible - species are: _B. edulis_, with thick, reticulate stalk; _B. - scaber_, with thin stalk and rough pileus; _B. luteus_, with a - ring on the stalk. _B. luridus_ is poisonous, its tubes have - red openings, and the flesh turns quickly blue when broken and - exposed to the air. - - _Fistulina hepatica_ (Beef-steak Fungus), has a red, fleshy, - edible fruit-body, with red juice. The tubes are individually - distinct; conidia are also developed. Grows on old Oaks. - - _Merulius lacrymans_ (“Dry-rot”) has a resupinate fruit-body - with white, cotton-like border, and the remaining portions - covered by reticulate, ramified veins of a rust-brown colour. - In favourable vegetative conditions it is fleshy and exudes - large drops of water--hence its specific name and also the name - “Tear Fungus.” The mycelium is at first colourless, and then - yellow-brown; when dry it is tough and leathery. It destroys - the timber in damp houses, extends far and wide over boards and - beams and even over the masonry, giving rise to a disagreeable - smell in the rooms in which it lodges. In woods the Fungus lives - on Pine-stems. It is brought from the forest on the logs of - timber, and is distributed from log to log by the mycelium and - the basidiospores. The living mycelium can be recognised by the - clamp-connections shooting out branches. The basidiospores are - often ejected a distance of a metre; they are elliptical (10–11µ - long and 5–6µ broad), and germinate easily on damp wood, or in - fruit-juice which has been neutralized with urine or alkaline - carbonates. - - _Dædalea_ (Labyrinth Fungus), has bracket-like, corky - fruit-bodies with irregularly-folded plates or discs on the - under side. It forms a transition to the Agaricaceæ. _D. - quercina_ is frequent on Oak-stumps. - - [Illustration: FIG. 171.--_Boletus edulis_ (about ¼th): _b_ - longitudinal section of a portion of the pileus.] - -Order 6. =Agaricaceæ= (=Mushrooms=, =Toadstools=). _The hymenophore -consists_ of knife-like plates (_lamellæ_, _gills_), which are situated -on the under side of the umbrella-like pileus of the fruit-body, and -radiate from the central stalk. Those which are first formed extend -from the edge of the pileus to the stalk; those formed later reach only -a longer or shorter portion of this distance, according to their age. -In structure the lamellæ (Fig. 174) consist of a central mass of hyphæ, -the _trama_, continuous with the hyphæ of the pileus; these terminate -in a layer of shorter cells, the _subhymenial layer_, immediately -beneath the hymenium which is composed of basidia and paraphyses. In a -few species, but not in the majority, the lamellæ are branched, and in -some they are decurrent. A few have the stalk placed excentrically, or -it may be entirely absent. - - [Illustration: FIG. 172.--Development of _Psalliota campestris_: - _a_, _b_, _c_, _d_ show the various stages of the development - of the fruit-bodies and the mycelium (_m_) (nat. size); _e_ the - fruit-body in a somewhat later stage, slightly magnified; _f_ - longitudinal section of _e_; _n_ first formation of the hymenium; - _g_ longitudinal section of a more advanced fruit-body (nat. - size); _n_ the hymenium; _o_ velum partiale (see Fig. 133.)] - -In the early stages of its development the fruit-body is more or -less enclosed in a hyphal tissue--the “veil” (_velum universale_, or -_volva_). The veil at first completely encloses the young fruit-body, -but is afterwards ruptured as the latter grows, part remaining at the -base of the stalk as the “sheath” (_annulus inferus_), and part on the -pileus as scales or warts. In the “Fly Mushroom” (_Amanita muscaria_) -the remains of the veil are especially conspicuous as white patches -on the bright red ground of the upper surface of the pileus, and as -a sheath at the base of the stalk (Fig. 178 _v._). Another veil--the -_velum partiale_--a hyphal tissue (Figs. 178 _a_; 173) stretches from -the edge of the pileus to the stalk, and encloses the lamellæ. This -veil is ruptured as the pileus expands, a portion attached to the stalk -remaining as the “upper ring” (_annulus superus_) (Figs. 173, 178 _a_), -or a part attached to the pileus hanging down as a fringe round its -edge.--Some genera have no veil, the under side of the pileus being -exposed from the first (_gymnocarpic_ Agaricaceæ). Those which have -a veil (_hemiangiocarpic_ A.) afford a transition to the angiocarpic -Gasteromycetes. - - [Illustration: FIG. 173.--The cultivated Mushroom (_Psalliota - campestris_).] - -The mycelium mostly grows in soils rich in humus or dung, on decaying -trees and similar objects. Many species, _e.g. Tricholoma personatum_ -and _Marasmius oreades_, form the so-called “fairy rings.” The -fruit-bodies in these species are confined to a larger or smaller -surface on which they are very regularly arranged in a ring. The reason -for this is found in the radial growth of the mycelium, so that the -oldest portion, or the starting point, is found at the centre of the -ring, and the younger ones, on which the fruit-bodies are formed, at -the circumference. The older hyphæ gradually die, and at the same time, -the radial growth continuing, the ring of fruit-bodies becomes larger -and larger. The “fairy-rings” are marked not only by the fruit-bodies, -but also by the more vigorous growth and darker colour of the grass -upon these spots. - -Some species are _parasites_. An example is presented by _Armillaria -mellea_, a remarkable and very destructive Fungus in woods and forests -(Figs. 176, 177). ~In addition to the filamentous, white mycelium, -it has also black, or black-brown, horny, root-like mycelium-strands -(rhizomorpha) which were formerly considered to belong to a special -genus of Fungi described under the name “_Rhizomorpha_.” The mycelium -lives parasitically on the Conifers and other trees, forcing its hyphæ -into the bark and between the bark and wood, and thence penetrating -into the wood so that the tree is very severely attacked. It may also -live saprophytically, and clusters of fruit-bodies are often found on -old stumps and stems, on old timber, and in the rich soil of woods. The -rhizomorpha, living underground, can extend for considerable distances -and infect the roots of neighbouring trees, and spreads in this way -the diseases known as “Harzsticken” and “Bark-Canker,” which are very -destructive to young trees.~ - - [Illustration: FIG. 174.--_Psalliota campestris. A_ Tangential - section of pileus showing lamellæ (_l_). _B_ Portion of gill - more highly magnified; _t_ trama; _hy_ hymenium with basidia and - basidiospores; _sh_, subhymenial layer. _C_ A portion of the same - more highly magnified; _s′ s′′ s′′′ s′′′′_ various stages - in the development of basidiospores; _q_ paraphyses.] - -The chief characteristics by which the numerous genera are separated -are the presence or the absence of the two kinds of veils, the nature -of the fruit-body, the form, branching of the lamellæ, and their -position and relation with respect to the stem, the shape of the -pileus, the colour of the spores, etc., etc. A knowledge of the colour -may be obtained by placing the pileus with the lamellæ turned downwards -on a piece of white or coloured paper, so that the spores, as they fall -off, are collected on the paper, and the arrangement of the lamellæ can -then be clearly seen. - - [Illustration: FIG. 175.--_Cantharellus cibarius_ (reduced).] - - [Illustration: FIG. 176.--_Armillaria mellea._ (½ nat. size): _a_ - root of a Fir; _b_ rhizomorpha-strands; _c-f_ fruit-bodies in - four different stages of development.] - - [Illustration: FIG. 177.--The mycelium of _Armillaria mellea_ - (“_Rhizomorpha_”) (nat. size).] - -About 4,600 species belonging to this order have been described. - - On account of the large number of species the order is divided - into several sections: - - 1. =Agaricinei=; fruit-body fleshy; lamellæ membranous, - knife-like, with sharp edge; basidia crowded together. The - FOLLOWING HAVE WHITE SPORES:--_Amanita_ (Fly Mushroom), with - volva, and generally also the upper ring on the stalk; many are - poisonous, such as _A. muscaria_ (Fig. 178) which has bright red - pileus with white spots, _A. pantherina_ and _A. phalloides_; - _A. cæsarea_ is edible.--_Lepiota procera_ (Parasol Fungus) - is one of the largest Mushrooms; it has a scaly pileus and - moveable ring (edible).--_Armillaria mellea_ has been mentioned - above (Figs. 176, 177).--_Tricholoma_, lamellæ indented near - the stalk; _T. gambosum_ (Pomona Fungus) belongs to the best - of edible Fungi; _T. personatum_ often forms fairy rings (see - above).--_Clitocybe_, lamella decurrent; _C. nebularis_ is - edible.--_Pleurotus_, stalk eccentric; _P. ostreatus_ (Oyster - Mushroom) grows in clusters on tree-stems (edible).--_Collybia_ - and _Mycena_, species numerous, small.--SPORES ROSE-RED: - _Volvaria_ and _Hyporhodius_.--SPORES BROWN: _Cortinarius_, - with cobweb-like veil; _Pholiota_, membranous veil and ring; - _P. squarrosa_ in clusters on tree-stems; _P. mutabilis_, on - tree-stumps (edible).--SPORES VIOLET-PURPLE: _Hypholoma_, - _Psalliota_; to this section the common edible Mushroom (Fig. - 172–174) belongs, with annulus and chocolate-coloured lamellæ; - it is cultivated for the sake of the fine flavour.--SPORES - BLACK: _Coprinarius_. - - [Illustration: FIG. 178.--Fly Mushroom (_Amanita muscaria_).] - - 2. =Marasmiei.= Fruit-body tough, almost leathery, and - persistent; spores white. _Marasmius oreades_ forms large, - regular fairy-rings on pastures and commons; it is used as - seasoning in food.--_Panus stipticus_ with eccentrically-placed - stalk, in clusters on tree-stumps.--_Schizophyllum_ has the edge - of the lamellæ divided longitudinally, and the split portions - revolute.--_Lentinus_ affords a transition to _Dædalea_ among - the Polyporaceæ. - - 3. =Russulei.= Fruit-body fleshy and fragile, in which two - different systems of hyphæ may be distinguished; spores thorny, - white, or pale-yellow. Many are poisonous.--_Russula_ has - generally fragile and thick lamellæ reaching from stalk to edge - of pileus; pileus frequently red.--_Lactarius_ has white or - yellow milky juice, which often is very acid. _L. deliciosus_ - has red-yellow milky juice, and is of a pleasant flavour. _L. - torminosus_ is poisonous. - - 4. =Hygrophorei.= Lamellæ thick and waxy, widely separated; - spores white. Many species of _Hygrophorus_ have - brightly-coloured pileus and grow among the grass on moors and - commons.--_Nyctalis_ is parasitic on larger Toadstools. It is - remarkable for its abundant formation of chlamydospores, whilst - the basidiospores are little developed. - - 5. =Coprinei.= Fruit-bodies very soft, quickly perishable; - lamellæ membranous and deliquescent. The basidia are separated - from each other by paraphyses. _Coprinus_ has coal-black spores, - grows on manure, and sometimes developes sclerotia. - - 6. =Paxillei.= Fruit-body fleshy; lamellæ easily detached from - the pileus and reticulately-joined near the stalk. They form a - connecting link between the Agaricaceæ and _Boletus_. - - 7. =Cantharellei.= Lamellæ reduced to dichotomously-divided - folds, decurrent on the stalk. _Cantharellus cibarius_ (Fig. - 175) is yolk-yellow, and grows on the ground in woods (edible). - It is allied to _Craterellus_. - - - Family 3. =Phalloideæ.= - -The fruit-bodies before they are ripe are spherical or ovoid, and -enclosed by a _fleshy covering_, the peridium, which is _perforated -at maturity_ and remains as a sheath (Fig. 179); the fruit-bodies are -_hemiangiocarpic_. - -Order 1. =Phallaceæ= (=Stink-horns=). The peridium has a complicated -structure and is composed of three layers, the intermediate one being -thick and gelatinous. The gleba (the tissue which bears the hymenium) -is situated upon a peculiar receptacle which expands into a porous -stalk and by its sudden distension, rupturing the peridium, elevates -the gleba and hymenium above the peridium, which remains as a sheath. -_The gleba becomes gelatinous and dissolves away as drops._ To this -order belong many peculiar and often brightly coloured forms, which are -natives of the Southern Hemisphere. - - _Phallus impudicus_ (Stink-horn) (Fig. 179), has a fruit-body - which at first is white, heavy, and soft, and resembles a hen’s - egg in shape and size. The peridium is divided into three layers - (Fig. 179 _e_, _g_, _f_) of which the external and internal - are membranous, and the middle one very thick and gelatinous; - each of these has again a laminated structure. The peridium - when ruptured remains as a sheath (_k_) at the base of the - stalk. The receptacle at first is strongly compressed (_h_) - but afterwards expands into a long stalk (_l_) which bears the - conical gleba (_m_). Prior to the rupture of the peridium the - gleba consists of a greenish mass (_i_) which, when exposed, - emits a carrion-like stench serving to attract flies, by whose - agency the spores are distributed. It is found commonly in - hedgerows and in woods, growing on the ground. The much smaller - and less common _P. caninus_ is found on rotten tree-stumps.--In - _Clathrus cancellatus_ the receptacle expands into a bright red, - reticulate structure. A native of the South of Europe. _Colus_, - _Aseroë_, _Mitromyces_. - - Order 2. =Sphærobolaceæ.= An intermediate layer of the - _peridium_ swells when ripe, becomes convex, and _ejects the - remaining_ spherical _portion of the fruit-body_ which contains - the spores. _Sphærobolus carpobolus_ has small, spherical - fruit-bodies which open in the form of a star. - - [Illustration: FIG. 179.--_Phallus impudicus_ (Stink-horn), - somewhat diminished. Fruit-bodies in all stages of development - (_b_, _c_, _d_ and _k-m_) are seen arising from a root-like - mycelium (_a_); _d_ longitudinal sections through a fruit-body - before the covering has ruptured.] - - - Family 4. =Gasteromycetes.= - -The fruit-body is _angiocarpic_, fleshy at first, and later generally -more or less _hard_ and _continues closed after the_ spores _are -ripe_. The tissue lying immediately inside the _peridium_ is termed -the _gleba_; it is porous, containing a larger or smaller number of -chambers lined with the hymenium, which is either a continuous layer of -basidia or else it fills up the entire cavity. The basidia as a rule -bear four spores, sometimes eight (_Geaster_), or two (_Hymenogaster_). -The tissue of the walls (_trama_) consists often (_Lycoperdaceæ_) -of two kinds of hyphæ, some thin and rich in protoplasm, divided -by transverse septa and bearing the basidia; others thicker and -thick-walled which do not dissolve like the former on the ripening of -the spores, but continue to grow and form a woolly, elastic mass, the -_capillitium_, which may be regarded as highly developed paraphyses. -The peridium may be either single or double, and presents many -variations in its structure and dehiscence. The mycelium is generally a -number of string-like strands, living in soils rich in humus. - - Order 1. =Tylostomaceæ.= Capillitium present. After the rupture - of the peridium the remaining part of the fruit-body is elevated - on a long _stalk_. _Tylostoma mammosum_, on heaths. - -Order 2. =Lycoperdaceæ.= The fruit-body has a double peridium; the -external one at length breaks into fragments (_Lycoperdon_, _Bovista_), -or it has a compound structure of several layers (_Geaster_) and -detaches itself as a continuous envelope from the inner layer, which -is membranous and opens at its apex. The interior of the fruit-body -consists either solely of the fertile gleba (_Bovista_, _Geaster_), -or, in addition, of a sterile tissue at the base (_Lycoperdon_). A -capillitium is also present. - - [Illustration: FIG. 180.--_Lycoperdon gemmatum_ (½ nat. size).] - - _Lycoperdon_ (Puff-ball) has a sterile part at the base of the - fruit-body which often forms a thick stalk. The surface of the - peridium is generally covered with warts or projections. When - young this Fungus is edible, but when ripe it is dry, and used - for stopping the flow of blood. _L. giganteum_, which is often - found growing in meadows, attains a considerable size, its - diameter reaching as much as eighteen inches. _L. gemmatum_ - (Fig. 180) is covered with pyramidal warts; in woods.--_Bovista_ - has no sterile basal part; the external peridium is smooth, and - falls away in irregular patches. _B. plumbea_, on links near the - sea.--_Geaster_ (Earth-star) has an external peridium composed - of several layers, which when the fruit-body opens, split into - several stellate segments. These segments are very hygroscopic, - and in dry weather bend backwards and so raise the inner - peridium into the air. The inner peridium contains the spores - and capillitia. _G. coliformis_ has several apertures in the - inner peridium. The other species have only one regular aperture - at the apex. _G. striatus_ has a pedicellate inner peridium, - with conical, striped peristome. _G. fornicatus_ has an external - peridium split into four segments. This last and several other - species produce “mycorhiza” on the roots of Conifers. - - [Illustration: FIG. 181.--I _Hymenogaster citrinus_ (nat. size); - II longitudinal section through _H. tener_ (× 5); III portion of - a section of _H. calosporus_; _g_ a chamber; _h_ hymenium; _sp._ - spores; _t_ trama (× 178); IV _Rhizopogon luteolus_ (nat. size); - V _Scleroderma vulgare_, VI section of V; VII basidia with spores - belonging to the same Fungus.] - -Order 3. =Sclerodermataceæ.= _Capillitium_ wanting. The peridium is -simple and thick, gleba with round, closed chambers, which are filled -with basidia. - - _Scleroderma_ has a corky peridium. The fruit-bodies commence - their development under ground. _S. vulgare_ (Fig. 181 V-VII), - has a hard, slaty-black gleba. - -Order 4. =Nidulariaceæ= (=Nest-Fungi=). Small Fungi of which the -fruit-body at first is spherical or cylindrical but upon maturity -it becomes cupular or vase-like, and contains several lenticular -“peridiola” lying like eggs in a nest. The peridiola are the chambers -which contain the hymenium, covered by a thin layer of the gleba, all -the remaining portion of the gleba becoming dissolved. On decaying wood. - - _Nidularia_ has spherical fruit-bodies containing a - large number of lenticular peridiola, embedded in a slimy - mass.--_Crucibulum_ has fruit-bodies resembling crucibles - with discoid peridiola, each with a spirally-twisted - stalk.--_Cyathus_ has a fruit-body, which when open is - campanulate, with stratified peridium, and long-stalked, - lense-shaped peridiola. - -Order 5. =Hymenogastraceæ.= Fruit-bodies tubercular, globose and -subterranean, resembling very closely the Truffles, from which they -can only be distinguished with certainty by microscopic means. The -peridium is simple, capillitium wanting, and the gleba encloses a -system of labyrinthine passages covered with a continuous hymenium. -The fruit-bodies persist for some time, and form a fleshy mass, the -spores being only set free by the decay of the fruit-body, or when it -is eaten by animals. The majority are South European. _Hymenogaster_, -_Melanogaster_, _Rhizopogon_ (Fig. 181 I-IV). - - - APPENDIX TO THE BASIDIOMYCETES: - - Basidiolichenes (Lichen-forming Basidiomycetes). - -Several Fungi belonging to the Basidiomycetes have a symbiotic -relationship with Algæ exactly similar to that enjoyed by certain -Ascomycetes, and these are therefore included under the term Lichens -(p. 136). They are chiefly tropical. - -Order 1. =Hymenolichenes.= To this order belong some gymnocarpic -forms: _Cora_, _Dictyonema_, _Laudatea_.[15] - -Order 2. =Gasterolichenes.= To this belong some angiocarpic forms: -_Emericella_, _Trichocoma_. - - - APPENDIX TO THE FUNGI. - - Fungi imperfecti (Incompletely known Fungi). - -1. The =Saccharomyces-forms= are Fungi which are only known in their -yeast-conidial form. They are _conidia of higher Fungi_ which can -multiply to an unlimited extent by budding in nutritive solutions, and -in this way maintain their _definite_ size and shape. The budding takes -place _only at the ends_ of the conidia. The wall of the conidium forms -at one or at both ends a small wart-like outgrowth, which gradually -becomes larger, and is finally separated from its mother-cell as an -independent cell, surrounded by a closed cell-wall (Fig. 182 _a_, _b_). - - [Illustration: FIG. 182.--Beer-yeast (_Saccharomyces cerevisiæ_): - _a-b_ (× 400); _c-f_ (× 750); _c_ a cell in the process of - forming spores; _d_ a cell with four ripe spores; _e_ the - spores liberated by the dissolution of the cell-wall; _f_ three - germinating spores; _g_ mycelium-like cell-chains. (× 1000: after - Em. Chr. Hansen.)] - -Under very favourable conditions multiplication occurs so rapidly that -the daughter-cells themselves commence to form buds, before they have -separated from their mother-cell, with the result that pearl-like -chains of cells are produced. When the yeast-cells have only limited -nutriment, with an abundant supply of air, at a suitable temperature, -an endogenous formation of _spores_ takes place. The protoplasm of the -cells divides into 1–4 (rarely a greater number) masses (Fig. 182 _c_, -_d_, _e_) which surround themselves with a thick cell-wall, and in this -state can withstand adverse conditions and periods of dryness lasting -for several months. - -The _sporangia are not asci_ since they have no definite form, and -a definite number, form and size of spores is not found. The spores -in the different species and kinds occupy varying periods for their -development, although exposed to the same temperature, a fact of -importance in determining one from another. On germination the wall of -the mother-cell is destroyed, and each spore gives rise to a new cell, -multiplication taking place by budding (Fig. 182 _f_). The majority of -Yeast-Fungi are able to produce alcoholic fermentation in saccharine -fluids. - -The most important of these Fungi is the Beer-yeast (_Saccharomyces -cerevisiæ_) with ovate, ellipsoidal or spherical cells (Fig. 182). It -is a plant which has been cultivated from time immemorial, on account -of its property of producing alcoholic fermentation in sugar-containing -extracts (wort), derived from germinating barley (malt). Carbonic -acid is also set free during this process. The “surface-yeast” (Fig. -182 _a_), which produces ordinary beer when the brewing takes place -at higher temperatures, has cell-chains; “sedimentary yeast” (Fig. -182 _b_), used in the brewing of Bavarian beer, has spherical cells, -solitary, or united in pairs. Both these and the following Yeast-Fungi -include, according to Hansen, several species and kinds. - - [Illustration: FIG. 183.--_Saccharomyces mycoderma._] - -The “Ferment of Wine” (_Saccharomyces ellipsoideus_) produces wine in -the juice of grapes. Uncultivated yeast-cells are always present on -grapes; an addition of this species to the “must” is not necessary to -secure fermentation. A large number of other “uncultivated” yeast-cells -appear in breweries mixed with the cultivated ones, and cause different -tastes to the beer (_S. pastorianus_, etc.). _S. ludwigii_, found, -for instance, on the slimy discharge from Oaks, produces abundant -cell-chains on cultivation. _S. apiculatus_ is very frequently met with -on all kinds of sweet fruits, it has orange-like cells. _S. mycoderma_ -has cylindrical cells, often united together in chains (Fig. 183): it -forms a whitish-gray mass (“fleur de vin”) on wine, beer, fruit-juice, -etc., standing in bottles uncorked or not entirely filled. It is -thought that this Fungus causes decomposition and oxydises the fluid -in which it is found, but it cannot produce alcoholic fermentation -in saccharine liquids, and it does not form endospores; hence it is -uncertain whether it is true _Saccharomyces_. - - [Illustration: FIG. 184.--_Oidium lactis_: _a_ branched hypha - commonly met with; _b_ a hypha lying in milk and producing aerial - hyphæ which give rise to oidia; _c_ a branch giving rise to - oidia, the oldest (outermost) oidia are becoming detached from - one another; _d_ a chain of divided cells; _e_ germinating oidia - in different stages (slightly more magnified than the other - figures).] - -The “Dry-yeast” used in baking white bread is “surface-yeast.” In -_leaven_, a kneaded mixture of meal, barm and water, which is used for -the manufacture of black bread, _Saccharomyces minor_ is present, and -a species allied to this produces alcoholic fermentation in dough with -the evolution of carbonic acid, which causes the dough to “rise.” - -2. =Oidium-forms.= Of many Fungi only the Oidium-forms are known, -which multiply in endless series without employing any higher form of -reproduction. _Oidium lactis_ (Fig. 184) is an imperfectly developed -form which frequently appears on sour milk and cheese. It can produce a -feeble alcoholic fermentation in saccharine liquids. Thrush or aphthæ -(_O. albicans_) appears as white spots in the mouths of children. -Several similar _Oidium-forms_ are parasites on the skin and hair -of human beings, and produce skin diseases, such as scurvy (_O. -schoenleinii_) and ringworm (_O. tonsurans_). - -3. =Mycorhiza.= These Fungi, which have been found on the roots of many -trees and heath-plants, particularly Cupuliferæ and Ericaceæ, consist -of septate hyphæ, and belong partly to the Hymenomycetes, partly to -the Gasteromycetes. It has been shown that the Mycorhiza enters into a -symbiotic relationship with the roots of higher plants. - - - - - DIVISION II. - - MUSCINEÆ (MOSSES). - - -In this Division a well-marked alternation of generations is -to be found. The development of the first or sexual generation -(_gametophyte_),[16] which bears the sexual organs, antheridia -and archegonia, commences with the germination of the spore, and -consists, in the Liverworts, of a thallus, but in the true Mosses of a -filamentous protonema, from which the Moss-plant arises as a lateral -bud. The second or asexual generation (_sporophyte_), developed from -the fertilised oosphere, consists of a sporangium and stalk. - -=The sexual generation, the gametophyte.= The protonema in the -Liverworts is very insignificant, and not always very sharply -demarcated from the more highly developed parts of the nutritive -system. In the true Mosses the protonema is well-developed, and -consists of a branched, alga-like filament of cells, the dividing -cell-walls being always placed obliquely. In the parts exposed to the -light it is green, but colourless or brownish in those parts which are -underground (Fig. 186). The protonema is considered to be a lower form -of the stem, and grows in the same manner by means of an apical cell; -at its apex it may directly develope into a leaf-bearing stem, or these -arise from it as lateral branches (Fig. 186 _k_). - -The more highly differentiated part of the vegetative system, the -“Moss-plant,” which is thus developed from the protonema, is in the -“thalloid” Liverworts generally a dichotomously-branched thallus -without any trace of leaf-structures (Fig. 194); in _Marchantia_ -(Fig. 197) and others, scale-like leaves (_amphigastria_) are found -on the under surface. The higher Liverworts and the Leafy-Mosses are -differentiated into a filamentous, ramified stem with distinct leaves -arranged in a definite manner, resembling the stem and leaves of the -higher plants (Figs. 186, 195, 200). - -_True roots are wanting_, but are biologically replaced by _rhizoids_. -These are developed on the stems or thallus: in the Liverworts they -are unicellular, but in the Leafy-Mosses generally multicellular and -branched. In the latter group they are considered identical with -the protonema, and may become true protonema, and new plants may be -developed from them (Fig. 186 _b_). - - [Illustration: FIG. 186.--_A_ Lower portion of a Moss-plant with - rhizoids (_r_), one of which bears a reproductive bud (_b_). The - dotted line indicates the surface of the ground; the portions - projecting above this become green protonema (_p_); _k_ is a - young Moss-plant formed on one of these. _B_ Germinating spore of - _Funaria hygrometrica_, with exospore still attached. _C_, _D_ - Older stages of the protonema.] - -The internal structure of the sexual generation is very simple. The -leaves in nearly all cases are formed of a single-layered plate of -cells; in the Leafy-Mosses, however, a midrib is very often formed, and -sometimes, also, marginal veins; and along these lines the leaves are -several layers of cells in thickness. The stem is constructed of cells -longitudinally elongated, the external ones of which are narrower and -sometimes have thicker walls than the more central ones. _Vessels are -not found_, but in several Mosses there is in the centre of the stem -a conducting strand of narrow, longitudinal cells, which represents -the vascular bundle in its first stage of development. This strand -contains elements for conveying water as well as sieve-tubes. Stomata -are entirely wanting in the sexual generation of the Leafy-Mosses; they -are found in a few Liverworts (_Marchantia_), but their structure is -not the same as in the higher plants. - -VEGETATIVE REPRODUCTION takes place by gemmæ or buds which arise on -the protenema, the rhizoids, the thallus, or the shoots, and become -detached from the mother-plant; or else the protonema and the older -parts of the plant simply die off, and their branches thus become -independent plants. This well-developed vegetative reproduction -explains why so many Mosses grow gregariously. In certain Marchantiaceæ -special cupules, in which gemmæ are developed, are found on the surface -of the thallus (Fig. 197 _A_, _s-s_). Again, protonema may also arise -from the leaves, and thus the leaves may act as reproductive bodies. -Certain Mosses nearly always reproduce vegetatively, and in these -species the oospheres are seldom fertilised. - - [Illustration: FIG. 187.--_Marchantia polymorpha_: _a_ mature - antheridium.] - - [Illustration: FIG. 188.--Spermatozoids.] - -The first generation bears the SEXUAL ORGANS; both kinds are found -either on the same plant (monœcious), or on separate plants (diœcious). -In the thalloid Liverworts they are often situated on the apex of small -stems (_gametophores_), springing from the surface of the thallus. -In the Leafy-Liverworts and true Mosses the leaves which enclose the -sexual organs often assume a peculiar shape, and are arranged more -closely than the other leaves to form the so-called “Moss-flower.” The -male sexual organs are called _antheridia_. They are stalked, spheroid, -club- or egg-shaped bodies whose walls are formed of one layer of cells -(Fig. 187), enclosing a mass of minute cubical cells, each one of which -is a mother-cell of a spermatozoid. The spermatozoids are self-motile; -they are slightly twisted, with two cilia placed anteriorly (Fig. 188), -while posteriorly they are generally a trifle club-shaped, and often -bear at that part the remains of the cytoplasm, the spermatozoid itself -being _formed from the nucleus_. In the presence of water the ripe -antheridium bursts, and its contents are ejected; the spermatozoids, -being liberated from their mother-cells, swarm about in the water in -order to effect fertilisation. - - [Illustration: FIG. 189.--_Marchantia polymorpha. A_ A young, - and _B_ a ripe archegonium with open neck. _C_ An unripe - sporangium enclosed by the archegonium _a_: _st_ the stalk; _f_ - the wall of the sporangium. Elaters are seen between the rows of - spores.] - -The female sexual organs are termed _archegonia_. They are flask-shaped -bodies (Fig. 189), the lower, swollen portion (_venter_) having a wall, -in most cases from 1–2 cells thick, enclosing the oosphere (Fig. 189 -_B_, _k_): the long neck is formed of tiers of 4–6 cells, enclosing -a central row of cells--_the neck-canal-cells_ (Fig. 189 _A_). When -the archegonium is fully developed, the walls of the neck-canal-cells -become mucilaginous and force open the neck of the archegonium. The -mucilage thus escapes, and, remaining at the mouth of the archegonium, -acts in a somewhat similar manner to the stigma and conducting tissue -of a carpel, by catching and conducting the spermatozoids to the -oosphere (Fig. 189 _B_, _m_), with whose cell-nucleus they coalesce. -With regard to the formation of the oosphere, it may further be -remarked that the lower part of the archegonium originally encloses the -so-called “central cell”; but shortly before the archegonium is ripe, -this cuts off a small portion, _the ventral-canal-cell_, which lies -immediately beneath the neck, and the larger, lower portion becomes the -oosphere. - - The organs mentioned here, antheridia and archegonia, are - present in the Cryptogams (Pteridophyta) and the Gymnosperms. - They have always the same fundamental structure, but with slight - modifications of detail. These plants are therefore known as the - ARCHEGONIATA. - -The fertilisation of the Mosses cannot be effected without water. Rain -and dew therefore play a very important part in this process, and for -this end various modifications of structure are found. - - [Illustration: FIG. 190.--_Andreæa rupestris._ Longitudinal - section through a sporangium at the time when the mother-cells - of the spores are dividing: _p_ pseudopodium; _f_ foot; _v_ - vaginula; _h_ neck; _c_ columella; _w_ wall of the sporangium; - _e_ external row of cells; _s_ the spore-sac; _t_ the - spore-mother-cells; _r_ the calyptra with the neck of archegonium - (_z_).] - - [Illustration: FIG. 191.--_Andreæa rupestris._ Transverse - section through a ripe sporangium. In the middle is seen the - four-sided columella, surrounded by the numerous spores, - drawn diagrammatically. Surrounding them is seen the wall of - the sporangium, whose outer layer of cells is thickened and - coloured. The layer of cells is unthickened in four places (_x_), - indicating the position of the clefts (see Fig. 193).] - -Among the sexual organs, paraphyses--filamentous or club-shaped -bodies--are to be found. - -=The asexual generation, the sporophyte= (Moss-fruit or sporogonium). -As the result of fertilisation the oosphere surrounds itself with a -cell-wall, and then commences to divide in accordance with definite -laws.[17] The embryo (Fig. 189 _C_) produced by these divisions -remains inside the wall _a-a_ of the archegonium (Figs. 190, 199 _D_, -_E_), and developes into the _sporogonium_, which remains attached -to the mother-plant, often nourished by it, as if the two were one -organism. The lower extremity of the sporogonium, _the foot_ (Figs. -190 _f_; 199 _D_), very often forces its way deep down into the -tissue of the mother-plant, but without an actual union taking place. -The central portion of the sporogonium becomes a shorter or longer -_stalk_ (_seta_), while the sporangium itself is developed at the -summit. At a later stage, during the formation of the spores, the -sporangium very often assumes the form of a _capsule_, and dehisces -in several ways characteristic of the various genera (Figs. 192, 193, -194, 195, 200). The basal portion of the archegonium grows for a -longer or shorter period, forming a sheath, the _calyptra_, in which -the capsule is developed, but eventually it ceases to enlarge, and -is then ruptured in different ways, but quite characteristically, in -each group. Anatomically, the asexual generation is often more highly -differentiated than the sexual; thus, for instance, stomata are present -on the sporangia of the true Mosses, but are absent in the sexual -generation. - -As the capsule developes, an external layer of cells--the -_amphithecium_--and an internal mass--the _endothecium_--are -differentiated. As a rule the former becomes the wall of the capsule -while the latter gives rise to the spores. In this Division, as in -the Pteridophyta, the name _archesporium_ (Fig. 190 _t_) is given -to the group of cells inside the sporangium which gives rise to -the mother-cells of the spores. The archesporium is in general a -unicellular layer; in _Sphagnum_ and _Anthoceros_ it is derived from -the most internal layer of the amphithecium, but with these exceptions -it arises from the endothecium, usually from its most external layer. -In the true Mosses and in _Riccia_ only spore-mother-cells are produced -from the archesporium, but in the majority of the Liverworts some -of these cells are sterile and become elaters (cells with spirally -thickened walls, Figs. 196, 189), or serve as “nurse-cells” for the -spore-mother-cells, which gradually absorb the nutriment which has been -accumulated in them. In _Anthoceros_, and almost all the Leafy-Mosses, -a certain mass of cells in the centre of the sporangium (derived -from the endothecium) does not take part in the formation of the -archesporium, but forms the so called “column” or “columella” (Figs. -190, 191). - -The _spores_ arise in _tetrads_, _i.e._ four in each mother-cell, and -are arranged at the corners of a tetrahedron, each tetrahedron assuming -the form of a sphere or a triangular pyramid. The mature spore is a -nucleated mass of protoplasm, with starch or oil as reserve material. -The wall is divided into two layers: the external coat (exospore) which -is cuticularized and in most cases coloured (brown, yellowish), and the -internal coat (endospore), which is colourless and not cuticularized. -On germination the exospore is thrown off, the endospore protrudes, and -cell-division commences and continues with the growth of the protonema -(Fig. 186, _B-D_). - - [Illustration: FIG. 192.--_Andreæa petrophila._ A ripe - sporogonium: _a_ an archegonium which has been raised with the - pseudopodium; _p_ the foot; _b_ the neck; _d-e_ the dark-coloured - portion of the sporangium, whose outer cell-walls are - considerably thickened; _c_-_c_ the thin-walled portions where - the dehiscence occurs; _o_ the lower extremity of the spore-sac; - _f_ calyptra; _g_ the apex of the sporangium. (Mag. 25 times.)] - - [Illustration: FIG. 193.--_Andreæa petrophila._ An empty capsule; - the calyptra has fallen off. (Mag. 25 times.)] - - The morphological explanation which Celakovsky has given of - the sporogonium, and which is not at all improbable, is, that - it is homologous with an embryo consisting of a very small - stem-portion and a terminal spore-producing leaf. This will be - further explained in the introduction to the Flowering-plants - (p. 236). - -In the Liverworts the young sporogonium lives like a parasite, being -nourished by the sexual generation (only in _Anthoceros_ has it a -slight power of assimilation). In the Leafy-Mosses, on the other -hand, with regard to the power of assimilation, all transitions are -found from abundant assimilation (_Funaria_, _Physcomitrium_) to -almost complete “parasitism” (_Sphagnum_, _Andreæa_). In the majority -of the operculate Mosses the sporogonium has a more or less perfect -system of assimilation, and is able itself to form a large portion of -the material necessary for the development of the spores, so that it -chiefly receives from the sexual generation the inorganic substances -which must be obtained from the soil. The more highly developed the -assimilative system of the sporogonium, the more stomata are present. - - APOSPORY. In some operculate Mosses it has been possible to - obtain a protonema with small Moss-plants from the seta, when - severed from its Moss-plant, and grown on damp sand. - -The Mosses are the lowest plants which are provided with stem and -leaf. They are assigned a lower place when compared with the higher -Cryptogams, partly because there are still found within the Division -so many forms with a mere thallus, partly because typical roots are -wanting and the anatomical structure is so extremely simple, and partly -also because of the relation between the two generations. The highest -Mosses terminate the Division, the Muscineæ and Pteridophyta having had -a common origin in the Algæ-like Thallophyta. - -They are divided into two classes:-- - -HEPATICÆ, or Liverworts. - -MUSCI FRONDOSI. True Mosses or Leafy-Mosses. - - - Class 1. =Hepaticæ= (=Liverworts=). - -The protonema is only slightly developed. The remaining part of the -vegetative body is either a prostrate, often dichotomously-branched -thallus, pressed to the substratum (thalloid Liverworts), with -or without scales on the under side (Figs. 194, 197); or a thin, -prostrate, creeping stem, with distinctly-developed leaves, which are -borne in two or three rows (Figs. 195, 198), viz., two on the upper -and, in most cases, one on the under side. The leaves situated on the -ventral side (amphigastria) are differently shaped from the others -(Fig. 198 _a_), and are sometimes entirely absent. In contradistinction -to the Leafy-Mosses, stress must be laid on the _well-marked -dorsiventrality_ of the vegetative organs; _i.e._ the very distinct -contrast between the dorsal side exposed to the light and the ventral -side turned to the ground. Veins are never found in the leaves. - -The _ventral part of the archegonium_ (calyptra) continues to grow for -some time, and encloses the growing embryo, but when the spores are -ripe it is finally ruptured by the sporangium, and remains situated -like a sheath (_vaginula_) around its base. The sporangium opens, -longitudinally, by _valves_ or _teeth_ (Fig. 194, 195, 197 _b_), very -rarely by a lid, or sometimes not at all. _A columella is wanting_ -(except in _Anthoceros_, Fig. 194); but on the other hand, a few of the -cells lying between the spores are developed into _elaters_ (Fig. 196), -_i.e._ spindle-shaped cells with spirally-twisted thickenings, which -are hygroscopic, and thus serve to distribute the spores. (They are -seen in Fig. 189 _C_, not yet fully developed, as long cells radiating -from the base of the sporangium. They are wanting in _Riccia_). - - [Illustration: FIG. 194.--_Anthoceros lævis_ (nat. size): _K_-_K_ - capsules.] - - [Illustration: FIG. 195.--_Plagiochila asplenioides_: _a_ unripe, - and _b_ an open capsule; _p_ involucre. The ventral edge of each - leaf is higher than its dorsal edge, and covered by the dorsal - edge of the next one.] - - [Illustration: FIG. 196.--An elater with two spores.] - - Round the entire archegonium, (or group of archegonia, when - several are developed on the same receptacle) a sheath--the - _involucre_--is often formed, which persists, and encloses the - base of the stalk of the sporangium, together with the sheath - of the archegonium (Fig. 195 _p_). In the Marchantiaceæ each - archegonium is enclosed in a loose investment, the perigynium, - which is developed as an outgrowth from the cells of its stalk. - -The majority of the Liverworts are found in damp and shady places, -pressed to the substratum; a few are found floating in fresh water. - - - Family 1. =Marchantieæ.= - -This embraces only forms with a thallus, which is more or less -distinctly dichotomously branched, in some, one or two rows of thin -leaves are situated on its under surface. On the upper surface of the -thallus are found large air-chambers. - -Order 1. =Ricciaceæ.= The sporogonia are, with the exception of a few -genera, situated singly on the surface of the thallus, and consist only -of a capsule without foot or stalk. They always remain enclosed by the -wall of the archegonium (calyptra), and open only by its dissolution. -Elaters are not developed. Some genera are found floating like -Duckweed.--_Riccia glauca_ grows on damp clay soil. _R. fluitans_ and -_R. natans_ float in stagnant waters. - - [Illustration: FIG. 197.--_Marchantia polymorpha. A_ Female - plant (nat. size): _a_ and _b_ are archegoniophores in various - stages of development; _s_ cupules with gemmæ (see page 183). _B_ - An archegoniophore seen from below, the short-stalked sporangia - are seen placed in 8–10 double rows. _C_ Male plant, with a - young and an older antheridiophore. _D_ Antheridiophore halved - vertically to show the antheridia (_h_); _m_ the aperture of the - pits in which they are sunk--the older ones to the left, the - younger to the right.] - -Order 2. =Corsiniaceæ.= (Not native). Intermediate forms between the -preceding and the following order. In internal and external structure -mainly resembling the Marchantiaceæ. _Corsinia_; _Boschia_. - -Order 3. =Marchantiaceæ=, are large, fleshy forms. The surface of the -thallus is divided into small rhombic areas, in the centre of each of -which is found a large, peculiarly constructed stoma (Fig. 197 _A_); -beneath each of these a large air-cavity is to be found. From the floor -of the air-cavity a number of alga-like cells project into it; these -contain chlorophyll and are therefore the assimilating cells. The -antheridia and archegonia are each found aggregated on specially formed -branches (somewhat resembling Mushrooms) projecting from the surface of -the thallus. The antheridia are developed on the upper surface (Fig. -197 _C_, _D_) and the archegonia on the lower (Fig. 197 _A_, _B_), -near the centrally-placed stalk. - -_Marchantia polymorpha_ is diœcious (Fig. 197), and very common on damp -places. _Lunularia_ (South Europe), frequently found on flower-pots in -conservatories; _Preissia_, _Fegatella_, _Reboulia_, _Targionia_. - - - Family 2. =Anthoceroteæ.= - - These have an entirely leafless, fleshy, flat, and - irregularly-shaped thallus. In its intercellular chambers - Nostoc-colonies are often found, which have forced their way - through the stomata situated on the under side. The antheridia - and archegonia arise from the cells lying inside the thallus. - The capsule resembles a long, thin pod; it has two valves and a - columella. _Anthoceros_ (_A. lævis_, Fig. 194, and _punctatus_). - - - Family 3. =Jungermannieæ.= - -Some forms in this family have a thallus in which leaf-like structures -are found (_Blasia_), while in others (_e.g. Metzgeria_, _Pellia_, -_Aneura_) they are entirely absent. The majority, however, have -round, thick stems, bearing dorsally two rows of leaves, and one row -ventrally. Some of these have the leaves “underlying” (Fig. 195), while -in others (Fig. 198) they are “overlying.” (See Figs. 195, 198, with -explanation). - -The sporangia are spherical, stalked, and situated singly on the apex -of the branches, and open by four valves (in _Sphærocarpus_ they -are indehiscent). - - [Illustration: FIG. 198.--_Frullania dilatata._ Portion of a - branch seen from the under side: _r_ and _b_ are the anterior - and posterior edges of the same dorsal leaf; _a_ ventral leaves - (amphigastria). The dorsal leaves are “overlying,” _i.e._ the - anterior edge of the leaf overlaps the posterior edge of the - preceding one.] - -All the species in this family were formerly reckoned as belonging to -one genus, _Jungermannia_, but now they are divided into several, -arranged as follows:-- - -I. ANACROGYNÆ. The archegonia are situated on the upper side of the -thallus or stem, _placed laterally_, and covered by an “involucre,” -formed by the calyptra together with the tissue of the stem or thallus. - -a. ANELATEREÆ. Without any elaters: _Sphærocarpus_, _Riella_. - -b. ELATEREÆ. α. Thalloid: _Aneura pinguis_, in damp situations; -_Metzgeria furcata_, on trees; _Pellia epiphylla_, in damp situations; -_Blasia pusilla_, on damp clay soil, in the shade (scales are present -on the thallus). β. Foliose and not dorsiventral: _Haplomitrium -hookeri_. - -II. ACROGYNÆ. The apex of the stem or of certain branches is adapted -for the formation of female shoots. The archegonia are most frequently -aggregated on the apex of the shoots, and are encircled by their leaves -(perichætium). Between these and the archegonia, enclosing the latter, -a peculiar cup-shaped organ (the involucre) is formed. This group only -includes leaf-bearing genera: _Frullania_, _Radula_, _Madotheca_, -_Ptilidium_, _Calypogeia_, _Lepidozia_, _Mastigobryum_, _Lophocolea_, -_Jungermannia_, _Scapania_, _Plagiochila_. - - - Class 2. =Musci frondosi or veri (True Mosses).= - -In this class the protonema is well developed, and resembles a -branched filamentous Alga, from which it can be easily distinguished -by its oblique septa (in _Sphagnum_ it is a cellular expansion). The -Moss-plant, which is developed directly from the protonema, generally -has an erect, thick, cylindrical stem similarly constructed on all -sides. The leaves are arranged spirally, the most frequent divergence -being 2/5 or 3/8 (Fig. 200 _A_). A midrib is often present and also -marginal veins formed by longitudinally elongated cells; at these veins -the leaf is more than one layer in thickness. In _Leucobryum_ the -leaves are generally constructed of more than one layer. - -The stem grows by means of a three-sided, pyramidal, apical cell which -gives rise to three rows of segments, each segment forming a leaf. The -lateral branches arise from the lower portions of the segments, the -upper portion of which does not take any part in the construction of -the leaf. From their mode of origin the branches are not axillary, and -differ in this respect from the Flowering-plants. - -The ventral portion of the archegonium is very early ruptured _at its -base_ by the growing sporogonium, upon which it remains, and it is thus -raised into the air, forming a “hood,” the calyptra (Figs. 192; 200 -_B_). In the Sphagnaceæ the hood is not present; in this order, as in -the Liverworts, the archegonium remains at the base of the sporogonium. -The sporangium opens by circumsessile dehiscence, the upper portion -(_operculum_) being separated along a specially constructed ring of -cells, and falls off like a “lid” (Fig. 200). Only in a few forms -(families 2 and 3) does any variation of this take place. Elaters are -never found, but (with the exception of _Archidium_) there is always -present in the sporangium a central mass of cells, the _columella_, -which take no part in the formation of the spores. The columella, in -some, does not reach quite to the operculum and in these cases the -spore-sac is bell-shaped and covers the columella (_Andreæa_, Fig. 190; -_Sphagnum_, Fig. 199 _D_); but in the majority of Mosses the columella -extends to the lid, so that the space containing the spores becomes a -hollow cylinder. - -The _sporangium_ is generally raised on a long stalk; in the great -majority this stalk is formed from the lower half of the oospore and -belongs to the asexual generation--it is then known as the _seta_. In -_Andreæa_ and _Sphagnum_ the seta is very short, and the sporangia are -raised upon a long stalk (_pseudopodium_) developed from the summit -of the sexual generation (Figs. 190, 192). In the latter figure an -archegonium (_a_) is seen attached to the pseudopodium, having been -carried up with this during the course of its development. The summit -of the pseudopodium is enlarged to embrace the foot of the sporogonium -(Figs. 192, 199 _D_). - - A. The sporangium is supported on a pseudopodium; the columella - does not extend to the operculum. - - [Illustration: FIG. 199.--_Sphagnum acutifolium._--_A_ The - upper portion of a plant: _a_ branches with antheridia; _ch_ - branches with terminal archegonia and perichætia; _b_ the - upper stemleaves. _B_ A male branch whose leaves are partly - taken off in order to show the antheridia. _C_ Group of three - archegonia: the central one (_a_) is formed from the apical - cell. _D_ Sporogonium in longitudinal section: the broad foot - (_sg’_) is sunk in the vaginula, _v_; _c_ calyptra; _ar_ neck - of the archegonium; _ps_ pseudopodium. _E_ ripe sporangium with - operculum, and the remains of the archegonium situated on the - pseudopodium which is still surrounded by the perichætium; to the - left is a barren branch. _F_ Portion of a foliage-leaf seen from - above: _l_ perforations; _b_ chlorophyll-containing cells; _s_ - spiral thickenings.] - - - Family 1. =Sphagneæ (Bog-Mosses).= - -The protonema has been already described. The stem is regularly -branched owing to the fact that a branch, or collection of branches, -arises at every fourth leaf. These branches are closely covered with -leaves, some are erect, while others hang down and surround the stem. -No rhizoids are developed. These Mosses are of a whitish-green colour, -and when water is present are always saturated with it like a sponge, -the reason for this being found in the construction of the stem and -leaves. The stems are covered by an external layer of large clear -cells, without chlorophyll, but with annular or spiral thickenings -on the walls, which are also perforated by large holes. By means of -capillary attraction, water is thus raised to the summit of the stem. -Similarly constructed cells are also found in the leaves, but they -are surrounded by a net of very narrow, chlorophyll-containing cells -(Fig. 199 _F_), whose colour is thus to a great extent lost amongst -those which are colourless. This anatomical structure is an essential -condition for the formation of peat. The Bog-Mosses grow by preference -on moors, which they cover with a thick carpet saturated with water. -The lower extremities of the plants perish very rapidly, and gradually -become converted into peat, and the branches thus separated from each -other become independent plants. The sporangia (Fig. 199 _D_, _E_) are -spherical, but with a very short stalk. They open by a _lid_, but have -no _annulus_. The _archegonium_ (Fig. 199 _C_) persists at the _base of -the sporogonium_ as in the Liverworts. Only one genus, _Sphagnum_. - - - Family 2. =Schizocarpeæ.= - - The Mosses which constitute this family are of a brownish-black - colour and are found living on rocks. The sporangium resembles - that of the Liverworts inasmuch as it opens by four valves, but - these continue attached to each other at the apex as well as at - the base (Fig. 193).--There is only one genus: _Andreæa_. - - =B.= The stalk is formed from the lower portion of the - sporogonium. The columella is continued to the summit of the - sporangium and united with it (_Archidium_ has no columella.) - - - Family 3. =Cleistocarpeæ.= - - The fruit does not dehisce in the regular way, but the spores - are liberated by decay. They are small Mosses which remain - in connection with their protonema until the sporangium is - mature. The archegonium remains sessile at the base of the - short capsule-stalk, and is not raised into the air (compare - Hepaticæ).--_Phascum, Ephemerum, Archidium, Pleuridium._ - - - Family 4. =Stegocarpeæ.= - -To this belong the majority of the Mosses, about 3,000 species. - -The capsule opens as in _Sphagnum_ by means of a _lid_ (_operculum_), -which is often prolonged into a beak. Round the mouth of the opened -capsule, a number of peculiar yellow or red teeth are to be found. -These constitute the _peristome_; their number is four, or a multiple -of four (8, 16, 32 or 64). The form and thickenings of these teeth are -widely different, and on this account are used by Systematists for -the purposes of classification. In some Mosses (Fig. 200 _C_, _D_) -there is a double row of teeth. Except in _Tetraphis_ they are not -formed from entire cells, but from the strongly thickened portions of -the wall of certain layers of cells belonging to the lid, and persist -when this falls off. They are strongly hygroscopic, and assist greatly -in the ejection of the lid, in which operation they are considerably -aided by a ring of elastic cells with thickened walls, situated in the -wall of the lid near the base of the teeth. This ring is known as the -_annulus_. The archegonium is raised into the air like a hood, the -calyptra, which either covers the sporangium on all sides (having the -shape of a bell), or is split on one side (Fig. 200 _B_, _h_). - - Among peculiar forms may be mentioned: _Splachnum_, which is - especially remarkable for the collar-like expansion at the base - of the capsule. _Fissidens_ deviates in having a flat stem and - leaves arranged in two rows. The leaves are boat-shaped and - half embrace the stem.--_Schistostega_ has two kinds of stems. - The barren ones resemble Fern-leaves; they have two rows of - leaves, which are attached together vertically, are decurrent - and coalesce at their bases. The fertile ones have an ordinary - appearance.--_Tetraphis_: the peristome is composed of four - teeth, which are formed from entire cells. _T. pellucida_ has - peculiar gemmæ. - -The family is divided into two groups: the Musci acrocarpi, the growth -of whose main axis is limited and terminated by the formation of the -sexual organs; and the Musci pleurocarpi, whose sporogonia are situated -on special lateral shoots, while the growth of the main axis is -unlimited. - - [Illustration: FIG. 200.--_A Hypnum populeum_. _B_ and _C_ - Sporangia, with hood (_h_), and operculum (_l’_), and without - these (_C_), showing the peristome (_p_). _D_ The mouth of the - capsule of _Fontinalis antipyretica_.] - - - A. =Acrocarpi.= - - Order 1. =Weisiaceæ.= Peristome, with 16 teeth arranged in - one series, rarely wanting. Leaf with midrib. _Campylopus_, - _Dicranum_ (_D. scoparium_, common in forests), _Dicranella_, - _Cynodontium_.--_Weisia_, _Gymnostomum_ (no peristome), - _Systegium_. - - Order 2. =Leucobryaceæ.= Peristome with 16 teeth. Leaves with - three or more layers of cells, of which the external ones are - air-conducting and perforated (as in the Sphagneæ), the middle - one containing chlorophyll. _Leucobryum._ - - Order 3. =Fissidentaceæ.= Peristome as in the preceding ones. - The leaves are arranged in two rows on the plagiotropic shoots; - in _Fissidens_ the midrib of the leaf bears wing-shaped - outgrowths. _Conomitrium, Fissidens._ - - Order 4. =Seligeriaceæ.= Peristome with 16 undivided teeth. Very - small Rock-mosses. _Seligeria.--Blindia._ - - Order 5. =Pottiaceæ.= Peristome with 16 teeth, which are - divided almost to the base, or with 32 teeth. Calyptra - hood-like.--_Barbula (B. muralis, B. ruralis), Trichostomum, - Leptotrichum.--Ceratodon purpureus.--Distichium.--Pottia._ - - Order 6. =Grimmiaceæ.= The leaf-cells are often papillose; - in the upper portion of the leaf, small, and of roundish - shape. The calyptra is most frequently hood-like or conical. - _Eucalypta._--_Orthotrichum_, often with short-stalked capsule, - is found on trees.--_Coscinodon._--_Hedwigia._--_Grimmia_, - _Racomitrium_.--_Cinclidotus._ - - Order 7. =Schistostegaceæ.= The stems are of two kinds (see - above); _Schistostega osmundacea_, in caves, has a bright - emerald protonema. - - Order 8. =Splachnaceæ.= The capsule has a large, collar-like - neck (see above). _Splachnum_ (especially on manure). - - Order 9. =Funariaceæ.= Capsule pear-shaped. _Funaria_ (_F. - hygrometrica_ has a very hygroscopic seta, becoming twisted - when dry, and straightening with moisture); _Physcomitrium_; - _Discelium_. - - Order 10. =Bryaceæ.= The capsule is thicker towards - the apex; most frequently pendulous. _Philonotis_, - _Bartramia_.--_Aulacomnium._--_Paludella - Meesea._--_Mnium._--_Bryum_, _Webera_, _Leptobryum_. - - Order 11. =Polytrichaceæ.= Single peristome, formed by 16, - 32, or 64 teeth. Leaves with longitudinal lamellæ on upper - surface.--_Polytrichum_ has long, hairy calyptra. _Catharinea_ - (_C. undulata_, in forests). - - Order 12. =Georgiaceæ.= Peristome with 4 teeth (see above). - _Tetraphis_ (_T. pellucida_ has gemmæ). - - Order 13. =Buxbaumiaceæ.= Capsule asymmetrical; double - peristome: the interior one conical, with 16 or 32 longitudinal - folds.--_Buxbaumia_ (_B. aphylla_); _Diphyscium_. - - - B. =Pleurocarpi.= - - Order 14. =Fontinalaceæ.= Long, floating Water-Mosses. - _Fontinalis_ (_F. antipyretica_ is found in streams). - _Dichelyma._ - - Order 15. =Hookeriaceæ.= _Pterygophyllum._ - - Order 16. =Leskeaceæ.= Dull-looking Mosses, with papillose or - warted leaves.--_Thuidium_, _Thuja_-like with regularly arranged - 1–3 doubly pinnate stems; _Anomodon_, _Leskea_. - - Order 17. =Pterogoniaceæ.= _Pterigynandrum filiforme_, etc. - - Order 18. =Fabroniaceæ.= _Anacamptodon._ - - Order 19. =Neckeraceæ.= Stems most frequently with flat, leafy - branches. The leaves are smooth, never with longitudinal - folds.--_Neckera._ - - Order 20. =Hypnaceæ.= The leaves are smooth with square, - often bladder-like, cells at the edge. _Hylocomium_ (_H. - splendens_, _H. triquetrum_); _Hypnum_; _Brachythecium_; - _Plagiothecium_.--_Eurhynchium._--_Homalothecium_, _Isothecium_, - _Orthothiecium_, _Homalia_.--_Climacium_, _Lescuræa_, _Leucodon_. - - The Mosses occur all over the globe. Many are found in great - numbers, and growing thickly massed together, they form an - important feature in landscapes (for example _Sphagnum_ and - _Polytrichum_ in the Arctic Tundra). In the Northern and - Arctic regions the Mosses are very plentiful, and often form a - considerable part of the vegetation, while in the Tropics they - are insignificant. - - Species of _Hypnum_ and _Polytrichum_, like _Sphagnum_, play an - important part in the formation of peat. - - - - - DIVISION III. - - PTERIDOPHYTA (VASCULAR CRYPTOGAMS). - - -The alternation of generations is as distinct in this Division as in -the Mosses, but the sexual generation consists of only a small thallus, -the prothallium, which bears directly the sexual organs, _antheridia_ -and _archegonia_; and the asexual generation, which arises from the -fertilisation of the oosphere, is no longer a single short-lived -sporangium, but a highly developed, generally perennial, plant provided -with stem, leaves and _true roots_ (Ferns, Horsetails, etc.), the -sporangia being borne on the leaves. In this latter generation the -tissues are differentiated into epidermis, ground tissue and vascular -tissue; in the last named the bundles are closed, and in the majority -of cases concentric. - -The =sexual generation=, =gametophyte=, or =prothallium=, is _always -a thallus_, although not always green and leaf-like (Figs. 205, 215, -222, 229, 235, etc.) It is very small, even in cases where it attains -the greatest development, and consists only of parenchymatous cells. -The prothallium is nourished by hair-like roots (rhizoids) and has -only a transitory existence, dying soon after the fertilisation of its -oosphere. - -The ANTHERIDIA exhibit great variations in structure which, however, -must be considered as modifications of the fundamental type which is -found in the Mosses. These modifications will be mentioned under the -various families. The _spermatozoids_ are always spirally-coiled, -self-motile, protoplasmic bodies, with most frequently a large number -of fine cilia on the anterior end (Figs. 206, 223, 234). They are -formed principally from the nucleus of the mother-cell, and portions of -the cytoplasm often remain for a time attached to their posterior end. - -The ARCHEGONIA are more uniform throughout the entire Division, -and more closely resemble those of the Mosses. They are, as in the -previous Division, principally flask-shaped; but the central portion, -which encloses the oosphere, is always embedded in the tissue of the -prothallium, so that the neck, which is formed of 4 rows of cells, -projects above the surface (Figs. 201 ^3, 222 _h_). The development -of the archegonium in a Fern is seen in the accompanying figure (Fig. -201). The archegonium is developed from a surface cell, which divides -into three cells by two walls in a direction parallel to the surface -of the prothallium (Fig. 201). The most internal cell becomes the -ventral portion of the archegonium. The external one (_b_) divides -perpendicularly to the surface of the prothallium into four cells, -which again divide parallel to the surface and form the neck (_b_, -in 2 and 3). The intermediate cell projects upwards into the neck -and divides into two, the lower one, after the separation of the -ventral canal-cell, becoming the _oosphere_, and the upper one the -_neck-canal-cell_ (_c_, in 2 and 3). - - [Illustration: FIG. 201.--_Pteris serrulata._ Development of - archegonia.] - -As in the Mosses, the divisional walls of the neck-canal-cells become -mucilaginous, causing the rupture of the neck of the archegonium. -Fertilisation takes place as in the Mosses, and the passage of the -spermatozoids, along the neck, to the oosphere, has been observed. -Water (rain or dew) is similarly necessary for the movements of the -spermatozoids, and hence for fertilisation. The other classes of the -Division chiefly deviate from the Ferns in having the archegonium sunk -deeper into the prothallium, and the neck reduced in length (compare -Fig. 201 with Figs. 216, 222, 235, 236). - -According to the nature of the spores, the three classes of the -Vascular Cryptogams are each divided into isosporous and heterosporous -groups. - -I. The =isosporous= Vascular Cryptogams have _only one kind of spore_. -The prothallium developed from this is in some cases monœcious, bearing -both antheridia and archegonia; but in others there is a distinct -tendency for each prothallium to bear only antheridia or archegonia -(diœcious)--true Ferns and _Lycopodium_. - -In _Equisetum_ there is only one kind of spore, but two kinds of -prothallia are developed, one of which bears only antheridia (male), -the other only archegonia (female); but the one that bears antheridia -may be transformed into the one that bears archegonia and vice versa. - -II. In the higher group, =heterosporous= Vascular Cryptogams -(_Selaginella_ and _Isoëtes_, etc.), there are two distinct kinds -of spores, the _small_, microspores, and the _large_, macrospores. -The _microspores_ are male, and produce prothallia which bear only -antheridia. The _macrospores_ are female, and produce prothallia which -bear only archegonia. - -Corresponding to this difference in the spores, there is also found -a difference in the development of the prothallium. In the Isosporeæ -the prothallium is large, and either green, leaf-like, and provided -with rhizoids (most of the Ferns, Horsetails, etc.), or subterranean, -pale-coloured, and globular (_Ophioglossum_, _Lycopodium_). It lives -vegetatively for a fairly long time, and generally produces a large -and varying number of archegonia and antheridia. The prothallium in -the Heterosporeæ is gradually more and more reduced, its independent -and vegetative life becomes of less and less importance, it becomes -more dependent on the mother-plant, and projects from the spore very -slightly, or not at all. The antheridia and archegonia become reduced -in number to one, and also degenerate in point of development. - -It may here be remarked that the gradual development of the asexual -generation, the development of the two kinds of spores, and the -progressive reduction of the prothallium and sexual organs which -is found in this Division, is continued to the Gymnosperms and -Angiosperms. The microspores are in these called pollen-grains, and -the male prothallium is very rudimentary. The macrospores are termed -embryo-sacs, and the female prothallium, the endosperm. - -The =asexual generation=, =sporophyte=. When the oosphere, which in -this case as in all others is a primordial cell, is fertilised, it -surrounds itself with a cell-wall and commences to divide into a number -of cells, to form the embryo. - - The first dividing wall (basal wall) is nearly horizontal, and - in the direction of the longitudinal axis of the archegonium. - The next wall is vertical, and the next perpendicular to the - other two. The oosphere, therefore, is now divided into eight - octants by these three walls. The basal wall divides the - embryo into a hypobasal and an epibasal half. From the first - one, by continued divisions, the first root is developed; from - the latter, the stem and leaves. After the formation of the - octants the development proceeds in somewhat different ways in - the various classes. In addition to the stem, leaf, and root, - a “foot” is developed from the hypobasal half which remains - enclosed in the prothallium, and conveys nourishment from the - prothallium to the young plant until it is able to sustain - itself (Fig. 202). The formation of these members in the embryo - depends on the position of the oosphere in the archegonium and - prothallium, and is independent of gravity. - - [Illustration: FIG. 202.--_Adiantum capillus veneris._ Vertical - section through a prothallium (_f f_), with a young plant - attached on its under side (mag. about 10 times); _r_ the first - root, and _b_ the first leaf of the young Fern-plant; _m_ the - foot. In the angle between _m_ and _b_ lies the apex of the - stem: _h_ the rhizoids of the prothallium; _æ æ_ unfertilised - archegonia.] - -In the Mosses the asexual generation is the sporogonium, which is -limited in its development and in a great measure dependent upon the -sexual generation, upon which it is situated; but in the Pteridophyta -this generation is an independent and highly developed plant, -provided with stem, leaf, and true roots, and has in many instances -an unlimited development. The Pteridophyta are the lowest Division -with _true roots_. The root which is first formed is very similar in -nature to the primary root of the Monocotyledons; it very soon dies -and is replaced by others which are more permanent, and developed -upon the stem (adventitious roots); roots are wanting in _Salvinia_, -_Psilotum_, and some Hymenophyllaceæ. The differentiation is, however, -not so complete as in the Flowering-plants, and so many leafy forms are -not found. The various members of these plants are anatomically much -higher than in the Mosses, having an epidermis, a ground tissue with -variously differentiated cells, and a highly developed vascular system. -The vascular bundles, like those in the Monocotyledons, are without -cambium, and closed; they are therefore incapable of any increase in -thickness. In general the bundles are concentric, with the bast round -the wood (Fig. 203). The wood is almost entirely made up of scalariform -tracheides. - - In _Isoëtes_ a secondary thickening takes place by a cambium, - which is formed inside the cortex, constructing secondary - cortex to the exterior, and secondary wood towards the - interior.--_Botrychium_ has also a thickening growth. Collateral - vascular bundles occur in _Osmundaceæ_, _Equisetaceæ_, and the - leaves of many _Polypodiaceæ_, etc. - - [Illustration: FIG. 203.--Portion of the stem of a Fern. Above is - seen the transverse section, with vascular bundles of different - form and size. The rhombic figures on the side of the stem are - leaf-scars.] - -It is a point of special interest, that the gigantic forms of Ferns, -Equisetums, and Club-Mosses (which flourished in earlier geological -periods, when these classes attained their highest development) -possessed some means of increasing in thickness. - -The _sporangia_ are in all cases _capsule-like_, and burst open when -ripe to eject the spores. They are nearly always situated on the leaves -(in _Lycopodiaceæ_, in the axils of the leaves, or above these, on the -stems themselves). In some forms (LEPTOSPORANGIATÆ), the sporangia are -developed from a single epidermal cell; in others (EUSPORANGIATÆ), -from a group of epidermal cells, or from cells which lie beneath the -epidermis. In the first group a primitive mother-cell (archesporium) -is formed, which divides commonly into sixteen special mother-cells. -In the latter group, on the other hand, a number of primitive -spore-mother-cells are developed. In each sporangium three different -tissues are generally developed; an innermost _sporogenous_ one (_s_ in -Fig. 204 _A_), which arises from the archesporangium; an outermost one, -which forms the _wall_ (_a_), and may be one or, more rarely, several -layers in thickness; and an intermediate one, the _tapetum_ (Fig. 204 -_A_, _B_, _b t_), which is rich in protoplasm, and whose cells are -dissolved so that the spores float freely in the fluid thus provided. -The spores arise as in the Mosses (in tetrads), by the cross-division -of the special mother-cells, and according to the manner in which they -are arranged in the mother-cell have either a tetrahedral form, with -a large base resembling a segment of a ball, or are oblong (bilateral -spores). Their construction is the same as in the Mosses (p. 187). - - [Illustration: FIG. 204.--_Selaginella inæqualifolia. A_ A - young sporangium, which may develope either into a macro-, or a - microsporangium. _B_ A microsporangium.] - -The spore-formation in its earliest commencement takes place in the -same way in the Isosporous and the Heterosporous Vascular Cryptogams; -but from a certain point, after the tetrahedral division, a difference -occurs with regard to the macrosporangia. All the spores formed in the -microsporangium may complete their development; but those which are -formed in the macrosporangium are generally aborted, with the exception -of one or four, and these consequently attain a much larger size (see -Fig. 239.--The series to the left are microsporangia; those to the -right, macrosporangia). - - APOGAMY. In some Ferns (_Pteris cretica_; _Aspidium filix mas_, - var. _cristatum_; _A. falcatum_; _Todea africana_) the young - plant is not developed as a consequence of fertilisation, but as - a bud from the prothallium. This is known as apogamy, or loss of - the power of sexual reproduction. The antheridia are generally - more or less developed; archegonia are entirely wanting in _Asp. - filix mas_, var. _cristatum_. This variety has probably only - become apogamous through cultivation. Many specimens of _Isoëtes - lacustris_, in a lake in the Vosges mountains, produce in the - place where the sporangia are usually found, a vegetative shoot - which grows into a new plant, so that the sexual generation is - wanting in this case. Some specimens have sporangia on some - leaves, and shoots on others. - - Apospory, or the formation of prothallia instead of sporangia - and spores on the leaves, is found in _Athyrium filix - femina_, var. _clarissimum_. In this case the development - of the sporangia proceeds only to a certain point, and from - these arrested sporangia the prothallia are produced. Normal - sporangia are entirely wanting in this variety, and in _Aspidium - angulare_, var. _pulcherrimum_, sporangia are completely - wanting. Compare the Mosses (page 188). - -The Vascular Cryptogams are divided into _three large classes_, -in each of which a progressive development can be traced from the -isosporous to the heterosporous forms, but some of these are now only -known as fossils. - -Class 1. =Filicinæ= (=Ferns=).--The stem is small in comparison with -the leaves, and branches only seldom, and then by lateral shoots. The -leaves are scattered, large, often deeply divided, and of various -highly developed forms. The undeveloped leaves are rolled up in the -bud, having what is termed circinate venation. The sporangia are -situated on the edge or on the lower side of the leaves, those on -which the sporangia are borne (_sporophylls_) being often the ordinary -foliage-leaves; but in a few cases the fertile differ from the barren -ones (a higher stage in development). The fertile leaves are not -confined to definite parts of the shoot, and do not limit its growth. -The archesporium is most frequently unicellular. - -_A_. =Isosporous=: Sub-Class 1. Filices (True Ferns). - -_B_. =Heterosporous=: Sub-Class 2. Hydropterideæ (Water Ferns). - -Class 2. =Equisetinæ= (=Horsetails=), in its widest meaning.--The -leaves in this class are small in comparison with the stem. They are -arranged in whorls, and unite to form a sheath. The sporangia are -situated on specially modified, shield-like leaves, which are closely -packed together and form a “cone.” The cone is borne terminally, and -limits the growth of the shoot. The sporangia are developed from a -large group of epidermal cells, the archesporium being unicellular. The -branches are arranged in whorls, and develope acropetally. - -_A_. =Isosporous=: Sub-Class 1. Equisetaceæ. Existing forms. - -_B_. =Heterosporous=: Sub-Class 2. Extinct forms. - -Class 3. =Lycopodinæ= (=Club-Mosses=).--Roots generally branching -dichotomously. The leaves are scattered or opposite, and in proportion -to the stem very small, undivided, and simple. They are scale-like and -triangular, tapering from a broad base to a point. The sporangia are -situated singly (except in _Psilotaceæ_), and almost in every case on -the upper side of the leaf or in the axil of a leaf; but in some cases -they are borne on the stem, just above the leaf-axil. The sporangia -arise from groups of epidermal cells. The sporophylls are often -modified, and differ from the foliage-leaves; they are then arranged in -cones placed terminally on branches, thus limiting their growth. - -_A_. =Isosporous=: Sub-Class 1. Lycopodieæ. - -_B._ =Heterosporous=: Sub-Class 2. Selaginelleæ. - - - Class 1. =Filicinæ= (=Ferns=). - -The characteristics of this class have already been given on page 204. - -The class is divided into two sub-classes:-- - -1. The TRUE FERNS, FILICES, have one kind of spore which generally -developes monœcious prothallia, relatively large and green. The -sporangia are most frequently situated in groups (_sori_), which are -often covered but not enclosed by an _indusium_. - -2. WATER FERNS, HYDROPTERIDÆ, have microsporangia with many (4 × 16) -microspores, and _macrosporangia, each with one macrospore_. The -prothallium is small, and projects but slightly from the germinating -spore. The sporangia are situated in groups (_sori_), which are either -enclosed by an indusium, or enveloped in a portion of a leaf, to form -“fruits” termed _sporocarps_. - - The old name for the Hydropterideæ, “Rhizocarpeæ,” _i.e._ the - “root-fruited,” originated from the erroneous supposition that - the sporocarps were borne on the roots. - - - Sub-Class 1. =Filices= (=the True Ferns=). - -Of the eight orders (with about 4,000 species) comprised in this -sub-class, the Polypodiaceæ is the largest (having about 2,800 species) -and the most familiar; for this reason it will be taken as typical. - -=The sexual generation.= When the spore germinates, the external -covering (exospore) is ruptured, as in the Mosses. The internal -cell-wall (endospore) grows out as a filament, which soon divides and -gives rise to the prothallium, a flat, cellular expansion resembling -the thallus of a Liverwort. In its fully developed state the -prothallium is generally heart-shaped, dark green, and provided with -root-hairs, and it attains a diameter of about one centimetre (Fig. -205). It is formed of one layer of cells, except along the central -line near the anterior depression, where it becomes several layers -of cells in thickness, forming the “cushion,” on the lower side of -which the archegonia are developed. The antheridia are first formed; -they are thus found on the oldest parts of the prothallium, on its -edge, or among the root-hairs. The archegonia are developed later, -and are therefore found near the apex. Several tropical Ferns have -prothallia[18] deviating from this typical form; _Trichomanes_ -(Order _Hymenophyllaceæ_) has filamentous, branched prothallia, -which resemble the protonema of a Moss. Others, again, have -strap-shaped prothallia, which resemble the thallus of certain -Liverworts. - - [Illustration: FIG. 205.--Prothallium (_p p_) of Maiden hair - (_Adiantum capillus veneris_) with a young plant attached: _b_ - first leaf; _w′_ primary root; _w″_ adventitious roots; _h h_ - root-hairs of the prothallium (× abt. 30).] - - [Illustration: FIG. 206.--Antheridia of Maiden-hair (× 550). - _A_ Unripe; _B_ ripe, but unopened; _C_ open and ejecting the - spermatozoids (_s_). Those which have been last ejected are still - lying enclosed in their mother-cells, the others are coiled up - and drag with them the cytoplasmic remains (_b_); _f_ cells of - the prothallium.] - -The ARCHEGONIA have been already mentioned (p. 199, Fig. 201). The -ANTHERIDIA are hemispherical or slightly conical bodies (Fig. 206). -They consist, as in the Mosses, of a wall formed by one layer of -cells, which encloses a number of spermatozoid-mother-cells (_A_ -and _B_). The antheridia when ripe absorb water, and are ruptured, -and the spirally-coiled spermatozoids liberated (Fig. 206 _S_). -The spermatozoids have been observed to pass down the neck of the -archegonium, and to fuse with the oosphere. - -=The asexual generation.= The first leaf, the “cotyledon,” of the -embryo developed from the oospore (Figs. 202, 205) is always small, -and has a very simple shape. The leaves which occur later become more -perfect, stage by stage, until the permanent form of leaf has been -attained.--The STEM is most frequently a subterranean or a semi-aerial -rhizome; it is only in the tropical, palm-like Tree-Ferns, that the -stem raises itself high in the air and resembles that of a tree, -with leaf-scars or with the remains of leaves attached (Figs. 207, -203); in certain species the stem is encased in a thick mat of aerial -roots (_Dicksonia antarctica_). When the rhizome is horizontal the -internodes are frequently elongated, and the leaves are arranged in two -rows, as in _Polypodium vulgare_ and in the Bracken-Fern (_Pteridium -aquilinum_), etc.; it is also generally _dorsiventral_, having a dorsal -side on which the leaves are situated, and a ventral side, different -from the former, on which the roots are borne. When the stem ascends -in an oblique direction, or is nearly vertical, its internodes are -extremely short, and the leaves are arranged in a spiral line with a -complicated phyllotaxis, _e.g._ in _Athyrium filix-fœmina_, _Aspidium -filix-mas_, etc. The BRANCHING upon the whole is extremely slight, and -is generally confined to the petiole (_e.g. Aspid. filix-mas_), or -to the stem near the insertion of the leaves. Several species normally -form buds on different parts of the lamina. The buds which are formed -on the stem are not confined to the leaf-axil as in the higher plants. -The Tree-Ferns, generally, do not branch at all. - -The VASCULAR BUNDLES are _concentric_, with the wood surrounded by -the soft bast. In transverse section they are seen as circles or -irregularly-shaped figures (Fig. 203), the name of “King Charles and -the Oak” (Bracken-Fern) having originated from the appearance which the -bundles present in oblique section. In _Osmunda_ they are collateral -and resemble those of the Flowering-plants. Round each individual -bundle is often a sheath of thick-walled, hard, brown, sclerenchymatous -cells, which act as a mechanical tissue; similar strands are also found -in other parts of the stem. - - [Illustration: FIG. 207.--Various Ferns (1, 2, 3, 4).] - -The LEAVES in nearly all species are only foliage-leaves, borne in a -spiral. They have an apical growth which continues for a long time, -and some require several years for their complete development. In the -buds they are rolled up (_circinate_); not only the midrib, but also -all the lateral veins, and even the terminal portions of a leaf are -sometimes rolled up together, the tissues of the leaf being already -fully developed and only waiting to expand. The leaves are often -excessively divided and compound, with pinnate branches, and have -an epidermis with stomata and a well-developed system of venation. -Stipules are only found in _Marattiaceæ_ and _Ophioglossaceæ_. - -Very often peculiar hairs or scales (_paleæ_, _ramenta_), dry, brown, -flat and broad, are found on stem and leaf. - -The SPORANGIA are small, round capsules, which, in a very large number -of Ferns, are formed on the back, but more rarely on the edge of the -ordinary foliage-leaves. It is very seldom that there is any difference -in form between the barren foliage-leaves and the fertile leaves, as is -found for example in _Blechnum spicant_ or _Struthiopteris_; or that -the fertile part of the leaf is differently constructed from the barren -portion of the same leaf, as in the Royal-Fern (_Osmunda_). In such -instances the mesophyll of the fertile parts is poorly developed. - -The sporangia in the _Polypodiaceæ_ are lens-shaped, with long stalk -(Fig. 211 _D_): their wall consists of one cell-layer on which a single -row of cells, passing vertically over the top (that is along the edge -of the sporangium), is developed into the “ring” (annulus). The cells -of the annulus are very much thickened on the inner and side walls, -and are yellowish-brown. The thickened cells, however, do not entirely -encircle the sporangium, and on one side, near the stalk, they pass -over into large, flat, thin-walled cells. These form a weak point in -the wall, and it is here that the sporangium is opened diagonally by -the elongation of the annulus. The sporangium of the Polypodiaceæ -opens as it dries. The cells of the annulus are very hygroscopic, and -in straightening, the annulus bends back with a jerk, thus ejecting -the spores to considerable distances. The cells of the annulus absorb -water with great readiness. [The sporangium arises as a single -epidermal cell, from which a basal stalk-cell is cut off. Three oblique -cell-walls, intersecting near the base, are next formed in the upper -cell, and a fourth between these and parallel to the free surface; an -inner tetrahedral cell enclosed by four others is thus formed, the -outer cells become the wall of the sporangium, while the inner cell, -by a series of walls, parallel to its sides, cuts off a layer of -cells which eventually form the tapetum, the remaining central cell -constituting the archesporium.] - -The SPORES are either oblong and bilateral, or they are tetrahedric -with curved sides, depending upon the way in which the tetrad division -has taken place. - -The sporangia are almost always situated on the nerves and gathered -into groups, _sori_, which differ in form in the various genera. The -sori, in many genera, may be covered by a scale-like structure, the -_indusium_ (Figs. 211 _B_, 212). - -In the majority of cases, each sorus is situated on a small papilla -(_placenta_, or _receptacle_), which is supplied by a small vascular -bundle. Between the sporangia, hairs (_paraphyses_) are often situated, -which spring either from the placenta or from the stalks of the -sporangia. - -=Systematic Division.= The Ferns may be divided into two groups, -characterized by the structure and development of the sporangia. -The sporangia in the EUSPORANGIATÆ take their origin from a group -of epidermal cells, and their walls are formed by several layers of -cells. The archesporium is the (not tetrahedric) hypodermal terminal -cell of the axial row of cells which give rise to the sporangium. -In the LEPTOSPORANGIATÆ the sporangia are developed from single -epidermal cells, and their walls are uni-layered. The archesporium is a -central, often tetrahedric cell, from which sixteen spore-mother-cells -are developed.[19] It is difficult to say which form is the oldest -(according to Prantl, those which have the sori on the nerve-endings); -however, the Eusporangiatæ would seem to have made their appearance -long before the others, and also well defined Marattiaceæ and -Ophioglossaceæ occur in the Kulm and Coal period, before the true -Polypodiaceæ. - -About 4,000 species of Ferns are now existing, and they are found -especially in tropical and sub-tropical forests. - - - Family 1. =Eusporangiatæ.= - -Order 1. =Ophioglossaceæ.= The prothallium differs from that of all -other Ferns in being _subterranean_, _free from chlorophyll_, _pale_ -and _tuberous_. The stem is extremely short, with short internodes, -most frequently unbranched, vertical, and entirely buried in the ground -(Fig. 208 _st_). In several species (among which are the native ones) -one leaf is produced every year, which has taken three to four years -for its development. In _Botrychium_ a closed, sheath-like basal part -of each leaf covers the subsequent leaves during their development. In -_Ophioglossum_ and others each leaf has at its base an intrapetiolar, -cap-like sheath, which protects the succeeding leaf. The leaves are -of two kinds: (_a_) foliage, which in _Ophioglossum vulgatum_ are -lanceolate and entire, but in _Botrychium_ however, are pinnate (_b_ -in Fig. 208 _A_, _B_); and (_b_) fertile, which are found facing the -upper side of the foliage-leaves. These latter in _Ophioglossum_ are -undivided and spike-like (Fig. 209 _A_), but pinnate in _Botrychium_ -(Fig. 208 _B_). Each foliage and fertile leaf are branches from the -same petiole. The large sporangia are placed laterally, and open by -two valves. No annulus is formed (Fig. 209).--_Ophioglossum_ reproduces -vegetatively by adventitious buds on the roots. - - [Illustration: FIG. 208.--_A Ophioglossum vulgatum_ - (Adder’s-tongue); _B Botrychium lunaria_ (Moonwort), both - natural size; _r-r_ roots; _bs_ leaf-stalk; _st_ stem; _b_ - foliage-leaf; _f_ fertile leaf.] - - [Illustration: FIG. 209.--Fertile leaf of _Ophioglossum_.] - -Three genera with about twelve species. - -Order 2. =Marattiaceæ= are tropical Ferns, whose gigantic leaves -resemble those of the Polypodiaceæ, but have stipules in addition. -The sporangia are grouped in sori, situated on the lower side of the -leaves, the sporangia in each sorus being arranged either in two rows -or in a ring. In _Angiopteris_ they are isolated (Fig. 210 _A_), -but in the other species (_Kaulfussia_, _Danæa_, _Marattia_), they -are united, and form “synangia” divided into a number of chambers -corresponding to the sporangia. These open by clefts or pores. -_Marattia_ presents the highest development, as its sporangia are -completely united in a capsule-like synangium, which is closed until -maturity, and then opens by two valves. In each valve there is a row -of three to eleven sporangia, each opening by a slit towards the -inside (Fig. 210 _B_, _C_). An indusium encloses the sorus, except in -_Kaulfussia_; it is formed of flat and lobed hairs, which resemble -the hairs of the other portions of the leaves. In _Angiopteris_ and -_Marattia_ the indusium is very rudimentary; in _Danæa_ it forms a kind -of cupule. - - The numerous fossil Marattiaceæ (15 genera, with 98 species) - present similar differences to those now living, but more - various forms are found, for example, with solitary free - sporangia. Those now living are the last small remnant (4 genera - with only 23 species) of a once dominant family, which existed - from very early times, and whose culminating point was reached - in the Kulm and Coal periods. - - The Ophioglossaceæ appear also in the Kulm and Coal periods, - and were about as numerous as at the present time (presumably 2 - genera, with 19 species). Leptosporangiate Ferns appear however - to have occurred first of all in the Trias-formation. - - [Illustration: FIG. 210.--Sporangia of the Marattiaceæ: _A_ - _Angiopteris_; _B_ and _C Marattia_; _C_ is a half sorus with - nine sporangia, each of which has opened by a longitudinal cleft.] - - - Family 2. =Leptosporangiatæ.= - -Order 1. =Polypodiaceæ.= Sporangia on the lower side of the leaves, -_stalked_ and provided with a _vertical_, incomplete annulus; dehiscing -by a transverse cleft (Fig. 211 _D_).--The genera are distinguished by -the form of the indusium and the position of the sori, etc. - -1. The sporangia cover the entire lower surface of the leaf (Tropical -America and Asia). _Acrostichum_, _Platycerium._ - -2. Sori without indusia, circular or oval. _Polypodium_ (Fig. 211 _A_). -The leaves are most frequently situated in two rows on the dorsal -side of the creeping rhizome, and fall off leaving a smooth scar -behind.--_P. vulgare_, common in woods, on stones. (_Phegopteris_ also -has no indusium; see page 214). - -3. The sporangia are situated in continuous lines just inside the -margin of the leaf.--_Pteris_[20]: the sporangia form a continuous -line along the entire margin of the leaf (Fig. 211 _C_), which bends -over and covers the sporangia, forming a “false-indusium.” _Pteridium_ -has linear sori situated on a marginal vascular bundle, covered by two -linear basal indusia, of which the outer is bent over like the edge of -a leaf.--_P. aquilinum_ (Bracken) has a wide-spreading rhizome with -large alternate leaves, placed on opposite sides, at some distance -apart. Only one leaf is developed from each branch every year. - - [Illustration: FIG. 211.--Portions of leaves with sori. _A_ - _Polypodium_. _B Aspidium_. _C Pteridium_. _D_ A sporangium - of one of the Polypodiaceæ: _r_ the annulus; _s_ spores.] - - _Adiantum_ (Maiden-hair): sori on the underside of small - portions of the edge of the leaf, which are bent over (false - indusium). _Cryptogramme_ (_Allosorus_), _Cheilanthes_. - -4. The sori are oval or linear, situated on one side of the vascular -bundle.--_Asplenium_ (Fig. 212 _A_): sori linear; indusium with one of -its edges attached at the external side. _A. ruta muraria_ (Wall-Rue); -_A. septentrionale_; _A. trichomanes_.--_Athyrium_: sori linear or -curved; _A. filix-fœmina_ (Lady-Fern).--_Scolopendrium_ (Fig. 212 _B_): -sori as in _Asplenium_, but situated in pairs across the lanceolate, -entire leaves. Each sorus is covered on the external side by an -indusium, whose free edges are parallel and approach each other. _S. -vulgare_ (Hart’s-tongue).--~_Blechnum_ (_B. spicant_, Hard Fern; the -fertile leaves differ from the barren, the pinnæ being narrower, while -the underside is almost entirely covered with sori, and hence they -are of a much darker brownish hue than the barren ones).--_Ceterach_: -indusium rudimentary or absent.~ - -5. Sori circular and covered by a shield-like, or reniform -indusium.--_Aspidium_ (Fig. 211 _B_); the leaves wither away and -leave no scar upon the root-stock. _A. filix-mas_ (Male-Fern); _A. -spinulosum_.--_Phegopteris_ has no indusium, the withered bases of the -leaf-stalks are persistent; _P. dryopteris_ and _P. polypodioides_. - -6. The indusium is situated below the sori, and has the shape of a -one-sided scale (_Cystopteris_, _Struthiopteris_), or of a cup or -cupule, which in _Woodsia_ is sometimes fimbriate (Fig. 212 _C_, _D_). - - [Illustration: FIG. 212.--_A Asplenium_. - _B Scolopendrium_. _C Woodsia_; _D_ - single sorus of the same. _E Cyathea_: the sporangia - have fallen off in the upper sori. (All magnified.)] - -7. The sori are situated on the margin of the leaf, and at the end of a -vascular bundle. Indusium, semi-cupular. _Davallia._ Principally -tropical species. 1 in S. Europe. - -This order is the greatest, comprising about 2,800 species, the -majority being perennial plants. A few are large, and known as -Tree-Ferns. - - As plants in conservatories and rooms the following are - cultivated: species of _Gymnogramme_ (tropical America), - _Lomaria_, _Nephrolepis_, _Pteris_ (_P. serrulata_, _cretica_). - - Officinal. _Aspidium filix-mas_, rhizome and the withered - petioles.--Species of _Alsophila_ and _Cibotium_ give Penghawar - Djambi. The rhizome of _Pteridium aquilinum_, var. _esculentum_, - contains so much starch that it is used as food. - - The other orders of true Ferns deviate from the Polypodiaceæ, - especially in the formation of the annulus, the bursting of the - sporangium and its mode of attachment and development, and in - the differences in the formation of the prothallium, etc. The - principal are:-- - -Order 2. =Hymenophyllaceæ.= To this order belong the lowest and most -Moss-like Ferns; the leaves, with the exception of the veins, are -most frequently formed of _only one layer of cells_, and consequently -stomata are wanting; the formation of the prothallium also somewhat -resembles the Mosses. Sori marginal, on the _extremities of the -vascular bundles_, and surrounded by a _cupular indusium_. The -sporangia are sessile, with equatorial annulus. _Hymenophyllum_ (_H. -tunbridgense_, European). _Trichomanes_ (_T. speciosum_, European). -Species about 200, which live especially on rocks and trees in damp and -shady tropical forests. Some have no roots. - -Order 3. =Cyatheaceæ.= Annulus _complete_ and oblique. To this order -belong, principally, the tree-like Ferns with palm-like habit. The -number of species is about 200, they are all tropical and form forests -in some regions of Australia. _Cibotium_ and _Dicksonia_ have marginal -sori, with cupular, basal indusium. (The stem of _D. antarctica_ is -covered with aerial roots.) _Alsophila_ (without indusium); _Cyathea_ -with cupular, inferior indusium (Fig. 212 _E_). - - [Illustration: FIG. 213.--_Gleichenia_: _A_ part of a leaf with - sori; _B_ a single sorus.] - -Order 4. =Gleicheniaceæ.= Sporangia with equatorial annulus, and -longitudinal dehiscence, most frequently groups of 3–4 in sori without -indusium (Fig. 213). _Gleichenia_: the apical growth of the leaves -continues for a long time. - -Order 5. =Schizæaceæ.= Annulus apical. To this order belongs _Aneimia_, -which is so commonly cultivated in conservatories. The two lowest pinnæ -are metamorphosed, having no leaf parenchyma and being covered with -sporangia. _Schizæa. Mohria. Lygodium_, a climber, whose leaves -have unlimited growth and attain a length of several metres. About 70 -species. Tropical. - -Order 6. =Osmundaceæ.= The sporangia have at the apex a lateral group -of strongly thickened cells, which gradually pass over into the -ordinary cells. The sporangia open by a longitudinal cleft. Indusium -wanting. _Osmunda_ bears the sporangia upon peculiar, branched -pinnæ, without parenchyma (the uppermost in the leaf). _O. regalis_ -(Royal-Fern): European. - - [Illustration: FIG. 214.--_Salvinia natans_: _A_ microsporangium - with germinating microspores and protruding prothallia (_s_); - _B_ a prothallium with the bicellular antheridium (_s_) growing - out of the microsporangium; _C_ the two cells of the antheridium - have opened by transverse clefts; beneath is seen the microspores - enclosed by the hardened mucilage; _D_ spermatozoids still - enclosed in the mother-cells.] - - [Illustration: FIG. 215.--_Salvinia natans. A_, _B_ Female - prothallia, _f-f_, protruding from the macrospore which is still - enclosed in the macrosporangium; _œ_ archegonia. _C_ An embryo (× - 16) still in connection with the spore (_s_): _a_ the scutiform - leaf; _b-e_ the subsequent foliage-leaves, of which _b_ and _c_ - stand singly, _d-e-v_ in a whorl; _v_ the submerged-leaf; _f-f_ - wing-like lobes of the prothallium: _m_ the foot.] - - - Sub-Class 2. =Hydropterideæ= (formerly Rhizocarpeæ), =Water Ferns=. - -The following further characteristics must be added to those given on -page 205:-- - -=Sexual generation.= The MICROSPORES produce an extremely rudimentary -prothallium, formed of only a single cell, and having also a very much -reduced bicellular antheridium with a small number of spermatozoid -mother-cells in each cell (in _Salvinia_ 4, in _Marsilia_ and -_Pilularia_ 16). In _Salvinia_ the microspores remain embedded in a -hard mucilaginous mass (at first frothy) which fills up the cavity of -the sporangium. The prothallium must therefore grow out through this -slime and also through the wall of the sporangium (Fig. 214), and it -thus terminates in a relatively long cell. - -In _Marsilia_ the microspores are set free from the microsporangium, -and the prothallia, with the antheridia, remain in them until the -spermatozoids are liberated. The latter are spirally-twisted threads. - -The MACROSPORES, on germination, give rise to a very reduced -prothallium, which in _Salvinia_ bears 3 archegonia; but, if these -are not fertilised, the prothallium may continue to grow and become a -fairly large, green body with several archegonia (Fig. 215 _A_, _B_). -In _Marsilia_ the prothallium is still more reduced, it is enclosed -in the macrospore, and only bears one archegonium. The archegonia are -similar in structure to those of the Ferns, but are smaller, and sunk -more deeply in the tissue of the prothallium. - - [Illustration: FIG. 216.--_Salvinia natans. A_ An archegonium, - unripe, seen in longitudinal section: _h_ the neck-cells; _k_ the - neck-canal-cells; _c_ the central cell. _B_ An open archegonium - of which the neck-cells have separated off. _C_ An open, old - archegonium seen from the top.] - -=The asexual generation= is developed from the fertilised egg-cell. -It is a dorsiventral, horizontal shoot. In _Salvinia_ it bears at -first a shield-like leaf, the scutiform leaf (Fig. 215 _C_, _a_), -which is succeeded by the ordinary foliage-leaves. The young plants of -_Marsilia_, likewise, have less perfect leaves in the very early stage. - -The formation of the sporangium is the same as in the Leptosporangiate -Ferns. (The 16 spore-mother-cells originate from one central, -tetrahedric archesporium.) - -The Hydropterideæ are divided into 2 orders, the chief differences -between them being found in the asexual generation. - - [Illustration: FIG. 217.--_Salvinia natans_ (natural size): _A_ - seen from above, floating on the water; _B_ a portion seen from - the side in its natural position in the water.] - - [Illustration: FIG. 218.--Sori of _Salvinia_ in longitudinal - section: _h_ microsporangia; _m_ macrosporangia. (× 10.)] - -Order 1. =Salviniaceæ.= This order more nearly approaches the true -Ferns, especially so on account of the form of the indusium. Only one -species is found in Europe, _Salvinia natans_ (Fig. 217). This is a -small, floating, annual, aquatic plant, entirely _destitute of roots_. -The dorsiventral, horizontal stem bears two kinds of leaves, which -are arranged in whorls of three. Two of these which turn upwards are -oval, entire, “_aerial foliage-leaves_” (Fig. 217 B, _b^2_-_b^3_); -the third, the “_water-leaf_” (_b^1_) is submerged and divided into a -number of hair-like segments, similar to the submerged leaves in many -aquatic plants, for instance, Water-buttercup (see also Fig. 215 _C_). -The whorls of leaves alternate with each other; there are thus 4 rows -of dorsally-placed aerial leaves, and two rows of ventrally-placed -submerged leaves. The sporangia are situated in sori, each sorus -being borne on a small column (receptacle or placenta) and enveloped -by a _cupular_, but _entirely closed indusium_ (Fig. 218). _The sori -are situated on the submerged leaves_ (Fig. 217 _B_, _s-s_) _and -are unisexual_, _i.e._ each sorus contains microsporangia only, or -macrosporangia. - - _Azolla_ belongs to this order. It is a very small, floating, - tropical water-plant (America and East India), with horizontal, - root-bearing stem. The stem branches profusely by lateral buds, - and bears the two rows of leaves on its dorsal side, the roots - on the ventral side. Each leaf is bifid, and divided into an - upper dorsal, and a lower ventral portion. The upper segments - float on the surface of the water and are arranged like tiles - on a roof, each one overlapping its neighbour. In each floating - segment a large cavity is found, in which _Anabæna_ is always - present. The lower segments are submerged. - -Order 2. =Marsiliaceæ.= The characteristic feature of this order, -and one not possessed by other Fern-like plants, is that the sori -(2–many) are enveloped _in leaf-segments_ which _close round them_ -and form a “sporocarp,” just in the same manner as the carpels, in -the Angiospermous Flowering-plants, close round the ovules and form -ovaries. The sori contain both micro-and macrosporangia. When the -spores are ripe, the sporocarp opens in order to disperse the spores -(Fig. 220). - - [Illustration: FIG. 219.--_Marsilia salvatrix_ (natural size): - _K_ terminal bud; _b_ leaves; _f_ sporocarps; _x_ point of - branching of petiole.] - -The two genera (with 57 species, Temperate, Tropics) are land-and -marsh-plants, whose dorsiventral, creeping stem bears roots on the -under surface, and the leaves in two rows on the upper side (Figs. -219, 221). The leaves of _Marsilia_ are compound, and divided into -four small leaflets springing from the apex of the petiole (Fig. -219), and resemble the leaves of _Oxalis_. In the bud the leaves are -circinate (Fig. 219 _b_), and at night they exhibit the well-known -sleep-movements. The sporocarps are borne on the petioles of the -fertile leaves, near their bases (Fig. 219 _f_); they are oblong and -resemble small beans, the outer cells being hard and sclerenchymatous, -while the inner ones are divided into a number of loculi arranged in -two rows. On germination, water is absorbed, the two sides separate -slightly, as valves (Fig. 220 _A_), and a long vermiform mass of -gelatinous, parenchymatous cells (Fig. 220), swollen by the water, -emerges, bearing a large number of sori arranged pinnately. Each -sorus (_sr_) is covered by a thin indusium. (The thin covering may be -considered an indusium physiologically, though not morphologically). - - [Illustration: FIG. 220.--_Marsilia salvatrix_: _A_ the - sporocarp commencing to germinate; _B_ a more advanced stage of - germination.] - - [Illustration: FIG. 221.--_Pilularia globulifera_ (natural size): - _s_ sporocarps; _b_ leaves; _k_ the growing point; _r_ roots.] - - _Marsilia quadrifolia_, in Europe. Many species are found in - Australia. The nutritious sporocarps of _M. salvatrix_ were - the means of saving the Burke expedition in the interior of - Australia, and hence this species has earned its specific name. - -_Pilularia_ has linear leaves, without lamina. The sporocarps are -spheroid (Fig. 221), brown and hard, and situated near the base of the -leaves. They are 2–4 chambered and open by a corresponding number of -valves. - - - Class 2. =Equisetinæ (Horsetails.)= - -The characteristics of this class have been described on page 204. - -It is divided into two sub-classes:-- - -1. THE ISOSPOROUS EQUISETINÆ. To this sub-class belong, with -certainty, only the EQUISETACEÆ now existent, which are -represented by only one genus, _Equisetum_. - -2. THE HETEROSPOROUS EQUISETINÆ. Forms which are now extinct. - - [Illustration: FIG. 222.--_Equisetum arvense._ The prothallium - highly magnified. _A_ Male; _s, s_ antheridia. _B_ Portion of a - female, cut through vertically; _œ œ_ archegonia, the central one - is fertilised; _h h_ root-hairs.] - - [Illustration: FIG. 223.--_Equisetum maximum._ Spermatozoids: _a_ - shows them still enveloped by the mother-cell.] - - - Sub-Class 1. =Isosporous Equisetinæ.= - -Order. =Equisetaceæ (Horsetails).= - -=The sexual generation.= The prothallium is green and leaf-like, as in -the majority of Ferns, but irregularly branched and curled. It is often -unisexual. The male prothallia bear antheridia only, and are smaller -and less branched (Fig. 222 _A_) than the female; the latter may attain -a diameter of ½ an inch, and bear archegonia only (Fig. 222 _B_). The -antheridia and the archegonia resemble those of the Ferns, but the -spermatozoids (Fig. 223) are larger and less twisted. On the last curve -is situated a more or less elongated appendage of cytoplasm (Fig. 223 -_c_). - -=The asexual generation.= The embryo is similar to that of the Ferns. -The fully developed _Equisetum_ is a perennial herb, with widely -creeping (in some species tuberous) rhizome, from which extend erect, -aerial, most frequently annual shoots. - - [Illustration: FIG. 224.--_Equisetum arvense_: _a_ fertile branch - with cone; _b_ vegetative shoot; _c_ cone; _d_ sporophylls.] - -The vegetative aerial STEMS are divided into a number of -internodes by the whorls of leaves (Fig. 224). The internodes are -hollow, the cavities being separated from each other by the transverse -partitions of the solid nodes. The lower portion of the internode, -which is encased by the leaves, has much thinner and softer cell-walls, -so that the stem is easily separated into segments just above the -nodes. Each internode has a large number of ridges and furrows, -and bears at its apex a whorl of leaves whose number and position -correspond to the ridges of the internode. As in the case of other -verticillate plants, the whorls are placed alternately, one above -the other; the same arrangement is also found in the ridges on two -successive internodes. In addition to the large air-cavity in the -centre of each internode (the central cavity), a whorl of tubular -air-passages is found in the cortex of the stems, opposite the furrows -(vallecular canals). There is also a similar air-passage (carinal -canals) in each of the vascular bundles, which are placed in a ring, -one opposite each ridge, and therefore alternating with the vallecular -canals. The vascular bundles are _collateral_ as in the majority -of Flowering-plants, but poorly developed. The xylem of each bundle -consists of two groups of annular or spiral vessels, close to the outer -border of the carinal canal, and two groups of scalariform tracheides, -each placed on a radius passing through a group of spiral vessels. -The phloëm is placed between these four groups, each of which has -only a few vessels. The stiffness of the stems is mainly due to the -large amount of silica in the cell-walls of the epidermis, and to the -sclerenchymatous cells of the ridges. - -All LEAVES are situated in _whorls_. The VEGETATIVE are simple, -undivided, 1-nerved, and are united into toothed sheaths (Fig. 224 _a_, -_b_). The branching of the stems in some species (_E. arvense_) is very -abundant. The branches break through the base of the leaf-sheaths (Fig. -224 _b_), and generally _alternate with the teeth_ (leaves). - -The FERTILE LEAVES (_sporophylls_) are different from the barren ones. -They are _free, shield-like_, each one having a short stalk bearing -usually an hexagonal plate (Fig. 224 _d_), and closely compressed into -an ear or cone (Fig. 224 _a_, _c_). The _Equisetums_ thus present an -advance in development distinctly beyond that of the Ferns, which is -further emphasized by the circumstance that a transition from the -sheath-leaves to the fertile-leaves is found in the involucre or -annulus, a “collar” of specially modified leaves situated at the base -of the cone (Fig. 224 _a_ and _c_). The cone may be considered as a -very rudimentary flower, and the annulus may be regarded as a very -early stage in the formation of a flower (perianth). See page 235. - -The SPORANGIA are situated on the underside of the sporophylls, one -at each angle; they are sac-like, and open inwardly by a longitudinal -cleft (Fig. 224 _d_). An annulus is wanting; but in the wall of the -sporangium, as in the pollen-sacs of the Flowering-plants, a layer of -cells, with annular or spiral thickenings, is developed, which assists -in the dehiscence of the sporangium. - -The SPORES are green; the walls composed of four distinct layers, -of which the outer is gradually separated, except at one point, and -becomes split into four long bands (_elaters_) (Fig. 225). The elaters -are extremely hygroscopic, coiling round the spore when moistened, and -expanding as soon as dry, presenting a most lively object under the -microscope when breathed upon and allowed to dry. The second layer, -when germination commences, becomes detached from the inner wall, which -is formed of the exospore and endospore. - -The order has become much reduced, and at the present time includes -only one genus, _Equisetum_, with about twenty-five species, which are -distributed over the entire globe, particularly in damp situations. In -SOME SPECIES the barren shoots are green and very much branched, but -the fertile ones are unbranched, pale brown, and possess no chlorophyll -(_E. arvense_, Field-Horsetail, Fig. 224, and _E. maximum_). IN -OTHERS the fertile and barren shoots are alike green, and either both -unbranched (_E. hiemale_), or branched (_E. palustre_, _E. limosum_, -etc). The fertile shoots of _E. silvaticum_, up to maturity, resemble -those without chylorophyll of _E. arvense_, but after that period they -produce green branches, and thus resemble the barren ones. - - [Illustration: FIG. 225.--Spores of _Equisetum_: _A_ damp, with - elaters (_e_) coiled round the spore; _B_ dry, with elaters - expanded.] - - EXTINCT ISOSPOROUS EQUISETINÆ. In addition to several true - species of fossilized _Equisetums_, the order of the CALAMITES, - which no doubt is closely allied to the Equisetinæ, is also - found in the fossil state. These were gigantic forms, attaining - about twenty times the size of those of the present day, and - stems of nearly 10–12 metres in height are known. They reached - the culminating point of their development in the Carboniferous - period, and died out towards the close of the Palæozoic. The - stems had hollow internodes and alternating grooves, similar - to their relatives of the present day. The leaves must either - have been absent or very perishable, since they have not been - identified with certainty. If the determinations of certain - remains of cones which of late have been discovered are correct, - they were heterosporous and had two kinds of sporangia as in - the following sub-class. A cambium formation and an increase in - thickness has been found in the stems. - - Their USES are very limited. A few species, such as _E. hiemale_ - are used for polishing on account of the hard siliceous - cell-walls of the epidermis, found in all species of _Equisetum_. - - - Sub-Class 2. =Heterosporous Equisetinæ.= - - The two orders which come under this head are united by the - characteristics, that the verticillate leaves are not united - into sheaths (Fig. 226), and that between each whorl of fertile - leaves there is also a whorl of barren ones. The fertile whorls - in ANNULARIÆ are situated about midway between the barren ones - (Fig. 227), but in ASTEROPHYLLITEÆ they occur immediately above - a barren whorl (Fig. 228) and contain only half as many members - as the latter. The lower whorls bear macrosporangia with one - macrospore, the upper, microsporangia with many microspores. - - [Illustration: FIG. 226.--A. fragment of _Annularia_.] - - [Illustration: FIG. 227.--Fragment of _Annularia longifolia_, - with sporangia; the leaves have partly fallen off: a barren - whorls; _s_ fertile whorls.] - - [Illustration: FIG. 228.--Fragment of cone of _Asterophyllites_ - (_Volkmannia elongata_): _a_ and _s_ as in Fig. 227.] - - The ANNULARIÆ were distichous (Fig. 226), and presumably - floating plants. The ASTEROPHYLLITEÆ had verticellate branches. - These also died out after the Carboniferous period, at the close - of the Palæozoic. - - - Class 3. =Lycopodinæ= (=Club-Mosses=). - -The characteristics of this class have been given on page 205. It -consists of two sub-classes, one embracing isosporous, the other -heterosporous forms. - - - Sub-Class 1. =Lycopodieæ= (ISOSPOROUS Lycopodinæ). - -One kind of spore. Prothallium large, partly green. Leaves without -ligule. - - [Illustration: FIG. 229.--_Lycopodium annotinum_: _A_ embryo - (nat. size), with prothallium (_pr_), one embryo is broken off; - _B_ the prothallium (slightly magnified); _C_ section through - the prothallium and embryo in the direction _a-b_ of _A_, and - vertically in the plane of the paper.] - - [Illustration: FIG. 230.--_Lycopodium clavatum_: portion of a - stem, bearing cones (_a_); _s_ a spore; _h_ sporangium in the - axil of a leaf, _s_.] - -Order 1. =Lycopodiaceæ.= The PROTHALLIUM is only known in a few species -at present, but in these it is more or less tubercular, and bears both -antheridia and archegonia. - - In _L. annotinum_ the prothallium is a relatively large mass - of cells, without chlorophyll, and subterranean, in which - the antheridia and archegonia are embedded (Fig. 229). In - the widely distributed tropical species, _L. cernuum_, and - in _L. inundatum_, it is a small tubercular body which has a - subterranean portion, with either little or no chlorophyll; - and an aerial green portion. The prothallia of _L. phlegmaria_ - and others live saprophytically in the crevices of the bark of - trees; they are partly filamentous, branched, and possess no - chlorophyll. - -The =asexual generation=. PERENNIAL PLANTS. The stem branches -monopodially (often apparently dichotomously), and is thickly covered -by small, simple, triangular or scale-like leaves. The leaves are -spirally arranged in some species (Figs. 229, 230), and in others, -whose stem is compressed with unequal sides, opposite (Fig. 231). The -roots of _Lycopodium_ are dichotomously branched. - -The SPORANGIA in _Lycopodium_ are situated singly at the base of the -leaves, almost in their axils; they are reniform, unilocular and open -like a mussel-shell by two valves (Fig. 230 _h_). The sporangia are -developed from a group of surface cells. The archesporium is formed -from one hypodermal cell (or perhaps a cell-row). - - [Illustration: FIG. 231.--_Lycopodium complanatum_: _a_ leaves on - the edges of the stem; _d_ leaves on the sides.] - - [Illustration: FIG. 232.--_Lycopodium clavatum._ A tetrahedral - spore seen from above, where the three borders join; and a tetrad - of bilateral spores, still lying in the mother-cell.] - -The fertile leaves are collected upon definite regions of the stem. -They are either similar to the barren ones, and then the fertile -portions of the stem pass gradually, without any break, into the barren -portion (_L. selago_); or they differ from the barren leaves, and are -then collected into special apical cones (Fig. 230 _a_). The SPORES are -tetrahedral or bilateral (Fig. 232). - -About 100 species, chiefly tropical. - - Five species of _Lycopodium_ are found in Great Britain. _L. - clavatum_ and _L. selago_ are common in mountainous districts. - _L. annotinum_ is common in the Highlands of Scotland. The other - genus of the order is _Phylloglossum_, with one species, _P. - drummondi_ (Australia, Tasmania, and New Zealand), a small plant - only a few centimetres high, with two tubers, and about eleven - linear leaves at the base of the stem which is terminated by a - cone of sporophylls.--FOSSIL Lycopodiaceæ in the Carboniferous - period. - - OFFICINAL: “Lycopodium,” the spores of _L. clavatum_. - - Family 2. =Psilotaceæ=. The sporangia are placed on the apex of - short, two-leaved stems, as 2–3, seldom four, small capsules. - Small herbs, with angular stems; leaves small, simple, and one - nerved. Only four species.--_Psilotum_ (Madagascar, Moluccas, - Sandwich Islands, etc.) is destitute of roots, their place being - supplied by special underground stems which bear a few modified - leaves, very much reduced, especially when buried deeply in the - soil. Three species.--_Tmesipteris_ (Australia), one species. - - - Sub-Class 2. =Selaginelleæ= (HETEROSPOROUS Lycopodinæ). - -Micro-and macrospores. The prothallia are very much reduced, especially -the male; the female does not leave the spore. The leaves are ligulate. - - [Illustration: FIG. 233.--Germination of the microspores of - _Selaginella_: _A_ the spore rendered transparent, seen from - above. In the interior is seen the prothallium (_f_), and the - first divisions of the antheridium (_a_, _b_, _c_, _d_); in _B_ - the spore-wall is removed and all the spermatozoid-mother-cells - formed; in _C_, the microspore has opened and the spermatozoids - and the mother-cells are escaping together.] - -=The sexual generation.= In the ~MICROSPORES~ are formed: (1) a very -small “vegetative” cell, representing the vegetative part of the -prothallium (_f_ in Fig. 233 _A, B_), and (2) a cell many times larger -and which divides into a number (4–8) of primordial cells, each of -which divides into four spermatozoid-mother-cells, though all of these -may not develope spermatozoids. On germination, when the spore-wall is -ruptured, the spermatozoids and spermatozoid-mother-cells are ejected -into the water. - -The ~SPERMATOZOIDS~ in _Selaginella_ are elongated and club-shaped, -with two cilia (Fig. 234); but in _Isoëtes lacustris_ they are -spirally-twisted threads which differ from all other spermatozoids by -having a bunch of cilia _at each end_; the other species of _Isoëtes_ -have cilia only at the anterior end. - -The MACROSPORES. Shortly after the macrospores have been set free, -or in _Selaginella_, while still enclosed in the sporangium of the -mother-plant, they germinate and soon become filled with the cellular -tissue of the prothallium, and even in _Selaginella_ the archegonium -begins to be formed before the rupture of the spore-cell-wall has -commenced (Fig. 235 _A_). - - [Illustration: FIG. 234.--Spermatozoids of _Selaginella_: _b_ - with a remnant of cytoplasm.] - - [Illustration: FIG. 235.--Macrospore of _Selaginella_: _A_ - longitudinal section, before the rupture of the wall, six - weeks after being sown. The endosperm (_e_) has not yet filled - the entire chamber. Cell-formation is still proceeding in the - lower part of the spore. The endosperm and prothallium (_f f_) - are separated by a distinct line (diaphragm). _B_ Germinating - macrospore seen from outside: _s_ wall of the spore; _æ_ - archegonia.] - - [Illustration: FIG. 236.--Archegonia of _Selaginella_: _A_ - unripe, in longitudinal section; _c_ the central cell; _k_ - neck-canal-cell, which is wedged in between the two-storied - neck-cells; _B_ ripe; _u_ ventral canal-cell; _C_ seen from - above, open. It will be noticed that the neck is formed of two - tiers of four cells each.] - -The ARCHEGONIA are constructed on the same plan as those of the other -Archegoniatæ, but are quite embedded in the prothallium (Figs. 235 _æ_, -236). - -=The asexual generation= varies very much in the different orders. - - [Illustration: FIG. 237.--_Isoëtes lacustris_ (slightly - diminished): _st_ the stem; _r_ roots; _b_ leaves.] - - [Illustration: FIG. 238.--_Isoëtes lacustris_. Longitudinal - section through the base of the leaf with a microsporangium. The - edge of the groove, in which the microspangium is placed, is - continued as a thin covering which envelopes the sporangium. The - inferior edge of the ligular groove (_L_) forms a lip (_J_); _t_ - sterile cell-rows (trabeculæ) which divide the sporangium into - compartments; _l_ vascular bundle.] - - [Illustration: FIG. 239.--_Selaginella inæqualifolia_. Cone in - longitudinal section; microsporangia are seen on the left side, - macrosporangia on the right (most frequently each with four - macrospores).] - -Order 1. =Isoëtaceæ (Quill-worts).= The only known genus, _Isoëtes_ -(Quill-wort), has an extremely short, tuberous, _unbranched_ stem -with very short internodes (Fig. 237). The STEM is remarkable as -being the only one among the Vascular Cryptogams which increases in -thickness (see page 202). The meristematic cells are situated round -the axial cylinder, and form, especially, parenchymatous tissue in -two or three directions, giving rise to 2–3 grooves in which the -dichotomously-branched ROOTS are produced. The LEAVES are arranged -spirally in a close rosette. They are awl-shaped and have at the -base a semi-amplexicaul sheath, with a groove (_fovea_), in which a -sporangium is situated (Fig. 238). The ligule is a foliar outgrowth -from the upper edge of the groove.--The MACROSPORANGIA (each with -a number of macrospores), are situated on the outer leaves, the -MICROSPORANGIA (Fig. 238), on the inner ones. Between each cycle of -fertile leaves there are a number of imperfect or barren ones as in -the case of the female plant of _Cycas_. The spores are liberated by -the decay of the sporangium. The two kinds of sporangia develope at -the commencement in the same way. The archesporium is, at first, a -hypodermal layer of cells which grow out in the direction perpendicular -to the surface of the leaf, and divide by a number of walls parallel -to this direction, forming a sporogenous mass of cells. Some of the -cell-rows of this sporogenous mass lose their rich protoplasmic -contents, and are arrested in their growth; thus incomplete divisional -walls of sterile cells, “_trabeculæ_” arise in the sporangium, -dividing it into a number of compartments one above the other (Fig. -238 _t_). (The trabeculæ, according to Goebel, play the same part as -the nutritive cells of the sporangium of _Riella_; the tapetal cells, -as in the Ferns, are in a great measure dissolved at a later period.) -The sporogenous cell-rows, in the microsporangia, give rise to a -large number of spore-mother-cells, but in the macrosporangia only -one spore-mother-cell, with tapetum, is developed from each fertile -archesporial cell. - -The two native species, and several others, are aquatic plants, the -remaining species are land plants, or are amphibious. About 50 species. -In temperate and tropical regions.--FOSSIL species in the Tertiary -period. - -Order 2. =Selaginellaceæ.= This order contains only one genus, -_Selaginella_. The STEM, in the majority of species, is dorsiventral, -long and slender, and apparently branches dichotomously, but in reality -_monopodially_, with well developed lateral shoots. The LEAVES are -small, round, or ovate, in the majority of species arranged in whorls -of two leaves each; these whorls, however, are not decussate, but are -considerably inclined towards each other, an arrangement by which four -rows of leaves are produced, each whorl having one large and one small -leaf. The two leaves in each whorl are of unequal size, the smaller one -being placed on the upper surface and the larger on the lower surface -of the stem (Fig. 240). Some species have spirally-arranged leaves, -more resembling the arrangement in the _Lycopodiums_. - -The ~FERTILE LEAVES~ most frequently differ from the barren ones, -and are collected into spike-like cones (a kind of flower; Fig. -239). Micro-and macrosporangia are found in the same cone (Fig. -239). Each sporangium arises from a group of superficial cells of -the stem, directly over the leaf on which it will be situated later -on. Each sporangium has a hypodermal, unicellular archesporium, and -contains a layer of tapetal cells; these are dissolved later, when -the spores are ripe, and not before as in the Ferns. In the very -early stages of their development, the micro-and macrosporangia are -precisely similar, and the differences between them arise later on. -In the microsporangium all the spore-mother-cells divide, and each -forms four tetrahedrically-arranged microspores (Fig. 204); but in -the macrosporangium only four macrospores are formed, by the division -of a _single mother-cell_, while the remaining spore-mother-cells -are aborted. It is rarely that the macrosporangia contain 2 or 8 -macrospores. - - [Illustration: FIG. 240.--_Selaginella martensii_: _s_ lower - leaves; _r_ upper leaves.] - - For the ~GERMINATION OF THE SPORES~, see pages 228, 229. The - prothallium arises in the macrospore (_f-f_, in Fig. 235 _A_), - probably by division of the meniscus-shaped protoplasmic mass, - which is marked off at the apex of the spore; primordial cells - are thus formed which later on are surrounded by a cell-wall. In - six to seven weeks after sowing, the spore-wall is ruptured by - the growing prothallium, which already has developed archegonia - (Fig. 235 _œ-œ_). The prothallium so formed does not occupy - the entire cavity of the spore, but four to five weeks after - sowing, the large-celled parenchyma is developed in the lower - portion of the spore by free cell-formation; this has been - termed by Pfeffer, “endosperm,” since it is similar to the - endosperm of Flowering-plants. Goebel, however, has termed it - “secondary prothallium,” as the homology with the endosperm of - the Angiosperms is very doubtful. - -The ~FERTILISED OOSPHERE~ divides into an upper (hypobasal) and a lower -(epibasal) cell; from the latter alone the embryo is developed with -its root, stem, foot, and two _cotyledons_, and the former gives rise -to an organ which appears in this instance for the first time, but -which occurs in all Flowering-plants, viz. the _suspensor_. This forces -the embryo down into the “endosperm,” which is entirely or partially -absorbed by the embryo. In the case of the Flowering-plants the embryo -is developed with its longitudinal axis in the elongation of the -suspensor, but in _Selaginella_ the embryo is situated _transversely_ -to it. - -_Selaginella_ (300–400 species), is essentially tropical, only one -species living in the North (_S. spinulosa_), but others grow in -Central and South Europe. - - Order 3. =Lepidodendraceæ= are extinct, tree-like Lycopods, - which are found especially in the Lower and Middle - Carboniferous. Vegetatively they are most nearly related to - _Lycopodium_, but the stem attained much larger proportions - (about eleven metres in height and one metre in thickness), - and had a cambium by which it increased in thickness. It was - regularly dichotomous, and closely studded with spirally-placed - leaves, which left behind them peculiar rhombic scars. The large - cones resemble Pine-cones, and bore sporangia much larger than - any which are now produced (the male ones as much as 2 cm.’s in - length). The macrosporangia were situated at the base, and the - microsporangia at the apex. - - Order 4. =Sigillariaceæ.= These are, presumably, another - group of extinct tree-like Lycopods (especially in the Middle - Carboniferous). The name has been derived from the seal-like - scars, which the fallen leaves have left behind in longitudinal - rows on the grooved stem. The rhizomes of these plants were - formerly termed _Stigmaria_, and placed in a separate genus. - - Order 5. =Sphenophyllaceæ= form an entirely extinct group. - They do not definitely belong to any of the three large - classes of Vascular Cryptogams, but it is perhaps best to - place them in juxtaposition to these. They were herbaceous - plants with verticillate, wedge-shaped leaves, with nerves - branching dichotomously into equally strong branches. Micro-and - macrosporangia were formed in the same cone; and were situated - in the axils of the leaves, as in the Lycopods. - - - - -The Transition from the Cryptogams to the Phanerogams. - - -All the plants considered in the preceding chapters are included -in the term CRYPTOGAMS; all in the following chapters under the -head of PHANEROGAMS (see page 3). Hofmeister’s pioneer works -(1851, _Vergleichende Untersuchungen der höheren Kryptogamen_, -etc.) and the numerous researches published later by other -investigators, have closed the gap which was formerly thought -to exist between these plants; so that we now, in the series: -Bryophyta--Pteridophyta--Gymnospermæ--Angiospermæ see the expression of -a single line of development in accordance with a definite plan. The -forms through which this gradual development has taken place have in -course of time, however, to a great extent died out, and only single -links of the chain connecting the lowest to the highest still remain. - -THE ALTERNATION OF GENERATIONS, which we found indicated in certain -Thallophytes, can be proved with the greatest clearness in all the -higher Cryptogams, from the Mosses upwards; it is also found in the -Phanerogams, but not in such a pronounced degree, because one of -the generations is so far reduced that it has almost given up its -independence. For the sake of greater clearness, we will begin with the -comparison of the sporophyte, asexual (second) generation. - - - =The asexual (2nd) generation of the Cormophytes.= - -The asexual generation which follows from the further development of -the fertilised oosphere, is, in the _Mosses_, only the sporogonium -(according to one theory it is perhaps homologous with a spore-bearing -leaf, situated upon a short stem, see p. 187); in _Filicinæ_, -_Equisetinæ_, and _Lycopodinæ_, on the other hand, it is a highly -developed plant differentiated into stem, leaf, and true root, and -bearing the sporangia on its leaves. The ~MODIFICATION OF THE SHOOT~ -is very slight in _Filicinæ_. The first leaves of the embryo are very -simple in form (Fig. 205), but after a certain age all the leaves -which arise are essentially alike. The fertile leaves do not differ -from the barren ones, and are found associated with them, and their -formation does not limit the growth in length of the stem. It is only -in a few of the true Ferns, and in the Hydropterideæ, that the fertile -leaves differ considerably from the barren ones. A division of labour -in which certain leaves are set apart for nutrition, and others for -reproduction, is found more pronouncedly in the _Equisetinæ_ and -_Lycopodinæ_, for in these groups, with a few exceptions, the fertile -and barren leaves are very dissimilar; the former are collected in -special ear-like _cones_, which _terminate the further growth_ of -the short stems on which they are borne. In connection with the cone, -leaves are sometimes developed which form a transition from the barren -to the fertile ones (the “annulus” in Equisetaceæ), and in these cases -the first indication of a flower with perianth or floral-leaves is to -be traced. Among the Cryptogams the highest division of labour is found -in _Selaginella_ and _Isoëtes_, which have the two kinds of sporangia -borne on _different_ leaves. The division of labour (modification) is, -however, still more pronounced in the _Phanerogams_: the leaves which -bear the microsporangia (“pollen-sacs”) have quite different forms -from those which bear macrosporangia (the “nucellus” in the ovule), -the former are termed _stamens_, the latter _carpels_; in certain -instances, too, there is even a contrast between the “male plants” and -the “female plants.” Moreover, a division of labour, in a much greater -degree, takes place in the leaves which do not directly take part in -reproduction, and it is thus possible in many plants to draw a sharp -line not only between stamens and carpels, but also between four or -five distinct kinds of leaves, which differ in _form_, _structure_, and -corresponding _functions_, and which appear in regular sequence on the -shoot: namely, between “scale-leaves” and “foliage-leaves,”[21] both -of which occur in the Cryptogams, and the “floral-leaves,” including -the bracts and leaves of the “perianth,” which latter often differ from -each other in form and colour, and are then separated into _sepals_ and -_petals_. The _leaves_--stamens and carpels--_which bear the sporangia_ -are termed sporophylls, and the shoot, or extremity of a shoot, whose -leaves are modified into sporophylls, is _terminated in its further -growth by their production, and is known as a flower_. The flower -which is most completely furnished has calyx, corolla, stamens, and -carpels arranged in this order. If the only sporophylls present are -stamens, then it is said to be a _male_ (_staminate_) flower, and if -only carpels, then a _female_ (_pistillate_) flower, and in both these -cases the flowers are _unisexual_, or diclinous. If stamens and carpels -are both present in the same flower, it is termed _hermaphrodite_. -Diclinous plants in which the female flowers are situated on one plant, -and the male flowers on another, are termed _diœcious_; and those -in which the same plant bears the two kinds of flowers are termed -_monœcious_. When the male, female, and hermaphrodite flowers are found -in the same species, the plant is said to be _polygamous_. - -=The sporangia-bearing leaves--Sporophylls.= In the Mosses the -asexual generation is only represented by the sporogonium, and if the -theory is correct which considers the sporogonium to be an embryo -consisting of a rudimentary stem and terminal leaf, then the spores are -produced on the leaves in these plants. The sporangia in the Filicinæ -are situated in groups (sori) on the back or on the edge of the leaves. -The number of sporangia in the sorus diminishes very greatly in the -Marattiaceæ and Gleicheniaceæ (three to four in the latter, Fig. 213). -In the Equisetinæ the sporangia are situated in a small number on the -underside of shield-like leaves, and in Lycopodinæ, singly, in the -axils of the fertile leaves, which are alike and bear either micro- or -macrosporangia. In the Phanerogams there is a great difference between -the stamens and carpels. - - [Illustration: FIG. 241.--_Cycas_: _a_ stamen (nat. size) seen - from the under side; _b_ four pollen-sacs, not yet open, forming - a “sorus”; _c_ three open pollen-sacs; _d_ a pollen-grain.] - - [Illustration: FIG. 242.--Stamens of _Araucaria_ (pollen-sacs - long and pendulous).] - - [Illustration: FIG. 243.--Male flower of _Taxus_.] - - [Illustration: FIG. 244.--_A_ Cross section through a - quadrilocular anther in different stages of development: _s_ the - seam where it bursts open; _vf_ vascular bundle; _k_ connective. - _B_ A stamen. _C_ Another stamen seen from the front (_f_) and - from the back (_b_).] - -=Stamens.= In the lowest Phanerogams (_Cycadeæ_) there are many -indications of relationship to the Ferns. The stamens are flat and -broad, and have _on the back many pollen-sacs_ (_microsporangia_) -arranged in small groups (true _sori_), which even have a small -“placenta,” similar to the one possessed by the Ferns, and open towards -the inside by a longitudinal cleft (Fig. 241, compare Fig. 213). A -section of the _Coniferæ_ agree more closely with the Equisetaceæ, in -having a few (three to eight) pollen-sacs arranged on the underside of -more or less shield-like leaves (Figs. 242, 243, compare with Fig. 224 -_a_, _c_, _d_). In the Abietaceæ the number of sporangia is diminished -to two, which are placed also on the lower side (Fig. 267) of a stamen. -The number of _pollen-sacs_ (microsporangia) in the _Angiosperms_ is -nearly always four to each stamen; they are longitudinal projections -which are placed in pairs on each side of the central line of the -stamen, two on the edge, and the other two generally on the side which -is turned inwards; the pollen-sacs generally dehisce longitudinally -(quadrilocular anthers, Fig. 244). A few, for instance Orchidaceæ and -Asclepiadaceæ, have only two pollen-sacs (bilocular anthers); and in -others, such as _Solanum_ and the Ericaceæ, they open by pores; in -Lauraceæ and Berberidaceæ, by valves. The part of the stamen which -bears the pollen-sacs is termed the _anther_. Most frequently this is -supported by a stalk known as the _filament_. - - [Illustration: FIG. 245.--A carpel of _Cycas revoluta_ with 5 - ovules (_s_), at half to one-third nat. size.] - - [Illustration: FIG. 246.--Carpel with 2 ovules of _Ceratozamia - robusta_ (1/1).] - -=Carpels.= The simplest forms of carpels are found in _Cycas_. In -this genus both the foliage and fertile leaves are pinnate, and hence -present great similarity; the ovules (macrosporangia) are situated on -the margin of the central portion, just as the sporangia are placed -on the edge of the fertile leaf of _Ophioglossum_ (Fig. 245, compare -with Fig. 209). The carpels of the other Cycadeæ present greater -divergence from the foliage-leaves, being peltate, for instance, in -_Zamia_ and _Ceratozamia_ (Fig. 246). The ovules in the Coniferæ are -situated on the upper side and near the base of the ovuliferous scales, -almost in the same position as the sporangia in the Lycopodinæ (Figs. -269, 272, 273 _H_, compare Figs. 230, 239). In _Taxus_ the uninclosed -ovule is placed on the apex of a shoot (Fig. 264). In all these plants -the ovules are _not enclosed_ by the carpels, that is, they are not -enclosed in chambers formed by the turning in of the walls of the -carpel, and hence the name _Gymnospermæ_ is given to them. In the -higher Flowering-plants, the _Angiospermæ_, the ovules are distinctly -situated on the edge, the upper surface, or base of the carpel; but -the carpel closes round the ovules which are therefore enclosed in a -chamber--the _ovary_. In a few cases, for example in the Polygonaceæ, -an ovule is situated apparently on the apex of the stem itself, as -in the Yew; in other cases, as in the Primulaceæ, many ovules are -apparently developed on the apex of the stem, which seems to have been -specially adapted as a placenta, but it is also possible and correct -in these cases to suppose that the ovules are in reality developed -on the carpels.[22] A single fully-developed carpel or a collection -of carpels joined together is termed the _pistil_. The extremity of -the carpel, which is specially developed to catch the pollen-grains -and form a suitable nidus on which they may germinate, is called the -_stigma_. The united edges of a carpel which bear the ovules are termed -the _ventral suture_. The back of the carpel forms the _dorsal suture_. -The Marsiliaceæ take a position among the Hydropterideæ analogous to -that occupied by the Angiosperms; the sporangia are in a corresponding -manner enveloped in a closed leaf. - -The collection of stamens in a flower is termed the _andrœcium_, -and all the carpels, whether individually free or united into one -pistil, the _gynœceum_. - -The =Sporangia=. The asexual generation of the _Mosses_ is the -sporogonium, in which the spores arise in tetrads from the -mother-cells. The sporangia in the _Filicinæ_ take their origin either -from a single cell (Leptosporangiatæ) or, what probably may be regarded -as an older stand-point, from a group of cells (Eusporangiatæ). In both -cases there may be distinguished in a mature sporangium three tissues, -which have different significance (Fig. 204): (1) an external layer, -the _sporangium-wall_, most frequently composed of one layer of cells -made up of cells of dissimilar structure, so that on desiccation the -wall is ruptured and the sporangium opens in a definite manner; (2) -an internal group of cells, consisting of the _spore-mother-cells_, -developed from an archesporium, and which by division into four gives -rise to the _spores_; (3) a layer of cells lying between the two -already mentioned, which is dissolved before maturity. The intermediate -cellular layer, which directly surrounds the spore-forming cells, is in -form and contents more worthy of note than the others, and is termed -the _tapetum_. The construction of the sporangium in the _Equisetinæ_ -and _Lycopodinæ_ is in the main the same. - - [Illustration: FIG. 247.--Development of an anther. _A_ - Transverse section of a young anther of _Doronicum macrophyllum_. - The formation of the 4 pollen-sacs commences by divisions of - the hypodermal cells (at _m_, for instance). These cells divide - by periclinal walls into external cells which only take part in - forming the anther-wall; and internal cells, which correspond to - the Archesporium, and from which the spores are derived. These - spore-forming cells are drawn with thicker walls in _B-E_. The - commencement of the vascular bundle is seen in the centre. _B_ An - older stage; the pollen-sacs already project considerably. It is - the cells in the hypodermal layer which are active and in which - tangential divisions particularly occur; _fv_ vascular bundle. - _C_ A corresponding longitudinal section. _D_ Transverse section - through an older anther, the thickness of the wall outside the - mother-cells of the pollen-grains is already increased, and it - becomes still thicker by the division of the hypodermal cells: - its most external layer of cells but one, becomes transformed - into the “fibrous cells.” _E_ Transverse section of a still - older pollen-sac of _Menyanthes_; _sm_ are the mother-cells of - the pollen-grains surrounded by the tapetum (_t_), external to - the tapetum is the anther-wall, which is still far from being - fully developed. The sub-epidermal layer becomes “fibrous,” and - the cells lying inside it become dissolved, together with the - tapetum.] - -In the PHANEROGAMS the =Microsporangia= are termed =Pollen-sacs=. -They take their origin from a large group of cells, which, in the -Angiosperms, lie immediately beneath the epidermal cells of the anther. -In the developed, but not yet mature, sporangium (pollen-sac) there are -to be found: (as in the Vascular Cryptogams) (1) an internal group of -mother-cells which give rise to the _pollen-grains_ (_microspores_), -in this case also formed in tetrads; (2) a group of cells surrounding -these, of which the internal ones form a _tapetal layer_, similar to -that in the Vascular Cryptogams; the tapetum and some of the cells -surrounding it in this group, become dissolved before maturity; the -more external ones, on the other hand, are provided with peculiar -thickenings, and form the “fibrous” layer by the aid of which the -dehiscence of the anther takes place; (3) an external layer, the -epidermis, enclosing all the other layers (Fig. 247). - - In some Coniferæ (_Cupressus_, _Thuja_, and several species - of _Juniperus_) the microsporangia (pollen-sacs), which are - situated on the under side of the stamen, are covered by a - thin structure which seems to be a continuation of the lamina - and which is supposed to be homologous with the indusium of the - Ferns. - - [Illustration: FIG. 248.--Development of the ovule in the Red - Currant, _Ribes rubrum_, arranged alphabetically in the order - of development. _A_ Is the youngest stage, _E_ the oldest. _ii_ - Inner integument; _ie_ outer integument; _nc_ nucellus; _m_ - archespore (mother-cell of the embryo-sac).] - -=The Ovule= in the Phanerogams arises most frequently on a projecting -portion of the carpel, termed the _placenta_. The ovules (compare the -sporangium of the Eusporangiatæ and especially the pollen-sac) take -their origin from a _group of cells which lies beneath the epidermis_ -(Fig. 248 _A_, _B_). First of all a small papilla is formed, which is -later on provided with a _vascular bundle_ and becomes the _funicle_; -this probably has the same value as the projections (“placenta”) on -which the sori in the Ferns are attached. Only _one_ =macrosporangium= -(_nucellus_; Fig. 248 _nc_) is developed at the apex of the funicle. -This arises by a process of cell-division exactly corresponding to -that by which the pollen-sacs are formed (Fig. 248 _C-E_), with this -difference only, that while a great _many_ cells may be distinguished -in each pollen-sac, which forms pollen-grains by tetrad-division, only -a few are found in the ovule, and all these moreover are _suppressed, -with one single exception_ which developes into the =macrospore= -(=embryo-sac=) without undergoing a division into tetrads. The wall of -the embryo-sac, in the Gymnosperms, may be thick and divided into two -layers and partly cuticularized, as in the spores of the Cryptogams -which are to be set free. In the Angiosperms, on the other hand, the -wall is extremely thin. - -The pollen-sac thus stands in the same relation to the nucellus as the -microsporangium does to the macrosporangium: in the pollen-sacs and -microsporangia a _number_ of spores arise by the tetrad-division of -several mother-cells; in the nucellus and macrosporangium, a reduction -of the cells already formed takes place to such an extent that the -number of macrospores becomes one (_Salvinia_, _Marsilia_, Phanerogams) -or four (_Selaginella_), or rarely a large number as in _Isoëtes_. - -In the Ferns, as stated on page 210, etc., _indusia_ covering the -sori very often occur. Horsetails and Club-Mosses have no indusium; -but in all Phanerogams cupular or sac-like structures (_integuments_) -are found which envelop the nucellus. These develope from the upper -end of the funicle (_ii_ and _ie_, in Fig. 248; _y_ and _i_, in Fig. -249) and enclose the nucellus on all sides as a sac, leaving only a -small channel at the apex of the nucellus--the _micropyle_--(Fig. 249) -through which the pollen-tube proceeds to the embryo-sac. The ovules -of the Gymnosperms have only one integument (Figs. 251, 264, 269, 274) -and the same is the case with the majority of the Sympetalæ and a few -Choripetalæ; but the Monocotyledons and most of the Choripetalæ have -two integuments (Fig. 249). - - [Illustration: FIG. 249.--Various forms of ovules: _A_ an erect - ovule (_orthotropous_); _B_ reversed (_anatropous_); _C_ curved - (_campylotropous_): _k_ the nucellus (shaded in all the figures); - _s_ the embryo-sac; _ch_ the base of the ovule (chalaza); _y_ - and _i_ the external and internal integuments, the dotted line - denotes the place where the scar (_hilum_) will form when the - seed is detached from the funicle.] - -In shape the integuments resemble very closely the cupular indusium of -the Hymenophyllaceæ, certain Cyatheaceæ (Fig. 212 _E_), and _Salvinia_ -(Fig. 218); that they are really homologous with these is probable, but -is not proven. Some authorities regard them as structures found only in -the Phanerogams. - -The ovule is thus a “_monangic_” (_i.e._ reduced to 1 sporangium, the -_nucellus_) _sorus_, situated on a funicle, and enclosed by one or two -cupular _indusia_, the integuments. Some of the ovules are _erect_ -(_orthotropous_), others _curved_ (_campylotropous_), the majority -_reversed_ (_anatropous_) (Fig. 249). - - [Goebel (1884 and earlier) with Strasburger considered the - entire ovule of the Phanerogams as homologous with the - macrosporangium, the integuments however as new structures in - contradistinction to the Ferns: the funicle then corresponds - to the stalk of the sporangium. The integuments of the ovule - (according to Goebel, 1882) differ from the indusium of the - Fern-like plants in being developed from the basal portion of - the nucellus and are not, as in the Ferns and _Isoëtes_, - a portion (outgrowth) of the leaf which bears the sporangia - (_K_).] - -The nucellus is the only macrosporangium which never opens; _the -macrospore remains enclosed in it_, and _the macrosporangium remains -attached to the mother-plant_. It is therefore essential that the -_method of fertilisation_ which is employed should be very different -from that of the Cryptogams. _The pollen-grains must be transferred -to the ovule_, and retained either by a drop of mucilage at the -micropyle (Gymnosperms) or by the stigma on the carpels (Angiosperms). -Fertilisation by spermatozoids, which are freely motile in water, is -abandoned in the Phanerogams. - -Many other modifications, unknown in plants of more simple structure, -take place, for instance, in the shoots which bear the fertile -leaves; especially in the form of the stem or _thalamus_ (hypogynous, -perigynous, epigynous); in the development of the perianth which stands -in intimate connection with the special means employed to effect -fertilisation; with respect to the different grades of union found -in the leaves; in the union of the flowers into aggregations of a -higher order (inflorescences), and at the same time the production of -“floral-leaves” (page 235). - - - =The sexual generation. The Fertilisation.= - -The sexual generation in the _Mosses_ is relatively well developed, -because not only the protonema, but all the other vegetative parts -of the Moss-plant, in addition to the archegonia and antheridia, -belong to it. In the groups which follow, a gradual but increasing -reduction of the sexual generation takes place, and at the same -time an indication of sex is found in the prothallia, which finds -expression in the forms of the spores themselves. In the majority -of cases among the _isosporous_ Vascular Cryptogams, the sexual -generation--prothallium--is a green, leafy expansion which can sustain -itself by the assimilation of carbonic acid, and by the absorption -of nutriment from the soil by means of root-hairs. In some plants -(_Ophioglossaceæ_, _Lycopodium annotinum_) the prothallium is a -subterranean, pale, tubercular body, but in these instances it is -relatively large. In the _heterosporous_ Vascular Cryptogams and -in the _Phanerogams_, the prothallium is much more reduced, both as -regards its size, and also with respect to the number and structure of -the antheridia and archegonia. - -1. =The Microspores.= The PROTHALLIUM in all Vascular Cryptogams which -have unequal spores, consists of a single, vegetative (barren) cell, -which plays a very unimportant part in the life of the prothallium -(Fig. 233 _A_). In _Salvinia_ it is somewhat elongated and tubular, -because it must break through the sporangium (Fig. 214); but in other -cases it is very small and lenticular. In all these plants only one -antheridium is formed. In _Salvinia_ it consists of 2 cells whose walls -are ruptured in order that the spermatozoids may be liberated (Fig. 214 -_B_, _C_). In _Marsilia_, _Isoëtes_, and _Selaginella_ the prothallium -does not leave the spore, and consists for the most part of primordial -spermatozoid-mother-cells _without cell-wall_, which on germination are -ejected so that the spermatozoids are set free. - -In the Phanerogams, the microspores have from olden times been termed -_pollen-grains_. - -In the GYMNOSPERMS the prothallium is reduced to 1, 2 or 3 small cells, -placed on one side of the mature pollen-grain (at the top in Fig. 250 -_I_, _II_, and in Fig. 267 _N_) and which do not play any part in -the germination of the pollen-grain. The antheridium is represented -by the remaining portions of the interior of the pollen-grain, that -is, it consists of a large cell with a nucleus which does not even go -so far as the antheridium of _Selaginella_ and become divided into -spermatozoid-mother-cells without cell-wall, for even these cells are -not formed. The unicellular antheridium grows, on the germination of -the pollen-grain, into a tubular body known as the _pollen-tube_, -formed from the inner wall of the pollen-grain (Fig. 250), which works -its way down the micropyle to the oosphere. The fertilisation takes -place by diosmosis through the cell-wall, and consists here also of the -coalescence of the nucleus of the pollen-tube (the sperm-nucleus, male -pronucleus) with that of the oosphere. - -In the ANGIOSPERMS the reductions proceed still further. The barren -cell, which represents the prothallium, was in the last group separated -from the antheridium by a true cell-wall, but in the Angiosperms a -membrane at most, but no firm cell-wall, is formed. The pollen-grain -contains two cells, a vegetative and a free generative cell. Both these -pass into the pollen-tube, but the vegetative cell disappears about -the time the pollen-tube reaches the ovule; while the generative cell -divides into two: one, the sperm-nucleus coalescing with the nucleus of -the oosphere, the other being absorbed (_Lilium_, after Guinard). - -The Gymnosperms prove in yet another point that they are more -closely related to the Cryptogams than are the Angiosperms. When the -pollen-grain begins to germinate the external wall ruptures as in the -Cryptogams (Fig. 250), but in the Angiosperms special germ-pores are -formed in the cell-wall for the emergence of the pollen-tube. - - [Illustration: FIG. 250.--_I_ Pollen-grains of _Cupressus_; at - the top is seen one prothallium-cell. _II_ Germinating; _c_ - pollen-tube; _a_ the extine; _b_ the intine.] - -2. =The Macrospores.= The prothallium in _Salvinia_ and _Marsilia_ is -still rather large, green, and capable of the independent assimilation -of carbon. It projects more or less from the macrospore and bears -(in _Marsilia_ only one, in _Salvinia_ several) archegonia, which -however are embedded to a greater degree in the prothallium, and are -more reduced than the archegonia of the true Ferns and Horsetails -(Figs. 215, 216). The prothallium is still more reduced in _Isoëtes_ -and _Selaginella_; _partly_ because it is smaller and is in a higher -degree enclosed in the spore, it also contains less chlorophyll, or -is entirely without chlorophyll, and in consequence incapable of -independent existence, whilst the number of archegonia is less; and -_partly_ because the archegonia are themselves reduced, the cells of -the neck are fewer and embedded to the level of the surface of the -prothallium without any, or with only a very slight projection (Figs. -235, 236).--Finally, the prothallium with its archegonia begins to -develope in _Selaginella_ while the macrospore is still within its -sporangium, and before it is set free from the mother-plant. After -the spores are set free and germination has commenced, the spore-wall -ruptures and the prothallium is exposed. - - [Illustration: FIG. 251.--Longitudinal section of ovule of _Abies - canadensis_. Inside the integument (_i_) is seen the nucellus, - _n_; _m_ the micropyle. In the interior of the nucellus is - seen an oval mass of cells, the endosperm, and at its top two - archegonia, _c_. The ovule is turned in such a way that the - micropyle points upwards, but usually it turns downward in the - _Abietineæ_.] - - [Illustration: FIG. 252.--The apex of the nucellus (_n_) of - an ovule of _Abies_: _l_ long-shaped cells which guide the - pollen-tube; _s_ the wall of the macrospore (embryo-sac); _h_ the - neck-cells of the archegonium; _k_ the ventral canal-cell; and - _c_ the central cell (oosphere). The archegonia of the Cryptogams - should be compared with this (see pages 181, 208, 216).] - -The GYMNOSPERMS go still further. The macrospore (embryo-sac) -germinates and forms internally a cellular tissue, designated in former -times by the name of _albumen_ (endosperm), which is _homologous with -the prothallium_. It always _remains enclosed in the embryo-sac_, and -is a parenchymatous mass containing a large supply of nourishment. In -the upper part of the endosperm a number of archegonia are developed -which are in the main constructed in the same manner as those in the -Cryptogams, but are still more reduced, the neck consisting only of 4, -2, or 1 cell (Figs. 251, 252). The ventral canal-cell is also formed, -in the majority, as a small portion cut off from the large central -cell just beneath the neck; the larger remaining portion becomes the -oosphere. When the pollen-tube has passed down to the oosphere (Fig. -253) and fertilisation has been effected, the oospore commences a -cell-formation, the final result of which is the formation of _an -embryo_ (_the asexual generation_) which is provided with a thinner, -lower end, termed the suspensor. The embryo is forced more or less -into the endosperm in which it may rest for a longer or shorter -time, and generally is developed to such an extent that it has a -distinct primary-root (radicle) and stem (plumule) with one or more -embryo-leaves (cotyledons). - - When the oosphere has been fertilised its nucleus sinks down - to its lower end, and by repeated division into two, forms - four cells lying in one plane (Fig. 253, see base of the left - archegonium). Three tiers of cells are now formed by transverse - division of these four. It is the intermediate one of these - which elongates and forms the suspensor, or four suspensors, if - they separate from each other, which push the lowermost four - cells deep down into the endosperm. It is from these four lower - cells that the embryo (or four embryos when the suspensors - separate) is developed, but never more than one embryo attains - full development. As several archegonia are contained in one and - the same ovule, all of which are capable of forming embryos, - there is the possibility that several embryos may be developed - in a seed (polyembryony), but usually only one embryo attains - perfect development. - - [Illustration: FIG. 253.--The apex of the nucellus (_n_) of - _Abies_ in longitudinal section: _c_, _c_ the oospheres of - the two archegonia; the embryo-formation has commenced at the - bottom of the left archegonium; _s_ wall of the macrospore; _p_ - pollen-grains; _r_ pollen-tubes.] - - [Illustration: FIG. 254.--Embryo-sac of _Carex præcox_: _syn_ - synergidæ; _kb_ the oosphere; _c_ the central nucleus; _ant_ the - antipodal cells.] - -At the same time that the embryo is being developed, other changes -are taking place in the ovule, especially in the integument which -becomes the shell of the seed (_testa_). The endosperm grows, and the -embryo-sac supplants the cells of the nucellus. The _seed_ is now -formed, and it consists in its most complete development, as in this -instance, of three parts: - -(1) The _testa of the seed_, formed by the enveloping integuments, -with the remainder of the tissue of the nucellus lying outside the -embryo-sac (the macrosporangium). - -(2) The _endosperm_ or prothallium. - -(3) The _embryo_. - - [Illustration: FIG. 255.--Diagrammatic longitudinal section - through an anatropous ovule shortly after fertilisation; _a_ - and _i_ are the two integuments; _f_ the funicle; _k_ the - nucellus; _S_ the embryo-sac, with the incipient formation of - nutritive-tissue; _E_ the embryo; _P_ the pollen-tube passing - through the micropyle (_n_) to the oosphere.] - -The reduction in the ANGIOSPERMS is carried to the extreme limit. In -the embryo-sac (the macrospore) the nucleus by continued division -produces a prothallium consisting of primordial cells (Fig. 254). -In the upper end of the embryo-sac (which is nearest the micropyle) -are three cells, two of which are termed the “co-operating cells” -(_synergidæ_) and the third is the _oosphere_. Three others are -placed at the opposite end of the embryo-sac and are therefore termed -the “antipodal cells.” Finally, a large cell is also formed, which -occupies the space between the two groups and whose cell-nucleus, the -central definitive nucleus, lies in the centre of the embryo-sac. -These primordial cells are the slight remnant of the prothallium. The -entire structure of the archegonium, with its neck and canal-cells, -has disappeared, and nothing is left but the indispensable _oosphere_. -When the oosphere has been fertilised, and has commenced the cellular -divisions which lead to the formation of the embryo (Fig. 255), the -synergidæ and antipodal cells are absorbed, and a cell-formation -begins by a new process which emanates from the definitive nucleus and -by which a parenchymatous cell-tissue, the nutritive-tissue, arises -which may perhaps be considered as homologous with the endosperm of -the Gymnosperms. The difference is that the nutritive-tissue of the -Angiosperms is formed in two parts with an intervening interruption; -the primary nutritive-tissue is first formed, and after fertilisation -is absorbed, with the exception of one cell, which continues the -development and gives rise to the nutritive-tissue proper, which is -formed in the first instance of primordial cells, and later on of a -cellular tissue; this nutritive-tissue formed in the embryo-sac is -termed “endosperm”; in a few instances[23] a tissue which is derived -from the nucellus functions as nutritive-tissue, and is termed -“perisperm.” In many plants the seeds, when ripe, contain a very -rich nutritive-tissue, in addition to the embryo, for the purpose -of its nourishment during germination. These are termed albuminous -(endospermous) seeds, in distinction to the ex-albuminous, or those in -which the nutritive-tissue is stored in the embryo itself, before it is -completely developed, and used for its sustenance. - -In addition to the changes which fertilisation produces in the ovule -itself, it also gives the impetus to a series of changes in the -entire shoot which bears the ovule. The perianth, stamens, and style, -generally wither, because the part they play is at an end; the wall -of the ovary grows and becomes the wall of the fruit (pericarp). -The entire gynœcium of a flower, transformed as a consequence of -fertilisation, is termed a _fruit_. It consists of two parts, the -_pericarp_ and the _seeds_, and according to the nature of the -pericarp, the fruit is termed a capsule, nut, berry, or drupe. - -The chief characteristic of the Phanerogams does not lie in the -formation of the flower (although they may quite properly be termed -“Flowering-plants”), because Equisetums and Lycopods have reproductive -shoots as highly differentiated as those of certain Gymnosperms and -other Phanerogams. As regards the SEXUAL GENERATION the characteristics -are found:--(1) in its great reduction; (2) in the transmission of the -microspore (pollen-grain) to the macrosporangium, and its germination, -with the formation of a _pollen-tube_ (antheridium), the protoplasm of -which is not differentiated into spermatozoids; (3) in the fact that -the macrospore (embryo-sac) never leaves its sporangium (nucellus); -and further in the Angiosperms, (4) in the peculiar development of the -nutritive-tissue in two parts; and (5) in the great reduction of the -archegonium. - -As regards the ASEXUAL GENERATION the characteristic feature is that -this generation is formed whilst the sporangium is still attached to -the mother-plant, and for a long time is nourished by it; and that -after the sporangium has become detached from the mother-plant, it -spends a longer or shorter resting period as the embryo in the seed -(enveloped by the testa), and does not make its appearance until -the “germination” of the seed. In addition the shoot which bears -sporangia undergoes greater modification than in the case of the -Flowerless-plants. - -The Phanerogams are separated into two Divisions as follows:-- - -Division 4. =Gymnospermæ.= The ovules, as well as the seeds, are borne -_naked_ on the surface of _open carpels_, or on the apex of a stem -(ovary wanting). The pollen-grains are conveyed by the wind to the -ovules, and caught by drops of mucilage, secreted by the micropyle. -A “stigma” is _wanting_. The entire _female prothallium_ (_the -endosperm_), which serves for the nourishment of the embryo, is _formed -before fertilisation_. The archegonia are _embedded in the upper part -of the prothallium. The pollen-grains are “multicellular,” i.e._ there -is always in their interior a distinct prothallium, formed by 1–3 -cells, and a larger cell which gives rise to the pollen-tube. - -Division 5. =Angiospermæ.= The carpels surround the ovules and form -an entirely closed chamber (_ovary_), in which the ovules mature and -ripen into seeds. The surface of a portion of the apex of the carpel -is transformed into the “stigma,” which, by a sticky fluid and also by -hair-structures, is capable of retaining the pollen-grains conveyed to -it by the wind, or more frequently by insects. The pollen-tube grows -from the stigma, through the “conducting cellular tissue” (_style_), -to the ovules. The pollen-grains contain two cells, a vegetative and -a free generative cell. The latter passes into the pollen-tube and -there divides into two, one of which is the sperm-nucleus. The female -prothallium, which is intended to serve as nutritive-tissue, is formed -_after fertilisation_. Archegonia are wanting. - - - - - DIVISION IV. - - GYMNOSPERMÆ. - - -The following characters should be added to those already given on page -2:-- - -The Gymnosperms comprise only trees or shrubs. The flowers are always -_unisexual_ and destitute of perianth (except _Gnetaceæ_); the female -plant of _Cycas_ is the only one which has no flower. The MALE FLOWERS -are constructed on the same type as the cones of the Horsetails and -Club-Mosses, and are _most frequently long shoots_ (Figs. 243, 258, 260 -_A_, 267 _J_) bearing a number of spiral or verticillate stamens. The -FEMALE FLOWERS are of a more varied structure (see the orders). The -OVULE _is orthotropous_ (except _Podocarpus_ which is anatropous) and -projects from the carpel uprightly, inverted, or horizontally; it has -usually _only one integument_ (compare however Taxaceæ) which proceeds -from the upper part of the nucellus, so that the embryo-sac in part is -placed below the integuments (Figs. 251, 264). The drop of mucilage -which catches the pollen-grains dries up and draws the pollen-grain -through the micropyle to a space just above the nucellus--_the -pollen-chamber_--in which the germination of the pollen-grain commences. - -In each seed, only one of the many embryos which are formed proceeds to -its full development. The seed is always _endospermous_, and the embryo -has one, two, or a whorl of several cotyledons. A vigorous primary -root is developed on germination. THE VASCULAR BUNDLES in the stem are -arranged in a ring, and _increase in thickness_ takes place by a closed -cambium-ring which forms bast (_phlœem_) externally, and wood (_xylem_) -internally with distinct annual rings, _as in the Dicotyledons_. Only -certain of the Cycadeæ deviate from this arrangement. The _secondary -wood_ is very uniform, as it is almost exclusively _formed of -tracheides_ with bordered pits, but _true vessels are wanting_; this -also indicates a relationship with the Pteridophyta (see page 202). - -The Gymnosperms are biologically lower than the Angiosperms; they are -wind-fertilised, and without extra floral-nectaries. - -This Division embraces three classes: CYCADEÆ, CONIFERÆ, And GNETEÆ. It -is no doubt monophyletic, and has taken its origin from heterosporous -Ferns, now extinct, most nearly related to the Ophioglossaceæ and -Marattiaceæ. The Cycadeæ appear to be the oldest class. The Coniferæ -are related to these through Ginkgo. The Gnetaceæ are more isolated. -The Division is not continued into the higher Flowering-plants; it has -evidently attained its highest development, and is now in a retrograde -condition. The similarity which has often been pointed out between -certain Coniferæ and Lycopodinæ is only in analogous resemblances, and -does not entitle one to suppose that there is a nearer relationship, or -that the former take their origin from the latter. - - - Class 1. =Cycadeæ.= - -The stem is very _rarely ramified_. The leaves are _large_, _pinnate_, -and arranged spirally. The flowers are _diœcious, without perianth_. - - [Illustration: FIG. 256.--_Cycas circinalis_ (female plant). The - carpels are seen hanging from the top of the stem. Three leaves - with the leaflets still rolled up project almost vertically into - the air, from the centre of the crown.] - -There is only one order, the =Cycadaceæ=.--In habit they resemble the -Ferns, especially the Tree-Ferns (compare Figs. 207 and 256). The stem -is tubercular (Fig. 258), or cylindrical (Fig. 256), but not very tall -(as much as about 12 metres), and very rarely ramified. [In Ceylon, -unbranched specimens of _Cycas_ are rarely met with in the wild state. -The stems of _C. circinalis_ occasionally branch in greenhouses.] - -The LEAVES are arranged spirally, and so closely together that no -free stem-surface is left between them, and have only a slight sheath -(which is not amplexicaul, as in the Palms). They are compound (most -frequently pinnate; in _Bowenia_, bipinnate); in some genera the leaves -are rolled up in various ways, resembling the vernation in Ferns (Fig. -257); they are leathery and perennial. In some, stipules are present, -as in the Marattiaceæ. Groups of scale-leaves alternate in the majority -with groups of foliage-leaves. - - [Illustration: FIG. 257.--_Cycas circinalis._ Part of a young - leaf with circinate leaflets.] - - [Illustration: FIG. 258.--A male plant of _Stangeria paradoxa_ - (about 1/15 nat. size).] - - [Illustration: FIG. 259.--Female cone of _Zamia integrifolia_ - (½-⅓ nat. size). The male cone is very similar externally.] - -The FLOWERS are without perianth. The MALE FLOWER is sometimes an -enormous collection of stamens (Fig. 258), which are flat in some -(_Cycas_, Fig. 241), shield-like in others (_Zamia_, _Ceratozamia_) -like the sporophylls in Horsetail (Fig. 259); but in all, the -pollen-sacs are situated in large and varying numbers on the back of -the stamens, and arranged in groups of 2–5, like the sporangia in the -sori of the Ferns (Fig. 241 _b_, _c_). FEMALE FLOWERS _are wanting_ in -_Cycas_, because the carpels do not terminate the apical growth of the -stem. After a group of foliage-and of scale-leaves, a group of carpels -is developed, which are pinnate and resemble the foliage-leaves, -bearing on their edges a number of ovules (most frequently 5–6) -(Figs. 245, 256); the same stem produces successively scale-leaves, -foliage-leaves, and carpels. The differentiation is not much more -advanced than in certain Ferns (_Struthiopteris_, _Blechnum_), where -barren and fertile leaves of different form regularly alternate. _The -other genera have female flowers_; the carpels are shield-like in -_Zamia_ and _Ceratozamia_ (Fig. 246), and collected into cone-like -flowers, which terminate the growth of the stem (Fig. 259). The number -of ovules in these instances is two to each carpel. - -The SEEDS are large (most frequently 2–6 centimetres long) and -plum-like; the external layer of the testa is fleshy, while the -internal one is hard and horny. There are two systems of vascular -bundles in the testa, one outside, the other inside the stone. The -embryo is straight, attached to the end of the suspensor, which is -often long, filamentous, and rolled up; it has one or two cotyledons. - - The embryo in _Ceratozamia_ and others is very slightly - developed, at the time when the ripe seed is detached from - the carpel; and it is not until after sowing that its further - development and germination proceed. This calls to mind the - Cryptogams, especially _Selaginella_, whose macrospores are - thrown off filled with endosperm; but the oosphere is not - fertilised till after the separation of the macrospore from the - parent-plant, while in the Cycadeæ fertilisation is effected - before the separation. In _Cycas_ the testa may rupture, and - the endosperm grow and become green in the light, even though - no embryo has been formed. This also is an indication of its - prothalloid nature. - - Gum-passages are present in all organs. Collateral vascular - bundles, with spiral and scalariform tracheides, are found; - and normal thickening takes place by means of a cambium. - An exceptional mode of growth is found in _Cycas_ and - _Encephalartos_, the cambium ceases to divide after a time - and is replaced by a new cambium which arises in the cortical - parenchyma just outside the bast, and which forms a new ring - of xylem and phlœem. This may be repeated so that a number of - concentric rings are produced. In _Ceratozamia_, structures - resembling corals extend from the roots in a vertical direction - and appear on the surface of the soil; these are peculiar roots, - in which a symbiotic Alga (_Anabæna_) is found. - - The Cycadeæ were formerly (from the Coal period to the Later - Cretaceous) far more numerous than at the present day. They - appear to have been most numerous in the Trias and Jurassic. - The remnant (75 species) which have persisted to the present - time are found in all tropical countries. _Cycas_ (Trop. and - Sub-trop., Eastern Hemisphere); _Dioon_ (Mexico); _Macrozamia_ - (Australia); _Encephalartos_ (Trop. and S. Africa); _Stangeria_ - (Fig. 258, Sub-trop. South and East Africa); _Bowenia_ (Trop. - Australia); _Ceratozamia_ (Mexico, New Granada, Western Brazil); - _Microcycas_ (Cuba); _Zamia_ (Trop. and Sub-trop. N. America.) - - USES. Sago is made from the starch-containing pith of _Cycas - revoluta_ and _circinalis_. The leaves are often used at - funerals and church festivals, under the name of “palm-branches.” - - - Class 2. =Coniferæ= (=Pine-trees=). - -The stem _branches freely_. The leaves are _entire_, relatively small, -linear or reduced to scales. The flowers are without perianth. The -ovules naked. It is seldom that the female flower is reduced to only -one carpel. - -Whilst the Cycadeæ principally resemble the Ferns, the Conifers partly -resemble the Lycopods, and partly the Equisetums--the former especially -in the _needle- or scale-like_, leathery, simple, and often perennial -leaves (“evergreen plants”), which _never possess stipules_ (Figs. 263, -270, 272). _Ginkgo_ deviates from this, being no doubt the oldest, -and the Conifer which stands nearest to the Cycadeæ (Fig. 260). The -resemblance to the Equisetums is especially owing to the fact that -the stem ramifies abundantly, and often very regularly, forming a -pyramid with verticillate branches. In addition to the foliage-leaves, -scale-leaves (bud-scales) are present in the majority of species. - -The FLOWERS are monœcious or more rarely diœcious. _Perianth is -wanting._ The stamens of the _catkin-like male flowers_ (Fig. 267, -_J_) are of different forms, but as a rule more or less shield-like. -As in the Cycadeæ, the pollen-sacs are in all cases situated _on the -underside_. There are, as a rule, two pollen-sacs (the Abietaceæ, Fig. -267), or 3–5, (the Cupressaceæ and Taxaceæ, Fig. 243); a few have more, -_e.g. Araucaria_ (Fig. 242); they dehisce by clefts. - -If, in commencing our consideration of the _female flower_, we begin -with that of _Ginkgo_, we shall observe in the corner of a scale- -or foliage-leaf a small flower, which consists of two carpels, each -bearing one ovule, and reduced almost to the ovule itself (Fig. 260 -_C_, _D_). The flower in _Podocarpus_ is still further reduced, viz. -to a single carpel with one ovule, which is anatropous and has two -integuments. This ovule is situated in the axil of a cover-scale (_c_, -in Fig. 262 _D_), and several female flowers of this description are -collected in a small cone, the stalk and bracts of which become fleshy -(Fig. 262 _C_). The external integument also becomes fleshy (an aril). -_Dacrydium_, which is clearly related to _Podocarpus_, has an external -integument which developes more independently as a fleshy aril (Fig. -262 _B_, _B’_). _Microcachrys_ also is clearly allied to these: the -bracts are more fleshy, and the ovule (_i.e._ the female flower) is -protruded beyond the bract (Fig. 262 _A_, _A’_). _Taxus_ stands in a -more isolated position: a flower which has been reduced to an ovule is -situated, in this instance, on the apex of a secondary branch which is -studded with floral-leaves (Figs. 263, 264); an external integument -is developed on all sides and surrounds the seed as a scarlet aril. -According to this conception _the aril corresponds to an external -integument_, and the Taxoideæ thus possess a partly dichlamydeous -ovule. Only _Ginkgo_ and _Cephalotaxus_ appear to deviate from this, -as in these there is only one integument (unless the small outgrowth -indicated by _ar_, in Fig. 260 _D_, really is a rudimentary, external -integument); in CYCADEÆ, to which _Ginkgo_ is most closely related, -there is likewise only one integument. But in these genera the testa -is differentiated into two layers, and the seed resembles a drupe; like -the Cycadeæ there is an external fleshy covering and an internal hard -one, and these two layers may probably be considered homologous with -the two integuments. This theory is also borne out by the arrangement -of the vascular bundles in _Cephalotaxus_ and _Podocarpus_, which -present the xylem in the fleshy external layer to the _outside_ of the -testa, which is therefore the upper side of the integument (Celakovsky). - -The coalescence of the integuments into one is only slight in -_Torreya_, more pronounced in _Podocarpus_ and strongest in -_Cephalotaxus_ and _Ginkgo_. Celakovsky terms these ovules -“holochlamydeous.” - -If we pass from these to the order PINOIDEÆ, we find the female flowers -collected into catkin-like cones, which have been considered from -various points of view to be sometimes single flowers, at other times -compound inflorescences. The structure in ABIETACEÆ is as follows: a -number of spirally arranged, scale-like leaves, _cover-scales_ (Figs. -267, 268), are situated on a long axis. In the axil of each cover-scale -a larger leaf-like projection, _the ovuliferous scale_, is borne, -which turns the upper side towards its cover-scale (which is shown by -the fact that the wood of its vascular bundles is turned downwards -and towards the wood in the bundles of the cover-scale: Fig. 269). -Two ovules, with micropyles turned towards the central axis, and with -apparently only one integument (Fig. 268), are situated on the dorsal -side of each ovuliferous scale, _i.e._ the side turned away from the -cover-scale. The ovuliferous scales grow after fertilisation, into the -woody or leathery “cone-scales,” which are usually much larger than the -cover-scales. This ovuliferous scale with its axis may, according to -Celakovsky, be considered as a dwarf-branch which is situated in the -axil of the cover-scale, and bears two ovules (in the same way as in -_Ginkgo_, one long-stalked flower, reduced to two ovules, is situated -in the axil of a leaf), and _in this case the external integument of -the ovules_ is expanded into leaf-like bodies, which have united to -form one “_symphyllodium_” (_ovuliferous scale_) which is inverted -so that its dorsal side is turned upwards and bears the nucellus and -the other integument (“hemichlamydeous” ovules). The carpel itself -is therefore in this instance extremely reduced. The keel, or (in -_Pinus_) “mucro” (Fig. 268 _B_), which is found in several genera, -represents then a third carpel, which is sterile. In the other orders -of the Pinoideæ the cover-scales and ovuliferous scales grow more and -more together and finally form one structure, which also is termed a -“cone-scale,” although from its development it cannot be homologous -with the cone-scales of the Abietaceæ. This connation is least in the -TAXODIACEÆ and ARAUCARIACEÆ and may be traced on the upper surface -of the “cone-scale” by the presence of a stronger or slighter ridge -or pad, the free portion of the ovuliferous scale (Figs. 256, 266, -269). It is most strongly pronounced in the CUPRESSACEÆ, in which the -two scales form one single structure, the cone-scale (Fig. 274). The -vascular bundles in the under portion corresponding to the cover-scale, -have the xylem towards the upper side as usual in leaves, whilst -the bundles present in the upper side of the cone-scale, which thus -represents the ovuliferous scale, turn their xylem downwards. The -hemichlamydeous ovules are then situated on the upper side of this -cone-scale. According to this theory the CUPRESSACEÆ appear to be -the youngest type, a view which corresponds with their vegetative -structure. If there is only one ovule in these orders as in _Agathis_ -(Fig. 265) and _Araucaria_, then the flower is reduced to a single -carpel and one ovule, as in the case of _Dacrydium_ and _Microcachrys_. -If two or more ovules are present, then the same number of carpels may -be supposed to exist, the external integuments of their ovules being -developed into leaf-like structures which collaterally coalesce to form -a “symphyllodium,” or are suppressed. - -According to this theory, which is based on the researches of -Celakovsky, the female flowers of the Coniferæ may be classed thus:-- - -1. In all cases situated in the axil of a bract and collected into -cones, with numerous flowers or with few or one flower. In _Ginkgo_ -only, are they situated in the axil of foliage- or scale-leaves. - -2. It is only in _Taxus_ that bracteoles are present. - -3. They are formed only from rudimentary carpels, in which the stem -takes no part. - -4. The number of carpels in each flower varies from one to many, most -frequently three, of which the central one remains sterile. - -5. Each carpel bears only one ovule. The flower which is formed of only -one carpel appears to consist of only one ovule. - -6. The ovule has in Taxaceæ either a double integument (Podocarpeæ, -Taxeæ), of which the external is the “aril,” or, as in the Cycadeæ, a -single one, which is homologous with the two united together. - -7. The external integument in the Pinoideæ is expanded to form a -leaf-like structure--the ovuliferous scale--and bears on its dorsal -side the ovules, which are thus only provided with one, and that the -inner, integument. - - This later interpretation of the female cones in the Coniferæ is - more probably correct than the older ones; that, however, which - appeared in the former issues of this book, may also be stated. - It was to the effect that each catkin-like female cone is in - reality a single flower; the cone-scales in the Cupressaceæ - were single leaves, namely carpels, which bore the ovules on - the side which is turned upwards; the division into two parts - which makes its appearance in the other orders, and becomes - most prominent in the Abietaceæ, was compared with the division - of a leaf into a barren and a fertile portion, which is found - especially in Ophioglossaceæ and Marsiliaceæ, or with the ligule - in _Isoëtes_. - -POLLINATION is accomplished by means of the wind. At the period -of pollination the leaves are always so widely separated from one -another, that the ovules can catch the pollen-grains carried to -them by the wind; this is often effected by the mucilaginous drops -which appear at the micropyle, and by the evaporation of which the -pollen-grains are brought in contact with the nucellus. The entire cone -grows considerably as soon as fertilisation has taken place, and the -cone-scales in Pinoideæ close together so that the seeds while maturing -are enclosed, and it is not until the seeds are ready for distribution -that the cone-scales again become separated. In the Pinoideæ, the fully -developed ovuliferous scales are hard and woody; and in this condition -the collection of female flowers is termed a _cone_. In the Taxoideæ, -true cones are the exception. 2–15 cotyledons are present, arranged in -a whorl. - -The characteristic feature of this class is the abundance of _resin_, -which is to be found in isolated cells (especially in the cortex), -partly in intercellular glands or passages (both in the cortex and -wood). _Taxus_ is the only genus which has no resin. - - There are about 350 species, mostly from the Northern Temperate - zone (especially North America and Siberia), where they grow - gregariously and form the most northern forests. The Juniper, - Scotch Fir, and Yew are natives of Great Britain. - -This class may be divided into two families:-- - -1. =Taxoideæ.= The ovules have either one integument, the external -part of which is fleshy, and the internal hard and stone-like; or two -integuments, of which the external is the fleshy and coloured “aril.” -“Ovuliferous scales” are wanting. The cones are never woody, but are -generally succulent, the bracts become fleshy, or cones usually are not -developed. The seeds project more or less freely beyond the bracts. - -2. =Pinoideæ.= The ovules have two integuments, the external one of -which is leaf-like and becomes developed as the “ovuliferous scale”; -if there are several of these in each flower they unite and form a -“symphyllodium.” This may remain free or unite with the bract. The -cones are most frequently woody, rarely succulent. The seeds are hidden -among the cone-scales. - - - Family 1. =Taxoideæ.= - -This family, considered to be most nearly related to the Cycadeæ, also -made its appearance at a very early period. There is only one order. - -Order. =Taxaceæ.= The characters have been given above. - -_A._ CEPHALOTAXEÆ is the oldest group, presumably the connecting -link between the Cycadeæ and the other Coniferæ. The flower consists -normally of two ovules. Aril wanting. One integument. Seeds -drupaceous.--The flowers in _Ginkgo biloba_ (_Salisburia_) are situated -in the axil of foliage- or scale-leaves. The stamens bear only two -pollen-sacs (Fig. 260 _A_). The female flower has two ovules, placed -together at the end of a long, bare axis (Fig. 260 _C_). Round the base -of the ovule a small collar (_ar_, in Fig. 260 _D_) is found, which -may probably be considered homologous with the collar-like outgrowth -which surrounds the base of the _Cycas_-ovule. The seed resembles a -Plum, and has a fleshy external coat, surrounding a hard internal -layer. The embryo is developed after the seed has fallen off. The -Ginkgo-tree has long-stalked, fan-shaped leaves, more or less indented, -with dichotomous veins resembling certain Ferns--the Adiantums. It is a -native of East Asia, and the only surviving species of a genus which in -earlier times was very rich in species, and distributed over the entire -Northern Hemisphere. _Cephalotaxus_ (Eastern Asia) is related to it. - - [Illustration: FIG. 260.--_Ginkgo_ (nat. size): _A_ a branch with - a small flowering dwarf-branch (male flower); _B_ a leaf; _C_ a - flower with two ovules; _D_ a ripe seed; _ar_ collar.] - - [Illustration: FIG. 261.--_Phyllocladus glaucus_: a branch with - female flowers (nat. size).] - -_B._ PODOCARPEÆ. The female flower is reduced to one ovule, placed in -the axil of a bract, or a little forward upon it. The ovule has an -aril (2 integuments).--_Phyllocladus_ (Fig. 261), from New Zealand and -Tasmania, has obtained its name from its flat, _leaf-like branches_, -the leaves proper being scale-like (_f_). The ovules stand _erect_ in -the axil of the scale-like leaves (_c_), and several are collected at -the end of short branches.--_Microcachrys tetragona_ (Tasmania) has -a small female catkin with several spirally-placed, fleshy bracts, -at the end of which the inward and downward turned ovule is attached -(Fig. 262 _A_, _A’_). The ripe cones are red, succulent, and resemble -Strawberries.--In _Dacrydium_ (Tasmania, New Zealand, Malaysia) the -female cone has most frequently only 1–2 (–6) bracts, which resemble -the vegetative leaves; they have also a fleshy aril (Fig. 262 _B_, -_B’_).--_Podocarpus_ (40 species, East Asia, S. Temp.); the bracts of -the female flowers become fleshy, and unite together; only 1 or 2 are -of use in supporting the flowers. The ovules project high above the -apex of the bract, and are _anatropous_, the micropyle being turned -downwards (Fig. 262 _C_, _D_). An aril commences to develope in the -flowering period as an external coating, and later on it becomes fleshy -and coloured. - - [Illustration: FIG. 262.--_A Microcachrys_: female cone (2/1). - _A’_ A single carpel with its ovule. _B Dacrydium_: branch with - female flower (3/1). _B’_ The flower; _cp_ the bract; _ar_ the - aril; _ov_ ovule. _C Podocarpus_: female flower with 2 ovules. - _D_ Another female flower with 1 ovule, in longitudinal section.] - - [Illustration: FIG. 263.--_Taxus baccata_: branch with two ripe - seeds (nat. size).] - -_C._ TAXEÆ. The female flower is reduced to one ovule, which is -situated _terminally_ on an axis which bears 2–3 pairs of opposite, -scale-like bracteoles; on this account the Taxeæ form a very isolated -group among the Coniferæ.--_Taxus_ (_T. baccata_, the Yew-tree). -_Diœcious_. _The female flower consists of only one ovule_, placed _at -the end_ of a short secondary branch (Fig. 264), which is studded with -scale-like leaves. The aril when ripe is thick, fleshy, and scarlet -(sometimes yellow), and only loosely envelopes the seed (Fig. 263). -The leaves are scattered, flat, linear, and pointed (Fig. 263, 264). -The short male flowers have 5–8 pollen-sacs, pendent from the stamens, -and are surrounded at their bases by scale-like bracteoles (Fig. 243). -_Torreya_ (4 species, N. America and Japan) is closely allied to -_Taxus_. The aril ultimately fuses with the woody inner integument, and -hence the ovule becomes drupaceous, as in Cephalotaxaceæ. - - [Illustration: FIG. 264.--_Taxus baccata_: _A_ shoot of _Taxus_ - with female flowers at the time when the ovules are ready for - pollination. _B_ Leaf with flower in its axil (nat. size). _C_ - Longitudinal median section through a female shoot; _v_ growing - point of primary shoot; _a_ commencement of aril; _i_ integument; - _n_ nucellus; _m_ micropyle.] - - USES. _Taxus baccata_ is usually planted in gardens, especially - in hedges. Its wood is very hard and is used for wood-carving. - The shoots are poisonous, but not the aril, which is often eaten - by children and by birds. - - - Family 2. =Pinoideæ.= - -The four orders differ from one another partly in the arrangement of -the leaves (_Cupressaceæ_ have opposite or verticillately placed -leaves, flowers, and inflorescences; in the others they are placed -spirally), but chiefly in the greater or less degree of union which -takes place between the female flower (the leaf-like “symphyllodium”) -and its supporting cover-scale, and in the position of the ovules (the -micropyle being turned upwards or downwards). The “cone-scales” in -_Abietaceæ_ are formed by “symphyllodia” alone, in the others by -their union with the cover-scale. - -Order 1. =Araucariaceæ.= This order most frequently has _solitary_ -ovules, _turned downwards_ and attached _to the centre_ of the -cone-scales. In _Agathis_ (_Dammara_) the arrangement is the most -simple, a winged seed (Fig. 265), which hangs _freely_ downwards, being -borne in the centre of the undivided cone-scale. In _Araucaria_, the -stamens with the _free, pendulous_ pollen-sacs have been represented -in Fig. 242; the ovuliferous scale is united for nearly its whole -length with the bract, and projects from its apex in the shape of a -sheath-like, dentate scale, resembling the ligule in _Isoëtes_, and may -therefore be termed a “ligule.” _Araucaria_ (S. America, Australia) has -often rather broad leaves (_A. brasiliensis_). The ovuliferous scale in -_Cunninghamia_ is more distinct, and stretches transversely over the -entire cover-scale; it bears three inverted ovules (Fig. 266) (Eastern -Asia). - - [Illustration: FIG. 265.--_Agathis (Dammara) australis._ - Cone-scale with the seed. _A_ Longitudinal section; _A’_ from - within; _fv_, _fv’_ vascular bundles; _v_ wing.] - - [Illustration: FIG. 266.--_Cunninghamia sinensis._ Cone-scale - with three ovules, interior view: _d_ cover-scale; _f_ - ovuliferous scale.] - - [Illustration: FIG. 267.--_A-G Pseudotsuga douglasii_: _A_ - cone, _B_ cone-scale, with the inner side turned forward; the - points of the cover-scale are seen behind it; _C-G_ transitions - from the acicular leaf to the cover scale, from the base of a - ♀ cone. _H Pinus montana._ Young ovuliferous scale, with the - inner side turned forward; the ovules are now in the stage for - pollination. _J-M Abies alba_: _J_ male cone; _b_ bud-scale; - _a_ anthers; _K L M_ individual anthers.--_Pinus montana_: _N_ - pollen-grain; the two lateral expansions are the air-bladders; in - the upper part of the interior of the grain a vegetative cell may - be seen, and in the centre the large cell-nucleus.] - - Dammara-resin, which is used for varnish, is obtained from - _Agathis_ (_Dammara_) species (New Zealand, Philippine - Islands). - -Order 2. =Abietaceæ (Pine and Fir Trees).= The leaves are spirally -arranged and needle-like. The flowers are _monœcious_. The male flowers -are long, and catkin-like, with numerous stamens, each bearing two -_oblong pollen-sacs_. The pollen-grains are most frequently tri-lobed, -having two bladder-like appendages, formed as outgrowths of the -exospore, to assist in their distribution by the wind (Fig. 267 _N_). -The bracts are arranged spirally. The union between the bract and the -ovuliferous scale, which is found in the preceding order, is not in -this instance so complete; these scales make their appearance as two -free parts, and are attached only at their bases (Fig. 268); the lower -portion, that is the cover-scale, in most instances remains quite -small (Fir, Red Pine, and others), it is only in the “Noble Pine” -(_Abies_) and _Pseudotsuga douglasii_, that it attains a greater length -than the ovuliferous scale (Fig. 267, _B-G_). On the other hand the -upper part, _the ovuliferous scale_ (the vascular bundles of which have -the bast turned upwards), grows strongly and elongates, especially -after fertilisation, becoming woody or leathery; it is commonly termed -the “_cone-scale_,” but is in reality only homologous with a part of -the “cone-scale” in the other order of Pinoideæ. On the side of the -ovuliferous scale, turned towards the axis, are situated _two ovules_ -with micropyles _directed inwards_. The seeds are most frequently -provided with _a false wing_ (a tissue-like part of the surface of -the ovuliferous scale). Cotyledons, _more than_ 2, _verticillate_. -_Fertilisation does not take place until some time after pollination._ -In _Pinus_, for instance, the pollen-tube only penetrates the nucellus -for a short distance during the year of pollination, and then ceases -its further growth, fertilisation not taking place until after the -middle of the next year; whilst the seeds ripen about a year and a half -after pollination. In the Larch and others, the seeds are mature in the -autumn succeeding pollination. - - [Illustration: FIG. 268.--_A Abies_: _c_ the cover-scale; - _s_ ovuliferous scale, or “cone-scale”; _sk_ ovules in a young - condition. _B Pinus_: ovuliferous scale with two ovules (_s_); - _m_ the two-lobed micropyle; _c_ “mucro”; _b_ the cover-scale - behind. _C Abies_: ripe “cone-scale” with two seeds (_sa_); _f_ - wing of seed.] - -_Abies_ (Fir). The leaves are often (_e.g. Ab. pectinata_) displaced -into 2 rows, flat and indented at the apex, with 2 white (wax-covered) -lines on the under surface, in which the stomata are situated. The -leaf-scars are nearly circular and do not project. The cones are erect. -_The cover-scales and the ovuliferous scales separate from the axis_, -to which they remain attached in other genera.--~_Tsuga_ has leaves -like _Abies_, but by the slightly projecting leaf-scars, and cones with -persistent scales, it forms the transition to _Picea_.--_Pseudotsuga_ -has leaves similar to those of _Abies_ and persistent carpels as in -_Picea_, but the cover-scales grow as in _Abies_ and project beyond -the ovuliferous scales (_P. douglasii_, Fig. 267). These two genera -are considered as sub-genera of _Abies_.~--_Picea_. The leaves project -on all sides, square and pointed; the leaf-scars are rhombic, on -projecting leaf-cushions. The cones are pendulous. The cover-scales are -much shorter than the leathery, persisting ovuliferous scales.--The -genus _Larix_ (Larch) differs from all the others in having deciduous -leaves (the three preceding have leaves which persist for eleven to -twelve years). It has _long-branches_ with linear foliage-leaves and -short, thick, _perennial dwarf-branches_, which each year form a new -rosette of foliage-leaves, similar to those on the long-branches. The -male flowers and the erect cones resemble those of _Picea_, and are -borne on dwarf-branches.--_Cedrus_ (Cedar) resembles _Larix_ to some -extent, but has persistent leaves (_C. libani_, _C. deodara_).--_Pinus_ -(Pine) has long-branches and dwarf-branches. The leaves of the -long-branches are scale-like and not green; the dwarf-branches have -very limited growth, and persist for three years; they arise in the -axils of the scales borne on the long-branches of the self-same year, -and each bears 2–5 foliage-leaves, they are also surrounded at the base -by a number of membranous bud-scales. The cone-scales have a _thick, -rhomboid extremity_ (the “shield”). - - The buds which develope into long-branches arise at the apex of - other long-branches, and being very close together, form false - whorls. The female cones occupy the position of long-branches, - and take about two years for their development. The male flowers - arise close together, and form a spike-like inflorescence at - the base of a long-branch of the same year. The male flowers - occupy the position of dwarf-branches, so that a female cone - may be considered to be a modified long-branch, and a male cone - a modified dwarf-branch. The main axis of the seedling has - needle-like leaves, similar to those found on the older parts, - and on dwarf-branches; it is not until some time later that - the dwarf-branches are developed and the permanent arrangement - attained. - - USES. Several species are commonly cultivated in this country, - partly on heaths and moors, and partly in plantations and as - ornamental trees, such as Mountain Pine (_Pinus montana_, Cen. - Eur.); Austrian Pine (_P. laricio_, Eur.); Scotch Fir (_P. - silvestris_, Eur.); Weymouth Pine (_P. strobus_, N. Am.); common - Red Pine (_Picea excelsa_, Cen. and N. Eur.); White Pine (_P. - alba_, N. Am.); _Abies pectinata_ (Common Fir, S. and Cen. Eur); - _A. nordmanniana_ (Crimea, Caucasus); _A. balsamea_ (N. Am.); - _Tsuga canadensis_ (N. Am.); _Pseudotsuga douglasii_ (N.W. Am.); - Larch (_Larix europæa_, Alps, Carpathians); _L. sibirica_ (N.E. - Russia, Siberia).--The wood of many species, especially Pine, - on account of its lightness and because it is so easily worked, - is very well adapted for many useful purposes. The wood of the - Yew-tree is very hard and is used for ornamental turning. Resin - and Turpentine (_i.e._ Resin with essential oils, the name being - derived from the Terebinth-tree, from which formerly a similar - material was obtained) are extracted from _Pinus laricio_ and - _P. pinaster_. Oil of Turpentine is obtained by distillation of - turpentine with water; Tar by dry distillation of Pine-wood. - Canada-balsam is from North American _Abies_-species (_A. - balsamea_ and _Fraseri_). The officinal Turpentine is mainly - obtained from _Pinus pinaster_ (South of France), _P. tæda_, - _australis_, _strobus_ (Weymouth Pine) and other North American - species; more recently also from _P. silvestris_ (Scotch Fir), - _maritima_, _laricio_, _Picea excelsa_, and others; Venetian - Turpentine, from Larch (S. Eur.) Amber is resin from a Tertiary - plant (_Pityoxylon succiniferum_), closely related to the Pine, - which grew especially in the countries round the South-East - coast of the Baltic. _Pinus pinea_ (the Pine, S. Eur.) has - edible seeds and also _P. cembra_ (in Cen. Eur. and Siberia). - -Order 3. =Taxodiaceæ.= The vegetative leaves and cone-scales are -arranged spirally. The ovules (2–9) are situated either at the base -of the ovuliferous scales, in which case they are erect; or at their -centre, when they are generally more or less inverted. The ovuliferous -scale is more or less united with the cover-scale, and projects -beyond the surface of the cone-scale, like a comb (Fig. 269). The -vascular bundles, which extend into the cover-scale, have the usual -leaf-arrangement, viz. the wood placed above the bast; while those -bundles which enter the ovuliferous scale have this arrangement of the -bundles reversed. - - [Illustration: FIG. 269.--_Cryptomeria japonica._ Portion of - longitudinal section through female flower. _d_ cover-scale; - _f_ ovuliferous scale; _ov_ ovules; _fv_ and _fv’_ vascular - bundles; the xylem is indicated by a wavy line, and the phlœm by - a straight line.] - - _Taxodium distichum_ (the North American “Swamp Cypress”) has - annual dwarf-branches, with distichous leaves, and cone-like - “pneumathodia.” In the Tertiary period it was very common in - the Polar regions. _Sequoia (Wellingtonia) gigantea_ is the - famous Californian Giant-Fir, or Mammoth-Tree, which attains - a height of 300 feet, a diameter of 36 feet, and is said to - live for 1,500 years. _Cryptomeria japonica_ (Japan, China) has - the least adnate ovuliferous scales; _Glyptostrobus_ (China); - _Arthrotaxis_ (Tasmania); _Sciadopitys verticillata_ (the only - species in Japan) has, like _Pinus_, scale-like leaves on - the long-branches, of which those which are situated at the - apex of the annual shoots support “double needles,” _i.e._ - _dwarf-branches_ similar to the two-leaved dwarf-branches in - _Pinus_, but without bud-scales, and with the two leaves fused - together at the edges into one needle, which turns its upper - surface away from the long-branch. - -Order 4. =Cupressaceæ= (=Cypresses=). _The leaves are opposite or -verticillate_, sometimes acicular, but most frequently scale-like -(Fig. 270). In the species with scale-like leaves, the seedlings -often commence with acicular leaves (Fig. 272), and branches are -sometimes found on the older plants which revert to this form, seeming -to indicate that the acicular leaf was the original form (atavism). -The so-called “_Retinospora_” species are seedling-forms of _Biota_, -_Thuja_, _Chamæcyparis_, which have been propagated by cuttings, and -retain the seedling-form. The flowers are monœcious or diœcious. The -male flowers are short, and have shield-like stamens, bearing most -frequently several pollen-sacs. The cover-scales and ovuliferous scales -are entirely fused together and form _undivided_ cone-scales, _opposite -or whorled_; _the ovuliferous scales_ have slight projections near _the -base_ on which 1–2–several _erect ovules_ are developed (Fig. 274). -Most frequently 2 cotyledons.--_Evergreen_ trees and shrubs. - - [Illustration: FIG. 270.--_Cupressus goveniana._] - - [Illustration: FIG. 271.--Portion of a branch of _Thuja - orientalis_ (magnified). The leaf at the base on the right has a - branch in its axil.] - - [Illustration: FIG. 272.--Seedling of _Thuja occidentalis_. The - branch (_g_) is borne in the axil of the leaf _s_.] - -_Juniperus_ (Juniper). _Diœcious._ The cone-scales become fleshy and -fuse together to form most frequently a 1–3 seeded “berry-cone.” -~_J. communis_ (Common Juniper) has acicular leaves, borne in whorls -of three, and the “berry-cone” is formed by a trimerous whorl -of cone-scales (Fig. 273). _J. sabina_ and _J. virginiana_ have -“berry-cones” formed from several dimerous whorls of cone-scales; the -leaves are connate and opposite, needle-and scale-like leaves are found -on the same plant.~ - -_Cupressus_ (Cypress). _Monœcious._ The cones are spherical; the -cone-scales shield-like, generally five-cornered and woody (Fig. 270), -each having many seeds. The leaves are scale-like.--_Thuja. Monœcious._ -Cones oblong. The cone-scales are dry, as in the Cypress, but leathery -and imbricate, and not shield-like; each cone-scale bears 2–3 seeds. -The leaves are most frequently dimorphic; those leaves which are -situated on the edges of the flat branches are compressed, and only -these bear buds, which are developed with great regularity, generally -alternately, on both sides of the branch; those which are situated -on the flattened surfaces are pressed flat and broad, and never bear -branches (Fig. 271). Along the central line of each leaf there is a -resin-canal (Fig. 271).--~_Chamæcyparis_, _Callitris_, _Libocedrus_, -_Thujopsis_ (1 species: _T. dolabrata_; in Japan).~ - - [Illustration: FIG. 273.--Branch of Juniper with “berry-cones.”] - - [Illustration: FIG. 274.--_Cupressus lawsoniana._ Longitudinal - section through female cone. Two ovules (_ov_) are bisected; _f_ - ovuliferous scales.] - - OFFICINAL. _Juniperus sabina_ from Central and South of Europe - (the young branches yield an essential oil). The wood of _J. - communis_ is used in the production of an essential oil, and - _J. oxycedrus_ in the production of empyreumatic oil. The - “berry-cone” of _J. communis_ is officinal, and is also used - for gin.--The wood of _J. virginiana_ (N. Am.) is known as red - cedar, and is used for lead-pencils. Sandarack resin is obtained - from _Callitris quadrivalvis_ (N.W. Africa). - - THE FOLLOWING ARE CULTIVATED IN GARDENS:--_Thuja occidentalis_ - (Arbor vitæ) (N. Am.), and _orientalis_ (China, Japan); - _Juniperus sabina_ and _virginiana_; _Thujopsis dolabrata_ - (Japan); _Cupressus lawsoniana_ (California), _C. sempervirens_ - (S. Eur., W. Asia), and other species, are grown especially - in conservatories, and in Southern Europe particularly in - cemeteries.--The _Retinospora_ species which are so often - planted, do not belong to an independent genus, but are obtained - from cuttings, taken from seedling-plants with acicular leaves - (see page 267). - - - Class III. =Gneteæ.= - -This class, independent of extinct forms, comprises the most highly -developed of the Gymnosperms, partly from the circumstance that a -perianth of 2–4 members encloses the _terminally placed ovule_, which -is provided with one, or (in _Gnetum_) two, integuments, and partly -owing to the fact that the wood has true vessels. There is only one -order. - - [Illustration: FIG. 275.--_Welwitschia mirabilis_ (considerably - reduced). The horizontal lines indicate the surface of the soil.] - - Order. =Gnetaceæ.= The three known genera differ very much in - appearance. _Welwitschia mirabilis_ (from the deserts of South - Western Africa) is the oldest (?) genus now living. It resembles - a giant radish, in that the hypocotyl is the only part of the - main axis of the stem which becomes developed. It attains a - circumference of upwards of four metres with a length of 1/2½-⅔ - of a metre. It bears _only_ two oblong, leathery leaves (Fig. - 275) which are torn into segments at the apex and lie on the - surface of the soil; these are the two first foliage-leaves - which succeed the cotyledons, and they are remarkable for - their enormous length (upwards of two metres) as well as for - their long duration, living as long as the plant itself. In - their axils are situated the 4-rowed, spike-like male and - scarlet-coloured female cones, upon dichotomous branches. The - perianth consists in the ♂ of 2 alternating pairs of leaves, - the inner ones of which are slightly united. The andrœcium - likewise consists of 2 whorls: the external (transverse) with - 2, the internal with 4 stamens; the lower halves of the 6 - filaments uniting to form a cup. Each of the terminal anthers - corresponds to a sorus of 3 sporangia, the sporangia being fused - together, and opening at the top by _one_ three-rayed cleft. - In the centre of the ♂-flower there is a sterile ovule. In the - ♀-flower a perianth of two connate leaves is present.--_Ephedra_ - (desert plants, especially in the Mediterranean and W. Asia) - at first sight resembles an _Equisetum_; the stems are thin, - long-jointed, and the leaves opposite, small, and united into - a bidentate sheath; ♂-perianth of two connate leaves (median - leaves); 2–8 stamens united into a column. Each anther is formed - of 2 sporangia (is bilocular). ♀ mainly, as in _Welwitschia_. - The seeds are surrounded by the perianth which finally becomes - red and fleshy. There are 30 species.--_Gnetum_ has opposite, - lanceolate, pinnately-veined, leathery leaves. They are mostly - climbers (Lianas) from Tropical Asia and America. The ♂-flowers - have a tubular perianth, (formed from two median leaves) which - surrounds a centrally-placed filament, bearing 2 anthers. In - the ♀-flower there is a similar perianth, surrounding an ovule - provided with 2 integuments. The perianth becomes fleshy and - envelops the hard seed. 20 species. - - From the circumstance of _Welwitschia_ having ♂ flowers - which, besides stamens, possess also a rudiment of an ovule, - Celakovsky draws the inference that the earliest Gymnosperms - had hermaphrodite flowers which from this structure became - differentiated entirely into ♂-and ♀-flowers, with the exception - of _Welwitschia_ only, in which this differentiation was only - carried out in the ♀-flower. This theory has so far been - scarcely proved. - - - =Fossil Gymnosperms.= - - The earliest continental plants which are known belong to the - CORDAITACEÆ, a group of plants which existed as early as the - Silurian period; they were Gymnosperms, but it has not yet been - determined whether they were Cycads or Conifers. The CYCADS, - even in the Coal period, were scarce; they attained their - fullest development in Jurassic and Cretaceous periods, during - which they were rich in species and genera, and extended as far - as the Polar regions. In addition to these, Taxaceæ, Abietaceæ, - and Taxodiaceæ appeared in the Carboniferous period. The TAXACEÆ - appear to have attained their culmination in the Jurassic and - Cretaceous periods; _Ginkgo_ appears in the Rhætic; _Torreya_, - in the Cretaceous; _Taxus_ and _Podocarpus_ in the Tertiary - periods. The ABIETACEÆ also appear in the Carboniferous; - _Pinus_ was first known with certainty in the English Weald - and in the Cretaceous; almost all other contemporary genera - are represented in this latter period. The ARAUCARIACEÆ first - appear, with certainty, in the Jurassic. The TAXODIACEÆ may - be traced back as far as the Carboniferous (?); _Sequoia_ is - first found in the lowest Cretaceous, at that period it spread - throughout the entire Arctic zone, and being represented by a - large number of species, formed an essential part of the forest - vegetation. _Sequoia_ played a similar part in the Tertiary - period. The CUPRESSACEÆ are first known with certainty in the - Jurassic, but they appeared more frequently and numerously in - the Tertiary period, in which most of the present living genera - were to be found. The GNETACEÆ, according to a theory advanced - by Renault were represented in the Coal period by the genus - _Stephanospermum_, which had four ovules enclosed by an envelope. - - - - - DIVISION V. - - ANGIOSPERMÆ. - - -See pages 3 and 224. To this Division belong the majority of the -Flowering-plants. They are divided into two parallel classes, the -Monocotyledons and the Dicotyledons, which differ from each other not -only in the number of cotyledons, which, with a few exceptions, is one -in the former, two in the latter, but also in the internal structure -of the stem, the venation of the leaves, the number of the parts of -the flower, etc. ~Assuming that these two classes have sprang from a -common origin, it is amongst the Helobieæ in the first, and amongst the -Polycarpicæ in the second class that we might expect to find closely -allied forms, which might reasonably be supposed to have varied less -from this original type. As for the rest, they seem to stand quite -parallel, without exhibiting any close relationship. It is scarcely -proved that the Monocotyledons are the older class.~ - -[Our knowledge of the forms included under the Angiosperms has -recently been considerably increased by Treub (_Ann. d. Jar. Bot. d. -Buitenzorg_, 1891), who has shown that the Casuarinas differ in many -important points from the typical Angiosperms. Among other characters -the pollen-tube is found to enter the ovule near the chalaza and -therefore at the opposite end to the micropyle, and Treub therefore -suggests that these plants should be placed in a subdivision termed -Chalazogams. - -According to this view the principal divisions of the Angiosperms would -be represented thus:-- - - =Angiospermæ.= - - Sub-division. Sub-division. - CHALAZOGAMES. POROGAMES. - - Class. Classes. - Chalazogames. Monocotyledones, Dicotyledones. - -More recently Nawaschin (_Bull. Acad. Imp. Sci. St. Petersb._, ser. -iii., xxxv.) has shown that _Betula_, and Miss Benson (_Trans. Linn. -Soc._, 1894) that _Alnus_, _Corylus_, and _Carpinus_ also belong to the -Chalazogams. - -Our knowledge, however, is still so incomplete that one would hesitate -to accord the full systematic value which Dr. Treub attaches to his -discovery until the limits of the Chalazogamic group are better -defined; and it would hardly be justifiable to include the Casuarinas -and the above-noted genera in one family.] - - - Class 1. =Monocotyledones.= - -_The embryo has only one cotyledon; the leaves are as a rule scattered, -with parallel venation; the vascular bundles of the stem are closed, -there is no increase of thickness. The flower is typically constructed -of five 3-merous whorls, placed alternately._ - -THE EMBRYO is generally small in proportion to the abundant endosperm -(exceptions, see _Helobieæ_), and its single cotyledon is often -sheath-like, and very large. On the germination of the seed either the -entire cotyledon, or its apex only, most generally remains in the seed -and absorbs the nutritive-tissue, while the lower portion elongates -and pushes out the plumule and radicle, which then proceed with their -further growth. The primary root in most cases soon ceases to grow, -but at the same time, however, numerous lateral roots break out from -the stem, and become as vigorous as the primary root, or even more so. -Increase in thickness does not take place in these roots; they branch -very little or not at all, and generally die after a longer or shorter -time. - -THE STEM is frequently a corm, bulb, or other variety of underground -stem, as the majority of the Monocotyledons are perennial, herbaceous -plants; it has scattered, closed vascular bundles (Fig. 276), and no -cambium by which a continuous thickening may take place. The stem of -the Palms, however, attains a very considerable thickness, which is due -to the meristem of its growing-point continually increasing in diameter -for a lengthened period (often for many years), until it has reached a -certain size. In this condition the growing-point has the form of an -inverted cone, and it is only when this cone has attained its requisite -size that the formation of a vertical cylindrical stem commences. -Certain tree-like Liliaceæ, as _Dracæna_, _Aloe_, etc., have a -continuous increase in thickness; this is due to a meristematic layer, -which arises in the cortex, outside the original vascular bundles, -which were formed at the growing-point of the stem. This meristem -continues to form thick-walled parenchyma and new, scattered vascular -bundles. The primary vascular bundles, in the Palms and others, run -in a curved line from their entrance into the stem at the base of -the leaf, towards the centre of the stem, and then bend outwards and -proceed downwards in a direction more parallel to the sides of the stem -(Fig. 277). The bundles formed later, in those stems which increase in -thickness, are not continued into the leaves. - -THE BRANCHING as a rule is very slight, the axillary buds of the -majority of the leaves never attaining development, _e.g._ in the -Palms, bulbous plants and others. As the cotyledon arises singly, -the succeeding leaves also must be scattered, but they are frequently -arranged in two rows (Grasses, Iris, etc). _The first leaf borne on a -branch_ (the “Fore-leaf,”[24]--the bracteole, if on a floral shoot) -has generally, in the Monocotyledons, a characteristic form and -position, being situated on the posterior side of its own shoot, and -hence turned towards the main axis; it is sometimes provided with two -laterally-placed keels (Figs. 279 _f_, 290 _øi_), but the midrib is -often absent. It arises in some cases from two primordia, which at the -beginning are quite distinct, and thus has been regarded as formed by -two leaves. It is, however, only one leaf, a fact which is evident from -several circumstances, one being that it never supports more than one -shoot, and this stands in the median plane (Fig. 279). - - [Illustration: FIG. 276.--Transverse section of the stem of a - Palm: _v v_ is the wood portion, _b b_ the bast portion of - the vascular bundled.] - - [Illustration: FIG. 277.--Diagrammatic representation of the - course of the vascular bundles, from the stem into the leaves in - a Monocotyledon.] - -THE LEAVES are _amplexicaul_, and have a large sheath but no stipules; -the blade is most frequently long, ligulate, or linear, entire, with -parallel venation, the veins being straight or curved (Figs. 300, 309). -Connecting the large number of veins which run longitudinally, there -are as a rule only weak transverse ones. It is very rarely that other -forms of leaves are found, such as cordate (Figs. 302, 312), or that -the blade is branched, or the venation is, for example, pinnate or -palmate (Figs. 225, 298); these deviations are especially found in the -Araceæ, the Palms, the Scitamineæ (Fig. 308), the Dioscoreaceæ, and in -several aquatic plants. The incisions in the Palm-leaf are derived by -the splitting of an originally entire leaf. - -THE STRUCTURE OF THE FLOWER is generally as follows: Pr3 + 3, A3 + 3, -G3, rarely S3 + P3 with the other members unchanged.[25] Instead of 3, -the numbers 2 and 4 may occur; rarely others. In all these instances -there are 5 whorls, which regularly alternate with one another, most -frequently in the 3-merous flower, as in the diagram (Fig. 278). This -diagram is found in the following orders: Liliaceæ, Convallariaceæ, -Juncaceæ, Bromeliaceæ, Amaryllidaceæ, Dioscoreaceæ, Palmæ, some -Araceæ, and in some small orders, and may be considered as the typical -structure and also the starting point for the exceptional orders. The -ovary in many Monocotyledons has many ovules, and the fruit becomes -a many-seeded berry or capsule; this form is no doubt the oldest. In -others the number of seeds becomes reduced to 1, and the fruit then -becomes a cypsela, or a drupe (_e.g. Gramineæ_, _Cyperaceæ_, _Palmæ_, -etc). - - [Illustration: FIG. 278.--Diagram of the ordinary, regular flower - in the Monocotyledons: _s_ is the bract.] - - [Illustration: FIG. 279.--Diagram of _Iris_: _f_ the bracteole; - in its axil is a shoot with its bracteole.] - - [Illustration: FIG. 280.--Diagram of _Orchis_: _l_ the lip; σ σ - the two staminodes.] - -Deviations from this typical floral structure in some instances may -be traced to _suppression_, very rarely to a _splitting_ of certain -members, the typical relative positions not being changed. Thus, -the Iridaceæ, the Cyperaceæ, most of the Gramineæ and some Juncaceæ -deviate in having only 3 stamens (Fig. 279), the inner whorl (indicated -by *) not becoming developed. The Musaceæ differ in the posterior -stamen not being developed; _Zingiberaceæ_ (Fig. 314), _Marantaceæ_, -and _Cannaceæ_, in the fact that only 1 of all the stamens bears an -anther, and the others are either suppressed or developed into petaloid -staminodes, with some perhaps cleft in addition. The Orchideæ deviate -in having, generally, only the anterior stamen of all the 6 developed -(Fig. 280). In this, as in other instances, the suppression of certain -parts of the flower is often connected with _zygomorphy_ (_i.e._ -symmetry in _one_ plane), chiefly in the inner perianth-whorl, but also -in the other whorls. In the Orchids, the perianth-leaf (the labellum, -Fig. 280 _l_) which is directly opposite the fertile stamen, is larger -and altogether different from the others. The perianth-leaves may also -be suppressed; see, for example, the two diagrams of the Cyperaceæ -(Fig. 284). In some orders the suppression of these leaves, which form -the basis of the diagram, is so complete that it is hard to reduce the -actual structure of the flower to the theoretical type, _e.g._ the -Grasses (Fig. 290) and _Lemna_ (Fig. 303). In the first family, which -especially comprises water-plants, a somewhat different structure is -found; thus Fig. 282 differs somewhat from the ordinary type, and other -flowers much more so; but the floral diagrams which occur in this -family may perhaps be considered as the most probable representatives -of an older type, from which the ordinary pentacyclic forms have taken -their origin. In favour of this theory we have the larger number of -whorls, the spiral arrangement of some of these in the flower, with -a large and indefinite number of stamens and carpels, the perfectly -apocarpous gynœceum which sometimes occurs, etc., etc. - - The Monocotyledons are divided into 7 Families:-- - - 1. HELOBIEÆ. This family forms a group complete in itself. It - commences with hypogynous, perfect flowers, whose gynœcium is - apocarpous and terminates in epigynous and more or less reduced - forms. - - 2. GLUMIFLORÆ. These have as a starting point the same diagram - as the following families, but otherwise develope independently. - - 3. SPADICIFLORÆ. Also an independent branch, or perhaps two - different ones which terminate in much reduced forms. - - 4. ENANTIOBLASTÆ. These ought perhaps to be amalgamated with the - following family. - - 5. LILIIFLORÆ. These advance from forms with the typical diagram - and hypogynous flower, to epigynous and reduced forms. - - 6. SCITAMINEÆ and - - 7. GYNANDRÆ. Two isolated families, which probably have taken - their origin from Liliifloræ, and have epigynous, mostly - zygomorphic, and much reduced forms. - - - Family 1. =Helobieæ.= - -To this family belong _only water- or marsh-plants_; _the endosperm is -wanting_, and they possess an embryo with a very _large hypocotyl_ -prolonged downwards and often club-like. The perianth is often -differentiated into calyx and corolla; the flower is regular, and in -the first orders to be considered, may be reduced to the ordinary -Monocotyledonous type; there are, however, _usually found two_ -3-_merous whorls of carpels_ (Fig. 282), and thus in all 6 whorls, or -again, the _number of carpels may be indefinite_; the number of stamens -also may be increased, either by the division of the members of a -whorl, or by the development of additional whorls. _Syncarps_,[26] with -nut or follicular fruitlets, are _very common_, for example, in the -first orders; in the last (Hydrocharitaceæ) the carpels are not only -united, but the ovary is even inferior. - - The primitive type appears to be a hypogynous flower, similar - to that of the Juncaginaceæ or Alismaceæ, with several 3-merous - whorls, and free carpels, each with many ovules; the green - perianth in this instance being no doubt older than the coloured - ones. If we take a flower with this structure as the starting - point, then the family developes partly into epigynous forms, - partly into others which are so strongly reduced and exceptional - that it is scarcely possible to refer them to the ordinary - type. The family, through the peculiar _Zostereæ_, appears to - approach the Araceæ, in which _Potamogetonaceæ_ and _Najadaceæ_ - are included by some authorities. However, the inclusion of - _Potamogeton_, and with it _Ruppia_ and _Zannichellia_, in the - Juncaginaceæ appears quite correct. It would scarcely be right - to separate _Zostereæ_ from these. Great stress has often been - laid upon the similarity with the Ranunculaceæ which is found - in the Alismaceæ, but it is scarcely more than an analogous - resemblance. - -Order 1. =Juncaginaceæ.= The ☿, regular, _hypogynous_ flowers have -the _perianth_ 3 + 3, _sepaloid_, stamens 3 + 3 (with extrorse -anthers), and carpels 3 + 3 (free or united), of which last, however, -one whorl may be suppressed (in _Triglochin maritima_ all 6 carpels -are developed, in _T. palustris_ the inner whorl is unfertile). -Inflorescence long spikes. Embryo _straight_.--Marsh-plants with -radical, rush-like leaves, arranged in two rows, and often sheathing -and ligulate (“squamulæ intravaginales”); the inflorescence is a spike -or raceme.--_Scheuchzeria._ Carpels almost free; in each at least two -ovules. Follicles.--_Triglochin_ has long, fine racemes without bracts -or bracteoles; one ovule in each carpel. The carpels in the two native -species are united, but separate when ripe as a schizocarp, loosening -from below; they open along the ventral suture or remain closed; a -linear central column remains. ~The most reduced is Lilæa (1–2 sp. -Am.)--Protogynous. About 10 species. Temp. Fossils in Tertiary.~ - -Order 2. =Potamogetonaceæ.= The aquatic plants belonging to this order -are perennial, living entirely submerged, or with floating leaves, and -preferring still water. The leaves are alternate, in some linear and -grass-like, in others there is an elliptical floating blade, supported -by a linear submerged petiole. Axillary scales. The fruit is generally -a syncarp with _nuts_ or _drupes_; the _embryo is curved_, of very -various forms. - -_Potamogeton_ (Pond-weed). The rhizome is creeping, sympodial (with two -internodes in each shoot-generation); the inflorescence is a terminal, -many-flowered spike, without floral-leaves; below it are found 2 -foliage-leaves placed nearly at the same height, from whose axils -the branching is continued cymosely. The flowers are ☿, 4-_merous_, -naked, and consist only of 4 _stamens_, with the _connectives, broadly -developed_ at the back of the anthers, _resembling a perianth_, -and of 4 _free, sessile carpels_. They are common plants in fresh -water. ~The spike, during the flowering, is raised above the water. -Wind-pollinated and protogynous.--Closely allied is _Ruppia_ (Tassel -Pond-weed), in salt or brackish water. The spike has only two naked -flowers, each consisting of 2 stamens and 4 carpels. The stalks of the -individual carpels are considerably prolonged.--_Zannichellia_ (Horned -Pond-weed) is monœcious; the ♀-flower consists of 4 (2–9) carpels, with -membranous, bell-shaped perianth; long styles; the ♂-flower has 1 (-2) -stamens. _Althenia._~ - -_Zostera_ (Grass-wrack) is an entirely submerged, marine plant -with creeping rhizome (with displacement of buds) and strap-shaped -leaves. The flowering shoots are sympodia with displacement of the -axes (Fig. 281). The inflorescence is a peculiar, flatly-compressed -spike, on _one_ side of which the flowers are borne (Fig. 281). ~This -inflorescence may be considered, no doubt correctly, to be derived -from the symmetrical spike of _Potamogeton_ by strongly dorsiventral -development, and by a strong suppression of the floral parts taking -place simultaneously. Two rows of flowers are developed, but of these -one is so pressed into the other that apparently only one is present.~ -Each flower consists of only 1 stamen and 1 carpel situated at the same -height (Fig. 281); the unilocular ovary encloses 1 pendulous ovule -and bears a bifid style. As regards the perianth (?) one leaf may be -present (_Z. nana_, Fig. 281 _D_). The pollen-grains are filamentous. -Pollination takes place under water. ~_Posidonia_ and _Cymodocea_ are -allied to these. About 70 species.~ - - [Illustration: FIG. 281.--_Zostera._ A Diagram of the - branching of the floral shoots: _I_, _II_ ... are the successive - shoot-generations, every other one being shaded; _g_{1}_ - _g_{2}_ ... fore-leaves; _sp_{1} sp_{2}_ ... spathes for the - successive spikes. Each shoot is united for some distance with - the parent axis (indicated by the half-shaded internodes). Each - shoot commences with a fore-leaf turning towards the parent - axis, _g_; succeeding this is the spathe, _sp_; and then the - inflorescence. The fore-leaf supports a new lateral shoot. - _B_ Diagram of a shoot, _II_, which is borne laterally in the - axil of the fore-leaf _g_{1}_, on the shoot _I_, _g_{2}_ its - fore-leaf; _sp_{2}_ its spathe; _sti_ squamulæ intravaginales. - _II_ Is the spadix with stamens and carpels; _b_ a perianth-leaf - (or connective expansion, similar to those which occur in - _Potamogeton_). _C_ The upper portion of a young spadix with - development of flowers. _D_ Part of a spadix with 2 flowers; the - parts which theoretically belong to one another are connected by - a dotted line.] - -Order 3. =Aponogetonaceæ.= Aquatic plants with tuberous stem. They -have a single, petaloid perianth (3–2–1–leaved), most frequently 6 -stamens and 3(-6) carpels. Straight embryo.--About 15 species (Africa, -Madagascar, Tropical Asia and Australia).--_Aponogeton distachyos_ and -_A._ (_Ouvirandra_) _fenestralis_ are grown in conservatories; the -latter has lattice-like, perforated leaves. - -Order 4. =Najadaceæ.= Only one genus _Najas_ (about 10 species); -annual fresh water plants with leaves in pairs and solitary, unisexual -flowers. The ♂ flower is remarkable in having a terminal stamen, which -has either 4 longitudinal loculi or 1 central one; on this account the -stamen of _Najas_ is considered by some authorities to be a stem and -not a leaf-structure. The unilocular gynœceum and the single, erect, -anatropous ovule are also terminal. Pollination takes place under the -water. - -Order 5. =Alismaceæ.= The regular, _hypogynous_ flowers are in some -species unisexual by the suppression of either andrœcium or gynœceum; -they have a 6-merous perianth, _generally_ differentiated into 3 -sepals and 3 petals; generally 6 _stamens in the outer whorl_ (by the -division of the 3; Fig. 282) and often several 3-merous whorls inside -these, and 6–∞ _free_ carpels arranged cyclically or spirally. Fruit a -syncarp.--Marsh- or water-plants with radical leaves and long-stalked -inflorescences. - -=A.= _Butomeæ. Follicles with many seeds, which are borne on -nearly the whole of the inner surface of the cyclic carpels_ (as in -Nymphæaceæ). Embryo _straight_.--_Butomus_ (Flowering Rush, Fig. -282), has an umbel (generally composed of 3 helicoid cymes). _S_ -3, _P_ 3, stamens 9 (6 + 3, _i.e._ the outer whorl doubled), _G_ 3 -+ 3. ~_B. umbellatus_; creeping rhizome with triangular Iris-like -leaves.--_Hydrocleis. Limnocharis._~ - - [Illustration: FIG. 282.--Diagram of _Butomus_: _f_ bracteole.] - -=B.= _Alismeæ._ Fruit achenes. Latex common (in the intercellular -spaces). The flowers are arranged most frequently in single or -compound whorls. Embryo _curved_, horse-shoe shaped.--_Alisma_ has -_S_ 3, _P_ 3, _A_ 6 (in 1 whorl, grouped in pairs, _i.e._ doubled in -front of the sepals), and 1 _whorl_ of 1-seeded achenes on a flat -receptacle. The leaves are most frequently radicle, long-stalked; -the lamina have curved longitudinal veins, and a richly branched -venation. _A. plantago._--_Elisma_ (_E. natans_) has epitropous -(turned inwards) ovules, whilst the ovules of _Alisma_, _Sagittaria_ -and others are apotropous (turned outwards).--_Echinodorus_ (_E. -ranunculoides_) has a convex receptacle, carpels many, united and -capitate. _Damasonium_.--_Sagittaria_ (Arrow-head) has _monœcious_ -flowers, several whorls of stamens and _spirally-arranged achenes_ on -a very convex receptacle. ~_S. sagittifolia_ reproduces by tuberous -buds formed at the end of long, submerged branches. The leaves, in deep -and rapidly running water, are long and strap-shaped, but in the air -arrow-shaped.~ - - Honey is secreted in the flower and pollination effected - by insects. _Alisma plantago_ has 12 nectaries. The - submerged flowers of _Elisma natans_ remain closed and are - self-pollinated. _Butomus_ has protandrous flowers. There are - about 50 species, which mostly grow outside the Tropics.--Uses - insignificant. The rhizome of some is farinaceous. - -Order 6. =Hydrocharitaceæ.= This order differs chiefly from the -preceding in its _epigynous_ flowers. These are in general unisexual -(_diœcious_), and surrounded by a 2-leaved or bipartite _spathe_; they -are 3-merous in all whorls, but the number of whorls is generally -greater than 5, sometimes even indefinite. The perianth is divided -into _calyx_ and _corolla_. The ovary is _unilocular_ with parietal -placentation, or more or less incompletely plurilocular. The fruit -is berry-like, but usually ruptures irregularly when ripe. Embryo -straight.--Most often submerged water-plants, leaves seldom floating on -the surface. Axillary scales (_squamulæ intravaginales_). - -_Hydrocharis._ Floating water-plants with round cordate leaves; S3, P3 -(folded in the bud); ♂-flowers: 3 (-more) flowers inside each spathe; -stamens 9–15, the most internal sterile. ♀-flowers solitary; three -staminodes; ovary 6-locular, with many ovules attached to the septa; -styles 6, short, bifid. [The petals of the ♀-flowers bear nectaries at -the base. In this and the following genus the pollination is without -doubt effected by insects.] ~_H. morsus ranæ_ (Frog-bit) has runners; -it hibernates by means of special winter-buds.~--_Stratiotes_; floating -plants with a rosette of linear, thick, stiff leaves with spiny margin, -springing from a short stem, from which numerous roots descend into -the mud. Inflorescence, perianth, and ovary nearly the same as in -_Hydrocharis_, but the ♂-flower has 12 stamens in 3 whorls, of which -the outer 6 are in 1 whorl (dédoublement), and inside the perianth in -both flowers there are numerous (15–30) nectaries (staminodes?). _S. -aloides_ (Water-soldier); in N. Eur. only ♀-plants.--~_Vallisneria -spiralis_ is a tropical or sub-tropical plant, growing gregariously -on the mud in fresh water. The leaves are grass-like, and the plants -diœcious; the ♂-flowers are detached from the plant, and rise to -the surface of the water, where they pollinate the ♀-flowers. These -are borne on long, spirally-twisted peduncles which contract after -pollination, so that the ♀-flower is again drawn under the water, -and the fruits ripen deeply submerged.--_Elodea canadensis_ is also -an entirely submerged plant. The leaves are arranged in whorls on a -well-developed stem. Only ♀-plants in Europe (introduced about 1836 -from N. Am). This plant spreads with great rapidity throughout the -country, the reproduction being entirely vegetative. _Hydrilla_, -_Halophila_, _Thalassia_, _Enhalus_.--In many of these genera the -number of whorls in the flower is remarkably reduced; for example, in -_Vallisneria_, in the ♂-flowers to 2: Pr 3, A (1-) 3, in the ♀ to 3: Pr -3, Staminodes 3, G 3.--About 40 species; Temp. and Trop.~ - - - Family 2. =Glumifloræ.= - -The _hypogynous_ flowers in the Juncaceæ are completely developed on -the _pentacyclic, trimerous_ type, with _dry, scarious perianth_. -Even in these the interior whorl of stamens becomes suppressed, and -the ovary, which in _Juncus_ is trilocular with many ovules, becomes -in _Luzula_ almost unilocular, but still with 3 ovules. The perianth -in the Cyperaceæ and Gramineæ is reduced from hairs, in the first of -these, to nothing, the flowers at the same time collecting more closely -on the inflorescence (spike) supported by _dry_ bracts (_chaff_); the -number of stamens is almost constantly 3; stigmas linear; the ovary -has only 1 loculus with 1 ovule, and the fruit, which is a capsule in -the Juncaceæ, becomes a nut or caryopsis.--The endosperm is large and -floury, the embryo being placed at its lower extremity (Figs. 286 _B_, -291).--The plants belonging to this order, with the exception of a few -tropical species, are annual or perennial herbs. The stems above ground -are thin, and for the most part have long internodes, with linear, -parallel-veined leaves which have long _sheaths_, and often a _ligule_, -_i.e._ a membranous projection, arising transversely from the leaf at -the junction of the sheath and blade. The underground stems are short -or creeping rhizomes. The flowers are small and insignificant. Wind- or -self-pollination. - -Order 1. =Juncaceæ= (=Rushes=). The regular, hermaphrodite, hypogynous -flowers have 3 + 3 brown, dry, free perianth-leaves projecting like -a star during the opening of the flower; stamens 3 + 3 (seldom 3 + -0) and 3 carpels united into one gynœceum (Fig. 283); the ovary is -3- or 1-locular; there is as a rule 1 style, which becomes divided -at the summit into 3 stigmas, often bearing branches twisted to the -right (Fig. 283). _Fruit a capsule_ with loculicidal dehiscence. The -embryo is an extremely small, ellipsoidal, cellular mass, without -differentiation into the external organs. - - [Illustration: FIG. 283.--Flower of _Luzula_.] - -_Juncus_ (Rush) has glabrous foliage-leaves, generally cylindrical, -rarely flat; the edges of the leaf-sheath are free (“_open_” -leaf-sheaths) and cover one another. The capsule, 1- or 3-locular, with -_many_ seeds--_Luzula_ (Wood-Rush) has flat, grass-like leaves with -ciliated edges; the edges of the leaf-sheath are united (“_closed_” -leaf-sheath). The capsule unilocular and _3-seeded_.--_Prionium_: S. -Africa; resembling a _Tacona_. - - The _interior_ whorl of stamens, in some species, disappears - partially or entirely (_J. supinus_, _capitatus_, - _conglomerates_, etc.) - - Some of the numerous _Juncus_-species (_e.g. J. effusus_, - _glaucus_, _conglomeratus_, etc.), have false, lateral - inflorescences, the axis of the inflorescence being pushed - to one side by its subtending leaf, which apparently forms - a direct continuation of the stem, and resembles it both - in external and internal structure. The foliage-leaves of - this genus were formerly described as “unfertile stems,” - because they are cylindrical, erect, and resemble stems, and - consequently the stem was said to be “leafless”: _J. effusus_, - _glaucus_, _conglomeratus_. Stellate parenchynatous cells are - found in the pith of these stems and in the leaves. Other - species have distinct terminal inflorescences and grooved - leaves; _J. bufonius_ (Toad-rush), _compressus_, and others. - The _inflorescences_ most often present the peculiarity of - having the lateral axes protruding above the main axis. - Their composition is as follows:--The flowers have either no - bracteoles, and the inflorescences are then capitulate; or - they have 1–several bracteoles. Each branch has then, first, - a 2-keeled fore-leaf placed posteriorly (“basal-leaf”), and - succeeding this are generally several leaves borne alternately - and in the same plane as the basal-leaf, the two uppermost - (the “spathe-leaves”) being always barren; those which lie - between the basal-leaves and the spathe-leaves are termed - “intermediate-leaves.” If only branches occur in the axils - of the basal-leaves, then the succeeding branches are always - borne on the posterior side of the axis, and form a fan[27]; - if the basal-leaf is barren, and if there is only one fertile - intermediate-leaf, then the lateral axes are always on the upper - side, and a sickle[27]-like inflorescence occurs; if there are 2 - fertile intermediate-leaves, then a dichasium is formed, and in - the case of there being several, then a raceme, or spike. - - _Juncaceæ_ are, by several authors, classed among the - Liliifloræ, but there are so many morphological and partly - anatomical features agreeing with the two following orders, that - they may, no doubt, most properly be regarded as the starting - point of these, especially of the _Cyperaceæ_, which they - resemble in the type of flowers, the inflorescence, the type of - mechanical system, and the stomata. - - POLLINATION by means of the wind. Cross-pollination is - often established by protogyny. _J. bufonius_ has partly - triandrous and cleistogamic, partly hexandrous, open - flowers.--DISTRIBUTION. The 200 species are spread over the - entire globe, but especially in cold and temperate countries; - they are seldom found in the Tropics.--USES. Very slight; - plaiting, for instance. - -Order 2. =Cyperaceæ.= The majority are _perennial_ (seldom annual) -_herbs_ living in damp situations, with a sympodial rhizome and -grass-like appearance. The stems are seldom hollow, or have swollen -nodes, but generally _triangular_, with the upper internode just below -the inflorescence generally very long. The leaves are often arranged -in 3 _rows_, the leaf-sheath is _closed_ (very seldom split), and the -ligule is absent or insignificant. The flowers are arranged in _spikes_ -(_spikelets_) which may be united into other forms of inflorescences -(chiefly spikes or racemes). The flowers are supported by a bract, -but have _no bracteoles_. In some genera the perianth is distinctly -represented by six bristles corresponding to six leaves (Figs. 284 -_A_, 286 _A_); in others it is represented by an indefinite number of -hairs (Fig. 284 _B_), and very frequently it is altogether wanting. -_The inner whorl of stamens is absent_, and the flower has therefore -3 stamens (rarely more or less than 3), the anthers _are attached by -their bases to the filament_ (innate) and are not bifid (Figs. 286). -Gynœceum simple, formed of 3 or 2 carpels; 1 style, which is divided -at the extremity, as in the Juncaceæ, into 3 or 2 arms; the single -loculus of the ovary contains one basal, erect, anatropous ovule; the -stigmas are not feather-like. _Fruit a nut_, whose seed is generally -not united with the pericarp. The embryo is small, and lies at the -_base of the seed in the central line_, surrounded on the inner side by -the endosperm (Fig. 286 _B_). On germination the cotyledon _does not -remain_ in the seed. - - [Illustration: FIG. 284.--Diagram of structure of: _A Scirpus - silvaticus_; _B Eriophorum angustifolium_.] - - A regular perianth, with 6 scale-like perianth-leaves in 2 - whorls, is found in _Oreobolus_. In _Scirpus littoralis_ the - perianth-leaves are spreading at the apex, and divided pinnately. - - The branching of the inflorescence is often the same as in the - Juncaceæ, and supports the theory that these two orders are - related. In _Rhynchospora_ and others, the “spikelets” are - really only “spike-like” and to some extent compound. - -=A.= SCIRPEÆ. HERMAPHRODITE FLOWERS. - -1. Spikelets cylindrical, the bracts arranged spirally (in many -rows). The lower ones are often barren, each of the others supports -a flower.--_Scirpus_ (Club-rush). The spikelets are many-flowered; -the perianth is bristle-like or absent, and does not continue to grow -during the ripening of the fruit (Fig. 286 _A_). Closely allied to this -is _Heleocharis_, with terminal spikes.--_Eriophorum_ (Cotton-grass) -differs chiefly in having the perianth-hairs prolonged, and forming a -bunch of white, woolly hairs (Fig. 284 _B_). - - _Cladium_ and _Rhynchospora_ (Beak-rush) differs especially in - the _few_-flowered, compound spikelets which are collected into - small bunches; the latter has received its name from the fact - that the lowermost portion of the style remains attached to the - fruit as a beak. - -2. Spikelets compressed, the bracts arranged only in _two rows_; the -other characters as in the first-mentioned. _Cyperus_ (spikelets -many-flowered); _Schœnus_ (Bog-rush); spikelets few-flowered; _S. -nigricans_ has an open sheath. - - [Illustration: FIG. 285.--_Carex_: _A_ diagram of a male flower; - _B_ of a female flower with 3 stigmas; _C_ of a female flower - with 2 stigmas; _D_ diagrammatic figure of a female flower; _E_ - similar one of the androgynous (false) spikelet of _Elyna_. The ♂ - is here represented placed laterally; it is terminal, according - to Pax.] - - [Illustration: FIG. 286.--_A_ Flower of _Scirpus lacustris_. _B_ - Seed of _Carex_ in longitudinal section.] - -=B.= CARICEÆ. UNISEXUAL FLOWERS. - -In the ♂-flowers there is no trace of a carpel, and in the ♀ no trace -of a stamen. Floral-leaves in many rows. In some (_Scleria_, certain -_Carex_-species), ♂-and ♀-flowers are borne in the same spikelet, the -latter at the base or the reverse; in the majority each spikelet is -unisexual. - -_Carex_ (Fig. 285) has _naked_, most frequently monœcious flowers. -The ♂-_spikes_, which are generally placed at the summit of the whole -compound inflorescence, are _not compound_; in the axil of each -floral-leaf (bract) _a flower is borne, consisting only_ of a short -axis with three stamens (Fig. 285 _A_). The ♀-_spikes are compound_; -in the axil of each floral-leaf is borne a very small branch (Fig. 285 -_D_, _a_) which _bears only one leaf_, namely, a _2-keeled fore-leaf_ -(_utriculus_, _utr._ in the figures) which is turned posteriorly (as -the fore-leaves of the other Monocotyledons), and being obliquely -sheath-like, envelopes the branch (in the same manner as the sheath -of the vegetative leaves), and forms a pitcher-like body. In the axil -of _this_ leaf the ♀-flower is situated as a branch of the 3rd order, -bearing only the 2–3 carpels, which are united into one gynœceum. -The style protrudes through the mouth of the utriculus. ~The axis -of the 2nd order (_a_ in Fig. 285 _D_) may sometimes elongate as a -bristle-like projection (normally in _Uncinia_, in which it ends as a -hook, hence the name); this projection is in most cases barren, but it -sometimes bears 1–several bracts which support male-flowers; this is -normal in _Elyna_ (or _Kobresia_) and _Schœnoxiphium_; the axis (_a_ in -285 _E_) bears at its base a female-flower supported by the utriculus, -and above it a male-flower supported by its bract.~ - - POLLINATION by means of the wind. Protogynous. Sometimes - self-pollinated. The order embraces nearly 3,000 species, found - all over the world. _Carex_ and _Scirpus_ are most numerous in - cold and temperate climates, and become less numerous towards - the equator. The reverse is the case with _Cyperus_ and other - tropical genera. They generally confine themselves to sour, - swampy districts; some, on the other hand, are characteristic - of sand-dunes, such as Sand-star (_Carex arenaria_). There are - about 70 native species of _Carex_. - - USES. In spite of their large number, the Cyperaceæ are of - no importance as fodder-grasses, as they are dry and contain - a large amount of silica; hence the edges of many of the - triangular stems or leaves are exceedingly sharp and cutting. - _Cyperus esculentus_ has tuberous rhizomes, which contain a - large amount of fatty oil and are edible (earth-almonds); it - has its home in the countries of the Mediterranean, where it is - cultivated. - - _Cyperus papyrus_ (W. Asia, Egypt, Sicily) attains a height of - several metres, and has stems of the thickness of an arm which - were used by the ancient Egyptians for making paper (papyrus). - Some serve for plaiting, mats, etc. (_Scirpus lacustris_, etc.). - _Isolepis_ is an ornamental plant. - - [Illustration: FIG. 287.--_Triticum_: _A_ axis (rachis) of ear - showing the notches where the spikelets were inserted; _B_ an - entire spikelet; _C_ a flower with the pales; _D_ a flower - without the pales, showing the lodicules at the base; _E_ glume; - _F_ outer pale; _G_ inner pale; _H_ fruit; _I_ longitudinal - section of fruit.] - -Order 3. =Gramineæ= (=Grasses=). The stems are cylindrical, generally -_hollow_ with _swollen nodes_, that is, a swelling is found at the base -of each leaf which apparently belongs to the stem, but in reality it -is the swollen base of the leaf. The leaves are _exactly alternate_; -the sheath is _split_ (excep. _Bromus_-species, _Poa pratensis_, _P. -trivialis_, _Melica_, _Dactylis_, etc., in which the sheath is not -split), and the edges overlap alternately, the right over the left, -and _vice versâ_; the _ligule_ is nearly always well developed. In -general, the flowers are hermaphrodite; they are borne in _spikelets_ -with _alternate floral-leaves_, and the spikelets themselves are -borne in either _spikes_ or _panicles_. The two (seldom more) _lowest -floral-leaves_ in each spikelet (Fig. 289 _øY_, _nY_) are _barren_ (as -the covering-leaves in many umbels and capitula); these are termed -the _glumes_. The succeeding floral-leaves, each of which supports -one flower as its bract, are called the _outer pales_ (_nI_); these -sometimes each bear an “awn” (a bristle-like body which projects in -the median line either from the apex or the back); sometimes the -upper ones are barren. Each flower has a _bracteole_, which is placed -on the inside opposite the main axis; it is thin, _binerved_ or -_two-keeled_, and never has an awn; it is known as the _inner pale_ -(_øI_). Immediately succeeding the bracteole are: (_a_) some _small, -delicate scales_ (_lodicules_, Figs. 287 _D_, 288 _C_, 290 _L_); (_b_) -_three stamens_ with anthers _versatile_, so as to be easily moved, -and usually notched at each end (Fig. 287 _C_); and (_c_) a simple -gynœceum formed of _one carpel_ with _two styles_ having generally -_spirally-branched stigmas_ (Figs. 287 _D_, 288 _C_). The ovary is -_unilocular_, and contains one ascending or pendulous, anatropous -ovule. _Fruit a nut_, whose seed is always _firmly united with the thin -pericarp_ (“caryopsis”). The embryo is larger than in the Cyperaceæ and -is placed at the base of the seed, but on the _outer convex surface_ -of the pericarp (Figs. 287 _I_, 288 288 _D_, 291), _outside the -endosperm_; plumule large with several leaf-primordia. On germination -the cotyledon remains in the seed. - -The majority of Grasses are annual or perennial herbs; tree-like forms -being only found in the Tropics, for example, the Bamboos; they branch -(in tufts), especially from the axils of the basal-leaves, while those -which are borne higher on the stem are separated by longer internodes -and have no vegetative branches in their axils, though a few forms, -like _Bambusa_ and _Calamagrostis lanceolata_, produce branches in -these axils. - - [Illustration: FIG. 288.--_Bromus mollis_: _A_ inflorescence; _B_ - the uppermost flower of a spikelet, with its axis turned forward; - in front is seen the two-keeled inner pale (bracteole) and the - stamens protrude between this and the outer pale (bract); _C_ an - ovary with the 2 stigmas on its anterior side, the 2 lodicules, - and the 3 stamens; _D_ the fruit seen from the dorsal side; _E_ - the same from the ventral side.] - - [Illustration: FIG. 289.--Diagrammatic outline of a spikelet: _n - Y_ lower glume; _ø Y_ upper glume; _n I_ upper pale; _ø I_ the - inner pale; _l_-_l_ lodicules; _st_ stamens; _I_-_I_ main axes; - _II_ lateral axes.] - - [Illustration: FIG. 290.--Diagram of the Grass-flower: _ni_ outer - pale; _øi_ inner pale; _l_-_l_ lodicules.] - - [Illustration: FIG. 291.--Longitudinal section of an Oat-grain: - _a_ the skin (pericarp and testa); _b_ the endosperm; _c_ the - cotyledon; _d_ the plumule.] - - Only a few Grasses have a _solid stem_, such as Maize, - Sugar-cane, and _Andropogon_. The _blade_ is flat in the - meadow-grasses, but the Grasses which live on dry places - (“prairie-grass”) exposed to the sun, often have the blade - tightly rolled up and almost filiform or bristle-like, with - anomalous anatomical structure. A _closed_ tubular _sheath_ is - found in _Melica uniflora_, _Bromus_-species, _Poa pratensis_ - and _trivialis_, _Briza_ and some _Glyceria_-species. The - sheath is developed for the purpose of supporting the young - internodes while their growth is proceeding at the base. The - “nodes” (the swollen joints which are seen on stems of Grasses) - are not really part of the stem but are formed by the base of - the leaf-sheath. They play a part in assisting the haulms - to regain a vertical position when laid prostrate by wind - or rain. The _awn_ on the pale is homologous with the blade - of the Grass-leaf, and the pale itself is the sheath. The - arrangement of the leaves in the _spikelet_ is similar to that - in _Cyperus_ and other Cyperaceæ, their floral-leaves being - borne in several rows in _Streptochæta_. More than two barren - “glumes” are found in _Streptochæta_, several Phalarideæ and - others. The spikelets, too, are again arranged in two rows in - the axils of suppressed floral-leaves. The inflorescence becomes - a “compound spike” (ear) when the spikelets are sessile. In the - majority of instances the spikelets are borne on long stalks; - when these branch, then the secondary branches, and similarly - all branches of higher order, are placed so far down upon the - mother-axis that they all appear to be of equal value and to - arise in a semicircle from the mother-axis itself, though in - reality they arise from each other (_Panicle_, Fig. 288 _A_). - Sometimes the main axis and branches of different orders unite - together as in _Alopecurus_, _Phleum_, and some other Grasses, - and hence the single (short-stalked) spikelets appear to arise - singly and spirally, or without any definite order, directly - from the main axis, with the production of a _cylindrical_ - inflorescence bearing “spikes” _on all sides_, that is, a - “_spike-like panicle_.”--Many inflorescences are somewhat - dorsiventral. The _flower_ is rarely unisexual (_Zea mais_) or - barren. Considerable difficulty is experienced in reducing the - Grass-flower to the ordinary 3-merous Monocotyledonous type. - Some authorities consider the _lodicules_, which are present - in all Grasses but absent in the Cyperaceæ, to be homologous - with a perianth. According to a more recent theory they are - bracteoles, and hence the Gramineæ, like many of the Juncaceæ, - have 2–3 bracteoles placed in two rows in the median plane. If - this theory be correct, the _flower is naked_. The lodicules - expand quickly and cause the opening of the flower (_i.e._ the - two pales become separated from each other). Generally only 3 - _stamens_ belonging to the outer whorl are present (Fig. 290), - as in _Iris_ (Fig. 279), certain Juncaceæ and Cyperaceæ (Fig. - 284), but in some, such as the Rice and certain species of - Bamboos, all 6 are found. _Pariana_ has more than 6. Only 1 of - the _carpels_ is present, namely, the anterior (of those in Fig. - 284), so that the ventral suture and the place of attachment - of the ovule are situated at the back of the ovary. The number - of styles does not correspond with the number of carpels, and - the styles may therefore be supposed to arise from the edges - of the leaf to the right and left--a position which is not - without analogy. In addition, a stylar projection is sometimes - found on the anterior side and in the median line (_e.g._ in - _Phragmites_), and the solitary style in _Nardus_ has exactly - this position; a similar arrangement is found in some species of - _Bambusa_ which have only one style; other species of _Bambusa_ - have three styles. A tripartite style is found in _Pharus_. - - [The Grass-flower may be reduced to the ordinary - Monocotyledonous type thus:--The outer pale is the bract of the - flower since it bears in its axil the floral shoot; the inner - pale occupies the customary position of the bracteole. The fact - that it is binerved can be explained by its having been pressed - against the main-axis during development. Similar binerved - bracteoles are found in _Iris_ (Fig. 279). These bracteoles in - both Grass and Iris arise from single primordia, and are not - produced by the coalescence of two leaves. The lodicules are the - only parts of the perianth remaining, the outer whorl having - been suppressed, and also the posterior leaf of the inner whorl; - a posterior lodicule, however, is found in the Rice and some - species of Bamboo. The outer whorl of stamens is usually absent, - though this again is present in the Rice and Bamboo. The three - carpels are reduced to one with two or sometimes three stigmas.] - - THE FLOWERING. In the panicles the flowers open in basipetal - order; the flowers in the spikes situated somewhat above the - middle, commence to open first, and the flowering proceeds - upwards and downwards. A few Grass-flowers never open - (cleistogamic); _Leersia oryzoides_, _Stipa_-species, and _e.g._ - Wheat and Rye in cold damp weather; some open their pales so - wide that the anthers and stigmas may protrude at the top; most - frequently the lodicules expand and force the pales suddenly - and widely apart. The filaments elongate considerably, so that - the anthers are pendulous and the stigmas unfold. In some - Grasses _e.g._ Wheat, the blooming of each flower only lasts - a short time. POLLINATION is generally effected by the wind. - The _Rye_ separates the pales very widely in the morning, and - allows the anthers and stigmas to appear; it is almost entirely - sterile when self-pollinated. The _Wheat_ flowers at any time - of the day, each flower lasting only a quarter of an hour. The - pales open suddenly, but only half way, and the anthers scatter - one-third of the pollen in their own flower and two-thirds - outside. Self-pollination is effectual, but crossing gives - better results. In _Hordeum vulgare_ (all flowers ☿) the flowers - of the 4 outer rows behave as in the Wheat, but those in the - two central rows always remain closed. The ☿-flowers in the - two central rows of _H. distichum_ remain closed and fertilise - themselves; they open exceptionally, and may be pollinated - by the ♂-flowers in the 4 lateral rows. _H. hexastichum_ is - cleistogamic. _Oats_ pollinate themselves. - - [Illustration: FIG. 292.--Barley grain: _A_ section through the - skin (_a-d_) and the most external part of the endosperm; _Gl_ - the “aleurone layer”; _st_ starch-containing cells; _B_ starch - grains.] - - [Illustration: FIG. 293.--Wheat-grain germinating: _g_ the - plumule; _b_ the first leaf succeeding the cotyledon; _r^1_ the - primary root; _r^2_ lateral root.] - - [Illustration: FIG. 294.--Older seedling of the Wheat: _s_ the - second sheathing-leaf; _l_ first foliage-leaf.] - - _The ripe Grass-fruit_, in some species of Bamboo, is a berry; - in some other Grasses a nut with _loosely_ lying seed, in some - even a capsule, but otherwise a “caryopsis.” In some instances - it is loosely enveloped by the pales (Oat), in others firmly - attached to these (Barley), and finally, in others, “naked,” - _i.e._ it is entirely free from the pales (Wheat and Rye). - On the ventral side there is a groove (Fig. 288 _E_); on the - anterior side (dorsal suture), which is turned towards the - inner pale, it is convex, and at the base on this side, inside - the testa, lies the embryo (Fig. 288 _D_). The apex of the - fruit is often hairy (Fig. 293). The _skin_ (Fig. 291, _a_) is - formed by the pericarp and testa, and in some cases (Barley) - the pales also form the outer portion. The endosperm (_b_) is - large, and formed of parenchymatous, starch-containing cells: - aleurone (proteid) grains may also be found among them. When - the starch-grains and the aleurone-grains adhere together - the endosperm becomes “horny,” but is “floury” when the - starch-grains lie loosely with air between them. In the most - external region, just beneath the skin, 1–several layers of - nearly cubical cells (filled principally with aleurone-grains - and fat) are found, the _aleurone_-layer (Fig. 292). The embryo - (Fig. 291 _c-d_) contains large quantities of fatty oil; - the large shield-like structure, attached to the embryo and - turned inwards towards the endosperm (_c_), is the cotyledon - (scutellum); it remains enclosed in the seed during germination, - and dissolves the endosperm by means of the peculiar epithelial - cells developed on the dorsal surface. The radicle, on - germination, is obliged to perforate a mass of cells derived - from the suspensor and which form the “root-sheath” (coleorhiza, - Fig. 293) round its base. In addition to the tap-root, lateral - roots are frequently developed before germination; these quickly - break through, and later on are followed by others which appear - at the base of the leaf (Figs. 293, 294). - - The DISTRIBUTION OF THE FRUIT is most frequently effected by the - wind. The spirally-twisted and hygroscopic awn which persists on - the fruits of some species (_Avena_, _Stipa_, etc.) assists in - their dissemination, and even helps to bury them in the ground. - - The two preceding orders are more closely related to each other - than they are to the Gramineæ. - - The generic differences are chiefly founded on the form of - the inflorescence, the number and sex of the flowers in the - spikelets, the shape and relative length of the pales, awns, - etc. In addition to these the structure of the fruit and - seed presents a great many differences; some have compound - starch-grains, while in others they are single; some have 1 - layer of aleurone-cells, others have several (Fig. 292), etc. - -=1.= BAMBUSEÆ. Tall Grasses with woody, very siliceous stems which bear -many branches in the axils of the leaves. 6 stamens. _Bambusa_ (Bamboo). - -=2.= ORYZEÆ. _Oryza sativa_ (Rice) is a herbaceous marsh-plant, with -panicle and small, 1-flowered spikelets, with two small glumes and two -large, boat-shaped, strongly siliceous pales. 6 stamens.--_Leersia._ -_Lygeum. Pharus. Zizania aquatica._ - -=3.= MAYDEÆ. _Zea mais_ (Indian-corn, Maize); the spikelets are -unisexual; the ♂-spikelets in a terminal panicle; the ♀-spikelets -closely crowded and arranged in many rows in a thick, axillary spike, -enclosed by large sheathing-leaves. The ♀-spikelets are 1-(2-) -flowered; the ovary bears one, long, filamentous style, with bifid -stigma.--_Euchlæna_; _Coix_. - -=4.= ANDROPOGONEÆ. _Saccharum_ (Sugar-cane); the spikelets -are exceptionally small, 1-flowered, and borne in pairs in -many-flowered, long-haired panicles. Tall grasses with solid, sappy -stem.--_Andropogon._ - -=5.= FESTUCEÆ. Grasses with panicle (or spike-like panicle) and -2–several-flowered spikelets. Glumes small, in each case shorter than -the spikelet.--_Festuca_ (Fescue) and _Bromus_ (Brome, Fig. 288) -have the awn placed at the _apex_ of the pale, or slightly below -it. _Festuca_ has perennial species, with only a sparsely-branched -panicle with branches solitary or in pairs, and round spikelets; the -leaf-sheath is widely open. _Bromus_ has the branches borne in half -whorls, and the leaf-sheath scarcely half open. _Brachypodium_ has very -short-stalked spikelets in a raceme.--_Poa_ (Meadow-grass), _Briza_ -(Quaking-grass) and _Glyceria_ have awnless spikelets; these in _Poa_ -are ovoid, compressed, and with sharply-keeled glumes; in _Briza_ they -are broad, cordate and drooping, with boat-shaped glumes; in _Glyceria_ -round, long, many-flowered, linear or lanceolate; some species of -_Glyceria_ have closed leaf-sheaths.--_Dactylis_ (Cock’s-foot) differs -from all others in the somewhat crowded and unilateral (subsecund) -spikelets, which are compressed and oblique (_i.e._ one side more -convex than the other).--_Phragmites_ (_P. communis_, Reed); the -lowermost flowers of the spikelet are ♂; its axis is covered with -long, silky hairs; pales without awns, but acuminate. Perennial -marsh-plants.--_Melica_; panicle small, sparsely-branched with -round, awnless, few-flowered, usually drooping spikelets. The upper -pales, with arrested flowers, are generally united into a club-like -mass.--_Molinia_, _Eragrostis_, _Koeleria_, _Catabrosa_.--_Cynosurus_ -(Dog’s-tail) has a small, spicate panicle with unilateral spikelets, -some of which are fertile, some barren, each supported by a pectinate -scale. _Arundo. Sesleria. Gynerium. Triodia._ - -=6.= AVENEÆ. Panicles with 2–many-flowered spikelets; at least one -of the glumes is quite as long as the entire spikelet.--_Avena_ -(Oat). The pale is boat-shaped, often bifid, and at about the middle -of the back has a twisted, bent awn.--_Aira_ (Hair-grass) has a -long-branched panicle with small, 2-flowered spikelets; the pale has -a dentate apex and bears an awn on the posterior side close to the -base.--_Weingærtneria._--_Holcus_ (Yorkshire-fog); a soft, hairy Grass -with an open panicle, keeled glumes; 2 flowers in the spikelet, of -which the lower one is ☿, the upper ♂; the pale which supports the -☿-flower has no awn, but that which supports the ♂-flower, on the -contrary, is awned. - -=7.= AGROSTIDEÆ. Panicles or spike-like panicles with 1-flowered -spikelets. Generally 2 glumes and only 1 pale.--The following have -PANICLES: _Milium_ with square panicle-branches and round spikelets; -_Agrostis_ (Fiorin), with compressed, glabrous spikelets, whose glumes -are longer than the pales. _Calamagrostis_ differs in having a chaplet -of long hairs at the base of the pale.--_Stipa_ (Feather-grass) has a -long, twisted awn.--The following have SPIKELIKE PANICLES: _Phleum_ -(Cat’s-tail, Timothy-grass) has sharply pointed, entirely free glumes, -which are much longer than the awnless pales. _Alopecurus_ (Fox-tail); -glumes united below; pale with awn. _Ammophila_ (_Psamma_). _A. -arundinacea_; pales hairy at base; perennial, stiff-leaved, glaucous -sand-grass with creeping rhizome. _Aristida. Sporobolus._ - -=8.= PHALARIDEÆ. Panicles and spike-like panicles. The spikelet has -in the upper part a single fertile flower; below it are placed 4 -pales, of which the upper 1–2 sometimes support ♂-flowers. On the -whole, 6 floral-leaves of the first order are present.--_Phalaris_ -(_P. canariensis_, Canary-grass) has an ovate, spike-like panicle, -the spikelets are compressed, convex on the outer side, concave on -the inner. The large glumes are winged on the back.--_Digraphis_ (_D. -arundinacea_) is closely allied to _Phalaris_, but the keel of the -glumes is not winged.--_Anthoxanthum_ (_A. odoratum_, Sweet-vernal) has -a small, lanceolate, open, spike-like panicle; the spikelets have below -2 barren flowers, and above these an ☿-flower with 2 stamens. The upper -glume is longer than the flower.--_Hierochloa._ - - =9.= CHLORIDEÆ. The spikelets are arranged in the form of a - spike in two rows on one side of an often flatly-compressed - axis; they are mostly 1-flowered.--_Chloris_; _Ctenium_; - _Cynodon_; _Eleusine_; _Microchloa_. - - =10.= PANICEÆ. The spikelets are borne in panicles or spikes, - which may be arranged like fingers or in a raceme. There - is a centrally-placed ☿-flower; below it is sometimes a - ♂-flower.--_Panicum_; _Paspalum_; _Oplismenus_; _Setaria_ has - an almost cylindrical spike-like panicle with several barren - branchlets, which project as stiff, rough bristles.--_Cenchrus_; - _Pennisetum_. - -=11.= HORDEÆ. Spikes compound; spikelets sessile in the -notches of a toothed axis. - -=A.= Spikelets solitary.--_Triticum_ (Wheat, Fig. 287) has in each -tooth of the main axis, a several-flowered spikelet which turns its -_flat side_ towards the central axis. The cultivated species (true -Wheat) are 1-2-annual, the wild ones (_T. repens_, Couch, also as an -independent genus, _Agropyrum_) are perennial, with creeping rhizome -and lanceolate glumes.--_Lolium_ (Rye-grass) has in each tooth of -the main axis a many-flowered, compressed spikelet, which is placed -_edgewise_ towards it and (with the exception of _L. perenne_) has -only one outwardly-turned glume (_L. temulentum_ has a rudiment of -the inwardly-turned lower glume); the terminal spikelet has two -glumes.--_Secale_ (Rye). A two-flowered spikelet in each tooth; small, -lanceolate, acuminate glumes. _Nardus_ and _Lepturus_ have very narrow -spikes, the former with unilateral spikelets. - -=B.= In each notch of the axis 2 or more spikelets are placed close -together.--_Hordeum_ (Barley). In each tooth three 1-flowered -spikelets. _H. hexastichum_ (6-rowed Barley), has 6 rows of fruits, -since all the spikelets are fertile, and _H. distichum_ (2-rowed -Barley) 2 rows, since the lateral spikelets are (♂, and barren (p. -292).--_Elymus_ has 2–6 many-flowered spikelets in each joint of the -main axis. _Ægilops_ has awns upon the glumes. - - DISTRIBUTION. 315 genera with 3,500 species. The order is - distributed over the whole world, and as regards number of - individuals is perhaps the richest. In the Tropics, large, - broad-leaved, tree-like forms are found (_Bambuseæ_, _Olyreæ_, - _Andropogoneæ_, etc.; in S. Europe, _Arundo donax_); in England, - next to the Compositæ, it is the order most rich in species - (about 134).--The origin of some of the cultivated Grasses - is lost in obscurity. The Maize, no doubt, was indigenous to - America, where its nearest relatives are found, and where it - has also been discovered in ancient Indian graves; Durra or - Guinea-corn, Millet and Sugar-cane are South Asiatic plants, and - our own cereals no doubt have sprung primarily from Western Asia - and South-Eastern Europe (Barley from Armenia and Persia, where - a very closely related wild species is found; Wheat from the - same districts; Rye from the perennial species _S. montanum_). - _Panicum altissimum_ and Rice have come from Africa. - - USES. The Grasses play a very important part as cereals and - fodder plants. The following are the most important of the - cultivated ones: _Triticum vulgare_ (common Wheat), _turgidum_, - _amyleum_, _polonicum_, _spelta_, _durum_, etc.; _Secale - cereale_ (Rye); Barley (_Hordeum_-species, see under the genus); - Maize; Oats (_Avena sativa_, _orientalis_, _nuda_); Millet - (_Panicum miliaceum_); Durra (Turkish Millet, or Guinea-corn, - _Sorghum vulgare_, _cernuum_ and _saccharatum_); Manna-grass - (_Glyceria fluitans_). As fodder-plants especially: Rye-grass - (_Lolium perenne_); Oat-grass (_Avena elatior_); Timothy - (_Phleum pratense_); Fox-tail (_Alopecurus pratensis_); - Cock’s foot (_Dactylis glomerata_); Dog’s tail (_Cynosurus - cristatus_); Sweet-vernal (_Anthoxanthum odoratum_); Soft grass, - or Yorkshire-fog (_Holcus lanatus_ and _mollis_); Quaking-grass - (_Briza media_); species of Meadow-grass (_Poa_); Fescue - (_Festuca_) and Brome (_Bromus_).--Several cultivated species of - Grass are also used in the preparation of _fermented liquors_, - the starch in the seeds being transformed to _sugar_ (beer - from “Malt,” _i.e._ the germinated Barley; arrack from Rice); - or the stem becomes specially saccharine before flowering: the - Sugar-cane, _Sorghum saccharatum_. - - OFFICINAL. The rhizome of _Triticum repens_, Oat-grain, flour of - Barley, and the starch of Wheat, also sugar. - - The seeds of _Lolium temulentum_ are considered - _poisonous_.--The stems of many species (including our common - grains) are used in the manufacture of paper, especially - “Esparto grass” (_Stipa tenacissima_) from Spain and N. - Africa, and the sheathing-leaves of the ♀-spike of _Maize_. - Sand Lyme-grass (_Elymus arenarius_), and especially _Psamma - arenaria_, are important.--But few Grass-species are - _sweet-scented_: _Anthoxanthum odoratum_ and _Hierochloa - odorata_ contain coumarin; _Andropogon_-species have essential - oils (“Citronella oil”).--ORNAMENTAL PLANTS are: the - “Ribbon-grass” (a variety of _Digraphis arundinacea_), _Stipa - pennata_ (whose awn is exceedingly long and feathery), _Gynerium - argenteum_ (Pampas-grass), _Lagurus ovatus_, _Hordeum jubatum_, - _Bromus briziformis_. - - - Family 3. =Spadicifloræ.= - -The primitive form resembles that of the preceding family. In it -we find the typical, perfectly developed, Monocotyledonous flower, -sometimes even with free carpels and with a dry or somewhat fleshy, but -never petaloid perianth; and this passes over into very different forms -by the suppression of the floral-leaves, perianth and sporophylls -(unisexual flowers are common), and by the close aggregation of the -flowers in the inflorescence. The flower is _hypogynous_ in every case. -The inflorescence is a _spike_ which may be either single or branched, -and has often a thick and fleshy axis (a _spadix_). In Palms and Araceæ -it is enveloped, at any rate prior to the opening of the flowers, by a -very large floral-leaf, _the spathe_, which may be petaloid (Figs. 297, -301). - -The fruit is most frequently fleshy (_berry_, _drupe_) or a _nut_, -never a capsule. The embryo is small, with large, fleshy endosperm -(Fig. 299 _C_); very rarely the endosperm is wanting. - - [Illustration: FIG. 295.--Piassava (_Attalea funifera_).] - - [Illustration: FIG. 296.--A portion of the stem of _Attalea - funifera_ with persistent leaf-bases.] - -The numerous plants belonging to this family are large, herbaceous or -tree-like, and the leaves seldom have the usual Monocotyledonous form, -_i.e._ linear with parallel venation, but most frequently have pinnate -or palmate venation. - -Order 1. =Palmæ (Palms).= The majority are trees with an _unbranched_, -cylindrical _stem_, having short internodes and covered with leaf-scars -or the bases of the leaf-stalks (Fig. 296), and at the summit a rosette -of large leaves closely packed together (Fig. 295). An exception to -this is found in _Calamus_ (Cane, “Rotang”), whose thin, creeping or -climbing stems have long internodes; sparsely[28] branched is, _e.g._ -the African Doum-palm (_Hyphæne_). Notwithstanding their often enormous -stems the Palms have fibrous roots, like the bulbous Monocotyledons. -The leaves are pinnate (Feather-palms, Fig. 298) or palmate (Fan-palms, -Fig. 295) and often very large; they have a well-developed petiole -with an _amplexicaul sheath_, which is often more or less separated -into a large number of fibres. _In the bud the blade is entire but -folded_, as the leaf expands the lines of folding are torn, either -those which are turned upwards (thus ∨ ∨ ∨ ∨, _e.g. Pritchardia_, -_Livistona_, _Phœnix_, _Chamærops_) or those turned downwards (thus -∧ ∧ ∧ ∧, _e.g. Cocos_, _Chamædorea_, _Calamus_). The inflorescence -is usually lateral; when, as in Sago-palm (_Metroxylon rumphii_) -or Talipot (_Corypha umbraculifera_) it is terminal, the plant is -monocarpic, and dies after flowering; it is often a very _large_ -and _branched spadix_ with numerous flowers either borne externally -or embedded in it, and enclosed either in one woody, boat-shaped -_spathe_ (Fig. 297) or several spathes, in the latter case one for each -branch. The flowers are sessile or even embedded, regular, generally -_unisexual_ (monœcious or diœcious) with the usual diagram (Fig. -278); the perianth is inconspicuous, green or yellow, persistent, and -more or less leathery or fleshy. 6, rarely 3 or many stamens. The 3 -carpels remain either _distinct_ or form one, generally 3-locular, -ovary. The style is short. There is _one ovule in each carpel_. Often -during ripening 2 carpels with their ovules are aborted. The fruit is -a _berry_, _drupe_ or _nut_, generally one-seeded, with a large horny -or bony endosperm with hard thick-walled cells (_e.g._ Date-palm). In -some (_e.g._ Cocoanut) it is thin-walled, soft, and oily; in several -“ruminate.” - - When _germination_ commences in the Cocoanut, Date, etc., the - apex of the cotyledon remains in the seed and developes into - a spongy mass to withdraw the endosperm; in the Cocoanut it - attains a considerable size (Fig. 299 _C_) and assumes the - form of the fruit. The endosperm in the Cocoanut is hollow and - the interior is filled with “milk.” In the Date-palm and the - Vegetable-ivory (_Phytelephas_) the cell-walls of the hard - endosperm serve as reserve material. - -=1.= PHŒNICEÆ. _Phœnix_ (Date-palm) has pinnate leaves with channeled -leaflets and diœcious flowers with 8 free carpels, of which usually -only one developes into a berry with membranous endocarp; the large -seed has a deep furrow on the inner side, and horny endosperm. - - [Illustration: FIG. 297.--Inflorescence of a Palm with spathe. At - the top ♂-, at the base ♀-flowers.] - - [Illustration: FIG. 298.--_Livistona australis._] - -=2.= SABALEÆ. These have fan-like leaves with channeled segments; -flowers ☿ or polygamous, rarely diœcious, with 3 separate or only -slightly united carpels, all of which are sometimes developed -into fruits (berry or drupe, with thin stone).--_Chamærops_, the -Dwarf-palm. The pericarp is externally fleshy, internally more -fibrous, and provided with a membranous inner layer. The endosperm is -ruminate (that is, the testa is several times deeply folded into the -endosperm).--_Sabal_, _Copernicia_, _Livistona_ (Fig. 298), _Thrinax_, -_Corypha_, _Brahea_, and others. - - [Illustration: FIG. 299.--_A_ Longitudinal section of a Cocoanut - (diminished), the inner layer only (the stone) not being divided - _B_ End view of the stone, showing the sutures for the 3 carpels - (_a_), and the 3 germ-pores; the embryo emerges from the lowest - one when germination begins. _C_ Germinating; inside the stone is - seen the hollow endosperm and the enlarging cotyledon.] - -=3.= COCOINEÆ. With pinnate leaves. Monœcious inflorescence. The -carpels are united into a 3-locular ovary. The fruit is most frequently -1-locular, only 1 of the loculi becoming developed, rarely 3-locular; -it is a drupe with a large, fibrous, external layer (_mesocarp_) and -most frequently a very hard inner layer (_endocarp_, stone) which -has 3 germ-pores, the 2 of these, however, which correspond to the -suppressed loculi are closed; internal to the third lies the small -embryo (Fig. 299). Endosperm containing abundance of oil. _Cocos_ (the -Cocoanut-palm), _Attalea_, _Elæis_, _Acrocomia_, _Bactris_. - -=4.= LEPIDOCARYINÆ. The floral-leaves and flowers are borne in 2 -rows on the spadix. The carpels are united into one 3-locular ovary; -the fruit is coated by a layer of hard, shining, imbricate scales. -The majority of the species are thorny, and climb by means of the -thorny leaves. Some have fan-like (_Mauritia_), others pinnate leaves -(_Raphia_, _Calamus_, _Eugeissonia_, _Metroxylon_; the stems of the -latter die after the first flowering). - - =5.= BORASSINÆ. Large Fan-palms without thorns, with 3-locular - ovary. Drupe with separate stones. _Latania_ and _Lodoicea_ have - many stamens; _Hyphæne_; _Borassus_ (Palmyra-palm). - - =6.= ARECINEÆ. The most numerous group. Feather-palms. Berry. - _Areca_, _Euterpe_, _Oreodoxa_, _Ceroxylon_, _Chamædorea_, - _Geonoma_, _Caryota_ with bipinnate leaves. - - =7.= PHYTELEPHANTINÆ. Flowers with rudimentary perianth united - in close capitula. _Phytelephas_ (Vegetable-ivory). _Nipa._ - - DISTRIBUTION. About 1,100 species are known. In Europe - only the Dwarf-palm (_Chamærops humilis_) is wild (Western - Mediterranean). The Date palm (_Phœnix dactylifera_) belongs - to North Africa and West Asia. Other African genera are - _Hyphæne_ (Doum-palm) and _Elæis_ (_E. guineensis_, Oil-palm). - A large majority of the genera are found in South America and - in the East Indies. The following are AMERICAN:--_Mauritia_, - _Acrocomia_, _Bactris_, _Chamædorea_, _Oreodoxa_, _Euterpe_, - _Attalea_, etc. ASIATIC:--_Metroxylon_, _Calamus_, _Areca_, - _Borassus_, _Lodoicea_ (“Double-cocoanuts,” Seychelles) and - others. The Cocoanut-palm has perhaps an American origin; all - the other species of the same genus being endemic in America; - it is the only Palm found on the coral islands of the Pacific - Ocean, and is also the only one which is common to both - hemispheres. - - USES. Palms belong to the most useful plants; they contain no - poison, and are of little medicinal interest, but are largely - employed in the arts and manufactures, the hard timber being - adapted for many purposes on account of the hard tissue in - which the vascular bundles are embedded. “Cane” is the stem - of _Calamus_-species (from India). SAGO is obtained from the - pith of _Metroxylon rumphii_ (Sago-palm, Sunda-Is., Moluccas), - _Mauritia flexuosa_, etc. Sugar-containing sap (“palm wine”) is - obtained from the American _Mauritia vinifera_ and _flexuosa_, - _Borassus flabelliformis_ (Asiatic Palmyra-palm), _Arenga - saccharifera_, etc., by cutting off the young inflorescences, - or by perforating the stem before the flowering (_arrack_ is - distilled from this). _Vascular strands_ for the manufacture of - mats and brushes, etc., are obtained from the outer covering - (mesocarp) of the Cocoanut, and from the detached leaf-sheaths - of _Attalea funifera_ (Brazil) (Fig. 296). WAX is yielded by the - leaves of _Copernicia cerifera_ (carnaueba-wax, Amazon region), - and by the stem of _Ceroxylon andicola_ (palm-wax, Andes); - East Indian _Dragon’s blood_ is from the fruit of _Calamus - draco_; the young buds of many species, especially _Euterpe_, - _Cocos_, _Attalea_, etc., are used as “cabbage.” Palm-oil is - obtained from the oily mesocarp of the plum-like fruits of - _Elæis guineensis_ (W. Africa), and from the seeds, when it is - largely used in the manufacture of soap. EDIBLE FRUITS from the - Date-palm (_Phœnix dactylifera_, Arabia, Egypt, W. Africa), and - the endosperm of the Cocoanut (_Cocos nucifera_). The seeds - and the unripe fruits of the Areca-palm (_Areca catechu_) - are chewed with the leaves of the Betelpeper, principally in - Asia. VEGETABLE IVORY from the hard endosperm of _Phytelephas - macrocarpa_ (S. America.)--Many species are cultivated in - the tropics as ornamental plants, but in this country only - _Chamærops humilis_, _Livistona australis_ and _chinensis_ are - generally grown. In addition to the few just mentioned, many - others are of importance, but these are much the most useful. - - Order 2. =Cyclanthaceæ.= This is a small order related to the - Palms (44 species from Tropical America), with fan-like, folded - leaves. The flowers are unisexual and arranged in whorls or - close spirals on an unbranched spadix. Ovary unilocular, ovules - numerous. To this belongs _Carludovica palmata_, whose leaves - are used for Panama hats. - - Order 3. =Pandanaceæ= (Screw-pines) is another small order, - forming a transition to the Araceæ. The woody, (apparently) - dichotomous stem is supported by a large number of aerial roots, - which sometimes entirely support it when the lower portion of - the stem has decayed. The leaves are closely crowded together, - and arranged on the branches in three rows, which are often - obliquely displaced, with the formation of three spiral lines; - they are, as in the Bromeliaceæ, amplexicaul, long, linear, - the edge and lower midrib often provided with thorns. The - ♂-flowers are borne in branched, the ♀ in unbranched spadices - or capitula, which resemble those of _Sparganium_, but have no - floral-leaves. Perianth absent. The drupes or berries unite into - multiple fruits.--About 80 species in the islands of the Indian - Ocean.--_Pandanus_, _Freycinetia_.--Fossils perhaps in the chalk - of the Harz. - -Order 4. =Typhaceæ.= The flowers are unisexual, monœcious, and borne -on a cylindrical spike or globose capitulum; ♂ inflorescences above, -the ♀ below. The perianth consists of a definite number of scales -(_Sparganium_), or in its place numerous irregularly-arranged hairs are -found (_Typha_); in the ♂-flower there are generally three stamens; the -gynœceum is formed of 1–2 carpels with 1 prolonged style; 1 pendulous -ovule. The seeds are furnished with a seed-cover, which is cast off on -germination.--The few species (about 20) which belong to this order are -marsh plants with creeping rhizome (and hence grow in clusters); the -leaves on the aerial shoots are borne in two rows, entire, very long -and linear. - -_Sparganium_ (Bur-reed). The flowers are borne in globose capitula; -the perianth distinct, generally consisting of 3 small scales; pistil -bicarpellate. Drupe, dry and woody. ~The stalk of the lower ♀ capitula -is sometimes united with the main axis, and consequently the capitula -are situated high above their subtending-leaf.~ - -_Typha_ (Bulrush, Reed-mace) has a long, cylindrical, brown spike, -the lower portion bearing ♀-flowers, and the upper ♂-flowers, which -is divided into joints by alternate leaves. The ♀-flowers have 1 -carpel. The perianth is wanting, represented by a number of fine, -irregularly-placed hairs; pistil unicarpellate. Fruit a nut. - - The two genera, according to some, are related to the 2nd order. - In both genera native species are found. The pollination is - effected by the wind, and consequently the anthers project - considerably, and the stigma is large and hairy. _Typha_ is - protandrous, _Sparganium_ protogynous. The small, fine hairs - surrounding the nut of _Typha_ assist in its distribution by the - wind.--Fossil _Typhas_ in the Tertiary. - -Order 5. =Araceæ= (=Arums=). The flowers are small, and always borne -_without bracts or bracteoles_ on _an unbranched_, often very fleshy -spike, which is enclosed by a spathe, often petaloid and coloured (Fig. -301). The fruit is a _berry_. Outer integument of the seed fleshy.--The -leaves have generally sheath, stalk, and blade with distinctly -_reticulate_ venation; they are chiefly cordate or sagittate (Fig. -302), seldom long with parallel venation as in the other Monocotyledons -(_Acorus_, Fig. 300). The Araceæ are quite _glabrous_, generally -_perennial herbs_ with tubers or rhizomes. Many have latex.--For the -rest the structure of these plants varies; for example, while some -have a perianth, in others it is wanting; in some the perianth-leaves -are free, in others united; some have hermaphrodite flowers, but the -majority unisexual (monœcious); some have free, others united stamens; -the ovules are orthotropous, anatropous, or campylotropous, erect or -pendulous; the ovary is 1–many-locular; some have seeds with endosperm, -others without. ~_In habit_ there are great differences. While some, -_e.g. Colocasia_ (Fig. 302), have a thick, more or less upright stem, -with leaf-scars, but not woody, others are climbers, epiphytic, and -maintain themselves firmly by means of adventitious roots, on the stems -and branches of trees, or even on steep rocks, _e.g. Philodendron_; -the cordate, penninerved leaf is the most common (Fig. 302), but -various branched forms appear; the pedate leaves of _Helicophyllum_, -_Dracunculus_, etc., are cymosely branched; the leaves of _Monstera -deliciosa_, perforated by tearing, should be noticed (the vascular -bundles while in the bud grow faster than the tissue between them, -causing the latter to be torn, and the leaf perforated). With regard to -the anatomical structure, the presence or absence of latex, raphides, -resin-passages, groups of mucilage-cells should be noted. Engler makes -use of these anatomical peculiarities for a scientific arrangement of -the order.~ - -=A.= ORONTIEÆ, CALAMUS-GROUP. ☿, hypogynous flowers of a completely -formed monocotyledonous type (number in the whorls 2, 3, or -4).--_Acorus_ (_A. calamus_, Sweet-flag) has a regular, 3-merous, -pentacyclic flower (Fig. 300 _C_, _D_). They are marsh-plants, with -creeping rhizome, triangular stem, and long, sword-like leaves (Fig. -300 _A_); the inflorescence is terminal, apparently lateral, being -pushed to one side by the upright, sword-like spathe (Fig. 300 -_B_).--~_Anthurium_ (Pr2+2, A2+2, G2); _Pothos_; _Orontium_ (unilocular -ovary with one ovule), etc.~ - - [Illustration: FIG. 300.--_Acorus calamus_: _A_ habit (much - reduced); _B_ inflorescence; _C_ a flower; _D_ diagram; _E_ - longitudinal section of an ovary; _F_ an ovule.] - - [Illustration: FIG. 301.--_Arum maculatum._ The spathe (_h_) in - _B_ is longitudinally divided.] - - [Illustration: FIG. 302.--_Colocasia Boryi._] - -=B.= CALLEÆ. Flowers hypogynous, naked, ☿.--_Calla_ (_C. palustris_). -All flowers in the spike are fertile, or the upper ones are ♂; 6–9 -stamens; ovary unilocular with many basal ovules. Marsh-plants with -creeping rhizome and cordate leaves.--_Monstera_, _Rhaphidophora_, etc. - -=C.= ARINEÆ. Flowers monœcious, naked, ♂-flowers on the upper, ♀ on the -lower part of the spadix.--_Arum_ (Fig. 301). The spadix terminates in -a naked, club-like portion (_k_); below this is a number of sessile -bodies (rudimentary flowers), with broad bases and prolonged, pointed -tips (_b_); underneath these are the ♂-flowers (_m_), each consisting -only of 3–4 short stamens, which eject vermiform pollen-masses through -the terminal pores; then follow, last of all, ♀-flowers (_f_), each of -which consists of one unilocular ovary, with several ovules. Perennial -herbs, tuberous, with cordate leaves.--~_Dracunculus_; _Biarum_; -_Arisarum_; _Pinellia (Atherurus) ternata_ with leaves bearing 1–2 -buds. _Zantedeschia æthiopica_ (_Richardia_, Nile-lily); ♂, 2–3 -stamens; ♀ with 3 staminodes, 1–5-locular ovary (S. Africa.)--In some -genera sterile flowers are present between the ♂ and ♀ portions of -the spadix (_e.g._ in _Philodendron_); in _Ambrosinia_ a lateral, -wing-like broadening of the axis of the spadix divides the cavity -of the spathe into two chambers, the anterior containing one ♀, and -the posterior 8–10 ♂-flowers in two series; in some the stamens in -the single ♂-flowers unite and form a columnar “synandrium” (_e.g._ -in _Dieffenbachia_, _Colocasia_, _Alocasia_, _Caladium_, _Taccarum_, -_Syngonium_). A remarkable spadix is found in _Spathicarpa_; it is -united for its entire length, on one side, with the spathe, and the -flowers are arranged upon it in rows, the ♀ to the outside, and the -♂ in the middle (_Zostera_ has a similar one).--_Pistia_ similarly -deviates considerably, it is a floating water-plant, with hairy, round -rosettes of leaves; in it also the spathe and spadix are united; at the -base a ♀-flower is borne, which consists of one unilocular ovary, and -above several ♂-flowers, each composed of two united stamens.~ - - BIOLOGY. The inflorescences are adapted for - _insect-pollination_; they are protogynous, since the viscous, - almost sessile stigmas come to maturity and wither before the - pollen, which is generally dehisced by apical pores, is shed; - some pollinate themselves freely by the pollen from the higher - ♂-flowers falling upon the ♀-flowers below them, and in some - it is conjectured that the pollination is effected by snails. - The coloured spathe, and the naked end of the spadix (often - coloured) of certain genera function as the coloured perianth in - other orders; during flowering a very powerful smell is often - emitted. _Arum maculatum_ is worthy of notice; small flies - and midges creep down into the spathe, between the sterile - flowers (Fig. 301 _b_), which are situated where the spathe is - constricted, and pointing obliquely downwards prevent the escape - of the insects; in the meantime, the stigmas are in a condition - to receive any pollen they may have brought with them; after - pollination the stigmas wither, and exude small drops of honey - as a compensation to the flies for their imprisonment; after - this the anthers (_m_) open and shed their pollen, the sterile - flowers wither, and the insects are then able to escape, and - enter and pollinate other inflorescences.--In many, a _rise - of temperature_ and evolution of carbonic acid takes place - during flowering; a spadix may be raised as much as 30°C. above - the temperature of the surrounding air.--Again, under certain - conditions, many species absorb such large quantities of water - by their roots that water is forced out in drops from the tip of - the leaf; this may often be observed in _Zantedeschia_. - - About 900 species in 100 genera. Home, the Tropics, especially - S. America, India, and the Indian Islands, preferably in shady, - damp forests growing as epiphytes upon trees, and on the banks - of streams. Outside the Tropics few are found. _Acorus calamus_ - was introduced into Europe from Asia about 300 years ago; it, - however, never sets any fruit, as the pollen is unfertile. In - England _Arum maculatum_ is a very common plant; this and _A. - italicum_ are the only native species. _Colocasia antiquorum_ - comes from Polynesia and the Indian Islands, and also _Alocasia - macrorrhiza_. Fossils in Cretaceous and Tertiary. - - USES. Many species have pungent, and even _poisonous properties_ - (_e.g. Dieffenbachia_, _Lagenandra_, _Arum_), which are easily - removed by boiling or roasting; the _rhizomes_ of many species - of _Caladium_, _Colocasia_ (_C. antiquorum_, _esculenta_, etc.), - are very rich in starch, and in the Tropics form an important - source of food. An uncommon occurrence in the order is the - highly aromatic rhizome of _Acorus calamus_; this contains - calamus-oil and acorin which are used in perfumery. Many are - ornamental plants, _e.g. Zantedeschia æthiopica_ (South Africa), - generally known as “Calla,” and _Monstera deliciosa_; many other - species are grown in greenhouses. - -Order 6. =Lemnaceæ (Duck-weeds).= These are the most reduced form of -the Spadicifloræ. They are very small, free-swimming water-plants. -The vegetative system resembles a small, leaf-like body (Fig. 303 -_f-f_), from which roots hang downwards; this branches by producing a -new, similar leaf-like body, which springs from a pocket-like hollow -(indicated by a dotted line in the figure) on each side of the -older one, at its base (or only on one side). ~The branching is thus -dichasial or helicoid (Fig. 303 _A_, where _f, f′, f″, f″′_ indicate -shoots of 1st, 2nd, 3rd, 4th generations respectively). The leaf-like -bodies are, according to Hegelmaier, leaf-like stems, and thus _Lemna_ -has no other leaves than the spathe and the sporophylls; according -to the investigations of Engler they are stems whose upper portion -(above the “pocket”) is a leaf, which is not sharply separated from -the underlying stem-portion. The inflorescence is a very much reduced -Araceous-spadix, consisting in _Lemna_ of 1 or 2 stamens of unequal -length (1-stamened ♂-flowers), 1 unilocular carpel (♀-flower), and -1 thin spathe (_B_). [The same is found in _Spirodela polyrrhiza_, -etc., whose daughter-shoots begin in addition with 1 basal-leaf. -_Wolffia arrhiza_, etc., have no roots, no spathe, and only 1 ♂-flower -in the inflorescence (Engler).]--On the germination of the seed a -portion of the testa is thrown off as a lid, so that an exit is opened -for the radicle.--19 species. In stagnant fresh water, both Temp. -and Tropical.--In Europe the species are _Lemna minor, trisulca, -gibba; Spirodela polyrrhiza_, and _Wolffia arrhiza_, the smallest -Flowering-plant.~ - - [Illustration: FIG. 303.--_Lemna_: _A_ vegetative system; _B_ - portion of a plant with flowers; one stamen and tip of the carpel - project; the remaining portions being indicated by the dotted - line.] - - - Family 4. =Enantioblastæ.= - -The flowers in this family are _hypogynous_ and have in part the -general monocotyledonous type with 5 trimerous whorls completely -developed in a regular hermaphrodite flower, and in part the flowers -so much reduced that the type is very difficult to trace. On the one -hand the family is well developed and has capitate inflorescences -(_Eriocaulaceæ_) and on the other hand it is distinctly reduced -(_Centrolepidaceceæ_). This family has taken its name from the fact -that the ovule is not, as in the Liliifloræ and nearly all other -Monocotyledons, anatropous, but _orthotropous_, so that the embryo -(βλάστη) becomes placed _at the end of the seed opposite_ (ἐναντίος) -_to the hilum_. Large, mealy endosperm.--The orders belonging to this -family are by certain authors grouped with the _Bromeliaceæ_ and -_Pontederiaceæ_, etc., into one family, FARINOSEÆ, so named on account -of the mealy endosperm, the distinguishing character of the Liliifloræ -then being that the endosperm is fleshy and horny. - - Order 1. =Commelinaceæ.= The complete Liliaceous structure - without great reductions in the number of whorls, but with - generally few ovules in each loculus of the ovary, is found in - the Commelinaceæ, an almost exclusively tropical order with - about 317 species; herbs, some of which are introduced into - our gardens and greenhouses. The stems are nodose; the leaves - often _clasping_; the flowers are arranged in unipared scorpioid - cymes, often so that they form a zig-zag series falling in - the median line of the bracts, and after flowering they bend - regularly to the right or left, outwards or inwards. They - are more or less _zygomorphic_, particularly in the stamens, - which in the same flower are of different forms or partially - suppressed. The outer series of the _perianth_ is sepaloid, - the inner petaloid, generally violet or blue; the filaments - are sometimes clothed with hairs formed of rows of bead-like - cells (well known for showing protoplasmic movements). Fruit - a trilocular _capsule_ with loculicidal dehiscence (generally - few-seeded); in some a nut. The radicle is covered by an - external, warty, projecting covering which is cast off on - germination.--The abundant raphides lie in elongated cells whose - transverse walls they perforate.--_Commelina, Tradescantia, - Tinantia, Cyanotis, Dichorisandra_. - - Order 2. =Mayacaceæ.= This order is closely allied to the - Commelinaceæ. 7 species. American marsh- or water-plants. - - In many of the following orders of this family the flowers are - united into compound inflorescences, with which is accompanied a - reduction in the flower. - - Order 3. =Xyridaceæ= (50 species). Marsh-plants with radical, - often equitant leaves arranged in 2 rows, and short spikes on - long (twisted) stalks. The flowers, as in the Commelinaceæ, have - sepals (which however are more chaffy) and petals, but the outer - series of stamens is wanting. Capsule (generally many-seeded). - - Order 4. =Rapateaceæ.= Marsh-plants with radical leaves, usually - in two rows, and several spikelets on the summit of the main - axis, clustered into a capitulum or unilateral spike. Each - spikelet has numerous imbricate floral-leaves and one flower. 24 - species. South America. - - Order 5. =Eriocaulaceæ.= The “Compositæ among Monocotyledons,” - a tropical order. The flowers are borne in a _capitulum_ - surrounded by an _involucre_, very similar to that of the - Compositæ. The flowers are very small, unisexual, ♂ and ♀ - often mixed indiscriminately in the same capitulum; they have - the usual pentacyclic structure; the leaves of the inner - perianth are often connate and more membranous than the outer; - in some the outer series of stamens are suppressed; in each of - the 3 loculi is one pendulous ovule. Capsule. The leaves are - generally radical and grass-like.--335 species; _Eriocaulon_, - _Paepalanthus_, etc., _E. septangulare_ on the west coast of - Scotland, and Ireland, and in North America. - - Order 6. =Restiaceæ.= A small, especially S. African and S. - Australian, xerophilous order (about 235 species), which is - quite similar in habit to the Juncaceæ and Cyperaceæ. The - leaves are often reduced to sheaths. The flowers are diœcious, - the perianth as in _Juncus_, but the outer series of stamens - suppressed. The ovary and fruit as in Eriocaulaceæ; the ovary, - however, may be unilocular, and the fruit a nut. _Restio_, etc. - - Order 7. =Centrolepidaceæ.= These are the most reduced plants - in the family; small grass- or rush-like herbs. The flowers - are very small, naked. Stamens 1–2, carpels 1–∞. 32 species. - Australia.--_Centrolepis_ (flowers generally ☿ with 1 stamen and - 2–∞ carpels). - - - Family 5. =Liliifloræ.= - -The flower is constructed on the general monocotyledonous type, with 5 -alternating, 3-merous whorls (Fig. 278), but exceptions are found as -in the Iridaceæ (Fig. 279) by the suppression of the _inner_ whorl of -stamens; in a few the position in relation to the bract differs from -that represented in Fig. 278, and in some instead of the trimerous, -di- or tetramerous flowers are found (_e.g. Majanthemum_, _Paris_). -Flowers generally _regular, hermaphrodite_, with simple, _petaloid_, -coloured perianth (except, for example, Bromeliaceæ); ovary trilocular, -generally with 2 ovules or 2 rows of ovules in the inner angle of -each loculus (Fig. 304 _C_, _D_). _Endosperm_ always present.--A very -natural family, of which some divisions in part overlap each other. -The habit varies; the leaves are however long, entire, with parallel -venation, except in Dioscoreaceæ (Fig. 313). - - In the first orders of this family the flowers are hypogynous, - and in the first of all the styles are free, and the capsule - dehisces septicidally; in the following the flowers are - epigynous and in some reduced in number or unisexual; capsule - with loculicidal dehiscence, or a berry. - - HYPOGYNOUS flowers: Colchicaceæ, Liliaceæ, Convallariaceæ, - Bromeliaceæ (in part). - - EPIGYNOUS flowers: Amaryllidaceæ, Iridaceæ, Bromeliaceæ (in - part), Dioscoreaceæ. - -Order 1. =Colchicaceæ.= The flower (Fig. 304 _A_) is ☿, regular, -_hypogynous_, trimerous in all five whorls (6 _stamens_); anthers -usually _extrorse_. Gynœceum with 3 _free styles_ (_A, D_); fruit a -_capsule with septicidal dehiscence_ (_E_); embryo very small (_F_). -The underground stem is generally a corm or rhizome, seldom a bulb. - -=A.= VERATREÆ.--_Veratrum_; perennial herbs, stem tall with long -internodes and broad, folded leaves; the flowers andromonœcious, -with free, widely opening perianth-leaves (Fig. 304 _A_), and -globular anthers; inflorescence a panicle.--_Zygadenus, Melanthium, -Schœnocaulon, Uvularia, Tricyrtis_. - -=B.= TOFIELDIEÆ.--_Narthecium_ and _Tofieldia_ have leaves alternate -(arranged in two rows), sword-like and borne in rosettes; racemes -or spikes. _Narthecium_ forms an exception to the order by having -a simple style and fruit with loculicidal dehiscence; _Tofieldia_ -by the introrse anthers. In this they are related to the Liliaceæ. -_Narthecium_ has poisonous properties, like many other Colchicaceæ. - - [Illustration: FIG. 304.--_Veratrum_: _A_ flower; _B_ stamen; - _C_ transverse section of ovary; _D_ gynœceum, with one carpel - bisected longitudinally, and the third removed; _E_ fruit after - dehiscence; _F_ longitudinal section of a seed.] - -=C.= COLCHICEÆ.--_Colchicum_ (Autumn Crocus); perennial herbs, with a -long, _funnel-shaped, gamophyllous perianth_, and introrse anthers. The -flowers of _C. autumnale_ spring up immediately from the underground -stem, which is in reality a _corm_ formed of one internode. ~_Colchicum -autumnale_ flowers in autumn without leaves; in spring the radical -foliage-leaves appear simultaneously with the fruit. The flower is -protogynous, and is pollinated by insects (humble-bees, etc.) which -seek the honey secreted by the free part of the stamen a little way -down the tube. The length of the tube protects the fruit, and not, -as in other cases, the nectary.--_Bulbocodium_ and _Merendera_ have -unguiculate perianth-leaves, free, but closing together like a tube.~ - - 175 species; chiefly in North America and South Africa. - _Tofieldia_ is an Arctic plant. The order is rich in pungent, - poisonous alkaloids (veratrin, colchicin, etc.). OFFICINAL; - the seeds of _Colchicum autumnale_ (Europe) and _Schœnocaulon - officinale_ (Mexico), and the rhizome of _Veratrum album_ - (mountains of Central Europe). - - [Illustration: FIG. 305.--_Colchicum autumnale. A_ Corm - seen from the front: _k_ corm; _s′ s″_ scale-leaves embracing - the flower-stalk; _wh_ base of flower-stalk with roots (_w_). - _B_ Longitudinal section of corm and flower-stalk: _hh_ brown - membrane surrounding the underground portion of the plant; - _st_ flower-and leaf-stalk of previous year, the swollen basal - portion forming the reservoir of reserve material. The new plant - is a lateral shoot from the base of the corm (_k_) and has the - following parts: the base bearing the roots (_w_), the central - part (_k’_) which becomes the corm in the next year, the axis - bearing the scale-leaves (_s’, s″_), the foliage-leaves (_l, - l′″_), and the flowers (_b, b’_) which are borne in the axils of - the uppermost foliage-leaves.] - -Order 2. =Liliaceæ (Lilies).= Flowers as in the Colchicaceæ but with -_introrse_ anthers; _ovary free, 3-locular, with single style; capsule_ -3-locular with _loculicidal_ dehiscence.--The majority are herbs with -_bulbs_; the inflorescence is _terminal_. In many species reproduction -takes place by means of bulbils (small bulbs) formed in the axils of -the foliage-leaves (_e.g. Lilium bulbiferum_, _lancifolium_, etc., -_Gagea lancifolia_, etc.), or in the bracts of the inflorescence (many -species of _Allium_); in many species several buds are developed as -bulbs in the axils of the bulb-scales themselves (accessory buds -arising close together), and in some the formation of buds is common on -the leaves. - -=A.= TULIPEÆ, TULIP GROUP. Bulbs. The aerial, elongated stem bears -the foliage-leaves. Flowers few but generally large, with free -perianth-leaves. _Tulipa_; style absent, no honey; flowers generally -solitary, erect.--_Fritillaria_ perianth campanulate with a round or -oblong nectary at the base of each perianth-leaf.--_Lilium_; perianth -widely open, generally turned back with a covered nectary-groove in the -centre of each segment. Anthers versatile.--_Lloydia; Erythronium._ - -=B.= HYACINTHEÆ, HYACINTH GROUP. Bulbs. Leaves radical; aerial stem -leafless with raceme or spike. In some the perianth-segments are free, -in others united. Honey is produced often in glands or in the septa of -the ovary (septal glands).--_Ornithogalum_ has a leafy stem; _Scilla_; -_Eucomis_ has a tuft of floral-leaves above the raceme; _Agraphis_; -_Hyacinthus_; _Puschkinia_; _Chionodoxa_; _Muscari_; _Veltheimia_; -_Urginea_. - -=C.= ALLIEÆ, ONION GROUP. Generally bulbs. Leaves radical. Stem -leafless with a compound umbellate or capitate inflorescence of -unipared helicoid cymes, which before flowering are surrounded -by two broad involucral leaves.--~_Allium._ Filaments often -petaloid and bidentate; in many species bulbils are found in the -inflorescence.--Some species have flat leaves: _A. sativum_, Garlic; -_A. porrum_, Leek; _A. ursinum_; others have round, hollow leaves: -_A. cepa_, Onion; _A. fistulosum_, Winter Onion; _A. ascalonicum_, -Eschalot; _A. schænoprasum_, Chive.~--_Gagea_; honey is secreted -at the base of the perianth, no special nectary; inflorescence -few-flowered.--_Agapanthus; Triteleia._ - - =D.= ANTHERICEÆ. Rhizome; raceme; the leaves not fleshy and - thick.--_Anthericum_; _Asphodelus_; _Bulbine_; _Chlorophytum_; - _Bowiea_ has an almost leafless stem with curved, climbing - branches. - - =E.= ALOINEÆ, ALOES. Stem generally aerial and tree-like, - bearing on its summit thick, fleshy leaves, often with a thorny - edge (Fig. 306). Raceme branched or unbranched.--_Aloë_; - _Gasteria_; _Yucca_ (has secondary thickening, p. 274). - - =F.= HEMEROCALLIDEÆ. _Phormium_, (_Ph. tenax._ New Zealand - Flax); _Funckia_ (_Hosta_); _Hemerocallis_. - - At this point the following are best placed: _Aphyllanthes_ - (_A. monspeliensis_); _Xanthorrhæa_ (Black-boy); _Xerotes_; - _Lomandra_; _Kingia_; the very membranous, dry perianth of the - last resembles that of the Juncaceæ, and also there are only - 1–few ovules in the loculi. - - POLLINATION by insects. Honey in some is produced on the - perianth (see Tulipeæ), in others by glands on the carpels (in - the septa and parietal placentæ, septal glands): _Hyacinthus_, - _Allium_, _Anthericum_, _Asphodelus_, _Yucca_, _Funckia_, - _Hemerocallis_, etc. Some _Allium_-species are protandrous. - _Fritillaria_ is visited by bees, _Lilium martagon_ by moths, - _L. bulbiferum_ by butterflies, _Phormium_ (New Zealand) by - honey-birds. - - [Illustration: FIG. 306.--Aloë.] - - About 1,580 species; rare in cold climates; their home is in - sunny plains with firm, hard soil, and warm or mild climate, - particularly in the Old World (S. Africa; As. Steppes; - Mediterranean); at the commencement of spring the flowers - appear in great profusion, and after the course of a few weeks - disappear; during the hot season their life lies dormant in the - bulb, hidden underground. The woody species are tropical.--The - majority of the _introduced_ Liliaceæ (_Fritillaria imperialis_, - Crown-imperial; _Lilium candidum_; _Tulipa gesneriana_; - Hyacinth; _Muscari_-species; _Scilla_-species; _Ornithogalum - nutans_; _Hemerocallis fulva_ and _flava_; _Asphodelus luteus_ - and _albus_) come from the Mediterranean and W. Asia; _Funckia_ - from China and Japan; several Lilies from Japan and the - Himalayas; _Agapanthus_ from the Cape; _Allium sativum_ is a - native of the Kerghis-Steppes; _A. cepa_ from Persia (?); _A. - ascalonicum_ is not known wild (according to others a native of - Asia Minor), perhaps a form of _A. cepa_; _A. schænoprasum_ from - the N. temp. region. - - Many bulbs have pungent properties; many Onions are used as - culinary plants. The bast fibres of _Phormium tenax_ (New - Zealand Flax) are used technically. Dyes are obtained from the - _Aloe_; gum for varnish from the stem of _Xanthorrhæa hostile_ - and _australe_. OFFICINAL; “Aloes,” the dried sap of S. African - species of _Aloe_ (_A. Africana_, _A. ferox_, etc.); the - bulb known as “Squills” from _Urginea_ (_Scilla_) _maritima_ - (Mediterranean). - -Order 3. =Convallariaceæ.= This order differs from the Liliaceæ in -having the _fruit a berry_ (Fig. 308) and _in never being bulbous_; the -seeds are less numerous. - -=A.= CONVALLARIEÆ, LILY OF THE VALLEY GROUP. Rhizome (Fig. 307) and -normal foliage-leaves.--_Polygonatum_: rhizome creeping; aerial -shoot leafy, bearing the flowers in racemes in the axils of the -foliage-leaves; perianth tubular. _P. multiflorum_ (Solomon’s seal), -_P. officinale_, etc.--_Majanthemum_: flower 2-merous; perianth -almost polyphyllous, spreading. _Smilacina. Streptopus_ (_S. -amplexifolius_; the flowers or inflorescence unite with the entire -succeeding internode).--_Convallaria_ (1 species _C. majalis_, Lily -of the valley); flowers in terminal racemes; 2 basal foliage-leaves; -perianth globose, bell-shaped. _Reineckea carnea_ (Japan, China) in -gardens.--_Paris_ (_P. quadrifolia_, Herb-Paris); flowers solitary, -terminal, 4-merous, polyphyllous; styles 4, free (approaching the -Colchicaceæ; it is also poisonous); a whorl of 4 (-more) 3-nerved, -reticulate leaves on each shoot.--Ornamental plants: species of -_Trillium_, _Aspidistra elatior_ (Japan). - - [Illustration: FIG. 307.--Rhizome of _Polygonatum multiflorum_: - _a_ bud; _b_ shoot; _c d_ scars left by shoots of previous - years.] - - [Illustration: FIG. 308.--_Smilax pseudosyphilitica_: _A_ shoot - of male plant; _C_ ♂-flower; _D_ berry, almost ripe; _E_ the same - in longitudinal section. _B Smilax syphilitica_: portion of - branch with base of leaf and tendrils.] - -=B.= ASPARAGEÆ, ASPARAGUS GROUP. Scale-like leaves and green -assimilating branches.--_Asparagus_: horizontal rhizome. The aerial -shoots are very richly branched; the numerous needle-like bodies upon -the plant are _leafless shoots_, which are crowded together in double -scorpioid cymes in the axils of the scale-leaves; the two first lateral -axes, placed outside to the left and right, generally bear flowers. -Polygamous.--~_Ruscus_ (Butcher’s broom) is a S. European _shrub_ with -_leaf-like_, ovoid or elliptical shoots (phylloclades) which are borne -in the axils of scale-like leaves, and bear flowers on the central -line. Diœcious. Stamens 3, united, anthers extrorse. _Semele androgyna_ -bears its flowers on the edge of the flat shoot.~ - -=C.= SMILACEÆ. _Smilax_ (Sarsaparilla) (Fig. 308); _climbing_ -shrubs with the leaf-sheath produced into tendrils. The leaves have -3–5 strong nerves proceeding from the base, and are reticulate. -Orthotropous or semi-anatropous ovules. Diœcious (Fig. 308 _C_, _E_). - - =D.= DRACÆNEÆ. Fruit in some a berry, in others a capsule. - The stem of DRACÆNA, when old, has the appearance of being - dichotomously branched; it has the power of increase in - thickness, and may become enormously thick. The Dragon-tree of - Teneriffe, measured by Humboldt, attained a circumference of - 14 m. and a height of 22 m.; the leaves are large, linear or - linear-lanceolate.--_Cordyline_ (East Asia), various species in - gardens and greenhouses (_Yucca_ is closely allied). _Astelia._ - - POLLINATION. _Paris quadrifolia_ and _Convallaria majalis_ - have no honey, and are chiefly visited by pollen-collecting - bees (in the absence of insect visits self-pollination takes - place); _Polygonatum multiflorum_ has honey secreted by septal - glands and protected by the base of the tubular perianth; it - is pollinated by humble-bees, etc. _Asparagus officinalis_ has - small, polygamous, greenish, honey-bearing flowers; the ♂-flower - is almost twice as large as the ♀; both have rudiments of the - opposite sex. - - About 555 species; especially from N. America, Europe, and - Central Asia. - - OFFICINAL: “Dragons’-blood,” a red resinous juice from the stem - of _Dracæna_ and the roots of some Central American species of - _Smilax_. The tuberous stems of the Eastern Asiatic _Smilax - glabra_ are officinal. The flowers of _Convallaria majalis_ - have been lately used as a substitute for _Digitalis_. Pungent, - poisonous properties are possessed by _Paris_. None of the - species are used as food, except the young annual shoots of - _Asparagus officinalis_, a shore-plant which is used as a - vegetable. - - Order 4. =Pontederiaceæ.= Flowers generally zygomorphic, - hypogynous, ☿, with handsome, white or violet, petaloid perianth - which forms a tube at its base. The stamens are inserted at - different heights in the perianth-tube, and are reduced to - three (in _Heteranthera_ seldom to one). In some the ovary is - trilocular with ∞ ovules (_Eichhornia_), in others reduced to - one loculus with one ovule (_Pontederia_). Fruit a capsule or - nut. Embryo as long as the abundant, mealy endosperm.--Tropical - water-plants (22 species) with peculiar sympodial branching, - nearly the same as in _Zostera_. Spikes without floral-leaves. - Many intercellular spaces in the stem and leaf.--In greenhouses: - _Eichhornia azurea_, _E. crassipes_ (both from tropical and - sub-tropical S. America); the latter has swollen petioles which - serve as floats and enable it to float freely on the water, - sending down its roots into the mud. _Heteranthera reniformis, - H. zosterifolia. Pontederia cordata._ - -Order 5. =Amaryllidaceæ (Narcissi).= The flower is _epigynous_, -otherwise exactly the same as in the Liliaceæ (6 stamens). The -majority, like these, are also _perennial_ herbs with bulbs and scapes. -The fruit and the other characters as in the Liliaceæ. The external -appearance is, however, very different. - -=A.= AMARYLLEÆ have bulbs and the leaves generally arranged in two -rows; the flowers are borne singly or in umbel-like inflorescences -on lateral scapes, while the main axis of the bulb is unlimited. -Beneath the inflorescence is an _involucre_ (Fig. 309).--_Galanthus_, -Snowdrop, has a polyphyllous perianth without corona; the three inner -perianth-leaves are emarginate and shorter than the outer; the anthers -dehisce apically. ~_Leucojum_ differs in having the perianth-leaves -equal in length.--_Amaryllis_ has a funnel-shaped perianth, entirely -or nearly polyphyllous, but somewhat zygomorphic. _Crinum; Hæmanthus; -Clivia._~--_Narcissus_ has a tubular _corona_, a ligular structure -arising from the perianth-tube exterior to the outer stamens. ~In -_Pancratium_ (Fig. 309) the corona is united with the filaments which -appear to spring from its edge. _Eucharis amazonica._~ - - [Illustration: FIG. 309.--_Pancratium caribæum._] - - =B.= HYPOXIDEÆ. The leaves, which are grass-like, dry, folded, - and in some hairy, spring from a rhizome, generally with a - divergence of 1/3. Flowers small, perianth polyphyllous, - persistent, on which account perhaps the Hypoxideæ may be - considered as the least altered type. The chief characteristic - is that the embryo is separated from the hilum. _Hypoxis_; - _Curculigo_ (_C. recurvata_, a favourite ornamental plant; S.E. - Asia). - - =C.= ALSTRŒMERIEÆ. (_Alstrœmeria_, _Bomarea_); stems long, - leafy, often climbing. - - =D.= VELLOSIEÆ (_Vellosia_, _Barbacenia_); stem woody, usually - dichotomously branched, with terminal, single flowers; it bears - numerous aerial roots which pierce the leaves and surround the - stem. Stamens often (by splitting) 6–18. High table-lands of S. - America and S. Africa. - - =E.= AGAVEÆ. Very similar to the Bromeliaceæ both in their - distribution (nearly all American) and in external appearance. - They appear as gigantic bulbous plants with perennial, aerial, - generally short stem, and perennial, large, lanceolate or - linear, stiff, thick, and often thorny leaves, which form a - large rosette; after the course of several (8–20) years the - terminal inflorescence is developed, which is 10–12 m. high, - paniculate, and freely branched. Before the inflorescence - expands, a large quantity of sugar-containing sap is collected - from _A. americana_ by removing the terminal bud; this on - distillation yields “pulque,” the national drink of Mexico. - After flowering the entire shoot dies, but the subterranean - lateral shoots survive and reproduce the plant.--_Agave - americana_, etc.; _Fourcroya_; _Polianthes tuberosa_ (Tuberose; - Central America). - - DISTRIBUTION. The 650 species are chiefly natives of S. Africa - and S. America. _Clivia_, _Hæmanthus_, _Amaryllis_ are from the - Cape; _Narcissus_ from S. Europe, whence many species have been - introduced; _Galanthus_ and _Leucojum_ are especially from S. - and Central Europe, and from the Caucasus. - - USES, few, except as ornamental plants: _Galanthus nivalis_; - _Leucojum_; _Narcissus pseudonarcissus_, _N. poeticus_, _N. - jonquilla_, _N. tazetta_, etc.; _Amaryllis_, _Alstrœmeria_, - _Eucharis_, _Crinum_, _Vallota_, etc. The vascular bundles of - the various species of _Agave_ (_Agave rigida_, var. _sisalana_, - sisal hemp,) are used for cordage, etc. - -Order 6. =Bromeliaceæ.= The flowers are hypogynous, epigynous or -semi-epigynous; the perianth is divided into _calyx_ and _corolla_; -stamens 6. The fruit is a capsule or berry with many seeds. Endosperm -_mealy_, embryo small, at the edge of the endosperm, but not enclosed -by it. - - [Illustration: FIG. 310.--_Aechmea miniata._] - - [Illustration: FIG. 311.--Multiple-fruit of _Ananassa sativa_.] - -Perennial herbs with a very _characteristic appearance_ (Fig. 310); -the stem is most often short, thick, and crowned by a _rosette_ of -many leaves, which are long, often very narrow, _leathery_, stiff, and -with a _spiny_ edge; they are usually channeled, completely closing -round each other, with their edges forming a tightly closed hollow, in -which generally water is collected (this among other things insulates -the inflorescence and thus prevents the access of creeping insects, -such as ants). The presence of numerous stellate, water-containing -hairs often gives the leaves a grey appearance, and the layers of -cells beneath the upper epidermis of the lamina form an “aqueous -tissue,” which serves as a protection against the rays of the sun and -regulates the evaporation. The stomata are often situated in furrows -on the underside of the leaf, and hence cause a striped appearance. -They _are all American_ (525 species), especially from S. America, -where they live partly as epiphytes _on trees_, partly in the _clefts -of rocks_, often on the steepest slopes, to which they firmly attach -themselves by aerial roots; some are terrestrial. The stem is seldom -tree-like or many metres in height (_Puya_, in Chili; _Hechtia_, in -Mexico). _The inflorescence_ is a terminal spike, raceme, or panicle, -often with large and brightly-coloured floral-leaves. The flowers are -without scent. The seeds, in the species whose fruit is a capsule, -are often provided with wings (hairs, expansions, etc).--_Ananassa -sativa_, Pine-apple (W. Indies, Central America) is cultivated for the -sake of its juicy, aromatic fruits, which coalesce with their fleshy -bracts and form a large spike-like fruit-cluster (multiple-fruits,[29] -Fig. 311) bearing on its apex a leafy shoot, which may be used as a -cutting. Seeds very rarely developed.--_Tillandsia_ (_T. usneoides_ is -a filamentous, richly branched, rootless epiphyte hanging in masses -from trees; Trop. Am.), _Aechmea_, _Billbergia_, _Pitcairnia_, etc. - - USES. The leaves of the Pine-apple, in its native country, are - used for the manufacture of cloth. - - Order 7. =Hæmodoraceæ.= 120 species; in all parts of the world - except Europe; perennial, often tomentose and resembling - the Bromeliaceæ, Iridaceæ and Amaryllidaceæ. _Hæmodorum_ - (Australia).--To this order belong _Ophiopogon_, _Peliosanthes_, - _Sanseviera_, and others. - -Order 8. The =Iridaceæ= have _epigynous_, hermaphrodite flowers with -petaloid perianth as in the Amaryllidaceæ, but the _interior whorl of -stamens is entirely suppressed_, and the 3 developed _outer_ stamens -have _extrorse_ anthers (Fig. 279); there is 1 style with 3 large, -generally _more or less leaf-like branches bearing the stigmas_. -Ovary and capsule as in the Amaryllidaceæ and Liliaceæ.--Perennial -herbs; _bulbs are rarely found_, but horizontal rhizomes, corms, etc., -take their place. The leaves are (except _Crocus_) as in the _Iris_, -_two-rowed_, _equitant_ and _sword-like_. Flowers or inflorescences -terminal. - -The _Iris_ (Flag) has a horizontal rhizome. The flowers are borne in -the leaf-axils in fan-like inflorescences (rhipidium). The branches of -the style are large and _petaloid_; on their under surface may be seen -a small projecting shelf (Fig. 312 _a_) having on its upper surface the -stigmatic hairs. Beneath the branches of the style are 3 well protected -stamens, and immediately outside these the external perianth-leaves. -~The honey is secreted in the perianth-tube, and the insects, -endeavouring to obtain it through the narrow passages at the base of -the stamens, settle upon the outer perianth-leaves, which are bent -backwards and often very hairy along their central line. The insects -then rub their backs on the anthers just above them, beneath the -branches of the style; they readily deposit the pollen on the stigma -of another flower as they enter it, but cannot do so in withdrawing, -since the stigma is pushed back, and self-fertilisation is thus -avoided. The stylar branches lie close to the outer perianth-leaves, -which are just beneath them, or separated by a distance of only 6–10 -mm.; the first form of flower is adapted for _Rhingia rostrata_, the -latter for bees~.--_Crocus_ has vertical, _tuberous_, underground stems -surrounded by the leaf-sheaths (corms), and terminal flowers; the -linear leaves _are not equitant_, but have two longitudinal furrows -on the under side. The perianth is gamophyllous and funnel-shaped. -The stylar branches (stigmas) are fleshy, _rolled together in the -shape of a horn_, and split along the edge.--_Gladiolus_ has corms -like the _Crocus_; spikes with slightly zygomorphic, almost bilabiate -flowers, most frequently turning to one side. Position of the leaves -as in the Iris.--~_Diplarrhena_ has 2 fertile and 1 barren stamen; -_Hermodactylus_ has a unilocular ovary with 3 parietal placentæ. -_Cypella_ and _Tigridia_ have bulbs.~ - - [Illustration: FIG. 312.--_Iris pseudacorus._ One external and - two internal perianth-leaves, and one of the stylar-branches - have been removed, _y_ The outer, _i_ the inner perianth-leaves; - _g_ stylar-branch; _a_ stigma; _s_ anther. The ovary is seen in - longitudinal section.] - - 770 species; chiefly in the countries round the Mediterranean, - and in Africa, especially the Cape (_Gladiolus_, _Ferraria_, - _Moræa_, _Galaxia_, _Sparaxis_, _Antholyza_, _Tritonia_, - _Ixia_, etc.), Australia and Tropical America (_Sisyrinchium_, - _Tigridia_, _Cipura_, _Cypella_, etc). A great number are - ornamental plants: the cultivated _Crocus_-species are from the - South of Europe and Asia; _Gladiolus communis_ from S. Europe; - the other species principally from S. Africa. The native species - of _Iris_ are _I. pseudacorus_ (yellow) and _I. fœtidissima_. - - OFFICINAL: the stigmas of _Crocus sativus_ (Oriental, cultivated - in France, Spain, Italy, and Austria), used as a colouring - matter, saffron; the rhizomes of the S. European _Iris - florentina_, _pallida_, and _germanica_ (“Orris-root”). - - [Illustration: FIG. 313.--_Dioscorea batatas_: _A_ ♂-plant; _B_ - ♂-flower; _C_ ♀-plant (nat. size); _D_, _E_ ♀-flowers (mag.); _F_ - seed; _G_ embryo.] - -Order 9. =Dioscoreaceæ.= Perennial herbs with fleshy, often very large -_tuberous rhizomes_ (or roots); _twining_ stems; leaves stalked, often -arrow- or heart-shaped, lobed, _palminerved_ and _finely reticulate_ -as in the Dicotyledons (Fig. 313). The flower is _diclinous_ (most -frequently _diœcious_), regular, _epigynous_, _small_, and of a -_greenish colour_, but otherwise typical (Pr3 + 3, and A3 + 3, or G3); -in most instances 2 ovules are placed one above the other in each -loculus. The inflorescence is a _spike_ or _raceme_, sometimes richly -branched and paniculate.--The order approaches most nearly to the -Amaryllidaceæ. - -_Tamus_ (Bryony) has a berry, _Dioscorea_ (Yam) a thin-walled, 3-edged -or 3-winged capsule (Fig. 313). Both have subterranean or aerial -tubers; the Yam very often also developes tubers in the axils of the -foliage-leaves; tuberous roots are said to occur in _D. batatas_. -The tubers of many species of Yams (_D. batatas_ from China and -Japan, _D. alata_, South Sea Islands and India, _D. bulbifera_) are -a very important source of food in the Tropics, especially the -first-named.--_Testudinaria_; _Rajania_.--~The tuberous stem of -_Tamus communis_ and _Testudinaria elephantipes_, and some species -of _Dioscorea_ is formed from one single internode (epicotyl), and -the aerial shoots are developed from adventitious buds; in _T. -elephantipes_ the stem is aerial, and covered with thick scales of -cork, regularly arranged, and separated by grooves.~ - - Tropical order (167 species); 2 species (_Tamus communis_ and - _Borderea pyrenaica_) in Europe. - - - Family 6. =Scitamineæ.= - -The flowers belong to the ordinary monocotyledonous type. They are -hermaphrodite, _epigynous_, and have either a petaloid perianth, or -calyx and corolla; they are, however, _zygomorphic_ or _unsymmetrical_, -and of the stamens most frequently only one is _completely developed_, -the others being generally represented by petaloid staminodes. The -ovary has 3 loculi, more rarely it is unilocular with the suppression -of 2 loculi. Endosperm is absent (except _Zingiberaceæ_); but, on the -other hand, there is a _large perisperm_. To this family belong large, -glabrous, especially _perennial herbs_ with rhizomes; leaves large, -distinctly divided into sheath, stalk, and blade, the latter being more -or less elliptical or lanceolate, entire, with pinnate venation, and -always with a very _well-pronounced midrib_, gradually tapering towards -the apex, and giving off numerous branches, which run outwards, towards -the margin, at a larger or smaller angle; these _lateral veins_ are -closely packed, and parallel, but with only weak, connecting branches -between them; the leaves, therefore, are easily torn pinnately (Figs. -314, 317). The leaf-sheaths close tightly round each other and form a -false stem. - -This very natural family comprises orders closely connected with each -other, but is not itself nearly allied to any other family. First in -the series stands:-- - -Order 1. =Musaceæ.= The _petaloid_ perianth is strongly zygomorphic, -the anterior leaf being very large (a kind of “labellum”), the -posterior one small; only the posterior stamen is wanting, or is -rudimentary, the other five are developed, and have quadrilocular -anthers; ovary, 3-locular. Seed with straight embryo in mealy perisperm. - - [Illustration: FIG. 314.--Two _Musa_-species.] - -The best-known genus is _Musa_, the Banana (Fig. 314). From the -short rhizome arise enormously large, spirally-placed leaves, whose -sheaths envelope one another, and form an apparently aerial stem, -several metres in height. The inflorescence is a terminal _spike_ -with floral-leaves placed spirally, and sometimes magnificently -coloured; in the axils of each of these several flowers are situated -in two transverse rows (accessory buds); the lowest flowers in the -inflorescence are ♀, the central ones ☿, the upper ones ♂, so that -fruits are only found in the lower region of the inflorescence, the -remaining portion persisting as a naked axis after the floral-leaves -and flowers have fallen off; the inflorescence terminates in an ovoid -bud formed by the flowers which have not yet opened (Fig. 314, the -left-hand figure). The perianth-leaves are united (except the posterior -one). The fruit (known as a “Banana”) is a _berry_, having the form of -a smooth, short, three-cornered Cucumber (as much as 30 cm. in length); -inside the tough skin is found a farinaceous, aromatic pulp. No seed -is developed in the cultivated species.--~Several _Musa_-species are -cultivated in the Tropics for the sake of the fruit (_M. paradisiaca_, -_M. sapientum_); for the fibrovascular bundles, _M. textilis_ (Manilla -Hemp).--Their home is, no doubt, the Tropics of the Old World; they -were introduced into America before the arrival of Europeans. _Musa -ensete_ has dry, leathery fruits; an ornamental plant.~ - - In _Musa_ the barren, posterior stamen belongs to the inner - whorl; and also in _Strelitzia_ and _Ravenala_; the latter - may have all 6 stamens developed. In _Heliconia_, on the - contrary, it belongs to the outer whorl; in _Heliconia_ the - perianth-leaves are differently arranged, and there is only - one ovule in each loculus. The three latter genera have dry - fruits and leaves arranged in two rows. In the “Travellers’ - Palm” (_Ravenala madagascariensis_) the foliage-leaves form an - enormous fan.--Tropical; about 50 species. - -The order may be divided as follows:--1. Museæ: _Musa_, _Ravenala_, -_Strelitzia_ in the Old World. 2. Heliconiæ: _Heliconia_ in the New -World. - - [Illustration: FIG. 315.--Diagram of a _Zingiberaceous_ flower - (_Kæmpferia ovalifolia_): _b_ bract; _v_ bracteole; _k_ calyx; - _p^1_, _p^2_, _p^3_ the petals; _sst_, lateral staminodes - (“wings”); _lab_ labellum (formed of two staminodes); _st_ the - fertile stamen; * position of suppressed stamen. The ovary is in - the centre of the diagram.] - -Order 2. =Zingiberaceæ.= Perianth most frequently divided into _calyx_ -and _corolla_. Calyx gamosepalous. Only 1 _fertile stamen_ (the -posterior, Fig. 315, belonging to the inner whorl) with quadrilocular -anther, which encloses the style in a furrow; the 2 stamens in the -outer whorl are staminodes, the median one (the anterior) is wanting. -The 2 lateral staminodes of the inner whorl form the “labellum” (Fig. -315 _lab_), which usually is the largest segment of the flower, and -is often bilobed. Ovules many. The fruit in some is a leathery, -3-valved capsule, with loculicidal dehiscence; in others it is more or -less berry-like and indehiscent, or irregularly dehiscent. Straight -embryo.--The aerial stem is seldom developed to any extent, and the -inflorescences, which are (compound) spikes or racemes, often with -coloured floral-leaves, spring in some (_e.g. Zingiber officinale_) -directly from the rhizome. The leaves are arranged in two rows.--The -ovary in a few instances (_Globba_ and others) is unilocular, with 3 -parietal placentæ. - - They are perennial herbs with fleshy and tuberous rhizomes, - which are used as condiments and in medicine on account of their - pungent and aromatic properties and also for starch, dyes, etc. - OFFICINAL: _rhizomes_ of _Zingiber officinale_ (Ginger, unknown - wild, but cultivated generally in the Tropics), of _Curcuma - longa_ (Turmeric, a dye, E. India) and _C. zedoaria_, of _C. - angustifolia_ and others (as E. India Arrowroot), of _Alpinia - officinarum_, China (galangal). “Preserved Ginger” from _Alpinia - galanga_. Similar aromatic materials (volatile oils) are present - also, for example, in _the fruits_; Cardamom fruits and seeds - (from _Elettaria cardamomum_, China, seldom from _E. major_). - - 315 species; Tropics, preponderating in the Eastern Hemisphere, - India, and especially S. Asia, whence all the aromatic - species originate; they are now commonly cultivated in the - Tropics. Some are ornamental plants in greenhouses, _e.g._ - _Hedychium_, _Costus_, etc. _Globba_ (with axillary buds in the - inflorescence, as in _Ficaria_), _Renealmia_, _Kæmpferia_. - - [Illustration: FIG. 316.--Flower of _Canna_: _f_ ovary; _pa_ - calyx; _pi_ corolla; _l_ labellum; _st_ stamens; _an_ anther; _g_ - stigma; α and β staminodes.] - -Order 3. =Cannaceæ.= American herbs without aromatic properties. -Flowers asymmetric (Fig. 316). Calyx polysepalous. The stamens are -_petaloid_ (Fig. 316 _st_) and barren with the exception of one (the -posterior), which bears on one of its _edges_ a bilocular anther; -another, which is especially large and coloured, is termed the -_labellum_. The style is compressed and leaf-like, with a small stigma -at the apex. Ovules numerous in the 3 loculi. The capsule is furnished -with warts or soft prickles. _Embryo straight._ - -_Canna_ (30 species; Trop. Am.). The inflorescence is a terminal -spike with 2-flowered unipared scorpioid cymes in the axils of the -floral-leaves. Ornamental plants: _Canna indica_, etc. - -The diagram of the andrœcium of the Cannaceæ and Marantaceæ may be -represented in the following manner (calyx, corolla and gynœceum being -omitted):-- - - CANNACEÆ. MARANTACEÆ. - - _w_ _w_ _w_ _w_ - _st_ _st_ - _w_ _lab_ _wi_ _c_ - * * - - _w_ The lateral staminodes, “wings;” _st_ fertile stamen; * the - suppressed stamen; _lab_ labellum; _c_ hood; _wi_ inner-wing. - - The labellum of the Cannaceæ corresponds with the hood of the - Marantaceæ and not with the labellum of the Zingiberaceæ. - - [Illustration: FIG. 317.--_Calathea zebrina._] - -Order 4. =Marantaceæ.= The flower is asymmetrical. Only 1 or 2 of the -3 stamens in the outer whorl are present as staminodes; in the inner -whorl 2 are petaloid and of the sixth stamen one-half is developed as a -staminode and the other half bears a bilocular anther. One ovule only -in each loculus. The style is strongly curved and at first enclosed -in one of the staminodes (hood) of the inner whorl; later on it -springs elastically forward towards the other staminode (inner-wing) -of the same whorl. The stigma is very oblique or 2-lipped. Two of the -three loculi of the ovary, in some (_Maranta_, _Thalia_) become small -and empty. Embryo _curved_. Leaves in two rows, with sheath, stalk, -and blade (Fig. 317); at the base of the last is a _characteristic -swelling_ (_articulus_).--~_Phrynium_, _Calathea_, _Stromanthe_, -_Ctenanthe_, _Saranthe_, etc. About 150 species; tropical, especially -America. The starch of the rhizome of _Maranta arundinacea_ is -OFFICINAL, “West Indian Arrowroot.”~ - - - Family 7. =Gynandræ.= - -The flowers are hermaphrodite and constructed on the ordinary 3-merous, -pentacyclic type with petaloid, _epigynous, strongly zygomorphic_ -perianth, and generally _one-stamened_ by the suppression of the -other 5 stamens. The family has derived its name from the fact that -the stamen is united with the style into a “_stylar column_” (except -_Burmanniaceæ_). All are herbs; many grow as epiphytes on other plants. - - This family and the Scitamineæ occupy correspondingly high - positions among the Monocotyledons; these two families may - therefore be placed close together, although one cannot be - derived from the other. The first of the two orders is very - small, but the second is very rich in species. The Apostasieæ - are best classed with the Orchidaceæ and have no independent - place. - -Order 1. =Burmanniaceæ.= This order forms a transitional link between -the Gynandræ and the epigynous Liliifloræ (_Amaryllidaceæ_), in having -a 6-leaved perianth, and 6–8 stamens; but some have a labiate perianth -(the median perianth-leaf of the _outer_ whorl being very large). The -ovary is most frequently unilocular with three parietal placentæ; but -in some it is 3-locular with axile placentation. Capsule. Seeds ∞, -small, with _endosperm_. The relationship to the Orchidaceæ is shown -especially in the very imperfectly developed embryo and in the ovary. -Small, tropical herbs (59 species); some are saprophytes. - - [Illustration: FIG. 318.--_A_ Diagram of an Orchid-flower. _B_, - _Cephalanthera_. Stylar-column: _a_ anther; _s_ stigma; at the - foot are seen scars indicating the position of the parts which - have been removed.] - -Order 2. =Orchidaceæ.= The epigynous, petaloid perianth is strongly -zygomorphic in having the _posterior_ leaf of the interior whorl, the -_lip_ (labellum), differing from all the other leaves in form, size, -and colour (except _Apostasieæ_); the position of the labellum is very -frequently reversed, being turned _forwards and downwards_ by the -twisting of the ovary (Fig. 318 _A_). _Only_ 1 of the stamens--the -anterior of the external whorl--is developed and bears an anther (by -the twisting of the ovary it is turned posteriorly and upwards); -the others are entirely wanting (indicated by * in Fig. 318 _A_) -or present as staminodes (Fig. 318 _A_, δ δ) (except _Apostasieæ_, -_Cypripedileæ_); the filaments are united with the style to form a -column (Fig. 318 _B_), the _stylar-column_[30] (_gynostemium_), and -the anther (_a_) is thus placed on its apex and exactly behind or over -the stigma (_s_). The anther is 4-locular; the pollen-grains do not -separate (except _Apostasieæ_, _Cypripedileæ_) but remain united either -in tetrads or in masses, which correspond to a pollen-mother-cell -(Fig. 320 _C_, _D_, _E_); or the pollen-grains, formed in each of -the two anther-halves, remain united and form one or a few wax-like -masses (pollen-masses, pollinia). The 3 carpels form a _unilocular -ovary_ with 3 parietal, deeply bifid placentæ (except _Apostasieæ_, -_Selenipedilum_). Only the two lateral carpels are prolonged and -developed into the stigma (Fig. 318 _B_, _s_), while the one lying in -the median line, which is situated just within the anther (Fig. 318 -_A_), becomes either rudimentary or developed into the “_rostellum_” -(“a small beak”), on which the sticky bodies (_glandulæ_) arise; by -aid of these the heavy, connected pollen-masses may be glued to the -insects which visit the flower, and pollination is thus secured (in -_Apostasieæ_ and _Cypripedileæ_ the 3 carpels each contribute to the -formation of the stigma). The fruit is a _capsule_ which most often -dehisces _by 6 valves_, 3 of which are broader and bear the placentæ, -and 3 alternating with them are narrower and barren (except _Vanilla_). -The very numerous and exceedingly small seeds have _no endosperm_, -and have a somewhat _spherical embryo without any trace of external -organs_. The testa is membranous and loose. - -The Orchids are _all perennial herbs_ with diverse habits and varying -morphological structure (see the genera); the leaves are scattered, -of the usual Liliaceous form, and the inflorescences in all cases are -_racemes or spikes_ (sometimes branched), with subtending bracts, but -without bracteoles. - -The forms which are the least modified are described first. - -=1.= APOSTASIEÆ. The perianth-leaves are almost alike and free. The -column is straight, with 3 equally-developed stigmas. _Neuwiedia_ has -3 perfect stamens (1 median of the outer whorl, and 2 lateral of the -inner whorl); _Apostasia_ has only 2 perfect (inner lateral) and one -barren (the median of the outer whorl), which however may be entirely -wanting. The 3 _posterior_ stamens are entirely suppressed. The pollen -is powdery. The ovary is 3-locular with axile placenta. 7 species -(Tropical East India, Australia). - - [Illustration: FIG. 319.--_Cypripedilum calceolus_: 1 front view - of the flower; 2 lateral view, after the removal of all the - perianth-leaves with the exception of the labellum, which has - been divided longitudinally; 3 the stylar-column; _ov_ ovary; - _s_-_s_ exterior, _p_ interior perianth; _p’_ the labellum; _a_ - the two fertile stamens; _a’_ the staminode; _st_ the stigma; _i_ - entrance for the insects; _ex_ exit.] - -=2.= CYPRIPEDILEÆ.[31] The flower is strongly zygomorphic with a large -boat-shaped labellum. There are two perfect stamens belonging to the -_inner_ whorl, and the median anterior (later on the posterior) stamen -of the outer whorl is transformed into a large, barren, shield-shaped -body (Fig. 319). _Selenipedilum_ has a 3-locular ovary, but -_Cypripedilum_ (Ladies’-slipper) has a unilocular ovary with 3 parietal -placentæ--the typical structure for the Orchids. The pollen-grains -are _separate_ (not in tetrads) and all the 3 lobes of the stigma are -constructed to receive them. This group is therefore, next to the -Apostasieæ, the least modified among the Orchids; in all the following -groups, one of the lobes of the stigma is differently developed from -the others, and there is only one stamen.--Terrestial Orchids.--~The -pollination of _C. calceolus_ is effected by the forcible entrance of -insects into the boat-shaped labellum (Fig. 319 _p’_) at _i_, and their -escape at _ex_ (in 2) where the anthers are situated; in this way the -stigmas will first be touched and then the anthers. The pollen-grains -are surrounded by a sticky mass in order that they may adhere to the -insects.~ - -=3.= NEOTTIEÆ. The majority are terrestrial Orchids with creeping, -sympodial rhizomes; the blades of the leaves are not detached from the -stem at joints, and have convolute vernation. The anthers do not drop -off, but persist in the withered condition; their _apex_ is brought -in contact with the rostellum (acrotonous Orchids). The pollen-grains -are united in _tetrads_, which, however, often hang loosely together -in pollinia, attached to a sticky part of the rostellum (“adhesive -disc”), so that they adhere to the insects, and are by them transferred -to the stigmas. _Spiranthes. Listera_; _Neottia_. ~_N. nidus-avis_ -(Bird’s-nest) is brown (it has little chlorophyll) in colour, has -no foliage-leaves, and lives mainly as a saprophyte; the rhizome -is studded with unbranched, fleshy roots which may form buds at -their extremities.~--_Vanilla_ climbs by aerial roots. The fruit -is fleshy and hardly opens, or does so irregularly.--_Epipactis_, -_Cephalanthera_.--_Epipogon_ and _Limodorum_ are saprophytes without -chlorophyll. - - [Illustration: FIG. 320.--A Flower of _Orchis maculata_ (front - view): a stamen; _b_ the cup; _n_ the stigmas; _x_ staminodes; - _sp_ the spur; _spe_ the entrance to it; _sm_-_sl_-_sl_ exterior - perianth-leaves; _pm_ the labellum, and _pl_-_pl_ the other 2 - interior perianth-leaves. _B-E Orchis mascula_: _B_ lateral - view of the column; _C_ a pollinium with massulæ (_p_), caudicle - (_c_) and adhesive disc (_d_); _D_ caudicles with the cup (_r_), - front view; the latter is depressed so that the adhesive disc is - seen lying inside it; _E_ a pollinium, more highly magnified; - some massulæ are removed. _F Ophrys aranifera_: rostellum and - the base of the anther-loculus; an adhesive disc is seen on the - right.] - -=4.= OPHRYDEÆ. Anthers 2-locular, not falling off, on a very short -column. The anther is united at _its base_ with the rostellum -(_basitonous_ Orchids, Fig. 320 _A_, _B_), while in all other Orchids -it is connected at the apex (acrotonous Orchids). The pollen-grains -in each loculus are united into small “masses” (massulæ), each of -which corresponds to a pollen-mother-cell in the anther, and which -hang together by elastic threads (Fig. 320 _C_, _E_). Each pollinium -is attached at the base by a stalk (caudicle) to an adhesive disc, -formed by the modified stigma (rostellum), and is easily liberated -from it (Fig. 320 _C_, _D_, _F_). The pollinium, which is formed in -an anther-loculus, together with its caudicle and adhesive disc, is -termed “pollinarium” (Fig. 320 _C_).--All Ophrydeæ are terrestrial with -_tuberous roots_, two of which are present in the flowering period, an -older one (from the preceding year) containing the nourishment for -the flowering-shoot of the year, and a young one which is intended to -contain the reserve material for the following year. Inflorescence -terminal. - -_Orchis._ The lip has a spur; each of the club-like pollinia is -attached to its own adhesive disc, the discs being enclosed in a common -pouch formed by the rostellum (Fig. 320 _C_, _D_). ~Tubers ovate, -undivided: _O. morio_, _mascula_; tubers palmate: _O. incarnata_, -_maculata_, _majalis_.~--_Ophrys_; no spur, the two adhesive discs -are each enclosed in a separate pouch (Fig. 320 _F_).--_Anacamptis_ -and _Serapias_ have one adhesive disc.--_Habenaria_, _Gymnadenia_, -_Platanthera_, _Herminium_, _Nigritella_, _Cœloglossum_, etc., have -naked adhesive discs (no rostellum). - - =5.= EPIDENDREÆ. Acrotonous Orchids with deciduous anthers - (except _Malaxis_); 2-8 wax-like pollinia, with or without - caudicles; generally no adhesive discs. _Malaxis_ (the flower is - twisted through a complete circle, causing the labellum to be - turned upwards), _Sturmia_ and _Corallorhiza_[32] (Coral-root); - the latter has a creeping, coral-like rhizome _without roots, - and is destitute of chlorophyll_ except in the ovary. The - other two somewhat resemble the tropical Orchids in having the - lower internodes of the axis of the inflorescence tuberous. - _Liparis_; _Calypso_. Most of the genera are tropical epiphytes - and many have aerial, green tubers formed from one or more - stem-internodes; _Dendrobium_, _Eria_, _Phaius_, _Bletia_, - _Epidendrum_, _Cattleya_, _Lælia_, _Pleurothallis_, _Restrepia_, - _Masdevallia_, _Bulbophyllum_, etc. - - =6.= VANDEÆ. These resemble the preceding but have only 2 - wax-like pollinia in each anther, which are attached by a - caudicle to the adhesive disc of the rostellum. Nearly all are - tropical epiphytes. _Stanhopea_, _Catasetum_, _Maxillaria_, - _Oncidium_, _Vanda_, _Polystachya_, etc. - - 6,000 (10,000?) species. The majority live in the Tropics and - occur, especially, as epiphytes on trees or in the crevices of - rocks, to which they are attached by aerial roots. These _aerial - roots_, like those of Araceæ, are covered by several layers of - spirally-thickened cells (tracheides) which contain air and form - the velamen--an apparatus to absorb moisture from the air. The - roots have a white appearance when the cells are filled with - air, which changes to a greenish hue when they are filled with - water, the chlorophyll then shining through. They generally - have horizontal rhizomes; the ascending shoots, which bear the - foliage-leaves, may vary, but they very often swell and assume - the form of a tuber, which persists for several years fresh and - green after the leaves have fallen off (Fig. 321). _Vanilla_ - is an exception (see above). Our Orchids are all terrestrial - (or marsh-plants); the largest number of species is found in - calcareous soils. - - POLLINATION takes place principally by means of insects, - but self-pollination occurs in some. The lip serves as a - landing-stage for the insect visitors, which, on sucking the - honey, cause the adhesive discs, with the pollinia attached to - them, to adhere to their bodies (generally to the probosces) - and so carry them away to other flowers. In some species parts - of the flower are sensitive or irritable, which has some - connection with the pollination. Without doubt there are a great - many biological differences which are closely connected with - the infinite multiplicity of forms; Darwin (1862) has already - shown an enormous variety, never even dreamt of before, in the - European species. The genus _Catasetum_ has ♂-♀-and ☿-plants - with flowers of such different appearances that they have - been classed in various genera (_Myanthus_, _Monacanthus_). - _Platanthera_ is pollinated by hawk-moths; _Ophrys_, by flies; - _Epipactis latifolia_, by wasps; _Orchis_, by bees, especially - humble-bees, etc. - - [Illustration: FIG. 321.--_Chysis bractescens._] - - The DISTRIBUTION OF SEEDS is effected by the wind, the seeds - being so exceedingly small and light. Many species moreover have - peculiar, elater-like, fine, hygroscopic hairs in the ovary, - which eject the seeds in a manner similar to the elaters of the - Liverworts. - - The USES are few, mostly as ornamental plants in conservatories. - The tubers of several _Orchis_-species are OFFICINAL; they - contain starch and mucilage and are used us “salep.” The fruits - of _Vanilla planifolia_ are used as condiments and differ from - other _Orchid_-fruits in being rather fleshy and in dehiscing - irregularly; the seeds are very small, shining and black. - - - Class II. =Dicotyledones.= - -In this class THE EMBRYO has 2 seed-leaves, a rule from which there are -few exceptions (_e.g. Ficaria_, _Cyclamen_, _Pinguicula_, certain -species of _Corydalis_, with only 1; and a few, mostly parasitic -forms, _e.g. Monotropa_, _Orobanche_, _Pyrola_, entirely without -cotyledons). On germination the cotyledons nearly always raise -themselves above the ground as green, assimilating leaves and are then -termed aerial or epigean, in contradistinction to the underground or -hypogean which are always buried. The structure of the seed varies -(endospermous or exendospermous); the embryo may be straight or curved. -In many instances the primary root grows as a vigorous tap-root, -with weaker branches arising acropetally (in annuals, biennials, -many perennials, especially woody plants); but in a large number of -herbaceous perennials, which have rhizomes, the root behaves very much -as in the Monocotyledons. The roots generally increase in thickness by -means of a cambium. - -THE STEM, when seen in transverse section, has its vascular bundles -arranged in a ring; in reality, however, they form a kind of -cylindrical network in the stem; the bundles are open, and thickening -takes place by means of a cambium; annual rings are formed in the -perennial stems. There is a rich and very varied form of _branching_. -The two first leaves of a shoot (fore-leaves) are placed nearly always -to the right and to the left; the same arrangement is found in the two -first leaves developed on the flower-stalk, and these are, as a rule, -the only two; they are found below the calyx and are usually termed the -“_bracteoles_.” It has become customary to indicate the bracteoles by -the letters α and β, according to their sequence of growth, and in that -sense these letters will be employed in the following diagrams. - -THE ARRANGEMENT OF THE LEAVES varies very much; there is also a great -variety of shapes in the leaves and their venation, but the linear -leaves, with parallel venation, so frequent in the Monocotyledons, -are seldom met with, as also the large sheaths (though the sheath is -well developed in the Umbelliferous plants); stipules occur much more -frequently. - -THE FLOWER is most commonly cyclic, but acyclic or hemicyclic forms -also occur. The type which may be taken as a basis consists in the -majority of instances, as in the Monocotyledons, of 5 whorls, of which -the 4 outer ones (calyx, corolla, and the 2 whorls of stamens) are -most frequently 4 or 5 in number and placed in regular alternation, -whilst the innermost one (the carpels) has generally fewer members, -probably on account of space (Figs. 360, 361, 421, 429, 487, etc.). -Trimerous (Figs. 384, 387, etc.) flowers, or those in which the members -of the flower are in threes or a multiple of three, also occur, as well -as dimerous flowers; other numbers are rare. It is of the greatest -importance in connection with the relative position of the members of -the flower to the axis and bract (orientation), whether the bracteoles -are typically present (even though they may not be developed), or -are typically absent. If there are 2 bracteoles present, then their -position in a pentamerous flower is often as follows: the first sepal -turns obliquely forward, the second is posterior and median, the -third obliquely forward, the fourth and fifth obliquely backward; -quincuncial æstivation is often found in these buds (Figs. 360, 429, -471, 475, 584). The first and third leaves, in the following chapters, -are most frequently alluded to as the “anterior,” the fourth and -fifth as the “lateral” leaves. The _reversed_ arrangement, with the -median sepal in the front, occurs for instance in _Papilionaceæ_ (Fig. -511), _Lobeliaceæ_ (Fig. 594), _Rhodoracecæ_. If any bracteoles are -present below a tetramerous flower, the relation is generally that -2 sepals (the first ones) stand in the median plane, the two next -ones transversely (Fig. 393), and the corolla then adopts a diagonal -position (Fig. 397); but a diagonal position of the calyx generally -shows that the flower is not, strictly speaking, tetramerous, as in -_Plantago_ (Fig. 567), _Veronica_ (Fig. 559 _C_) and others. - -If the bracteoles are _not_ typically present, then the position of the -sepals is changed accordingly, and the two outer sepals endeavour to -assume the position which the bracteoles would otherwise have occupied, -_e.g._ in _Primula_ (Fig. 547). Other positions are also found when the -number of bracteoles is more or less than two. - -The leaves which follow the sepals occupy definite positions with -regard to them, which we may consider later. An arrangement must, -however, be mentioned here; when the flower is “_diplostemonous_” that -is, has two whorls of stamens (thus, Sn, Pn, An + n), these may be -arranged in two ways. _Either_ the first-formed whorl of stamens, which -are termed the “calyx-stamens,” stands directly in front of the sepals -(that is “episepalous”), and is the _outermost_ whorl, and in this case -a regular alternation takes place between sepals, petals and the two -whorls of stamens, which is also continued into the carpels if their -number is the same as that of the other whorls: the carpels are then -placed opposite the sepals (Fig. 278) and the flower is _isomerous_ -and Gn should be added to the formula above. _Or_, the calyx-stamens -form the _innermost_ whorl, and the corolla-stamens, which are -subsequently formed (“epipetalous” stamens), stand _outside_ these -(Figs. 360, 429); if the number of carpels is the same as that of the -preceding whorls, they are often placed _right in front_ of the petals -and the corolla-stamens. The first-mentioned arrangement is termed -_Diplostemonous_, and the second _Obdiplostemonous_. ~Both arrangements -may be found in one and the same order, _e.g._ Caryophyllaceæ. The -size and relation of the members of the flowers, and also the contact -with other members in the early stages of their development, play an -important part in determining the arrangement.~ - -The great number of structural arrangements found in this enormously -large class, may, as is the case in the Monocotyledons, be further -varied by _suppression and division_ of certain leaves (especially the -stamens). Instances of this will occur in the following (Figs. 559, -568.--426, 441, 445, etc.). - -The Dicotyledons were formerly divided into 3 sub-classes: Apetalæ -(those without corolla), Sympetalæ or Gamopetalæ (those with the petals -united), and Choripetalæ or Polypetalæ (the petals not united). This -division has now been abandoned because it has been proved that the -Apetalæ were merely reduced or incomplete forms of the Choripetalæ, and -they have therefore been distributed among the various families of the -latter sub-class. - -With regard to the Sympetalæ (or Gamopetalæ) it may be stated that -they form to a very great extent a closely connected and natural -group, having in common not only the character that the corolla is -gamopetalous and the stamens united with it (this being also found in -the Choripetalæ), but also a great many others (such as persistent -calyx, cyclic flowers with the formula S5, P5, A5 and as a rule G2, -the two carpels being united to form the ovary; seeds with a thick -integument and a very small nucellus). They are therefore considered -as an independent sub-class, and must be placed at the close of the -system of classification as the forms which presumably have arisen the -latest. In the future systems of classification this arrangement will -very probably be changed, and the first families of the Sympetalæ, the -Bicornes and others will for instance be to a certain extent united -with the families or orders of the Choripetalæ. The Sympetalæ may -certainly be considered as the youngest types, the strongly pronounced -metamorphosis supporting this theory, as also the formation of the -integument of the ovule, the one thick integument being undoubtedly -derived from the coalescence of two--a holochlamydeous ovule, etc. - -The Apetalæ and Choripetalæ are united into one sub-class. The leaves -of the perianth in this case are, as a rule, free from each other, the -structure of the flowers presents many differences, and the ovules have -as a rule 2 integuments and a large nucellus. Considerable uncertainty -still prevails regarding the arrangement and the relationship of the -individual families of the Choripetalæ, and some of the following -families are hardly quite natural; but the best arrangement arrived at -so far has been adopted here. - -At the beginning of the book a review of the orders of the Dicotyledons -will be found. - - - Sub-Class 1. =Choripetalæ. Petals free.= - - - Family 1. =Salicifloræ.= - -Trees and shrubs, which, in the structure of the vegetative shoot and -the catkin-like inflorescences, resemble the Quercifloræ, but the -structure of the flower differs so much from them, that the only order -brought under this heading--_Salicaceæ_--well deserves to be separated -and to form a family of its own, the nearest relatives of which are -still doubtful. ~As Juglandaceæ and Myricaceæ also deserve to be placed -in a special family, the name _Amentaceæ_ (_Catkin-bearers_), hitherto -applied to all of these plants, cannot be retained as the name of a -family.~ - - [Illustration: FIG. 322.--Male and female catkins of _Salix - caprea_.] - -There is only one order. - -Order. =Salicaceæ= (=Willows=). Trees with simple, scattered, -_stipulate leaves_. _Diœcious_. The flowers are arranged in _simple -inflorescences_ (spikes or racemes) which are termed catkins, and which -fall off as a whole after flowering (♂) or after the ripening of the -fruit (♀) (Fig. 322). The perianth is very imperfect[33] or wanting, -particularly in _Salix_ (Fig. 323 _o_); the ♂-flower with 2–several -stamens and without any trace of a carpel (_a_, _b_, _c_): the -♀-flower has a free bicarpellate ovary, _unilocular_, and formed from 2 -lateral carpels with 2 _parietal_ (_median_) _placentæ_ and generally ∞ -ovules; the style divides into two stigmas (_d_, _e_, _f_). The fruit -is a two-valved _capsule_ and the very small seeds bear a _tuft of -hairs_ at the base. _Endosperm absent._--~The catkins are situated on -dwarf-branches, which in some species often develop before the leaves -and bear at their base only scale-leaves; in others foliage-leaves -are borne beneath the catkins. The vegetative bud commences with 2 -bud-scales which are united on the anterior side into a scale. The -capsule opens by the dorsal suture. The seed-hairs spring from the -funicle.~ - - [Illustration: FIG. 323.--_Salix_: male flowers of _S. pentandra_ - (_a_), _S. aurita_ (_b_), _S. rubra_ (_c_), female flowers of _S. - aurita_ (_d_), _S. nigricans_ (_e_), _S. mollissima_ (_f_).] - -_Salix_ (Willow) has short-stalked, most frequently lanceolate leaves -and erect catkins with undivided bracts (Fig. 322). The flowers are -naked; 1 (_o_ in _a-f_) or 2 yellowish glands situated in the median -line. In the ♂-flower generally two stamens, situated laterally like -the carpels in the ♀-flower. ~Various forms are seen in Fig. 323.--The -terminal bud of the branches often aborts regularly, the uppermost -lateral bud taking its place.~ - -_Populus_ (Aspen, Poplar) has long-stalked, more or less round or -cordate leaves with drawn-out apex; catkin pendulous; lobed bracts; -perianth cup-like with oblique edge; stamens usually numerous; stigmas -often divided.--~_P. tremula_ (Aspen) has received its name from the -tremor of the leaves: _cf._ “to shake like an aspen leaf.”~ - - POLLINATION. The Poplars are wind-pollinated. The Willows have - sticky pollen and are pollinated by insects. The catkins of - the Willows, especially the ♂, are more conspicuous, from the - numerous, closely-packed, yellow flowers, rich in honey and - pollen. The catkins often appear before the foliage and so - are much more easily seen, whilst at this time of the year the - number of competing honey-flowers is smaller, and the insect - visits consequently more numerous. On many catkins of the Willow - the flowers open earliest on the side which is turned towards - the sun and in descending order, _i.e._ the upper flowers - develop before the lower ones. Hybrids frequently appear. - - There are about 180 species existing in the northern, cold and - temperate latitudes. Some in the Polar regions are scarcely more - than an inch in height, and have a creeping rhizome (_Salix - herbacea_, _polaris_, _reticulata_). Fossil forms are found in - the Tertiary and perhaps also in the Upper Cretaceous. - - USES. Principally for ornamental trees, as they grow very - quickly and are easily propagated by cuttings, _S. babylonica_, - Weeping Willow; _S. purpurea_; _Populus alba_, Silver Poplar; - _P. pyramidalis_, Pyramid Poplar--a form of _P. nigra_; _P. - monilifera_, Canadian Poplar. The wood is very poor and - little used; the branches of many Willows are cultivated for - basket-making, etc. The wood of the Aspen is used for matches. - The bark contains tannin and, in many Willows, a very bitter - extract, _Salicin_ (_S. pentandra_, _fragilis_). Salicylic - acid (officinal) is obtained from _Salix_. Balsam is extracted - from the buds of many Poplars, especially when the leaves are - shooting. - - - Family 2. =Casuarinifloræ.= - -Trees with verticillate, scale-like leaves forming sheaths at the -nodes. Monœcious. Flowers unisexual. ♂-flowers in catkins; ♀ in short -spikes. _Pollen-tube entering the ovule at the chalaza_, and not -through the micropyle. Ovary 1-seeded, unilocular. Carpels uniting into -a multiple fruit. Only one order. - -Order. =Casuarinaceæ.= Trees (30 species), from Australia and certain -parts of S.E. Asia, with peculiar, equisetum-like appearance. The -leaves are verticillate, scale-like and united into sheaths. The -internodes are furrowed. Branching verticillate. The unisexual flowers -are situated in catkins or short spikes. The ♂-flower has a central -stamen, surrounded by 2 median, scale-like perianth-leaves and 2 -lateral bracteoles. The ♀-flower has a 1-chambered ovary (2 ascending, -orthotropous ovules), no perianth, but 2 large, lateral bracteoles -which finally become woody and form two valves, between which the -nut-like fruit is situated. The multiple-fruits therefore resemble -small cones.--_Casuarina equisetifolia_, cultivated, gives “iron-wood.” - - [The Casuarinas differ from the ordinary Dicotyledons in many - important respects which may be briefly summarised thus:--The - bicarpellate ♀-flower has a well-pronounced stylar-cylinder - terminated by two stigmas, but the cavity of the ovary closes - very soon after its formation, and in it are developed two - parietal ovules; these are united by a bridge of cellulose to - the stylar-cylinder or summit of the ovary, and hence the ovules - are connected with the walls of the ovary by the bridge (above), - as well as by the funicle (below). The archespore is developed - from the hypodermal cells at the summit of the nucellus, - two primordial mother-cells are first formed and from these - by tangential divisions a central cylindrical mass of cells - (sporogenous-tissue) is produced which is surrounded by tapetal - cells. The cells of the sporogenous tissue correspond to the - mother-cells of the embryo-sac of other Angiosperms; they divide - transversely and from 16–20 macrospores are formed together with - inactive cells which are not crushed together as in the case - of other Phanerogams. The sexual apparatus is developed from a - single cell, but the number of cells composing this apparatus - is subject to variation, the oosphere being accompanied by one - or two neighbouring cells which resemble canal-cells rather - than synergidæ. The sexual apparatus is found in the majority - of the macrospores, but in most of these it remains as a number - of naked cells; while in the fertile macrospores the cells - are invested by walls of cellulose (usually only one fertile - macrospore is found in each ovule). Antipodal cells are never - developed. The macrospores elongate considerably towards the - chalaza, into which some penetrate. The pollen-tube traverses - the stylar-cylinder and enters the ovules at the chalaza, its - passage through the tissue of the nucellus being assisted by - the prolongation of the macrospores. About the centre of the - nucellus the pollen-tube is ruptured; the apical portion which - alone takes part in the fertilisation being firmly attached to - the macrospore. Although the actual impregnation has not been - observed, Treub considers that the endosperm begins to be formed - before fertilisation.] - - - Family 3. =Quercifloræ.= - -_Trees_ and _shrubs_ with small, unisexual, _monœcious_ flowers, having -no perianth or a simple inconspicuous one. The ♂ and ♀ flowers are -very different and generally placed in separate inflorescences. The -♂-flowers are most often adnate to the bracts. The stamens are placed -_opposite the perianth-leaves_, when they are present in equal numbers. -The ♀-flower is _naked_, or has a _superior_ perianth. The ovary at -the base is 2- or 3-(-6) locular with 1 or 2 pendulous ovules in each -loculus, only one of which is developed; the fruit is a one-seeded -_nut_; _endosperm absent_; embryo straight. The inflorescences, which -are either compound and mixed (small dichasia in spikes) or simple, -are here also termed _catkins_; but, strictly speaking, this term is -applied to the ♂-inflorescences only. In all Quercifloræ the leaves are -_scattered_ (usually in 2 rows) _simple_, and _penninerved_, and with -_deciduous stipules_. - - It is worthy of remark that in _Betulaceæ_, _Corylaceæ_ and - _Quercus_ the ovules, and to some extent the loculi of the - ovary are not developed till after pollination, so that the - development of the pollen-tube proceeds very slowly. The - smallness of the flowers, the absence of honey, the dryness - and lightness of the pollen, the size of the stigma and the - abundance of hairs found on many stigmas are all adaptations for - wind-pollination. It is also an advantage that the flowers are - generally pollinated before the foliage-leaves are developed, - thus preventing the pollen being entangled by the leaves. - - The two orders _Betulaceæ_ and _Corylaceæ_ mentioned here are - by other authors united into one order. [It is doubtful whether - these two should be retained in the family Quercifloræ, as - recent researches (p. 273) have shown that they differ from - the Cupuliferæ in many important points, and agree with the - Casuarinas in the fact that the pollen-tube enters the ovule - through the chalaza.] - -Order 1. =Betulaceæ= (=Birches=). Monœcious, with thick, cylindrical, -_compound_ ♂ and ♀ inflorescences (2- or 3-flowered dichasia in a spike -with spirally-placed floral-leaves) (Figs. 324, 326, 328). When the -perianth in the ♂-flower is completely developed, it is composed of 4 -somewhat united leaves, which are placed opposite the 4 stamens (Figs. -325, 326 _A_). The female flowers are _naked_; the ovary is bilocular, -with two styles and one _pendulous_ ovule in each loculus. The -subtending floral-leaves unite with the bracteoles and form a 3–5-lobed -cover-scale, which is not attached to the fruit (Figs. 325 _D_, 326 -_B_). Fruit a _nut without cupule_ (see _Corylaceæ_ and _Cupuliferæ_). -~In the bud the leaves are flat. The stipules are deciduous. On -germination the cotyledons are raised above the ground. Terminal buds -are only found on old Alder trees; the Birch has sympodial branches.~ - - [Illustration: FIG. 324.--_Alnus glutinosus._ Branch of Alder - with ♂-(_n_) and ♀-(_m_) catkins: _k_ bud; _b_ fruit-bearing - catkin (“cone.”)] - -_Alnus_ (Alder) (Figs. 324–326). In the majority of species the ♂-and -♀-catkins are both developed in the year previous to their flowering, -and pass the winter naked and bloom before the leaves expand. ♂-flower: -4 stamens. ♀-flower: the 5-lobed cover-scales of the ♀-catkin are woody -and remain attached to the axis, so that the entire catkin when ripe -resembles a small cone (Fig. 324 _b_). Each cover-scale supports two -winged or wingless nuts. ~In the native species of Alder the buds are -stalked (Fig. 324 _k_). The bud-scales are formed by the stipules of -the lowest leaves.~ - -_Betula_ (Birch). The ♂-catkins, in the native species, appear -in autumn, the ♀-catkins in the flowering year on leaf-bearing, -short-lived shoots. ♂-flowers: 2 stamens, divided (Fig. 328 _A_). The -3-lobed cover-scales (Fig. 327 _a_) of the ♀-catkin are detached from -the axis; each cover-scale supports 3 broadly winged nuts (_b_). -~The stem has cork with annual rings. The young twigs and leaves have -aromatic resin glands.~ - - [Illustration: FIG. 325.--_Alnus glutinosa_: _A_ dichasium - of ♂-flowers seen from the front; _B_ the same from inside; - _C_ the same from the back; _D_ dichasium of ♀-flowers with - subtending-leaf and four bracteoles. The letters _b_, α, β, β′, β - are the same as in Fig. 326 _A_.] - - [Illustration: FIG. 326.--_Alnus glutinosa_: diagram of dichasia - of ♂ (_A_) and ♀ (_C_) catkins; _B_ a cone-scale. All the - bracteoles in _A_ and _C_ are slightly pressed from their normal - position.] - - THE INFLORESCENCES OF THE ALDER.--In the axil of each - cover-scale [_b_ in the Figs] is situated, in the ♂-catkins - (Figs. 326 _A_, 325 _A-C_) a 3-flowered dichasium, the - flowers of which have a 4-partite perianth, the posterior - perianth-segments being sometimes almost suppressed, and 4 - stamens with undivided filaments. In the ♀-catkin (Figs. 325 - _D_, 326 _C_) a 2-flowered dichasium is found, the middle - flower being suppressed (indicated by a star in _C_). In both - instances the inflorescences have two bracteoles (α-β) and the - flowers borne in their axils have each one bracteole (β′), the - other one (α′) being suppressed and therefore in 326 _A_ and _C_ - only represented by a dotted line; these four bracteoles unite - with the cover-scale (_b_) which supports the entire dichasium, - to form the 5-lobed “cone-scale” (Fig. 326 _B_) which in the - ♀-catkin eventually becomes woody. - - THE INFLORESCENCES OF THE BIRCH.--A 3-flowered dichasium is - situated in the axil of the cover-scale in both ♂-and ♀-catkins - (Fig. 328 _A_, _B_); only the central flower has bracteoles - (α-β) (the lateral flowers having no bracteoles), and these - bracteoles unite, as in the Alder, with the supporting - cover-scale (_b_), and form a three-lobed cone-scale (Fig. 327 - _a_). - - While the ♀-flower exactly resembles that of the Alder, the - reduction of the ♂-flower, already described in the Alder, is - carried further, so that often only the 2 median perianth-leaves - are developed (Fig. 328 _A_); there are also _only_ 2 stamens, - these being deeply cleft, while the other 2 are suppressed. - - About 50 species; N. Temp.--Fossil-forms certainly occur in - the Oligocene. During the Glacial period the Dwarf-birch (_B. - nana_) extended over Europe; at the present time it is confined - to the moors and mountains of N. Europe and N. America and Asia. - Wind-pollinated. - - USES.--Important forest trees. The bark contains tannic acid. - The tar of the Birch is used in the preparation of Russia - leather; whilst its spring sap is very saccharine, and is used - in some places for making a fermented drink. Its external bark - is used for roofing, for baskets, etc. - - [Illustration: FIG. 327.--_Betula verrucosa_: _a_ cone-scale; _b_ - fruit.] - - [Illustration: FIG. 328.--Diagrams of dichasia in the ♂-(_A_) and - ♀-(_B_) catkins of Birch.] - -Order 2. =Corylaceæ= (=Hazel-nuts=). Monœcious. The ♂-catkins are long -and cylindrical; the ♂-flowers are placed singly in the axil of the -subtending-leaf (cover-scale); they are _naked_ and formed of a number -of _divided_ stamens, which are partly united with the cover-scale, -4 in the Hazel, apparently 8 (Figs. 330 _A_, 329 _B_, _C_), more on -the Hornbeam. The ♀-flowers have a very small, _superior_ perianth; -in the axil of each cover-scale a 2-flowered dichasium (Fig. 329 -_D_) is present, of which the central flower (* in Fig. 330 _B_) -is suppressed. The gynœceum is bicarpellary as in the Birches; the -ovary is bilocular, with two long styles (Fig. 329 _D-F_); the loculi -have 1 (-2) ovules (Fig. 330 _B_). Each single ♀-flower and fruit is -surrounded by a _leaf-like covering_, the _cupule_ (husk), which is -_formed of three floral-leaves_ (namely, the bract of a lateral flower, -and its own bracteoles; thus in Fig. 330 _B_, α, α′, β’ form the cupule -for the left-hand flower, and β, α_[1}, β_[1}, the cupule for the -right-hand). - -_Corylus_ (Hazel-nut, Fig. 329). The long, cylindrical ♂-catkins pass -the winter naked, 2–3 together, on short branches. The very small -♀-catkins are enclosed in buds, in which they pass the winter; these -buds are situated in the axils of the fallen foliage-leaves, and it -is only by their larger size that they may be distinguished from the -ordinary foliage-buds. In spring the ♀-catkins are easily recognised -by their red, projecting stigmas (Fig. 329 _A_). The cupule--the -“husk”--is tubular, fringed, and envelopes the nut. ~The leaves are -alternate and unsymmetrical, the external side being larger than -the internal; this is connected with the vernation, the blade being -conduplicate in the bud; the stipules are deciduous. The bud-scales -are formed of stipules, the most internal having a leaf-blade attached -to them which is suppressed in the external ones. The cotyledons remain -underground on germination.~ - - [Illustration: FIG. 329.--_Corylus avellana_: _A_ branch at - the time of flowering with ♂-and ♀-catkins; _B_ ♂-flower with - subtending-leaf (bract) and two bracteoles; _C_ the same without - the anthers; _D_ view of interior of ♀-dichasium shortly after - fertilisation; _E_ young fruit with cupule; _F_ similar one with - the cupule opened; _G_ mature ♀-fruits; _H_ nut.] - -_Carpinus_ (_C. betulus_, Hornbeam). The ♂-and ♀-catkins do not appear -till the leaves are shooting. The ♀-catkin in this instance is also -long and cylindrical. The cupule in _C. betulus_ is 3-lobed, and -to a slight extent only embraces the base of the ribbed nut (Fig. -331); each lobe corresponds to a floral-leaf. ~Whilst the carpels -are placed medianly in _Corylus_, in _Carpinus_, on the other hand, -they are situated transversely, as in the case of the _Betulaceæ_. -The lamina of the leaf is not conduplicate in the bud, but flat, -and folded only along the lateral veins, which are also indicated -in the form of the fully-developed leaf; otherwise the vegetative -characters are essentially the same as in the Hazel. The cotyledons -are aerial.--_Ostrya_ resembles the Hornbeam, but the cupule completely -envelopes the nut, as a sac open at the apex (Eur., N. Am., Japan).~ - - N. Am., Asia, and Europe; 25 species.--Fossil forms in the - Oligocene. Wind-pollinated. USES. As timber (_Carpinus betulus_) - and firewood. The fruits of _C. avellana_ (ordinary Hazel-nut), - _C. tubulosa_ (Lambert’s nut) and _C. colurna_ (Turkish Filbert) - are edible. - - [Illustration: FIG. 330.--Diagrams of the ♂-flower (_A_) of - _Corylus_ and the dichasium of the ♀-flowers (_B_).] - - [Illustration: FIG. 331.--Nut of the Hornbeam with cupule.] - -Order 3. =Cupuliferæ.= Monœcious. The inflorescences make their -appearance with the leaves, arising in the axils of the leaves of -the same year. _A woody cupule_ furnished externally with scales or -spines is _common_, and surrounds 1-several flowers (the cupule in -the Corylaceæ never encloses more than a _single_ flower or fruit). -The ♂-flower has a united perianth, which is, however, 4–6 partite, -and encloses an indefinite number of undivided stamens. The ♀-flower -has a _superior, 6-merous_ perianth (3 + 3, compare Figs. 332 _D_, -334); the gynœceum is formed of 3 (or in _Castanea_ 4–6) carpels with -a corresponding number of stigmas (Figs. 332 _D_, _H_; 334, 335); and -the ovary has at the base 3 (-6) loculi (Fig. 333), each of which has 2 -pendulous anatropous ovules; the fruit is a one-seeded nut (Figs. 332 -_H_, 336). - -The cupule of the Cupuliferæ, according to the opinion of Eichler, is -formed by united bracteoles, (compare Fig. 333, where the four valves -in the cupule of Castanea are considered as bracteoles of the lateral -flowers of the dichasium); according to another view (see Prantl, in -Engler’s _Bot. Jahrb._, viii., 1889), it is a ring-like axial outgrowth -independent of the bracteoles of the flower, whose scales and spines -are floral-leaves. The cupule in the Oak only encloses the base of the -fruit, but in the Eating-chestnut and Beech the fruit is completely -enclosed, and consequently the cupule must divide into a number of -valves (generally 4) to allow the fruit to escape. In the 3-flowered -dichasia of _Pasania_, Sect. Eupasania (Trop. Ind.), each individual -flower has its own cupule of the same structure and development as in -_Quercus_; and, moreover, each group of flowers has externally the -typical six bracteoles. - - [Illustration: FIG. 332.--_Castanea vesca_: _A_ branch with - inflorescences; _B_ ♂-flower; _C_ young cupule with three - ♀-flowers; _D_ ♀-flower; _E_ the same in longitudinal section; - _F_ cupule with 3 nuts (diminished); _G_, _H_ nuts (_G_ in - longitudinal section to show embryo).] - -_Castanea_ (Eating-chestnut, Fig. 332). The catkins are erect (_A_), -cylindrical, with the ♀ at the base and the ♂ at the top, or some -are entirely ♂ and _composed of small dichasia_. The _cupule_ (_C_, -_F_) is 4-_valved_, provided with spines, and entirely envelops the 3 -_nuts_; it is already developed at the time of flowering.--~♂-flowers -are most frequently borne in 7-flowered dichasia, and have a well -developed perianth, most frequently consisting of 6 leaves in two -whorls (Fig. 332 _B_), and a large number of stamens. ♀-flowers are -most frequently borne in 3-flowered dichasia (Figs. 332 _C_, 333); the -letters in Fig. 333 indicate the older theory, according to which the -4 bracteoles (α′-β′) of the two lateral flowers are thick and united -into a single 4-valved, _woody cupule_, which surrounds the 3 nuts, -and is furnished externally with spines; the spines are well developed -hair-structures.--6 carpels in two whorls.--The leaves in the vertical -shoots have a divergence of 2/5, 3/8, 5/13; on the horizontal shoots -they are alternate. The cotyledons remain underground on germination.~ - - [Illustration: FIG. 333.--Diagram of the cupule of _Castanea_.] - - [Illustration: FIG. 334.--Female flower of _Fagus_ (mag.)] - -_Fagus_ (Beech). The ♂-catkins are pendulous, capitate; the ♂-flowers -have an obliquely bell-shaped, fringed perianth, with 6–20 stamens. -♀-catkins erect, 2-flowered, borne singly in the axil of foliage-leaves -of the same year; the ♀-flower has a gynœceum formed of 3 carpels, -bearing an epigynous, 6-leaved perianth (Fig. 334). In this genus -_the dichasium has only 2 flowers_, the central one being suppressed. -_The cupule contains_, therefore, only 2 triangular nuts (“mast”). -~All the shoots have the leaves arranged in two rows; the rows are -on the underside, being only about 90° distant from each other; the -buds on the other hand approach each other towards the upper side. The -bud-scales are stipules without laminæ; in vernation the laminæ are -folded along the lateral ribs, the upper lateral portion being the -largest (as in Hornbeam and Chestnut). The cotyledons are folded, and -at germination are aerial, large, and reniform. 4 species (Europe, -Japan, N. Am.)--_Nothofagus_ (S. Am., New Zealand, S. Austr.)~ - -_Quercus_ (Oak, Fig. 335). Catkins simple. ♂-catkins long, -thin, _pendulous_, few-flowered. ♀-catkins erect; the cupule is -_cup-like_, _entire_, and encloses only the base of the solitary nut -(“acorn”).--~The ♂-flower has a similar construction to that of the -Chestnut. The ♀-catkin has not more than 5 flowers (single-flowered -dichasia, in which _only the central flower is developed_). The -scales on the cupules are no doubt leaf-structures in this case also. -According to another theory, the scales are hair-structures; they arise -on the internal face of the young cupule apparently in descending, but -really in ascending order. The rim of the cupule gradually expands. -In the ♀-flower (Fig. 335) the loculi of the gynœceum, together with -the ovules, are not developed until _after_ pollination.--The leaves -in all cases have a divergence of 2/5; the lowermost leaves on the -shoots are reduced to stipules which serve as the bud-scales (5 rows). -The laminæ are conduplicate, as in _Corylus_, and the external side is -the broadest. The cotyledons are fleshy and remain underground. 200 -species.--_Pasania_ (100 species).~ - - [Illustration: FIG. 335.--_Quercus_: _A_ ♀-flower in its cupule - (mag.); _B_ longitudinal section through _A_, showing cupule, - perianth, and inferior ovary.] - - [Illustration: FIG. 336.--Fruit of _Quercus_.] - - 368 species, in temperate climates, especially in Europe and - N. America. Authenticated forests have been found in the - Oligocene. The Beech has one species, _Fagus sylvatica_, in - Europe; it is a most important forest tree (in Denmark the most - important) and reaches its most northern limit near Alvesund - in Norway (60° N.L.), its northern boundary line passing - from Alvesund in a zig-zag line through Ludwigsort, south - of Königsberg, in Prussia, towards the Crimea. According to - Steenstrup and Vaupell, the Beech did not make its appearance - in Denmark until a comparatively recent time, the Oak then - being partially supplanted. Other species of Beech are found - in N. America and Japan. Several species of _Nothofagus_ - occur in the South West of S. America, and in the colder - regions of the southern hemisphere. The Oaks grow especially - in temperate regions, _e.g._ in Western Asia, N. America, - and the mountains of Mexico. Evergreen species are found in - Tropical Asia, Himalaya, Japan and the Mediterranean region. - In this country there is one species of Oak (_Q. robur_), of - which there are three varieties (_Q. pedunculata, intermedia, - sessiliflora_). The Eating-chestnut is found in the South of - Europe, but is cultivated in the midland and southern counties - of England.--USES. The wood of these trees is very useful as - timber. The wood of _Q. tinctoria_ has a yellow colouring - matter (Quercitron-wood). The bark of the Oak contains a large - quantity of tannic acid, and is used for tanning; for this - purpose also the cupules of _Q. vallonea_, _ægilops_, _græca_, - and others from the Eastern Mediterranean, are used under the - name of “Valloons.” The Cork-oak (_Q. suber_; S.W. Europe) is - the most important tree from which cork is obtained, its bark - being very largely developed and stripped for cork. Gall-nuts - are found on many species; those of _Q. lusitanica_, var. - _infectoria_ (Eastern Mediterranean) are officinal, and likewise - the fruits (acorns) and the bark of _Quercus pedunculata_ and - _sessiliflora_. Oil is obtained from the Beech “mast.” The nuts - of the Chestnut tree are edible. - - - Family 4. =Juglandifloræ.= - -This family resembles the Quercifloræ in the catkin-like -inflorescences, the imperfect, _unisexual_ flowers, the epigynous -perianth and the woody shoots with scattered leaves, etc., though it -is in other respects very dissimilar; one point of difference is the -presence of _aromatic_ compounds, but a more important divergence is -found in the structure of the gynœceum, which is formed of two carpels -with _one loculus_ and has one _basal_, _orthotropous and erect_ -ovule, which, as in the Quercifloræ, does not become developed until -after pollination; the fruit too is very different, being generally a -_drupe_. _Endosperm absent._ - - [Illustration: FIG. 337.--_Juglans regia_: _A_ ♂-flower seen - from below with bract (cover-scale) (_b_), bracteoles (α and β), - perianth-leaves (_p_); _B_ the same from the front; _C_ lateral - view of the same; _D_ diagram of _A_; _E_ ♀-flower with bract, - the bracteoles are united with the ovary, their edge being - visible as an indented line below the perianth; _F_ 2 ♀-flowers - at the end of a foliage-shoot; _G_ fruit (without the fleshy - covering) in longitudinal section; _H_ transverse section of the - same.] - -Order 1. =Juglandaceæ (Walnuts).= Leaves _scattered_, _imparipinnate_, -rich in _aromatic_ compounds. _Stipules absent._ Flowers unisexual. -_Monœcious._ The ♂-catkins are lateral, generally on naked branches -of the previous year, cylindrical, pendulous, many-flowered; the two -bracteoles and the 2–4-leaved perianth of the ♂-flower unite with -the subtending bract; the ♂-flower has indefinite stamens (6–20 in -_Juglans_, Fig. 337 _A-D_). The ♀-catkins are terminal, generally on -branches of the same year, few-flowered (Fig. 337 _F_); the ♀-flowers -have a _superior_, 4-leaved perianth, a bicarpellate gynœceum, two -styles with stigmas on the internal surface. The ovary, bracteoles -and bract all unite together (Fig. 337 _E_). The fruit is generally a -green or black _drupe_,[34] whose flesh (outer soft portion) in _Carya_ -and _Juglans_ ruptures more or less irregularly, and frees the stone -(“Walnut”).--~The stone in _Juglans_ is divided internally by one true -(Fig. 337 _H_) and by several false, low partition walls into several -_incomplete_ compartments, so that the two large _cotyledons_ become -lobed and incised to fit like a cast into the irregularities of the -inner surface of the stone; the embryo is exendospermous and covered -with a thin testa.--THE LEAF SCARS are large and cordate with 3 groups -of vascular bundles. The PITH in _Juglans_ and _Pterocarya_ is divided -into chambers. The stone ruptures, on germination, along the dorsal -suture into 2 valves; the cotyledons remain underground. In _Juglans -regia_ a long row of accessory buds is found on the lowest internode -(epicotyl) above the axils of the cotyledons. _Pollination by the -wind._ Both protogynous and protandrous examples of _Juglans regia_ -occur.--33 species, mostly in temperate North America.--USES. Walnuts -are obtained from _J. nigra_ and _regia_; Hickory from North American -species of _Carya_. The oil-containing seeds of several species are -edible. _Pterocarya_ and others are cultivated as ornamental plants.~ - - [Illustration: FIG. 338.--_Myrica gale_: _a_ young fruit; × the - bracteoles with numerous glands; _b_ longitudinal section of - fruit.] - -Order 2. =Myricaceæ=. To this order belong shrubs or trees which -have penninerved, simple, at most lobed or pinnatifid leaves, with -or without stipules, and with yellow, aromatic, resin glands (Fig. -338 _a_). The flowers, situated in catkin-like spikes, are unisexual -and _naked_, and supported by scale-like floral-leaves. ♂-flower: 4–6 -(–16) stamens with short filaments; ♀: generally situated singly. The -gynœceum has a short style with 2 long stigmas, and unites with the -bracteoles, which form wing-like outgrowths on the ripe drupe as in -_Pterocarya_ in the Juglandaceæ (Fig. 338). Cotyledons fleshy (Fig. 338 -_b_).--_Myrica_; _Comptonia_. - - 40 species; Temperate.--_Myrica gale_ (Sweet-gale, Bog-myrtle) - has been used in the preparation of beer (Sweet-willow beer) - on account of its resinous essential oil. _M. cerifera_ (N. - America) and species from the Cape, _M. quercifolia_ and others, - form wax on the fruit which is used in the preparation of - candles. - - - Family 5. =Urticifloræ.= - -The flowers are regular, _hypogynous_, nearly always unisexual, _small_ -and insignificant, with _single_, green perianth of 4–5 leaves. Stamens -4–5, _placed opposite_ the leaves of the perianth. Ovary formed of 1 -or 2 carpels, most frequently _unilocular_, with one ovule (Fig. 340). -The fruit is a _nut_, more rarely a drupe, with one seed, _generally -endospermous_. ~The Nettles are the sole order in the family which has -only one carpel (1 stigma); this turns the posterior side to the front -(Fig. 340). The others have two carpels (2 stigmas) but the anterior -only is fertile (Fig. 346) except in a few Ulmaceæ and Moraceæ.~ - -The majority are trees or shrubs with petiolated leaves, _stipulate_; -_rough hairs_ are very frequently developed upon the leaves. The -flowers are very often crowded together in the inflorescence, which is -rarely catkin-like. Peculiar aggregations of fruits are found in some -orders. _Latex_ and tough _bast_, which is used technically, are also -frequently found. Cystoliths are found in the epidermis of many species -of _Ficus_, _Urtica_, and others. ~_Wind-_ or _self-pollination_ -is most common, as in the Quercifloræ and Juglandifloræ.~ In ~the -Urticaceæ, _Morus_ and some others, the stamens lie incurved in the -bud, and when ripe straighten themselves suddenly and elastically, -and thus small clouds of pollen-grains are ejected with considerable -violence on to the stigmas, which are often provided with brush-like -hairs (Fig. 341). The formation of honey does not take place.~ - -Order 1. =Ulmaceæ= (=Elms=).--Trees or shrubs without latex. Leaves -simple, arranged in two rows (divergence 1/2), oblique (the inner side, -nearer the axis, being the larger), strongly penninerved, dentate, -hispid; stipules deciduous. In opposition to the other Nettle-like -plants the flowers are often ☿ with a united cup- or saucer-like, -generally 4–(5)–6-divided perianth, and a corresponding or larger -number of opposite _erect_ stamens. The gynœceum has two carpels -(2 stigmas), generally one loculus with one pendulous, anatropous -or amphitropous ovule,[35] seldom two loculi and 2 ovules. Fruit -one-seeded (nut or drupe). Embryo without endosperm. - -=A.= ULMEÆ. The fruit is a _winged nut_ (Fig. 339), the embryo -straight, without endosperm. Anthers extrorse.--_Ulmus_ (Elm). The -flowers are situated in inflorescences which develop from the lower -buds of the shoot of the preceding year. ~The lowermost bud-scales -are empty, the uppermost support either solitary flowers, or small, -dichasial or unipared scorpioid inflorescences. The terminal bud on the -vegetative shoot quickly falls off, and the upper lateral bud continues -the growth sympodially. Flowering takes place before the leaf-buds -open. The flowers are wind-pollinated and have no honey. Fossil species -have been found in the Oligocene.~ - - 20 species; North Temp. (2 species in this country). Important - as timber. The Cork-elm (_U. suberosa_) has a rather thick cork, - which, however, is of no technical use. The bast is used as - Lime-bast. - - =B.= CELTIDEÆ. The fruit is a drupe, the embryo curved, with - folded or rolled up cotyledons, with or without endosperm. - The anthers are introrse. The flowers are borne on a shoot of - the same year. _Planera_ (N. America); _Zelkova_.--About 114 - species; especially N. Temp., Trop. - - [Illustration: FIG. 339.--_A Ulmus campestris_, flower with - exceptionally aborted gynœceum; _B_, _U. effusa_, flower with - 8 stamens; _C_, _U. campestris_, fruit opened in front to show - the seed pendulous from the apex of the loculus; one loculus is - aborted.] - -Order 2. =Urticaceæ= (=Nettles=).--The majority of species are herbs -with simple, stipulate leaves; they have _no latex_; _stinging -hairs_ abundant. The flowers (Fig. 340) are _unisexual_, generally -2-merous and arranged _in clusters_, which are united into catkin-like -inflorescences. The perianth is composed very often of 4 (2 + 2) -free, or in the ♀-flowers generally united, green leaves; the 4 (2 -+ 2) stamens are opposite the perianth-leaves, the filaments are -_bent inwards_ in the bud and throw themselves elastically towards -the outside. The gynœceum has _one style_ and _one stigma_ (capitate -or brush-like, Fig. 341); the ovary is unilocular, with _one -orthotropous_, _erect_ ovule (all other orders of this family have -inverted or curved ovules). Fruit, a nut or drupe. _Endosperm present_ -(in _Urtica_ very little), oily. Embryo straight. ~The STINGING HAIRS -are club-shaped, very turgid, and provided with a siliceous, brittle -apex, which breaks off in an oblique direction and allows the poisonous -cell-sap to be forced out. In many tropical Nettles this is so strong -that it may produce partial paralysis. There is no rudiment of an ovary -in the ♂-flowers (Fig. 340 A). The PERIANTH in the ♀-flower differs -from that of the ♂ in having the two internal leaves generally much -larger and enveloping the fruit (Fig. 340 _B_); it often happens that -all the perianth-leaves are united to form a gamophyllous envelope. -☿-flowers may occur among the others.--THE INFLORESCENCES among our -native species are dichasia, which become transformed into unilateral -scorpioid cymes by the development of the bud of the 2nd bracteole. In -_Parietaria_ they are more pressed together, and the floral-leaves at -the same time are also raised on their axillary shoots to just beneath -the flower. As a rule, not only in this order but also in those related -to it, a small vegetative branch is situated in the axil of the -foliage-leaf, and this bears an inflorescence on each side at its base.~ - -_Urtica_ (Nettle) has opposite leaves with distinct stipules and -stinging hairs. The perianth-leaves of the ♀-flower are free (Fig. -340).--_Parietaria_ (Pellitory) has scattered leaves without large -stipules, and stinging hairs are absent. The ♀-perianth is 4-toothed, -flask- or bell-shaped.--~_Pilea_ is a tropical genus with trimerous, -zygomorphic ♀-flowers, the posterior perianth-leaf being much larger -than the two others, and more or less hood shaped.--The flower of -_Forskohlea_ is the most reduced; the ♂-flower has only one stamen, and -the ♀-as well as the ♂-flowers have a one-sided, tongue like perianth -(?). _Pouzolzia._~ - - [Illustration: FIG. 340.--Diagram of ♂-and ♀-flowers of _Urtica - dioica_.] - - [Illustration: FIG. 341.--_Parietaria diffusa_; hermaphrodite - flower: _a_ in the female, _b_ at the commencement of the male - stage; the stigma has fallen off, but the anthers have not yet - dehisced.] - - WIND-POLLINATED. The pollen is shot out of the anthers, when - they spring forward, and is caught by long stigmatic hairs. - _Parietaria diffusa_ is protogynous (Fig. 341). - - 500 species; chiefly in the Tropics, although the few species - which occur in Europe are represented by a much larger number - of individuals.--USES. The bast of the native species _Urtica - dioica_ and _urens_, of _U. cannabina_ (Siberia), etc.; of - _Boehmeria nivea_ “Ramié” and “China-grass” (from Sunda Is., - China), and others, is used in the manufacture of muslin. - -Order 3. =Moraceæ= (=Mulberries=). Nearly all trees or shrubs, seldom -herbs, generally with latex. The leaves are scattered, and not -infrequently lobed. The flowers are _unisexual_ (monœcious or diœcious) -and arranged in catkin- or capitulum-like, compound inflorescences. -Perianth-leaves 2–6, generally 4, with an equal number of stamens -opposite to them, as in the Nettles. The ovary is 1–seldom 2-locular, -and has 2 stigmas (it is thus formed from 2 carpels) seldom only one -style with one stigma. One ovule in each loculus, more or less curved, -and _pendulous_; micropyle directed upwards. Fruit usually a drupe. -The embryo is generally curved inside the _fleshy endosperm_, or it is -exendospermous. - - [Illustration: FIG. 342.--_Morus alba_ ♂ flower (6/1).] - - [Illustration: FIG. 343.-_Morus alba_ ♀ inflorescence.] - - [Illustration: FIG. 344.--_Morus nigra_ fruits.] - -=A.= MOREÆ. The filaments are incurved in the bud. Leaves folded in the -bud--_Morus_ (Mulberry) (Figs. 342–344). Monœcious. The inflorescences -are catkin-like in appearance, but in reality composed of many small -dichasia. The flowers are similar to those of the Nettle, but with 2 -carpels: in the ♂ with perianth 2 + 2, and stamens 2 + 2 (Fig. 342), -in the ♀, perianth 2 + 2, and 2 carpels in regular alternation. The -small drupes are enveloped by _the perianth, which eventually becomes -fleshy_, and as all the flowers on the axis very accurately fit -together, the collection of fruits is formed, which we call a Mulberry -(Fig. 344). The leaves are folded in the buds, and have small stipules. -~The following are allied to _Morus_:--_Maclura_, _Broussonetia_ (the -Paper-mulberry tree) which has spheroid ♀ inflorescences (made up of -dichasia), etc.~ - - _Dorstenia_ presents an interesting transitional form to the Fig - in its flat, open, and, in some instances, lobed inflorescence - on which the ♂ and ♀ flowers are sunk in grooves. Indications - of a somewhat similar structure are found in certain Nettles, - the sympodial axes of the dichasia becoming flatly expanded. The - fruits are 1-seeded, but, nevertheless, spring open and eject - their seeds. - -=B.= ARTOCARPEÆ. Filaments straight in the bud; foliage-leaves with -convolute vernation. An interpetiolar leaf-sheath (ocrea) formed in the -axil of each leaf by the connate stipules, covers the younger leaves -as a hood. It falls off as the leaf expands, and leaves a ring-like -scar on the stem.--_Ficus_ (the Fig). The inflorescence (the so-called -syconus) has a pear-shaped, fleshy, but hollow axis, on the interior -surface of which the flowers are situated (Fig. 345). It is a kind -of capitulum, with a hollow receptacle, whose “involucral” leaves -close over the entrance to the interior; it is not, however, a simple -capitulum, but a coalescence of cymose inflorescences. The edible parts -are the fleshy stem-portion and perianth-leaves. The ♂-flower has a -2–6 divided perianth, 1–2 (–6) stamens; the ♀-flower has an oblique -ovary. The fruits are drupes, with thin flesh.--~Many species have -aerial roots, and some live as epiphytes on trees. POLLINATION, in the -edible Fig, is effected by a small Gall-wasp (_Cynips psenes_ L.), -which lays its eggs in the Fig, and hence carries the pollen away. Even -in very ancient times it was customary to hang infected wild Figs on -the branches of cultivated ones, so that the young Gall-wasps, as they -emerged, could immediately effect the pollination (caprification). -_Ficus carica_, and other species, have two kinds of ♀-flowers, besides -the ♂-flowers. One kind has a short style and no stigmatic hairs, -and it is only in the ovaries of these that the wasps lay their eggs -(gall-flowers); the other kind has a long style and well-developed -stigmatic-hairs, but the wasps cannot reach their ovaries--these are -“seed-flowers.” There are, moreover, two kinds of plants of _Ficus -carica_; ♀-plants, which have only seed-flowers, and bear the edible -Figs, and ♂-plants (called “Caprificus”), which bear inedible fruits, -and have ♂-flowers at the upper part of the Fig, but gall-flowers at -the base. [The Caprificus, at Naples, bears three crops of inedible -Figs each year, viz. _Mamme_ (April), _Profichi_ (June), _Mamnoni_ -(August). The ♂-flowers are produced especially in June, the first -Figs being almost entirely ♀, and the last having but few ♂-flowers. -Each crop produces a new generation of Fig-wasps. The female wasp -enters the Figs on the Caprificus, and lays one egg in each flower, -with the result that the flower developes into a kind of gall. The -mother-wasp dies within the Fig. The male wasp is wingless; it bites -a small passage into the ovaries containing the female wasps, and -impregnates them; the female wasps then escape from the Fig, those in -the _Profichi_ carrying pollen away with them as they pass out. They -then enter another Fig, lay their eggs, and die. The edible Fig-tree -similarly has three crops in the year, _Fiori di fico_, _Pedagnuoli_, -_Cimaruoli_. The wasps, entering these Figs, are unable to lay their -eggs in the ovary, but, nevertheless, they effect cross-pollination on -entering the _Pedagnuoli_, which bear fertile seeds.]~ - - [Illustration: FIG. 345.--A Fig in longitudinal section.] - - The flowers of _Brosimum_ are the most reduced. The perianth - is wanting, and the ♂-flower has only 1 stamen. _Cecropia_ - (Trumpet-tree), in S. Am., has its pith divided into chambers; - these are inhabited by ants, which feed upon small food-bodies - formed on the swollen base of the petioles. The leaves are - petiolated, often shield-like, fringed or lobed, and sometimes - with white felted hairs. They serve as food for _Bradypus_ - (the Sloth). _Sorocea_; _Castilloa_. - - About 300 species exclusively in the warmer climates. The white - Mulberry (_M. alba_, from China, India, Mongolia) is cultivated - for the sake of its leaves, which are the indispensable food - for silkworms. The black Mulberry (_M. nigra_, W. Asia) is - cultivated for its fruits, which are used for the officinal - Mulberry juice. The ordinary Fig-tree (_Ficus carica_) is from - the Mediterranean. The fruit of the well-known Oriental Sycamore - (_F. sycomorus_) is edible. The Bread-fruit tree (_Artocarpus - incisa_) and the Jack (_A. integrifolia_) have their home in the - South Sea Islands, and are cultivated in tropical countries. - The Bread-fruit is morphologically the same as the Mulberry. It - has a very large, spheroid inflorescence, whose floral-leaves - and perianth become fleshy and united into one nutritious mass, - together with the axis, which is also fleshy. The milky juice - of the India-rubber tree (_Ficus elastica_, East Indies, a - common house-plant), and of _Castilloa elastica_ (Am.) is the - raw material of India-rubber. The milky juice of _Galactodendron - utile_ (Cow-tree, S. Am.) is saccharine and nutritious, but in - _Antiaris toxicaria_ (the Upas-tree, of Java) it is a strong - poison. The bast of the Paper-Mulberry tree (_Br. papyrifera_, - Eastern Asia); is used in Japan for paper. Shellac is obtained - from a small, hemipterous insect (_Coccus lacca_), which lives - upon _Ficus laccifera_ and _F. religiosa_ (the Bo-tree, sacred - to Buddha), E. India. The wood of _Maclura aurantica_ (Am.) has - a yellow colour, and is known as yellow Brazilian wood. - -Order 4. =Cannabaceæ.= The plants which belong to this order are -_aromatic herbs_, either annuals or perennials, _without latex_. -Leaves _palminerved_, and more or less divided, hispid, and with free, -persistent stipules. Flowers always _diœcious_; ♂-flowers in panicles, -formed of dichasia, passing over into uniparous scorpioid cymes. They -differ from the Nettles, particularly in the 5-leaved perianth of the -♂-flower, the 5 stamens (Fig. 346–351) with filaments _erect_ in the -bud, and in the ♀-flower by the small, entire, cup-like perianth, which -surrounds the base of the ovary (Fig. 346, p. 352). The ovary has two -styles, or one divided into two, with two stigmas and a pendulous, -curved ovule (Fig. 346 _B_, 352 _B_); the fruit is a nut; the _embryo_ -is _curved_ (Hemp, Fig. 353), or rolled (Hop, Fig. 349), _without -endosperm_. - - [Illustration: FIG. 346.--Diagram of male and female flowers of - the Hop and Hemp: _b_ the bract, _p_ the perianth. The position - of the embryo is indicated.] - -Only 2 genera with 3 species (Asiatic), of which two are -cultivated.--_Humulus lupulus_ (Hop, Figs. 347–349) is a twining, -perennial plant, twisting to the right, with opposite, palmilobed, -rough leaves, and large, interpetiolar stipules. The ♀-flowers are -situated in closely-flowered, cone-like, compound inflorescences, with -ultimately large, thin, imbricate floral-leaves (Fig. 348) which bear -the yellow, glandular hairs, containing lupulin. ~This inflorescence is -made up as follows:--The most external floral-leaves are situated in -pairs, and are the persistent stipules of a leaf, the blade of which -has become suppressed, or in any case is rudimentary. Such a pair of -stipules supports 4 (2–6) flowers in a double uniparous cyme, whose -central axis does not develope into a flower. The bracts of these -flowers (bracteoles of the partial inflorescence) become, at maturity, -very large, spathe-like, and, together with the stipules, produce a -cone-like appearance.~ - - [Illustration: FIG. 347–348.--_Humulus lupulus_: 347, twining - stem; 348, branch with strobiles.] - -_Cannabis sativa_ (Hemp, Figs. 350–353) is an East Indian herb, with -palmilobed leaves, and differs from the Hop in being annual, erect, -and in having its leaves opposite at the base and scattered above. -The ♀-inflorescence is not cone-like as in the Hop, but the flowers -are similar in construction. ~The main difference is to be found in -the axillary shoot, which was suppressed in the Hop, and is in the -Hemp developed into a leaf-bearing shoot which on each side bears only -one ♀-flower, and in the fact that the bracts are not so strongly -developed.~ - - The “Hops” (the female inflorescences) are used in brewing, - and medicinally on account of the yellow glands which contain - lupulin. The Indian variety of _Cannabis sativa_ contains - an abundance of glandular hairs and resin. The withered - inflorescences are used in medicine and are officinal. The bast - of the stems of the Hemp is also used and the fat oil of the - seeds. In Oriental countries the entire plant is used in the - preparation of an intoxicating drink (haschisch), the narcotic - material being found in the glandular hairs. - - [Illustration: FIG. 349.--_Humulus lupulus_: fruit in - longitudinal section.] - - [Illustration: FIGS. 350–353.--_Cannabis sativa_: - - Fig. 350, ♂-plant; - - Fig. 351, ♂-flower; - - Fig. 352, ♀-flower, entire and in longitudinal section; - - Fig. 353, fruit in longitudinal section.] - - - Family 6. =Polygonifloræ.= - -This family is on one side closely allied to the _Urticaceæ_ by its -solitary, _basal_, _vertical_, and _straight_ ovule, and by the conical -ocrea which envelopes the younger leaves in the bud, similar characters -being present in the Urticaceæ. On the other side it is related to -the Curvembryæ. The flowers are small, often _trimerous_, regular and -slightly perigynous (~in _Chloranthaceæ_, if they properly belong to -this family, and _Houttuynia_, more or less epigynous~). Syncarps are -present in some Piperaceæ, but the fruit is generally a single fruit, -one-seeded berry, nut or drupe. The leaves are generally scattered. - -Order 1. =Polygonaceæ.= The majority are herbaceous plants with -round, often jointed stems, scattered leaves and _ocrea_, that is a -membranous, tubular, ligular or stipular structure _inside_ the base -of the leaf, which clasps the stem and axillary bud; the edges of the -lamina are rolled backwards in the bud. The flowers are regular, small, -generally ☿, slightly perigynous, with inconspicuous, simple, green or -white perianth of 5–6 free segments; stamens 5–9 (Fig. 354) sometimes -arranged in two series; gynœceum 2–3 carpels, ovary _unilocular_ with -_one basal_, _straight_ (orthotropous) _ovule_, 2–3 _free styles_. -The fruit is a 2–3-angular nut; the embryo, with mealy endosperm, -is straight or curved (Fig. 355 _H_), often unsymmetrical.--~The -inflorescences are compound, and generally branch from the axils of -the bracteoles, so that the last partial-inflorescences become coiled, -uniparous scorpioid cymes; in _Polygonum_ the two bracteoles unite into -a membranous tube; in _Rheum_ and _Rumex_ there is only one bracteole.~ - - [Illustration: FIG. 354.--_A_ Diagram of _Rheum_; _B_ of _Rumex_; - _C_ of _Polygonum fagopyrum_; _D_ of _P. lapathifolium_. The - ovules are indicated inside the ovaries; bracts and bracteoles - are not shown.] - -_Rheum_ (Rhubarb, Fig. 354 _A_) has a 6-leaved, _petaloid_ perianth (Pn -3 + 3) and 9 stamens (A 3^2 + 3). The _3-winged_ nut is _not_ enclosed -by the perianth. - -_Rumex_ (Dock, Fig. 354 _B_) has 6 stamens (A 3^2 + 0); the perianth is -6-leaved (Pr 3 + 3), green or red, and the triangular nut is enveloped -by the 3 interior perianth-leaves, which point upwards and continue to -grow after flowering. These perianth-leaves often have warts on their -outer surface. ~The following are monœcious: _R. acetosa_ and _R. -acetosella_.~ - -_Polygonum_ (Knot-grass, Figs. 354 _C_, _D_; 355). The _petaloid_ -perianth is most frequently 5-merous (2/5 spiral); 5–8 stamens. The nut -is triangular (Fig. 354 _C_, 355), or lenticular (Fig. 354 _D_). ~There -are two whorls of stamens, the external with introrse, and the internal -with extrorse anthers. The gynœceum is often bicarpellate (Fig. 354 -_D_).~ - - The flowers may be considered as constructed upon the - monocotyledonous type. _Pterostegia_ has a perfectly - monocotyledonous flower with 5 trimerous whorls. _Rheum_ - likewise, but here the external staminal whorl is doubled (Fig. - 254 _A_). _Oxyria_ has a dimerous _Rheum_-flower (4-leaved - perianth, 6 stamens, 2 stigmas). _Rumex_ has a _Rheum_-flower - with the suppression of the internal whorl of stamens (Fig. - 354 _B_); _Emex_ is a dimerous _Rumex_. _Polygonum_, to which - _Coccoloba_, _Muehlenbeckia_ and others are related, differs - from _Rheum_ chiefly in having one of the leaves, which in the - latter takes part in the formation of the perianth, developed - in this case into a bracteole (so that the perianth is reduced - to five members), and several or all the stamens in the inner - whorl become suppressed.--The perianth in _Coccoloba_ and - _Muehlenbeckia_ is more or less perigynous and becomes fleshy, - enclosing the fruit. _Muehlenbeckia platyclada_ has flat branches - with rudimentary leaves; sometimes branches with normal, - arrow-shaped leaves are found. _Atraphaxis._ - - [Illustration: FIG. 355.--_Polygonum fagopyrum_: _A_ branch - with flower and fruits (nat. size); _B_ flower; _C_ the same - in longitudinal section; _D_ anterior and posterior view of - stamen; _E_ gynœceum; _F_ fruit (mag.); _G_ fruit in longitudinal - section; _H_ transverse section, showing the curved cotyledons - embedded in the endosperm; _I_ the embryo.] - - POLLINATION. _Rumex_ is wind-pollinated, the stigmas are - therefore large and brush-like (indicated in Fig. 354 _B_). - _Rheum_ and _Polygonum_ are insect-pollinated and have therefore - capitate stigmas, etc.; honey-glands are situated at the base - of the stamens (_d_, in Fig. 354 _C_, and _n_ in Fig. 356); a - few small-flowered _Polygonum_ species are self-pollinated; - Buckwheat (_P. fagopyrum_) is dimorphic and has long-styled and - short-styled flowers (Fig. 356). _Pol. bistorta_ is protandrous - and homostyled. - - About 750 species, most of which are found in the temperate - regions of the Northern Hemisphere, some reaching as far as the - snow line or into the Arctic regions (_Oxyria_, _Kœnigia_). - Trees and shrubs are found in the Tropics: _Coccoloba_, - _Triplaris_. _Rheum_ is Central Asiatic.--The thick rhizomes of - _R. officinale_ (_Rhubarb_) are _officinal_. The rhizomes of the - ordinarily cultivated species, _R. undulatum_ and _rhaponticum_, - are used in veterinary medicine. The following are cultivated as - culinary plants for the sake of their leaves:--_Rumex acetosa_ - (Sorrel), _R. patientia_, _R. scutatus_, and _Rheum undulatum_ - (petioles). Several species of _Polygonum_ (_P. hydropiper_ and - others) have a sharp, pungent taste. “Buckwheat” is the mealy - fruit of _Polygonum fagopyrum_ (Central Asia) and is of value as - a farinaceous food. _P. cuspidatum_ (_P. sieboldi_, Japan) is an - ornamental plant.--_Calligonum_ in sandy and stony deserts. - - [Illustration: FIG. 356.--Flower of _Polygonum fagopyrum_ in - longitudinal section: 1, long-styled; 2, short-styled; _a_ the - anthers; _st_ the stigmas; _n_ nectary.] - -Order 2. =Piperaceæ (Peppers).= Shrubs or herbs, often with nodose, -jointed stem; leaves simple, entire, often with curved veins; stipules -wanting (_Peperomia_) or intrapetiolar and cap-like, often enclosing -the terminal buds (_Piper_). The flowers in the group _Pipereæ_ -(_Piper_, Fig. 357, and _Peperomia_) are borne in spikes with fleshy -axes (_club-like_), seldom in racemes, the outer ones are crowded and -are ☿ or unisexual, always small, _naked_ and without bracteoles; -~generally stamens 3 + 3, and gynœceum 3, but the number of the -stamens may be reduced by suppression to 2, and the carpels to 1~. The -flowers are situated in the axils of the small, generally shield-like -floral-leaves. The ovary is always _unilocular_ and has _one upright, -orthotropous_ ovule. Fruit a berry or drupe. Both endosperm and -_perisperm_ are present, the latter being especially well developed -(Fig. 359). - -_Piper_; generally shrubs with scattered leaves, and terminal -inflorescences which are crowded to one side by the development of the -highest lateral bud, so that they are situated opposite the leaves -(Fig. 357). Many species have stems with an abnormal anatomical -structure.--_Peperomia_; chiefly succulent herbs, often epiphytes, with -opposite or verticillate leaves having aqueous tissue on the upper side. - - [Illustration: FIG. 357.--_Piper nigrum_: branch with fruit (½)] - - The group _Saurureæ_ (considered by some as an order, and - perhaps representing a more original type) has 3–4 carpels - with many ovules. _Lactoris_ stands the highest with regular - 3-merous perianth, 3 + 3 stamens and 3 carpels, which are - united at the base. Fruit a capsule with several seeds. (It - has one species from the island of Juan Fernandez, and is also - placed in an order of its own, Lactoridaceæ, allied to the - Magnoliaceæ, through _Drimys_).--_Saururus_ has naked flowers; - most frequently 6 stamens, and 4 carpels, free or united at - the base, each with 2-4 orthotropous ovules. Fruit, small - berries.--_Houttuynia_; stamens situated a little upward on the - ovaries; placentation parietal; capsule many-seeded. - - About 1,000 species; entirely tropical, especially from - South America and East India. They are found chiefly among - the underwood in damp, shady places; some, which are fleshy - (_Peperomia_), live as epiphytes on trees; a few climb by - roots.--USES. Several Piperaceæ are used medicinally and - for spices on account of their pungent properties and the - essential oils found in nearly all parts of the plant. The - following are _officinal_: “Black-pepper” (the unripe, dried - fruits) and “White-pepper” (the seeds of the ripe fruits) of - _Piper nigrum_ (climbing shrub, East Indian); “Cubeb” berries - of _P. cubeba_ (climbing shrub, Java). “Long-pepper” is the - unripe inflorescence of _P. longum_, East India. The leaves of - _P. angustifolia_ (Matico) are officinal. The leaves of the - Betelpepper (East India) are used together with the nuts of - the Areca-palm to form the well-known East Indian intoxicating - compound “Betel.” A good many others are also used. - - [Illustration: FIG. 358.--_Piper nigrum_ (Diagram). In addition - to the bract there are two structures resembling bracteoles.] - - [Illustration: FIG. 359.--_Piper nigrum_: Fruit in longitudinal - section, showing the endosperm, perisperm, and pericarp.] - - Order 3. =Chloranthaceæ.= (_Chloranthus_, _Hedyosmum_) have - opposite leaves, with stipules more or less united at the base, - and inferior “drupes.” Ovules pendulous. Only endosperm. About - 33 species, Tropical. - - - Family 7. =Curvembryæ.= - -The plants in this family have a _curved ovule_, and most frequently -a _kidney-shaped seed_ (generally provided with fine, cuticular, -projecting warts, Fig. 362 _B_), with a _curved, peripheral embryo -enclosing the endosperm which is most frequently floury_ (Figs. 362 -_C_, 365 _H_; for exceptions, see Fig. 366); the seeds in all cases -are borne on a _centrally-placed_, and in most cases _free_, placenta -(they are “basal” when there is only 1 ovule in the ovary, Fig. 364). -The flower is regular, hypogynous or perigynous (Fig. 364) (only -rarely epigynous) and usually 5-_merous_. The flower which is most -complete has 5 whorls (S5, P5, A5+5, G2-3–5), as in some genera of -the Caryophyllaceæ (Figs. 360, 361); but from this type it becomes -reduced, the petals and stamens being suppressed, so that finally -5 perianth-leaves, 5 stamens (opposite the perianth-leaves), and 2 -carpels (Fig. 361 _F_) only are present; for example, in certain genera -of the _Caryophyllaceæ_, in the _Chenopodiaceæ_, _Amarantaceæ_, and -others. When the number of stamens is increased to more than 5 in the -whorl, it is always possible to show that some of the stamens have been -divided. The number of the carpels and ovules also becomes reduced; in -the highest there is a central placenta, not free in its early stages, -with a large number of ovules; in those which are most reduced there is -only a single ovule, which is placed centrally at the base of the ovary -[Fig. 364]. Somewhat corresponding changes are found in the fruit, -which is a many-seeded _capsule_ in those which have many ovules, but -a one-seeded _nut_ where there is one ovule. In the most reduced forms -the flowers are generally unisexual.--Similar features are also present -in the vegetative parts. Almost all the species are herbaceous, the -leaves are simple and most frequently without stipules. ~The structure -of the stem, especially in Chenopodiaceæ, Amarantaceæ, Nyctaginiaceæ -and others, often differs from that of the ordinary Dicotyledon. In the -woody portion of the stem and root several rings are sometimes formed -which resemble annual rings but which are formed by new cambium-rings -arising outside the old ones which then cease to divide.~ - -Order 1. =Caryophyllaceæ.= Herbaceous plants, with round, nodose -stem; leaves _opposite_, slightly amplexicaul, simple, with sessile, -undivided, entire lamina; stipules nearly always absent; the -inflorescences are _dichasia_ passing over into unipared scorpioid -cymes. The flowers are regular, ☿ or unisexual, hypogynous or -perigynous, 5-(or 4-) merous with 2–3–4–5 carpels; calyx persistent; -corolla polypetalous. The ovary is unilocular (or originally, and -sometimes also in the later stages, plurilocular below, _e.g._ -_Viscaria_), with _free styles_ and 1–several curved ovules on a -_central_, free placenta. The fruit is a nut or a capsule opening -apically with long or short valves (teeth, Fig. 362), equal to or -double the carpels. For the seeds refer to the family. ~In _Dianthus_ -the embryo is straight.~ - - The flowers which are most complete have _Sn_, _Pn_, _An_ + _n_ - (obdiplostemonous), _Gn_ where _n_ = 5 (Figs. 360, 361 _A_) or - 4 (Fig. 361 _B_); the carpels may be placed opposite to the - sepals (Fig. 360) or opposite to the petals (Fig. 361 _A_, _B_). - Without any change taking place in the position of the other - whorls, the carpels are next found reduced to 2–3–4 (see the - genera); their number may easily be recognised by that of the - styles. This is the construction in the majority of the genera - in the two first groups. _Stellaria media_ differs considerably. - It may have (_a_) the flower as described above, with _G3_; - (_b_), the corolla only absent, or (_c_) only the petal-stamens - (A5 + 0, Fig. 361 _C_), or (_d_) all these as well as some of - the sepal-stamens. The same applies to _Sagina_, _Alsine_, - _Cerastium_, and others, and, finally, a series of genera are - formed, with certain conditions of reduction which have become - constant, and by a gradual series of steps lead to the most - reduced form, which has only 5 sepals and 5 (or even as far as - only 1) sepal-stamens (Fig. 361 _D_, _E_, _F_).--The PETALS in - the _Alsineæ_ are often deeply bifid. The sepal-stamens are most - frequently the longest, and bear nectaries at the base (Fig. 363 - _st_). In the most complete forms the ovary has partition-walls - in the lower portion (Fig. 360); these do not, however, reach - to the top, and generally soon disappear. The ovules, when - numerous, are situated on the placenta in as many double rows as - there are carpels. In the number of ovules a reduction from many - to 1 takes place (Fig. 361). A comparison proves that the “free, - centrally placed” placenta is formed by the ventral portion of - the carpels. The single basal ovule in _Herniaria_ (Fig. 364), - _Scleranthus_, and others, is also borne on the carpels. - - The vegetative _branching_ is characteristic. One of the leaves - in a pair is formed before the other, and has a more vigorous - axillary bud; these stronger leaves stand in a ¼-spiral, the - fifth above the first one, and the branches are consequently - arranged in the same manner. In the inflorescence, however, it - is the upper or second bracteole (β) whose axillary bud (_w_ in - Fig. 361) is most advanced. The bud of the first bracteole (α) - becomes sometimes entirely suppressed, or in some this bracteole - itself is suppressed. - - [Illustration: FIG. 360.--Diagram of _Lychnis_: α, β bracteoles.] - - [Illustration: FIG. 361.--_A-F_ Diagrams of flowers of the - Caryophyllaceæ: _A Agrostemma_; _B Sagina_; _C Stellaria_; - _D Corrigiola_; _E Paronychia_; _F Herniaria_.] - - The most original type appears to be represented by the Alsineæ. - From this form on one side the Sileneæ, adapted in a higher - degree for insect-pollination, are developed, and on the other - side the Paronychieæ, with various reductions. - -=1.= ALSINEÆ, STITCHWORT GROUP. Sepals free, and connected with them -stellately expanded, slightly unguiculate (white or inodorous) petals; -these, however, often become suppressed (Fig. 363). The fruit is a -capsule. - - [Illustration: FIG. 362.--_Cerastium arvense_: _A_ fruit; _B_ - seed; _C_ section of seed.] - -=a.= As many carpels as sepals (4 or 5). _Cerastium_ (Chickweed). The -petals are bifid. Capsule cylindrical, frequently _curved_ at the top, -and opening by 10 teeth (Fig. 362).--~_Malachium_ differs only in the -5-toothed capsule with bifid teeth.~--_Spergula_ (Spurry). The petals -are not bifid, capsule 5-valved; seeds winged. The leaves are linear, -and appear as if placed in large numbers in a whorl, a branch being -situated in the axil of each with leaves placed very close together at -its base; _stipules membranous_.--~Sagina has Sn, Pn, An + n, or An, -Gn, where n = 4 or 5. The corolla is often wanting.~ - -=b.= 3 (rarely 2) carpels (Fig. 361 _C_). _Stellaria_ (Stitchwort) -has deeply cleft petals. The number of stamens varies (see -above).--_Arenaria_ has entire petals. ~(To this group belong _Alsine_, -_Moehringia_, _Halianthus_, or _Honckenya_ (Fig. 363), which differ -from each other, especially in the form of the seed and number of -the capsular valves.) _Spergularia_ has membranous stipules, as in -_Spergula_.--_Holosteum._~ - - [Illustration: FIG. 363.--_Arenaria_ (_Halianthus_) _peploides_: - ♀-(_A_) and ♂-flower (_B_, _C_).] - -=2.= PARONYCHIEÆ (Figs. 361 _D_, _E_, _F_; 364). Small, greenish -plants. The leaves, in the majority, are opposite, with _membranous -stipules_. The flowers are most frequently arranged in small -_dichasia_; they are small and insignificant, perigynous (Fig. 364) -or hypogynous. The corolla is in most cases wanting, and when present -is very small; in general the calyx-stamens are developed, but the -corolla-stamens may be represented by small scales (Fig. 364). Ovary -most frequently with 1 ovule. Fruit, a _nut_, rarely a capsule; it is -enclosed by the strongly perigynous floral axis (torus). - -_Scleranthus_ (Knapwell) is perigynous with bell-shaped torus; no -corolla; corolla-stamens are wanting or rudimentary; some calyx-stamens -may also be absent.--_Corrigiola_ (Fig. 361 _D_); _Illecebrum_; -_Paronychia_ (Fig. 361 _E_); _Herniaria_ (Figs. 361 _F_, 364). - -=3.= SILENEÆ, PINK OR CARNATION GROUP. This has a _gamosepalous_ calyx -and unguiculate, white or red, petals, with _outgrowths_ (_ligule_, -_corona_, _paracorolla_) at the throat of the corolla. These structures -are not found in the other groups, and are merely outgrowths at -the junction of the limb and claw. The corolla, stamens and ovary -are frequently raised above the calyx, upon a lengthened internode -(_gynophore_). The flower has S5, P5, A5 + 5; fruit a capsule with many -seeds. - -=a.= 5-(rarely 3–4) carpellate ovary.--_Lychnis_ (Campion, Fig. 360). -The corolla is longer than the calyx; corona present. The capsule -is 10- or 5-toothed, completely 1-chambered or 5-chambered at the -base,--the genus has been divided accordingly into several genera: -_Melandrium_, _Lychnis_, _Viscaria_. ~Some species are unisexual by -the abortion of stamens or carpels (_L. vespertina_, _diurna_).~ -_Agrostemma_ (_A. githago_, Corn-cockle, Fig. 361 _A_) has a -long-toothed calyx, the teeth exceeding the corolla; corona absent; -5-toothed capsule. - - [Illustration: FIG. 364.--_Herniaria glabra_: _a^1_ flower; _b^1_ - longitudinal section through the flower; _c^1_ stigma with two - pollen-grains.] - -=b.= Tricarpellate.--_Silene_ (Catch-fly). Six-toothed capsule; corona -present in the majority.--~_Cucubalus_ has berry-like fruits which -finally become dry but do not dehisce.~ - -=c.= Bicarpellate (2 styles, 4-toothed capsule).--_Dianthus_ -(Pink); at the base of the calyx 1–several pairs of floral-leaves -are situated; corona absent. The _straight embryo_ is a peculiar -exception.--_Gypsophila_ has a campanulate, open calyx, 5-nerved, -membranous between the nerves; corona absent; the flowers are generally -small and numerous, in a large, paniculate dichasia.--_Saponaria_ -(Soapwort) has corona. - - POLLINATION. _Alsineæ_ has ordinary nectaries at the base of - the calyx-stamens (Fig. 336): they are frequently protandrous - but may often, in the absence of cross-pollination (in the - less conspicuous species) pollinate themselves. Their open - flowers are accessible to many kinds of insects (particularly - flies and bees). _Gynodiœcious_ flowers are found in several - species, and the ☿-flowers are then generally more conspicuous - than the ♀-flowers. That the ♀-flowers have descended from - ☿-flowers is seen by the large staminodes found in them (Fig. - 363). _Arenaria peploides_ is diœcious (Fig. 363). The _Sileneæ_ - are as a rule adapted for pollination by insects with long - probosces--especially butterflies,--and they are frequently - protandrous, so that at first the calyx-stamens open, later - on the corolla-stamens, then the stigmas expand. The honey is - secreted by a ring-like nectary round the base of the ovary or - by nectaries at the base of the stamens. Some only blossom and - emit scent at night or in the evening (_Lychnis vespertina_, - _Silene nutans_, _Saponaria officinalis_) and, like other - night-flowers, are of a white or pale colour. - - DISTRIBUTION. 1,100 species, especially in temperate climates, - fewer in the colder zone, less still in the Tropics. The - Paronychieæ are especially found in dry, sandy fields. - - USES. “Soap-root” (with _Saponin_, forming a lather in water) - from _Saponaria officinalis_ was formerly officinal, and - _Gypsophila struthium_. The seeds of _Agrostemma githago_ are - said to be poisonous.--The following are ornamental plants: - species of Pinks (_D. caryophyllus_, garden Pink, often - with double flowers; _D. barbatus_, _plumarius_, _etc._). - _Lychnis_, _Gypsophila_, _Silene_, _Cerastium_ (_C. tomentosum_ - as edging for borders), _Saponaria officinalis_ (often - coronate).--_Spergula arvensis_ is sometimes cultivated. - - Order 2. =Amarantaceæ.= The flowers are essentially the same as - in the _Chenopodiaceæ_ and the extremely reduced Caryophyllaceæ - (Fig. 361 _F_); they are regular, hypogynous, generally ☿, - have 5 free (rarely slightly united) perianth-leaves; in front - of these 5 stamens, which _are often united_ at their base - into a shorter or longer tube and have stipule-like teeth - between them (the division _Gomphreneæ_ has 2-locular anthers, - each of which opens longitudinally); and a 2–3 carpellate - gynœceum with one loculus and most frequently one, more rarely - several ovules; the fruit is a nut, more rarely (in _Celosia_, - _Amarantus_, _Gomphrena_) a capsule, dehiscing irregularly, - or like a pyxidium. The characters which especially separate - them from the allied orders are found in the perianth. The - perianth-leaves are not green and herbaceous, but _membranous, - dry, and often coloured_; they are frequently produced into a - bristle or awn; they have also both subtending floral-leaves - and _2 large bracteoles similar to the perianth_; all these dry - leaves persist without alteration after the withering of the - flower.--The flowers are without scent. They are arranged in - spike- or capitulum-like inflorescences; sometimes placed singly, - sometimes aggregated in the panicle-like inflorescences; in - others, on the contrary, in dichasia. The majority are herbs, - some are shrubs. The leaves are scattered, or opposite, but - always simple and without stipules; some are smooth, others - hairy. - - 450 species; especially in the Tropics, principally S. Am. and - E. Ind.: few are found outside these countries.--Only a few - are used; some, chiefly E. Indian species, are cultivated as - ornamental plants: _Amaranthus_ (Fox-tail); _Gomphrena globosa_; - _Celosia cristata_ (Cock’s-comb) remarkable for its fasciated - inflorescence; _Alternanthera_. Some are employed as culinary - plants in the Tropics, and in a few of the E. Indian species the - seeds are farinaceous, and used for food. - -Order 3. =Chenopodiaceæ.= Generally herbaceous plants like the -Caryophyllaceæ, but the leaves are arranged spirally (except -_Salicornia_), and are simple, exstipulate; they are generally fleshy -and like the stem “mealy,” that is, covered with small hairs, whose -large spherical terminal cell readily falls away; otherwise they are -seldom hairy. The inflorescences are generally flower-clusters borne in -panicles. Bracteoles generally absent. Flowers generally _unisexual_: -with the single exception of _Beta_ the flowers are hypogynous; they -are regular, small and inconspicuous, with _single, green_, 5-leaved, -but _more or less united_ perianth; 5 stamens opposite the perianth, -and a _2–5-carpellate, unilocular_ ovary with 1 basal, curved ovule; -but in some genera the number of the perianth-leaves and stamens is -reduced to 3–2–1–0. The fruit is generally a _nut_,--thus this flower -and fruit are the same as in the reduced Caryophyllaceæ (Fig. 361 -_F_). The seed is similar to that generally found in the family (for -exceptions see the genera). - - The floral diagram most frequently present is the same as - in Fig. 361 _F_. There is no indication of corolla or of - corolla-stamens, which may be supposed to have belonged - to the plant, but which are now entirely and completely - suppressed. This order appears to have been an offshoot from - the Caryophyllaceæ.--The perianth persists after the withering - of the flower, and envelopes the nut; it is very variable, and, - together with the position of the seed, the form of the embryo, - the sex of the flowers, etc., gives the characters of the genera. - -=1.= CHENOPODIEÆ, GOOSEFOOT GROUP (Fig. 365), has ☿ (or polygamous) -flowers, with regular 5-parted perianth (_C_); the embryo is ring-like -(_H_). The leaves have the ordinary flat forms.--_Chenopodium_ -(Goosefoot). The flower is hypogynous, and the fruit (which is -compressed) perfectly free; Mulberry-like collections of fruits are -formed in some species (sub-genus _Blitum_) by the perianth becoming -finally fleshy and coloured.--_Beta_ (Beet, Mangold, Fig. 365) differs -from all genera in the perianth, which finally becomes cartilaginous, -being epigynous (_D_). Small, most frequently 2–3-flowered clusters -without bracteoles, situated in a long, interrupted axis (_A_, _B_); -the flowers and fruits in each cluster are more or less united -individually, and fall off together--they are commonly known as seeds -(_E_, _F_). The seed lies horizontally.--_Hablitzia_ (_H. tamnoides_). - - [Illustration: FIG. 365.--_Beta vulgaris._] - - [Illustration: FIG. 366.--_Salsola soda_: embryo.] - -=2.= SALSOLEÆ, SALTWORT GROUP, has cylindrical or semi-cylindrical -leaves. Perianth as in the preceding group; the fruit is most -frequently compressed. The two first mentioned genera differ from -most of the others in the order in having a spirally-coiled, and not -a ring-like embryo, so that the endosperm is slight or wanting (Fig. -366). These plants are sometimes placed as a group by themselves, -SPIROLOBEÆ--in contradistinction to which the others are termed -CYCLOLOBEÆ.--_Salsola_ (Saltwort); leaves subulate, with spiny tips; -the flowers have 2 spinous bracteoles: during the ripening of the -fruit a tough leathery wing is developed transversely to the back of -the perianth.--~_Chenopodina_ deviates from _Chenopodium_ chiefly in -the embryo and want of endosperm.--_Kochia_ has a somewhat similar -perianth to _Salsola_, but a ring-like embryo; it differs from the -others in being hairy.~ - -=3.= SALICORNIEÆ, GLASSWORT GROUP. _Salicornia_ (Glasswort) has a very -different appearance. The stems are succulent, jointed, and almost -leafless; the leaves opposite, very small, sheath-like and connate; -there is a depression in the axil of each leaf, in which a small -3-flowered dichasium without bracteoles is sunk; the flowers have -a trimerous perianth, 1–2 stamens and 1 carpel. No endosperm. _S. -herbacea_ on clayey beaches. - -=4.= ATRIPLICEÆ. This group has most frequently unisexual flowers; -the ♂-flower has a 4–5 partite perianth, but the ♀-flower differs -from it. _Atriplex_ is monœcious or polygamous, the ♀-flower is -naked, but has 2 large, herbaceous bracteoles which expand during the -ripening of the fruit, and often become warted and fringed, enveloping -the _compressed nut_. ~The section _Dichospermum_ has two kinds of -♀-flowers, one like those just described, the other similar to the -_Chenopodium_-flowers, which have been deprived of their stamens, and -the fruits of which are _depressed_, not pressed together from the -sides; some (_e.g. A. hortensis_) have even three kinds of nuts. -All the flowers of _Atriplex_, which present vertical fruits, are -accessory shoots, which stand beneath the ordinary flower-clusters, a -rather singular relation.~--_Spinacia_ (Spinach) is diœcious; ♂-flower: -perianth, 4 (-5); stamens, 4 (-5); ♀-flower: tubular, 2–4-partite -perianth, hardening during the ripening of the fruit, and uniting with -the compressed nut; in _S. oleracea_, it also forms _thorns_; 4 long -stigmas.--_Halimus_ has the 2 long bracteoles almost entirely united -and ultimately adhering firmly to the fruit. - - =5.= BASELLEÆ. A somewhat exceptional group with more - or less perigynous flowers and 2 bracteoles. _Basella_, - _Boussingaultia_, _Ullucus_. The perianth is sepaloid; ovary - 1-ovuled. In _Basella_ the perianth is fleshy, enveloping the - nut, and the cotyledons are so rolled together that a tranverse - cut divides them in two places (as in Spirolobeæ). Herbaceous - climbing plants. - - POLLINATION. Wind-and self-pollination, as far as is known; - the insignificant flowers, devoid of honey, appear to exclude - insect-pollination.--520 species. Most of them are annual - (out of 26 native species only 5 are perennial); inhabiting - salt-marshes and salt-steppes, and growing as weeds (most - frequently on garden or field soil containing manure) in this - country, especially species of _Chenopodium_ and _Atriplex_. - The majority are found outside the Tropics, and play a very - important part, for example, in the Asiatic salt-steppes. They - grow gregariously in large masses. - - USES. Comparatively few. The only important one is _Beta - vulgaris_ (from the Mediterranean basin), with its different - varieties, viz. Beet-root, Cattle-beet or Red-beet, Sugar-beet, - and others. These are biennial, making in the first year a root - which acts as a reservoir of reserve material, with a rosette - of leaves, and in the second year using this material in the - production of a long stem, leaves and flowers. The primary - root has been developed by cultivation into a very thick and - fleshy tap-root; its mode of increase in thickness deviates - from that of other roots, concentric rings of vascular bundles - being formed from a cambial ring developed outside the previous - ring. In this way several rings of vascular bundles separated - by medullary rays, alternating with rings of parenchyma, may - be found in the root of a Beet. Besides _Beta vulgaris_, var. - _hortensis_ (Beet-root), the following are also cultivated: var. - _cicla_ (Leaf-beet, “Mangold,” or “Roman Spinach ”), _Spinacia - oleracea_ and _Atriplex hortensis_ as Spinach; a form of the - latter and of Spinach are grown as ornamental plants. The tubers - of _Ullucus tuberosus_ are used as potatoes; _Chenopodium - quinoa_, in Chili and Peru, is an important farinaceous plant. - Soda is made from some (_Salsola kali_, _Chenopodina maritima_ - and others). Aromatic properties are rare: _Chenopodium - ambrosioides_ and _botrys_. - - Order 4. =Batidaceæ.= _Batis maritima_, a bushy West Indian - maritime plant. - - Order 5. =Phytolaccaceæ.= The ☿ (sometimes unisexual), regular, - sometimes slightly perigynous flowers are inconspicuous - and have a single sepaloid or coloured 4–5-leaved perianth - (generally united at the base); stamens either in 1 whorl in the - spaces between the perianth-leaves or in 1 whorl opposite the - perianth-leaves, or in 2, one of which alternates with these; - but the number may be increased by the splitting of one or of - both the whorls to as many as 10–15–20–25. _Carpels_ sometimes - only one, sometimes _many_ (4–10) placed in a whorl, either free - or united into a gynœceum with a corresponding number of loculi - in the ovary; but in all cases _each carpel bears only its own - style and 1 ovule_. The fruit is a _berry_ (or nut, capsule, or - schizocarp).--Mostly herbs or herbaceous shrubs, with scattered, - simple leaves without stipules (_Petiverieæ_; have stipules). - Inflorescences, most frequently _racemes_ or spikes, which in - some instances are apparently placed opposite to a leaf, being - displaced by a more vigorous growth of the axillary bud. Embryo - always bent.--_Petiveria_ has a straight embryo with rolled - cotyledons.--_Phytolacca_, _Pircunia_, _Microtea_, _Seguieria_, - _Rivina_ (Pr4, A4, G1; berry), and others. - - The following plant is, with some doubt, placed near this - order: _Thelygonum cynocrambe_; monœcious. ♂-flowers: perianth, - 2-leaved; stamens indefinite. ♀-flowers: perianth-leaves united, - 3-toothed; G1, style gynobasic. Fruit a drupe. An annual plant; - Mediterranean. Branching anomalous. - - About 90 species; in tropical and temperate countries, - principally America and Africa.--The red juice in the fruits, - especially of _Phytol. decandra_, is used for colouring wine. - -Order 6. =Portulacaceæ= (=Portulacas=). The flowers are regular -(except _Montia_), hypogynous (except _Portulaca_) and ☿. The diagram -which applies to the majority of genera is that in Fig. 367, but with -all the 5 stamens completely developed: it may be considered as the -Chenopodiaceous diagram with the addition of 2 _bracteoles_ in the -median line (_m-n_, these by some are considered as sepals), and with -a petaloid perianth (usually designated “corolla”). The “petals” fall -off very quickly, and are sometimes wanting. Most frequently 5 stamens, -situated opposite the “petals,” but in other genera the number varies; -_Montia_ has only 3 stamens (by suppression of the two anterior and -lateral, Fig. 367), others again have more than 5, some a large and -indefinite number. This may be explained partly by the appearance of -a second whorl of stamens alternating with the first, and partly by -the splitting (dédoublement) of the stamens. Gynœceum most frequently -tricarpellate, ovary unilocular with 1–several basal ovules (sometimes -on a branched placenta, as in certain _Caryophyllaceæ_). The fruit is -a _capsule_, more rarely a nut.--The majority are annual herbaceous -plants with scattered, entire leaves, often fleshy and smooth, with or -without rudimentary stipules (dry, membranous, modified into hairs). -Inflorescence cymose. - - [Illustration: FIG. 367.--_Montia._ - - Diagram of flower.] - -_Portulaca_ (Portulaca): flower, epigynous or semi-epigynous; fruit, a -pyxidium. The stamens vary in number, and are most frequently placed in -groups (in consequence of splitting) opposite the petals.--_Montia_: -the corolla is slightly gamopetalous, but cleft on the posterior side -(Fig. 367), and as a consequence of the larger size of the lateral -petals, slightly zygomorphic; 3 stamens.--_Calandrinia_; _Talinum_; -_Anacampseros_; _Claytonia_. - - 125 species; mostly in warm and temperate countries, especially - the arid parts of S. Am. and the Cape. _Montia fontana_ (Blinks) - is a native plant. _Portulaca oleracea_ is cultivated as a - pot-herb in the south of Europe. A few species of _Portulaca_ - and _Calandrinia_ are ornamental plants. - -Order 7. =Nyctaginiaceæ.= The characteristic feature of this order -is the _single_, regular, _united_, and often petaloid perianth, the -lower part of which generally persists after flowering and embraces -the fruit as a false pericarp. The upper portion is most frequently -_valvate and folded_, or simply valvate in æstivation. The number of -stamens varies. The free gynœceum is _unicarpellate_ and has 1 ovule. -The fruit is a _nut_, but becomes a _false drupe_, since the lower -persistent portion of the perianth becomes fleshy (as in _Neea_, where -this fleshy part is almost always crowned by the upper persistent -part of the perianth. In the majority of the Mirabileæ the lower part -becomes the dry _anthocarp_, while the upper petaloid part falls away -after flowering). Finally, a peculiar involucre is formed around the -flowers by free or united floral-leaves.--The majority are herbs, some -are trees (_Pisonia_, etc.); _Bougainvillea_ is a liane. The stems -are often nodose and swollen at the nodes; the leaves are simple, -penninerved, scattered, or opposite, without stipules. ~In some, the -vascular bundles are scattered; stem anomalous.~ - -_Mirabilis_; the structure of the stem is abnormal. Dichasial branching -with continuation from the second bracteole, thus forming unipared -scorpioid cymes. The perianth is petaloid, funnel-shaped, and has -a folded and twisted æstivation resembling that of the corolla of -the _Convolvulaceæ_; the upper coloured portion falls off after -the flowering. Outside, and alternating with it, is a 5-partite, -sepaloid involucre of 5 spirally-placed floral-leaves.--_Oxybaphus_; -the involucre envelops 1–3 dichasial flowers.--_Bougainvillea_; the -involucre is rose-coloured, 3-leaved, and envelops 3 flowers (placed -laterally; the terminal flower wanting). The leaves of the involucre -in _Boerhaavia_, _Pisonia_, _Neea_, and others are reduced to teeth or -scales. - - 157 species; mostly in tropical countries, and especially S. Am. - Species of _Mirabilis_ (Am.) are ornamental plants. Theïn is - found in _Neea theïfera_ Oersted (discovered by Lund in Lagoa - Santa, Brazil), which may be used as a tea-plant. - - Order 8. =Aizoaceæ.= Only 3 _whorls_ are found in the flower, - which _alternate_ with one another when their leaves are equal - in number. The first is sepaloid, the third one the carpels, - and the intervening one is either uncleft, in which case it is - developed as stamens, or it is divided into a large number of - members which then all become stamens (arranged in groups), or - the outermost ones become developed as petals. The fruit is most - frequently a capsule with several loculi. Most of the species - are herbs with thick, fleshy stems, and exstipulate leaves. The - structure of the stem is usually anomalous. - - =1.= AIZOIDEÆ have hypogynous or perigynous flowers with (4–) - 5 perianth-leaves; stamens single, or (by splitting) in groups - of 2–3, alternating with the perianth-leaves. The gynœceum - (with 3–5 carpels) has 3–5 loculi in the ovary, and most - frequently numerous ovules in each loculus, borne on the central - placenta formed by the edges of the carpels. The fruit is a - capsule. The inflorescences are dichasia and unipared scorpioid - cymes.--_Aizoon_, _Mollugo_, _Sesuvium_, and others are herbs or - bushes, most frequently hairy. - - =2.= MESEMBRIANTHEMEÆ have semi- or wholly-epigynous - flowers.--_Tetragonia._ The perianth is 4 (more rarely - 3–5–6)-merous. Stamens single, or (by splitting) in groups - alternating with the perianth-leaves. There is an indefinite - number of carpels, and each loculus of the ovary contains - _only_ 1 pendulous ovule. Fruit a nut or drupe. The flowers - arise singly in the leaf-axils, with an accessory foliage-bud - below them; in some instances there is also an accessory - flower between this bud and the flower. Southern hemisphere, - especially at the Cape; _T. expansa_, New Zealand Spinach, is a - fleshy plant which is cultivated as a pot-herb (Japan, Austr., - S. Am.).--_Mesembrianthemum_: the flowers are 5-merous; the - numerous linear petals and the still more numerous stamens all - arise by the splitting of 5 or 4 protuberances (primordia) - alternating with the sepals. The ovary presents another - characteristic peculiarity: the carpels alternating with the - 5–4 stamens form an ovary (with several loculi) with the ovules - at first borne, as in other cases, on the _inner_ corner of the - inwardly-turned carpels; but during the subsequent development - the whole ovary is so turned round that the placentæ become - parietal and the ovules assume, apparently, a position very - rarely met with in the vegetable kingdom: on the dorsal suture - of the carpels. Shrubs or under-shrubs, more rarely herbs - with fleshy stems and simple, entire, more frequently thick - or triangular leaves, containing a quantity of water. The - flowers open about noon, and are brightly coloured, generally - red or red-violet, but odourless. The capsules dehisce in - rainy weather. 300 species, mostly found at the Cape. Some are - ornamental plants. _M. crystallinum_ (the Ice-plant) and others - are covered with peculiar, bladder-like, sparkling hairs, the - cell-sap of which contains salt--these serve as reservoirs of - water. - - - Family 8. =Cactifloræ.= - -The position of this family is very doubtful; but it seems in many -respects to approach _Mesembrianthemum_. Some botanists place it near -to the Ribesiaceæ; others, again, to the Passifloraceæ. Only 1 order. - - [Illustration: FIG. 368.--_A Echinocactus_: _a_ position of a - leaf-lamina; _b_ a lateral shoot on the displaced axillary bud. - _B_ Pereskia: _b_ a foliage-leaf on a small thorny branch which - is subtended by a foliage-leaf which has fallen off and left a - scar(_a_).] - - [Illustration: FIG. 369.--_Echinopsis._] - -Order =Cactaceæ= (=The Cacti=). The flower is epigynous, ☿, regular, -and remarkable for its _acyclic_ structure; there are, for instance, a -large number of spirally-placed sepals and petals, which gradually pass -over into one another, and which in some species, to a certain extent, -arise from the walls of the ovary as in _Nymphæa_ (Fig. 383 _A_, _B_). -The petals are free; rotate, opening widely in _Opuntia_, _Pereskia_, -and _Rhipsalis_; erect and united at their base into a shorter or -longer tube in _Cereus_, _Epiphyllum_, _Mammillaria_, _Echinocactus_, -_Melocactus_, and others (Fig. 369). _Stamens numerous_, attached to -the base of the corolla; gynœceum formed of _many carpels_, with one -style, dividing into a number of branches corresponding to the number -of carpels; the ovary has _one loculus_ with _many parietal_ placentæ; -the ovules are anatropous, on long and curved funicles. Fruit a berry -with exendospermous seeds. The fruit-pulp is mainly derived from the -funicles.--The external appearance of the Cactaceæ is very peculiar; -_Pereskia_, which has thick and fleshy leaves (Fig. 368), deviates -the least; foliage-leaves of the usual form are wanting in the other -genera, or are usually very small, and quickly fall off and disappear -(_Opuntia_), or are modified into thorns; the stem, without normal -foliage-leaves,--so characteristic a feature in this order,--makes its -appearance after the two normally developed cotyledons. The stems -are fleshy, perennial, and may finally become woody. In some they are -elongated, globose, pointed, and more or less dichotomously branched, -_e.g._ in several of the _Rhipsalis_ species, which live mostly as -epiphytes on trees; in others, elongated, branched, globose, or, most -frequently, more or less angular (prismatic) or grooved and provided -with wings, and either columnar and erect (as much as about 20 metres -in height and 1 metre in circumference, as in _C. giganteus_ in New -Mexico) or climbing by roots (_Cereus_ and _Rhipsalis_-species); -in others again, compressed, more or less leaf-like, often with a -ridge in the centre (winged), branched and jointed: _Epiphyllum_, -_Phyllocactus_, _Opuntia_, some species of _Rhipsalis_; others are -thick, short, spherical or ovoid, unbranched or only slightly branched, -and either studded with prominent warts (_mammillæ_) each of which -supports a tuft of thorns (Fig. 368 _A_; _Mammillaria_ and others) or -with vertical ridges, separated by furrows (rows of mammillæ which -have coalesced) in _Melocactus_, _Echinocactus_, _Echinopsis_ (Fig. -369); at the same time the ovary in some is embedded in the stem so -that leaves or leaf-scars, with tufts of thorns in their axils, may be -observed on the ovary just as on the stem.--The flattened shoots of -the Cactaceæ are formed in various ways, either by the compression of -cylindrical axes (_Opuntia_) or, as in _Melocactus_, etc., from winged -stems in which all the wings are suppressed except two. - - The thorns are produced directly from the growing points of - the axillary buds, and are modified leaves. The axillary bud - is united at its base with its subtending leaf, which as a - rule is extremely rudimentary; and these together form a kind - of leaf-cushion, larger in some genera than in others. This - leaf-cushion attains its highest development in _Mammillaria_, - in which it is a large, conical wart (see Fig. 368 _A_), bearing - on its apex the tuft of thorns and rudimentary lamina.--The - _seedlings_ have normal cotyledons and a fleshy hypocotyl. - - All the species (1,000?) are American (one epiphytic species of - _Rhipsalis_ is indigenous in S. Africa, Mauritius and Ceylon), - especially from the tropical table-lands (Mexico, etc.). Some - species, especially those without thorns, as _Rhipsalis_, are - epiphytes. _Opuntia vulgaris_, the fruits of which are edible, - is naturalized in the Mediterranean. The cochineal insect - (_Coccus cacti_) lives on this and some closely allied species - (_O. coccinellifera_, etc.), particularly in Mexico and the - Canary Islands. Several are ornamental plants. - - - Family 9. =Polycarpicæ.= - -The flowers _as a rule are_ ☿, _regular_ and _hypogynous_; however -in some orders they are unisexual, _e.g._ in the Myristicaceæ, or -zygomorphic (in Monkshood and Larkspur in the Ranunculaceæ); in the -Lauraceæ, (Fig. 386) for example, perigynous, and in _Nymphæa_ (Fig. -383) even partially epigynous flowers are typical.--The flowers are -acyclic in very many of the genera of the two first orders, if not -completely so, at any rate in the numerous stamens and carpels, thus -denoting an old type. It is a remarkable characteristic that in the -majority of the orders the number 3 prevails in the calyx and corolla; -the number 5 also occurs, but the number 2 is seldom met with. Most -orders have a double perianth; chorisis does not occur, suppression -is rare, and the parts of the flower are developed in acropetal -succession. The most characteristic feature in the order is the _free, -one-leaved_, as a rule _numerous carpels_ (apocarpous gynœceum). The -number of carpels in some of the last mentioned orders dwindles down -to 1 (_e.g._ the _Berberideæ_ and _Myristicaceæ_). The carpels in -_Nymphæaceæ_ become united into _one pistil_ (syncarpous), a condition -which we also find distributed among the other orders. - -_Endosperm occurs in almost all_ the orders (except _e.g. Lauraceæ_). -The nutritive tissue in _Cabombeæ_ and _Nymphæeæ_ is chiefly -_perisperm_. - - [Illustration: FIG. 370.--Diagram of _Aquilegia vulgaris_: _sp_ - spur. A cyclic flower.] - - [Illustration: FIG. 371.--Diagram of a dichasium of _Ranunculus - acer_: α_{1}, α^1, and β_{1}, β^1, bracteoles (the buds - in the axils of the bracteoles, α and α^1, are continued - antidromously). The flower has cyclic calyx and corolla, bub - acyclic (8/21) stamens.] - - [Illustration: FIG. 372.--Diagram of an acyclic Ranunculaceous - flower (only 3 stamens are indicated). The spiral of the sepals - has a divergence of 3/5; that of the corolla and subsequent - leaves 3/8.] - -Order 1. =Ranunculaceæ.= Nearly all are _herbs_ (except _Clematis_). -The leaves are scattered (except _Clematideæ_), they have a large -sheath with broad base (no stipules), and are most frequently -palminerved with palmate lobes. The flowers are hypogynous, with most -frequently a well pronounced convex receptacle (Figs. 374 _B_, 380), ☿, -regular (except _Delphinium_ and _Aconitum_); their structure varies -very much; in some the leaves are verticillate, in others arranged -spirally; in others, again, both modes of arrangement are found. It is -a characteristic feature that the various series of leaves (especially -calyx and corolla) are not so distinct or so sharply divided as -is usual. The leaves of the perianth are free, imbricate (except -_Clematideæ_); stamens _numerous_, with most frequently extrorse -anthers; gynœceum _free_, _apocarpous_ (except _Nigella_ and partly -_Helleborus_), with 1 or several ovules (Figs. 373, 378, 379) borne on -the ventral suture. The fruit is either a nut or a follicle (_Actæa_ -has berries). The seed has a _large, oil-containing_ endosperm and a -small embryo (Fig. 374). - - The main axis generally terminates in a flower, and the - lateral axes branch in a cymose manner (Fig. 371). The flowers - show the following differences in construction: VERTICILLATE - (EUCYCLIC), _i.e._ constructed all through of alternating - whorls: _Aquilegia_ (Fig. 370), _Xanthorhiza_, and sometimes - _Eranthis_. SEMIVERTICILLATE (HEMICYCLIC) _i.e._ with sepals and - petals in alternate whorls, and the others arranged spirally: - _Ranunculus_ (Fig. 371), _Myosurus_, _Pæonia_ and several other - genera entirely, or in certain species only. SPIRAL-FLOWERED - (ACYCLIC) _i.e._ all the leaves are arranged spirally, so - that sepals and petals do not alternate the one with the - other, even though they are the same in number: _Adonis_ (Fig. - 372), _Aconitum_, _Delphinium_-species, _Nigella_-species, - _Helleborus_. The leaves of the calyx are in this instance - arranged on a spiral of 2/5; those of the corolla on 2/5, - 3/8, 5/13 or 8/21, and stamens and carpels likewise on higher - fractions of the same series. - - The genera _Caltha_, _Anemone_, _Thalictrum_ and _Clematis_ - have a _single perianth_, which is most frequently petaloid; - it is thus apparent that the sepals are petaloid, and the - leaves, which in other genera have developed as petals, are in - these instances stamens. The calyx is similarly petaloid in - the genera _Helleborus_, _Eranthis_, _Nigella_, _Delphinium_ - and _Aconitum_; but the petals are present in these instances - in unusual (horn-like) forms, and almost entirely given - up to the function of nectaries, a function they already - possess in _Ranunculus_. According to a more recent theory - the “honey-leaves” are transformed stamens, which have lost - the function of reproduction; the perianth is then single, - and most frequently petaloid. [Those leaves in the flowers of - many Ranunculaceæ which bear nectaries are termed by Prantl - honey-leaves, and comprise those leaf-structures of the flower - whose essential function lies in the production of nectar, - and which, independent of the differentiation of the perianth - into calyx and corolla, are derived from the stamens by the - loss of their reproductive functions. Clear transitional - forms are found between the two series of the perianth - (_e.g._ between the sepaloid and petaloid perianth-leaves - of _Anemone japonica_, _A. decapetala_, _Trollius_-species) - while transitional forms are never found between perianth-and - honey-leaves (with the exception of _Aquilegia vulgaris_, var. - _stellata_). In _Anemone_ and _Clematis_ the honey-leaves - pass gradually into the stamens, and agree with the stamens - in the other Ranunculaceæ in their arrangement, development, - and scant system of veins (except _Nigella_). In _Delphinium_, - sect. _Consolida_, the two honey-leaves placed in front of - the unpaired perianth-leaf are united into one, as shown by - the veins (twice three veins arranged symmetrically). The - honey-leaves of _Aquilegia_, _Callianthemum_, and the majority - of the _Ranunculus_-species serve by reason of their large - circumference, as organs of attraction, and on this account - are considered as petals by other authors.--The same position - in the flower which the honey-leaves assume is found occupied - by staminodes, without nectar, in some _Coptis_-species, in - _Anemonopsis_, _Actæa_ sect. _Euactæa_, (_e.g. A. racemosa_), - _Clematis_ sect. _Atragene_; in the last-named they closely - surround the stamens, in _Actæa_ they are petaloid.--A perianth, - sharply differentiated into calyx and corolla, and destitute of - honey-leaves, is found in _Anemone_, sect. _Knowltonia_ (Cape), - - _Adonis_, _Pæonia_.--The perianth of the Ranunculaceæ is - considered by Prantl to be usually petaloid.--The nectaries - arise in the Ranunculaceæ (1) on normal stamens (_Clematis_ - sect. _Viorna_), (2) on the honey-leaves (this is generally the - case), and (3) on the carpels (_Caltha_ and the majority of - _Trollius_-species).--As the result of his researches upon the - Ranunculaceæ, Prantl does not agree with the view advanced by - Drude (Schenk, _Hand. d. Bot._ iii.) that the petals in general - have proceeded from the metamorphosis of the stamens (_K_)]. - - [Illustration: FIG. 373.--Ovaries in longitudinal section: _v_ - the ventral suture; _d_ the dorsal suture: _A_, _B Clematis_; - _C Ranunculus_; _D Myosurus_.] - - The most primitive form of fruit is undoubtedly the pod formed - by one carpel, on the edges of which (along the ventral suture) - two rows of ovules are situated: Pæonieæ, Helleboreæ, Delphinieæ - (Fig. 379). In a great many genera the number of ovules has been - limited to _one_ perfect one, which is placed in the central - plane under the united leaf-edges, and sometimes also some - barren ovules above it (Fig. 373). The fruitlets in this case - become achenes, and are present in much larger numbers than when - there are follicles. - - [Illustration: FIG. 374.--_Helleborus niger_: _A_ flower; _B_ - receptacle; _pet_ petals (honey-leaves); _pi_ stamens and - carpels; _C_ seed; _D_ anther (cross section); _alb_ endosperm.] - - [Illustration: FIG. 375.--_Caltha palustris_: fruit.] - -The following have FOLLICLES: _Pæonieæ_, _Helleboreæ_ (except _Actæa_) -and _Delphinieæ_; ACHENES: _Ranunculeæ_, _Anemoneæ_ and _Clematideæ_. - -=A. Follicles= (Figs. 375, 379), with many ovules, situated in two rows -along the ventral suture. ~_Actæa_ has berries, _Nigella_ has capsules -of several loculi.~ - -=1.= PÆONIEÆ, PEONY GROUP. This has regular, acyclic flowers with a -normal, most frequently 5-leaved, imbricate calyx; large, coloured -petals, and introrse anthers. Slightly perigynous. Surrounding the -base of the carpels a ring-like swelling of the receptacle (“disc”) is -present, which is largest in _P. moutan_. The follicles are more or -less fleshy or leathery. Mostly herbs, with pinnatisect or decompound -leaves and large, solitary flowers; a gradual transition may be traced -from the foliage-leaves to the petals. _Pæonia; Hydrastis._ - - [Illustration: FIG. 376.--_Aquilegia vulgaris._] - - [Illustration: FIG. 377.--_Caltha palustris_ (nat. size).] - - [Illustration: FIG. 378.--_Nigella_: _A_, _B_ fruit of _N. - damascena_, entire, and cut transversely. _C_ Petal (honey-leaf) - of _N. arvensis_. _D_ Petal of _N. damascena_.] - -=2.= HELLEBOREÆ, HELLEBORE GROUP. This has regular flowers with most -frequently a coloured calyx. The petals (honey-leaves) are modified -into nectaries; they may be horn-like, provided with a spur, or of a -similarly unusual form, or they may be entirely absent. Anthers often -extrorse.--_Trollius_ (Globe-flower[36]). The flower is acyclic: many -petaloid sepals, succeeding these, most frequently, several _linear_, -dark yellow petals, which bear a naked nectary at the base; finally, -many stamens and carpels arranged in a spiral (3/8, 8/21).--_Caltha_ -(Marsh-marigold, Figs. 375, 377); 5 (-7) yellow sepals, no petals. -The foliage-leaves have a large amplexicaul sheath.--_Helleborous_ -(Hellebore) has pedate leaves. The flower is acyclic, with 5 large, -regular, _persistent_, often petaloid sepals (2/5); small, _horn-like_ -petals (honey-leaves; most frequently 13, divergence 8/13) and -generally few carpels (Fig. 374).--_Coptis._--_Isopyrum._--_Eranthis_ -(Winter Aconite), like _Anemone_, has a 3-leaved involucre and most -frequently trimerous flowers, ~6 large petaloid sepals, 6 petals -(tubular honey-leaves), 6 oblique rows of stamens, 3–6 carpels~. -_Aquilegia_ (Columbine, Fig. 376); the flower is entirely cyclic and -has large spurs on all the 5 petals (funnel-shaped honey-leaves); S5 -coloured, P5, A5 × (8–12), G5 in regular alternation (Figs. 376, 370); -the innermost stamens are often staminodes (Fig. 370).--_Nigella_ -(Love-in-the-mist, Fig. 378) has 5 sepals and 8 small, _two-lipped_ -petals cleft at the apex (the nectary is covered by the under-lip; -Fig. 378 _C_, _D_). The 5 carpels are more or less completely united; -and a many-carpellate ovary with free styles is formed in some. Large -air-chambers in the external wall of the ovary are formed in _N. -damascena_ (Fig. 378).--_Actæa_ (Baneberry) has coloured sepals, either -no petals or an indefinite number, and only 1 carpel. The fruit is a -berry (or follicle).--~_Cimicifuga_, _Garidella_, _Xanthorhiza_ (S5, -P5, A5 + 5, G5).~ - - -=3.= DELPHINIEÆ, LARKSPUR GROUP. Zygomorphic flowers with coloured -calyx; the 2 posterior petals (honey-leaves) are transformed into -nectaries, the others are small or absent altogether.--_Aconitum_ -(Monkshood); 5 sepals, of which the _posterior one_ (Fig. 379 _A_) -_is helmet-shaped_; most frequently 8 petals (as in Fig. 372), of -which the two posterior ones (honey-leaves) are developed into -long-clawed nectaries (Fig. 379 _A_, _k_) enveloped by the helmet-like -sepal; the others are small, or are to some extent suppressed. -~Stamens on a spiral of 3/8–5/13; generally 3 carpels.~ Perennial -herbs.--_Delphinium_ (Larkspur); very closely allied to _Aconitum_, but -the anterior 4 petals are most frequently wanting, and the 2 posterior -ones have each a spur, which is enclosed by the _posterior sepal_, -the latter being also provided with _a membranous spur_. ~Stamens and -carpels arranged on a spiral of 3/8, 5/13, 8/21. In _D. ajacis_ and -_consolida_ there is apparently only 1 petal (by the fusion of 4) and 1 -carpel.~ - - [Illustration: FIG. 379.--_Aconitum napellus. A_ Flower in - longitudinal section, below are the 2 bracteoles; _a_ half - of helmet-like sepal; _b_ and _c_ other sepals; _k_ nectary; - _f_ carpels. _B_ Ovary in longitudinal section; _C_ the same - transversely; _d_ dorsal suture; _v_ ventral suture.] - -=B. Fruit achenes.= Many carpels, each with only 1 ascending (Fig. -373 _C_), or pendulous (Fig. 373 _D_), perfect ovule; often also -rudimentary ovules above it (Fig. 373 _A_, _B_). Fruit achenes. - -=4.= RANUNCULEÆ, BUTTERCUP GROUP, has double perianth. _Myosurus_ -and _Adonis_ have pendulous ovules as in Anemoneæ (Fig. 373 _D_); -~_Ranunculus_, with _Batrachium_ and _Ficaria_, erect ovules (Fig. 373 -_C_) and downwardly-turned radicle.~--_Ranunculus._ Most frequently -S5, P5, many spirally-placed stamens and carpels (Figs. 371, 380). The -petals (honey-leaves) have a nectary at the base, covered by a small -scale. ~_Batrachium_, Water Ranunculus, deviates by the achenes being -transversely wrinkled; dimorphic leaves. _Ficaria_ has 3 sepals and 7–8 -petals arranged in 2/5–3/8. _F. ranunculoides_ (the only species) has -tuberous roots, which spring from the base of the axillary buds, and -together with these, serve as organs of reproduction. The embryo has -only 1 cotyledon.~--_Myosurus_ (Mouse-tail) has small prolongations -from the 5 sepals; 5 narrow petals which bear the nectaries near the -apex; sometimes only 5 stamens, and an ultimately very long receptacle, -with numerous spirally-arranged achenes (Fig. 381).--_Adonis_ is -acyclic (Fig. 372); most frequently 5 sepals with a divergence of 2/5, -8 petals of 3/8, indefinite stamens and carpels of 3/8 or 5/13. The -corolla has no nectary. - - [Illustration: FIG. 380.--Flower of _Ranunculus sceleratus_ in - longitudinal section.] - - [Illustration: FIG. 381.--_Myosurus minimus_: _c_ cotyledons; _m_ - the foliage-leaves; _f_ the floral axis with the carpels, and _g_ - the same without; _y_ insertion of perianth.] - -=5.= ANEMONEÆ, ANEMONE GROUP, has a single perianth. ~(Pendulous ovules -(Fig. 373 _D_), radicle turned upward).~--_Anemone_ has a single, -petaloid, most frequently 5–6-leaved perianth, and beneath the flower -most frequently _an involucre of 3 leaves_, placed close together in -the form of a whorl. In _A. nemorosa_, _ranunculoides_, etc., the -involucral leaves resemble foliage-leaves; in _A. hepatica_ they are -situated close under the perianth, and resemble sepals, and in the -sub-genus _Pulsatilla_ they stand between the foliage-leaves and -floral-leaves. The style of _Pulsatilla_ finally grows out in the form -of a feather. ~The main axis of _A. hepatica_ has unlimited growth (it -is biaxial), and the flowers are borne laterally in the axils of the -scale-leaves; in the others (uniaxial) the flower is terminal, and the -rhizome becomes a sympodium after the first flowering.~--_Thalictrum_ -(Meadow Rue) has no involucre; 4–5-leaved, greenish perianth. The -receptacle is flat. ~The stamens are brightly-coloured and have long -filaments; 1–5 accessory flowers may occur in the leaf-axils of the -panicle-like inflorescence.~ - -=6.= CLEMATIDEÆ, CLEMATIS GROUP. This differs from all the others -in the _valvate æstivation_ of the calyx and its opposite leaves. -There are 4 (-several) petaloid sepals; petals are absent, or linear -(_Atragene_). Ovule 1, pendulous. Achenes, often with prolonged, -feathery style. The majority of the genera are shrubs, and climb by -their sensitive, twining leaf-stalks.--_Clematis; Atragene._ - - POLLINATION. The flowers are conspicuous either by coloured - petals (honey-leaves) (_Ranunculus_, _Pæonia_) or coloured - sepals (_Helleborus_, _Anemone_, _Caltha_, etc.), or by both - (_Aquilegia_, _Delphinium_), or by the coloured stamens - (_Thalictrum_). Some have no honey (_Clematis_, _Anemone_, - _Thalictrum_), and are generally visited by insects for - the sake of their pollen. Others have nectaries on the - corolla (_Ranunculus_, _Trollius_, _Helleborus_, _Nigella_, - _Aconitum_, etc.), more rarely on the stamens (_Pulsatilla_, - _Clematis_-species), or the carpels (_Caltha_), or the calyx - (certain species of _Pæonia_). The honey is readily accessible - in the flat, open flowers, and these flowers also may easily - pollinate themselves. There is marked protandry where the - honey lies deeply hidden, as in _Aquilegia_, _Delphinium_, and - _Aconitum_. _Helleborus_ and some _Ranunculus_-species are - protogynous. - - About 680 species; especially in northern temperate climates, - and extending to the Polar and Alpine regions. Only the - _Clematideæ_ are tropical. - - The order has an abundance of _acrid_, vesicant properties - (_R. acer_, _sceleratus_, etc.), and _poisonous_ alkaloids - (_Helleborus niger_ is poisonous). OFFICINAL: _Aconitum - napellus_ (aconitine; leaves and tuberous roots); the rhizome of - _Hydrastis canadensis_ from N. Am. (the alkaloid hydrastine). - The order, however, is best known for its ornamental plants; - almost all the genera have species which are cultivated for - their beauty. Sweet-scented flowers are absent. - -Order 2. =Nymphæaceæ (Water Lilies).= WATER PLANTS; generally with -large, floating leaves, and large solitary flowers; sepals 3–5, petals -3–∞, stamens 6–∞, carpels 3–∞. The flower is hypogynous, but in the -_Nymphæeæ_ different degrees of epigyny are found, and from this fact, -as well as from the carpels being united into one pistil, the family -forms a lateral offshoot from the Ranunculaceæ, with much greater -modification. The seed often has an aril, and, in the majority, a -farinaceous nutritive tissue, partly endosperm, partly perisperm (Fig. -383 _C_). The embryo has 2 thick cotyledons and a small hypocotyl; the -plumule is well developed, with 2–4 leaves. - - 1. CABOMBEÆ. 3–4 species (Tropical S. Am.), resembling the - Water Ranunculus, with two kinds of leaves, the submerged being - dissected and the aerial peltate. The flowers are eucyclic, - trimerous, with 2–3 free, epigynous carpels. The ovules are - situated _on the central line_ of the carpel--an almost unique - circumstance. Endosperm and perisperm. _Cabomba; Brasenia._ - -2. NELUMBONEÆ. The leaves are _peltate_, raised on long stalks high -above the water. Large, _hypogynous_ flowers (Fig. 382); sepals 4–5; -petals numerous; stamens numerous; _carpels several_, _distinct_. The -receptacle is very remarkable, being raised above the stamens, and -developed into an _inverted conical_ body on the apex of which the -nut-like fruits are _embedded in pits_. _Endosperm is wanting_, but -the embryo is large and has well developed cotyledons.--~_Nelumbo_, -2 species. _N. lutea_ (N. Am.); _N. speciosa_ (E. Ind.) was sacred -amongst the ancient Hindoos and Egyptians, (the Lotus flower); its -seeds are used as food.~ - -3. NYMPHÆEÆ, WATER LILY GROUP. The carpels are united into _one_, -_many-locular ovary_, _whose numerous ovules are situated on the -surface of the partition walls_ (as in the Poppies); the stigma is -sessile and radiating, the number of rays corresponding to the number -of carpels (Fig. 383). The fruit is a spongy _berry_ with many seeds, -which have a large perisperm in addition to the endosperm (Fig. 383 -_C_). - - [Illustration: FIG. 382.--_Nelumbo nucifera_: vertical section - through the receptacle.] - -Sepals, petals, and stamens often pass gradually over the one into the -other, the petals becoming narrower by degrees, and bearing anthers -on each side of the apex, which gradually become larger anthers in -proportion to the filament, until the perfect stamen is developed. -The long-stalked leaves are floating, and most frequently cordate, -elliptical, leathery, with a shiny surface, sometimes (as in _Victoria -regia_ and _Euryale ferox_) with strongly projecting thorny ribs on the -lower surface. In the intercellular passages of the leaves are some -peculiar, stellate cells. - -_Nuphar_ has 5 sepals, and an _hypogynous_ flower. ~The petals, which -are small, have a nectary on the back; the coloured inner side of the -sepals functions as petals; the ovate gynœceum is quite free.--_N. -luteum_ is a native plant (Yellow Water-Lily), with, most frequently, -13 petals and 10–16 loculi in the ovary. The rhizome is horizontal, as -much as 5–6 cm. in thickness, and bears on its under surface a number -of roots, which on dying-off leave deep scars; the leaves are borne in -spiral lines, and the flowers are solitary in certain leaf-axils. The -construction of the rhizome is very peculiar; the vascular bundles are -scattered and closed as in a monocotyledonous stem.~ - - [Illustration: FIG. 383.--_Nymphæa_: _A_ flower in longitudinal - section, the most external leaves being removed; _B_ fruit; _C_ - seed of _Nuphar_ (longitudinal section); the perisperm at the - base, the endosperm at the top surrounding the embryo.] - -_Nymphæa_ has 4 sepals, and the flower is more or less _epigynous_. -Petals and stamens are inserted at different heights on the ovary to -just beneath the stigma (Fig. 383). _Nymphæa alba_ (White Water-Lily). -_Victoria regia_ from the Amazon, and _Euryale ferox_ from Asia, have -entirely epigynous flowers. ~The shield-like leaves of _Victoria_ are -as much as 2 metres in diameter, and the edge is bent up to a height -of 5–14 cm.; the flowers are 20–40 cm. in diameter, and change in -twenty-four hours from white to rose-red. A development of heat, as -much as 14°C. above the temperature of the air, together with a strong -formation of carbonic acid, has been observed during flowering.~ - - POLLINATION. _Nymphæa alba_ and other species of the - sub-genus _Symphytopleura_ are self-pollinated; the sub-genus - _Leptopleura_ is insect-pollinated. _Nuphar_ and _Victoria_ can - effect self-fertilisation; _Euryale_ is self-fertilised, often - in entirely closed and submerged flowers.--The dissemination - of the seeds in _Nuphar luteum_ is effected by the fruit, - which rests on the water, becoming detached from its stalk, - and dehiscing from the base upwards so that the seeds are - set free; while in _Nymphæa alba_ the spirally-twisted stalk - draws the fruit under water, and it dehisces by its upper part - being thrown off as a hood, and the seeds which are enclosed - in air-tight sacs rise to the surface of the water. In this - condition they are able to float and can only sink to the bottom - when the air has disappeared. - - 53 species; in fresh water in all parts of the world, but - especially in the Tropics.--The rhizomes and seeds of some may - be used as food; _Euryale ferox_ is even cultivated. _Nymphæa - cœrulea_ and _Lotus_ were sacred among the Egyptians. - -Order 3. =Ceratophyllaceæ.= About 3 species. Aquatic plants, submerged, -rootless; leaves cartilaginous, verticillate, dissected into repeatedly -dichotomous branches which are finely toothed; only one of the leaves -in a whorl supports a vegetative branch. The flowers are _monœcious_, -axillary. Inside the 6–12 perianth-leaves are situated in the ♂-flower -10–20 stamens with thick connective, and in the ♀-flower a gynœceum -formed by one carpel, with one orthotropous and pendulous ovule, which -has only one integument. Fruit a nut, which, in some species, bears on -each side a pointed horn, and at the apex a similar one, formed by the -persistent style.--The embryo has an unusually well developed plumule -with several whorls of leaves. The plant is rootless throughout its -whole life.--_Ceratophyllum_ (Horn-wort). - - Order 4. =Annonaceæ.= Sepals 3; petals 3+3 (most frequently - _valvate_); succeeding these (as in the _Ranunculaceæ_) are - _numerous acyclic_ stamens and an _apocarpous gynœceum_; the - flowers are hypogynous, regular and ☿, generally very large - (2–3 cm. in diameter), and the leaves of the perianth are - more or less fleshy or leathery. The majority have syncarps - with berry-like fruitlets, but in _Annona_ and some others - the carpels fuse together into a large, head-like fruit--a - kind of composite berry. The seeds have _ruminate_ endosperm - as in _Myristica_.--Trees or shrubs with _alternate_, simple, - entire, penninerved leaves without stipules. 450 (700?) species; - especially tropical. The best known are _Anona cherimolia_, - _squamosa_ and _reticulata_ (all from America) cultivated on - account of their large, delicious fruits. Some have acrid and - aromatic properties (_Xylopia_, _Cananga_--the flowers of the - latter yield Ylang-ylang); _Artabotrys odoratissimus_; _Asimina_ - (N. Am.). - - Order 5. =Magnoliaceæ.= Trees or shrubs with scattered, often - leathery, entire leaves, generally with _stipules_, which (as in - _Ficus_) are rolled together and form a hood round the younger - internodes above them, and are cast off by the unfolding of - the next leaf, leaving a ring-like scar. The endosperm is _not - ruminate_. Corolla imbricate. Fruit a syncarp. - - =A.= MAGNOLIEÆ. The flowers are borne singly, and before opening - are enveloped in an ochrea-like spathe which corresponds to - the stipules of the foliage-leaves. The perianth generally - consists of 3 trimerous whorls, the external one of which - is sometimes sepaloid (_Liriodendron_, and the majority of - _Magnolia_species), sometimes coloured like the others; the - perianth is sometimes many-seriate. _Numerous spirally-placed_ - stamens and carpels. The latter are situated on the _elongated_, - cylindrical receptacle, and are individually more or less - united, except in _Liriodendron_, where they are free. This last - genus has winged achenes; the fruitlets in _Magnolia_ open along - the dorsal and ventral sutures, and the seeds then hang out, - suspended by elastic threads formed from the vascular bundles - of the funicle and raphe; they are red and drupaceous, the - external layer of the shell being fleshy--a very rare occurrence. - - =B.= ILLICIEÆ has no stipules. The carpels are situated in a - whorl on a short receptacle. Follicles, one-seeded. The leaves - are dotted by glands containing essential oil. _Illicium; - Drimys._ - - 70 species; in tropical or temperate climates; none in Europe - or Africa. They are chiefly used as ornamental plants, _e.g._ - the Tulip-tree (_Liriodendron tulipifera_, N. Am.), _Magnolia - grandiflora_ (N. Am.), _M. yulan_ and _fuscata_ (China), and - others. The remains of _Liriodendron_ occur as fossils in the - Cretaceous and Tertiary periods.--The fruits of _Illicium - anisatum_ (Star-aniseed from Eastern Asia) are OFFICINAL. The - bark of _Drimys winteri_ (S. Am.) is also strongly aromatic. - - Order 6. =Calycanthaceæ.= These are very closely related to - the Magnoliaceæ, but differ in having _perigynous_ flowers - with many perianth-leaves, stamens and (about 20) carpels in a - continuous _spiral_, seeds _almost devoid of endosperm_ with - rolled up, leaf-like cotyledons, and leaves opposite on a square - stem.--There are some species in N. America (_Calycanthus - florida_, _occidentalis_, etc.) and 1 in Japan (_Chimonanthus - præcox_), all strongly aromatic. - - Order 7. =Monimiaceæ.= Aromatic shrubs with opposite leaves. - Perigynous flowers. The anthers dehisce by valves like those of - the _Lauraceæ_, and the Monimiaceæ may thus be considered as an - apocarpous form of this order. They are also closely related to - _Calycanthaceæ_. 150 species, tropical.--_Hedycarya, Mollinedia, - Monimia._ - - [Illustration: FIG. 384.--Diagram of _Berberis_.] - - [Illustration: FIG. 385.--_Berberis_: carpel with 2 stamens.] - -Order 8. =Berberidaceæ (Barberries).=--The regular, ☿, hypogynous -flowers are dimerous or trimerous and have regularly alternating -whorls of free sepals, petals, and stamens and 1 unilocular carpel; -the corolla and stamens have each 2 whorls, the calyx at least 2. The -anthers open, as in Lauraceæ, by (2) _valves_, but are always introrse -(Fig. 384). The pistil has a large, disc-like, almost _sessile_ stigma -(Fig. 385), and in the ovary _several_ erect ovules are placed close to -the base of the ventral suture. The fruit is most frequently a _berry_. -Seeds endospermous.--Shrubs or herbs with scattered, most frequently -compound leaves (without stipules), and racemose inflorescences.--~They -show a relationship to the Lauraceæ in the number of the parts of the -flower and the dehiscence of the anthers.~ - -_Berberis_ is a shrub; it has sepals 3 + 3, petals 3 + 3, stamens 3 -+ 3 (Fig. 384). The petals (honey-leaves) bear internally at the base -2 darkish-yellow nectaries. The filaments are sensitive at the base, -and suddenly bend inwards if touched at that spot (Fig. 385). ~The -racemes often have a terminal, 5-merous flower; they are borne on -dwarf-branches. The leaves on the long-branches develope into thorns, -but the buds in their axils, in the same year as themselves, develope -as the short-branches with simple foliage-leaves, _articulated_ at -the base, from which fact some authorities have considered that the -leaf is compound with a single, terminal leaflet.~--_Mahonia_ has -imparipinnate leaves. The flower has 3 whorls of sepals. Otherwise as -in _Berberis_.--~_Epimedium_; herbs with spurred petals; the flowers -dimerous; 4–5 whorls of sepals, 2 of petals and stamens. Fruit a -capsule. _Leontice_, fruit dry. The anthers of _Podophyllum_ dehisce -longitudinally.--_Nandina. Aceranthus._~ - - 100 species; North temp., especially Asia: fossils in Tertiary. - _Berberis vulgaris_ is a native of Europe. This and other - species, together with _Mahonia aquifolium_ (N. Am.), _Epimedium - alpinum_, etc., are cultivated as ornamental plants. Several - have a yellow colouring matter in the root and stem. OFFICINAL: - the rhizome of _Podophyllum peltatum_ (from N. Am.) yields - podophyllin. - - Order 9. =Menispermaceæ.= This order has derived its name from - the more or less crescent-like fruits and seeds. Diœcious. - The flowers are 2–3-merous, most frequently as in _Berberis_ - (S3 + 3, P3 + 3, A3 + 3), with the difference that there are - 3 _free carpels_, each with 1 ovule; in some genera, however, - the number is different. Stamens often united into a bundle - (as in _Myristica_); anthers dehiscing longitudinally; fruit a - drupe.--The plants (with herbaceous or woody stems) belonging - to this order are nearly all _twining_ or _climbing_ plants, - and have scattered, palmate or peltate, sometimes lobed leaves - without stipules. Structure of stem anomalous. _Cocculus, - Menispermum, Cissampelos, Anamirta._ - - 150 species; Tropical; very rich in bitter and poisonous - properties. OFFICINAL: Calumba-root from _Jateorhiza columba_ - (E. Africa). The following are cultivated as ornamental - plants:--_Menispermum canadense_ (N. Am.) and _M. dahuricum_ - (Asia). The fruits of _Anamirta cocculus_ (E. Ind.) are very - poisonous (“Grains-of-Paradise”; the poisonous matter is - picrotoxine). - - Order 10. =Lardizabalaceæ.= This order, by the free, apocarpous - carpels, belongs to a more primitive type, and by the united - stamens to a more developed one. _Akebia_; _Holbœllia_; - principally climbing or twining shrubs. About 7 species in S.E. - Asia and S. Am. - -Order 11. =Lauraceæ= (=True Laurels=). Trees or shrubs; the leaves, -always without stipules, are simple, most frequently scattered, -lanceolate or elliptical, entire, penninerved, finely reticulate -(except _Cinnamomum_ with 3–5-veined leaf), leathery and evergreen -(except, _e.g. Cinnamomum_); they are frequently studded with clear -glands containing _volatile oil_. The flowers are borne in panicles -and are small and of a greenish or whitish colour. They are _regular, -perigynous_, with most frequently a bowl or cup-shaped receptacle -(Fig. 386), usually ☿, and _trimerous_ (rarely dimerous) through all -(most frequently 6–7) whorls; viz. most frequently, perianth 2 whorls, -stamens 3–4 and carpels 1 (P3 + 3, A3 + 3 + 3 + 3, G3) in regular -alternation (Fig. 387). Each of the 2 or 4 loculi of the anthers _open -by an upwardly directed valve_ (Fig. 386); of the stamens, the 2 -outermost whorls are generally introrse, the others extrorse, or 1–3 -whorls are developed as staminodes (Fig. 387 _g_). The gynœceum has -1 loculus with 1 style and 1 pendulous ovule (Fig. 386), and may be -considered as formed of 3 carpels. The fruit is a _berry_ (Fig. 388) -or _drupe_, which often is surrounded at its base by the persistent -receptacle (as an acorn by its cupule), which becomes fleshy and -sometimes coloured during the ripening of the fruit. The embryo has 2 -thick cotyledons, but _no endosperm_ (Fig. 388). - - [Illustration: FIG. 386.--Flower of the Cinnamon-tree - (_Cinnamomum zeylanicum_) (longitudinal section).] - - [Illustration: FIG. 387.--Typical diagram of the Lauraceæ: _g_ - staminodes.] - - [Illustration: FIG. 388.--_Laurus nobilis_: longitudinal section - of fruit.] - - The Lauraceæ present affinities with the Polygonaceæ, in - which there is found perigyny, as well as a similar number of - parts in the flower and a similar gynœceum, but with erect - and orthotropous ovule. From their general characters they - should be classed among the Polycarpicæ, but stand, however, - isolated by the _syncarpous_ gynœceum, if it is in reality - formed by 3 carpels and not by 1 only. _Hernandia_, which has - epigynous monœcious flowers, deviates most.--_Cassytha_ is - a _Cuscuta_-like, herbaceous, slightly green parasite with - twining, almost leafless stems. The flower however agrees with - the diagram in Fig. 387. Some Lauraceæ have curved veins or - palminerved and lobed leaves (often together with entire ones) - _e.g. Sassafras_. - - [Illustration: FIG. 389.--_Myristica_: fruit.] - - [Illustration: FIG. 390.--Seed with aril entire and in - longitudinal section.] - - There are 1000 species; especially in the forests of tropical - S. America and Asia, of which they form the principal part. - Only _Laurus nobilis_ is found in Europe, and there is little - doubt that its proper home is in Western Asia. They are - rare in Africa.--On account of _the volatile oil_ found in - all parts of the plant, they are used as _spices_, _e.g._ - the false Cinnamon-tree (_Dicypellium caryophyllatum_, in - the Brazils). The OFFICINAL ones are--the Cinnamon-tree - (_Cinnamomum zeylanicum_ from Ceylon, E. India, Eastern Asia), - which is also cultivated; the Camphor-tree (_Cinnamomum - camphora_, Eastern Asia). The Laurel-tree (_Laurus nobilis_, - Mediterranean), the berries and leaves of which give laurel oil, - is medicinal.--Scented wood for furniture, etc., is obtained - from _Sassafras officinalis_ (from N. Am.). The wood from its - roots is officinal. Pichurim “beans” are the large cotyledons - of _Nectandra pichury_, whilst the famous “Greenheart” wood - of Demarara is the wood of _Nectandra rodiæi_. The pulp and - seeds contain a _fatty oil_. The pear-like fruit of _Persea - gratissima_ (Mexico, also cultivated) is very delicious. - _Lindera benzoin_ is a garden shrub; _Laurus nobilis_ likewise. - - Order 12. =Myristicaceæ= (=Nutmegs=). In this order there is - only 1 genus, _Myristica_. Trees or shrubs. The leaves agree - closely with those of the Lauraceæ, with which this order has - many points in common. The majority of the species are aromatic, - having in their vegetative parts pellucid glands with volatile - oils. The flowers are regular, diœcious, trimerous, and have a - single gamophyllous (cupular or campanulate) 3-toothed, fleshy - perianth. In the ♂-flowers the anthers vary in number (3–15), - and they are extrorse and borne on a centrally-placed column; - in the ♀-flower the gynœceum is unilocular, unicarpellary, with - 1 ovule. The FRUIT (Fig. 389) has the form of a pear; it is a - fleshy, yellow capsule, which opens along the ventral and dorsal - sutures, exposing the large seed. This seed has a large, red, - irregularly branched aril--the so-called “mace”; the “nutmeg,” - on the other hand, is the seed itself with the inner thin - portion of the testa, which has pushed its way irregularly into - the endosperm, and causes the marbled appearance of the cut seed - (Fig. 390); the external, dark brown, hard, and brittle part - of the seed-shell is however removed. Mace and nutmeg contain - volatile and fatty oils in abundance.--80 species. Tropical. The - majority are used on account of their aromatic seeds and aril, - the most important being _M. fragrans_ (_moschata_), from the - Moluccas. This is cultivated in special plantations, not only in - its native home, but in other tropical countries also. Nutmegs - were known as commodities in Europe in very ancient times - (_e.g._ by the Romans), but it was not until the year 1500 that - the tree itself was known. The seed is OFFICINAL. - - - Family 10. =Rhœadinæ.= - -The plants belonging to this family are almost exclusively herbaceous, -with scattered, exstipulate leaves. The flowers are eucyclic di- or -tetramerous, with the calyx and corolla deciduous, _hypogynous_, -☿, _regular_, the gynœceum with 2–several carpels (generally 2, -transversely placed) (Figs. 391, 392, 393, 397). The ovary is -_unilocular with parietal placentæ_, but in _Cruciferæ_ and a few -others it becomes bilocular by the development of a _false_, membranous -wall between the placentæ. The stigmas in the majority of cases -are _commissural_, _i.e._ they stand above the placentæ, and not -above the dorsal line of the carpels. The fruit is nearly always a -_capsule_, which opens by the middle portions of the carpels detaching -themselves as valves, bearing no seed, whilst the placentæ persist -as the seed-bearing frame. Endosperm is found in _Papaveraceæ_ and -_Fumariaceæ_, but is absent in _Cruciferæ_ and _Capparidaceæ_.--~This -family through the Papaveraceæ is related to the Polycarpicæ (the -Nymphæaceæ), through the Capparidaceæ to the Resedaceæ in the next -family.~ - - Exceptions to the above are: _Eschscholtzia_, _Subularia_ (Fig. - 403) and a few Capparidaceæ, in which perigynous flowers are - found. A few Papaveraceæ and Fumariaceæ have trimerous flowers. - In _Fumaria_ and certain Cruciferæ, the fruit is a nut. The - Fumariaceæ have zygomorphic flowers. Trees and shrubs are almost - entirely confined to the Capparidaceæ, in which order stipules - also are found. - -Order 1. =Papaveraceæ= (=Poppies=). Herbaceous plants with stiff hairs -and _latex_; flowers _regular_ (Fig. 391) with generally 2 (-3) sepals -(which _fall off_ as the flower opens), 2 + 2 petals (imbricate -and crumpled in the bud) _without spur, numerous stamens in several -alternating whorls_ (generally a multiple of 2); carpels 2–several, -united into a unilocular gynœceum. Trimerous flowers also occur. -Capsule with very numerous seeds on the parietal placentæ; embryo -small, with large, oleaginous _endosperm_ (Fig. 392).--The leaves have -no stipules and are generally pinnately lobed. - - [Illustration: FIG. 391.--A Diagram of the flower of _Glaucium_ - and the dichasium (which becomes transformed into a scorpioid - cyme). _B Papaver argemone_, transverse section of the ovary - with indication of the position of the stigmas.] - - [Illustration: FIG. 392.--_Papaver somniferum_: _A_ capsule; - _st_ the stigma; _v_ valves; _h_ pores; _B_ seed in longitudinal - section; _alb_ endosperm; _emb_ embryo.] - -_Papaver_ (Poppy) has large, solitary, terminal flowers; petals firmly -and irregularly folded in æstivation; gynœceum formed by many (4–15) -carpels; stigmas velvety, _sessile_ and _stellate_ (the rays stand -above the placentæ) (Fig. 391 _B_). The edges of the carpels project -deeply into the ovary, but do not meet in the centre, so that it -remains unilocular. The capsule opens by pores placed close beneath -the stigma, and formed of small valves alternating with the placentæ -and the rays of the stigma (Fig. 391). _P. dubium_, _P. argemone_, _P. -rhœas_.--_Chelidonium_ (Greater Celandine) has _yellow_ latex, flowers -in umbellate cymes (the terminal, central flower opening first) and -only 2 carpels; the fruit resembles the siliqua of the Cruciferæ in -having two _barren valves_, which are detached from the base upwards, -and a _seed-bearing frame_, but there is no partition wall formed -between the placentæ. _Ch. majus._--~The majority of the other genera -have, like _Chelidonium_, 2 carpels (lateral and alternating with the -sepals: Fig. 391 _A_) and siliqua-like fruit, thus: _Eschscholtzia_ -(perigynous) with a linear, stigma-bearing prolongation extending as -far above the placentæ as above the dorsal suture of the carpels; -_Glaucium_ (Horn-Poppy); _G. luteum_, whose extremely long, thin -capsule differs from that of _Chelidonium_ by the formation, during -ripening, of a thick, spongy (_false_) replum, which persists when -the valves are detached; _Sanguinaria_ with red latex, the 2 petals -divided into 8–12 small petals (perhaps by dédoublement); _Macleya_ and -_Bocconia_ (1-seeded capsule) with 2 sepals and no petals.--Trimerous -flowers are found in _Argemone_ and _Platystemon_ (with a curious -fruit, carpels free, and transversely divided and constricted into -joints which separate as nut-like portions).--_Meconopsis._--_Hypecoum_ -(Fig. 393 _C_) has tri-lobed and three cleft petals, 4 free stamens -with 4-locular anthers and a jointed siliqua; it presents a -transitional form to the Fumariaceæ, with which order it is sometimes -included.~ - - POLLINATION. _Papaver_ and _Chelidonium_ have no honey, and - are without doubt only visited by insects for the sake of - the pollen. The anthers and stigmas mature about the same - time.--There are 80 species; especially from warm climates. - OFFICINAL: _Papaver somniferum_ (Opium-Poppy); the latex - of its unripe capsules is obtained by incisions, and dried - (_opium_); it contains many alkaloids: morphine, papaverine, - narcotine, thebaine, etc. The oleaginous seeds are also used - in the manufacture of oil. Its home is in the East, where it - is extensively cultivated. The petals of the Corn-poppy (_P. - rhœas_) are also officinal. Several species are cultivated as - ornamental plants. - -Order 2. =Fumariacæ= (=Fumitories=). This order differs from the -closely allied Papaveraceæ in the absence of latex, a poorer flower, -generally _transversely zygomorphic_ (Fig. 393 _B_), in which case one -or both of the outer lateral petals are gibbous, or prolonged into -a spur; the stamens are especially anomalous. Sepals =2=, caducous; -petals 2 + 2; stamens 2, _tripartite_; each lateral anther is -_bilocular_ (Figs. 393 _A_, _B_; 395); gynœceum bicarpellate. The fruit -is a nut or siliqua-like capsule. _Endosperm._--_Herbs_ with scattered, -repeatedly pinnately-divided leaves without stipules, generally quite -glabrous and glaucous; the flowers are arranged in racemes with -subtending bracts, but the bracteoles are sometimes suppressed. - -_Dicentra_ (syn. _Dielytra_) and _Adlumia_ have a doubly symmetrical -flower, with a spur or gibbous swelling at the base of _each_ of -the laterally-placed petals (Figs. 393 _A_, 394). _Corydalis_ has a -zygomorphic flower, _only one of_ the lateral petals _having a spur_, -and consequently there is only one nectary at the base of the bundle of -stamens, which stands right in front of the spur (Fig. 393 _B_, 395, -396). The fruit is a many-seeded siliqua-like capsule. ~A peculiarity -of the flower is that the plane of symmetry passes _transversely_ -through the flowers, whilst in nearly all other zygomorphic flowers -it lies in the median line. Moreover, the flower is turned, so that -the plane of symmetry ultimately becomes nearly vertical, and the spur -is directed backwards.--Many species have subterranean tubers; in -these the embryo germinates with _one cotyledon_, which is lanceolate -and resembles a foliage-leaf. The tuber is in some the swollen -hypocotyl (_C. cava_), in others a swollen root (_C. fabacea_, etc.), -which grows down through the precisely similar swollen root of the -mother-plant. The sub-genus _Ceratocapnos_ has dimorphic fruits (nuts -and capsules) in the same raceme.~ _Fumaria_ differs from _Corydalis_ -only by its almost drupaceous, one-seeded nut (Fig. 395). - - [Illustration: FIG. 393.--Diagram of _Dicentra_ (_A_), - _Corydalis_ (_B_), and _Hypecoum_ (_C_).] - - [Illustration: FIG. 394.--_Dicentra spectabilis_: _A_ flower - (2/5); _B_ the same, after removal of half of one outer petal; - the cap, formed by the inner petals, is moved away from the - anthers and stigma; the insect does this with the lower side of - its abdomen, and thus rubs the stigma on the hairs of its ventral - surface; the dotted line at _e_ indicates the direction of the - proboscis; _C_ andrœcium and gynœceum; _D_ stigma.] - - THE STRUCTURE OF THE FLOWER. _Hypecoum_ among the Papaveraceæ - is the connecting link with the Fumariaceæ. The diagram (Fig. - 393 _C_) corresponds both in number and in the relative position - of its members with that of most of the other Papaveraceæ (Fig. - 391), except that there are only four stamens (with extrorse - anthers). In _Dicentra_ (Fig. 393 _A_), the two central - (uppermost) stamens are absent, but each of the two lateral ones - are divided into three filaments, of which the central one bears - a four-locular anther, and each of the others a two-locular - (half) anther. _Corydalis_ and _Fumaria_ stand alone in the - symmetry of the flower, differing from _Dicentra_ in having only - one of the lateral petals (Fig. 393 _B_, _sp_) prolonged into - a spur, while in _Dicentra_ both the petals are spurred. This - structure has been interpreted in various ways. According to Asa - Gray the median stamens are absent in the last-named genera, and - the lateral ones are split in a similar manner to the petals of - _Hypecoum_. Another, and no doubt the most reasonable theory - (adduced by De Candolle), is: that two median stamens are split, - the two parts move laterally, each to their respective sides - and become united with the two lateral stamens; this affords a - natural explanation of the two half-anthers, and establishes a - close relationship to the Cruciferæ. A third interpretation, - held by Eichler and others, is as follows: the median stamens - are _always_ wanting; when they appear to be present, as in - _Hypecoum_, it is due to the fact that the side portions of - the lateral stamens _approach each other_ (as interpetiolar - stipules) and coalesce into an apparently single stamen. - - [Illustration: FIG. 395.--_Fumaria officinalis_: _A_ the flower - in longitudinal section; _B_ the andrœcium and gynœceum; nectary - to the right.] - - [Illustration: FIG. 396.--_Corydalis cava_: _a_ a flower (lateral - view); _b_ the anthers lying round the stigma; _c_ the anthers - shortly before the opening of the flower; _d_ the head of the - stigma; _e_ relative position of the parts of the flower during - the visit of an insect.] - - 130 species; mostly from the northern temperatures. - - POLLINATION. _Fumaria_, with its inconspicuous flowers, has to - a great extent to resort to self-pollination. _Corydalis_, on - the other hand, is dependent on cross-pollination; _C. cava_ - is even absolutely sterile with its own pollen. _Corydalis_ - is pollinated by insects with long probosces (humble-bees, - bees), which are able to reach the honey secreted in the spur; - as they alight on the flowers they press the exterior petals - on one side (Fig. 396 _e_), so that the stigma, surrounded by - the anthers, projects forward; the proboscis is introduced in - the direction of the arrow in the figure, and during this act - the under-surface of the insect is covered with pollen, which - is transferred by similar movements to the stigma of another - (older) flower.--Ornamental plants; _Dicentra_ (_spectabilis_ - and _eximia_), _Adlumia_, _Corydalis_. - -Order 3. =Cruciferæ (Crucifers).= The flowers are _regular_, ☿; sepals -4, free (2 + 2), deciduous; petals 4, free, deciduous, unguiculate, -placed _diagonally_ in one whorl, and alternating with the sepals; -stamens 6; the 2 _outer_ are _short_, the 4 _inner_ (in reality the two -median split to the base) _longer_, placed in pairs (tetradynamia of -Linnæus); gynœceum syncarpous formed by 2 (as in the previous order, -lateral) carpels, with 2 parietal placentæ, but divided into two -loculi by a _spurious_ membranous dissepiment (_replum_) (Fig. 397). -Style single, with a capitate, usually two-lobed stigma, generally -commisural, that is, placed above the parietal placentæ (Fig. 397), but -it may also be placed above the dorsal suture, or remain undivided. -Ovules _curved_. The fruit is generally a bivalvular _siliqua_ (Fig. -398 _B_, _C_), the valves separating from below upwards, and leaving -the placentæ attached to the replum; other forms of fruits are -described below. The oily seeds _have no endosperm_ (endosperm is -present in the two previous orders); the _embryo is curved_ (Figs. -398 _E_, _F_; 399, 400).--In general they are _herbaceous_ plants, -without latex, with scattered, penninerved leaves, without stipules; -the inflorescence is very characteristic, namely, a raceme with the -flowers aggregated together at the time of flowering into a corymb, and -_destitute of both bracts and bracteoles_. - - [Illustration: FIG. 397.--Diagram of a Cruciferous flower.] - - [Illustration: FIG. 398.--_Brassica oleracea_: _A_ raceme; _B_, - _C_ siliqua; _D_ seed; _E_ embryo; _F_ transverse section of - seed.] - - [Illustration: FIG. 399.--Transverse section of seed and embryo - of _Cheiranthus cheiri_.] - - [Illustration: FIG. 400.--Transverse section of seed of - _Sisymbrium alliaria_.] - - Many are biennial, forming in the first year a close - leaf-rosette. By cultivation the tap-root can readily be induced - to swell out into the form of a tuber (Turnips, Swedes, etc.). - _Stipules_ are found indicated by small glands on the very - young leaves; in _Cochlearia armoracia_ they are fairly large - triangular scales. _Stellate hairs_ often occur. _Floral-leaves_ - are occasionally developed. Terminal flowers are never found in - the inflorescences. _Iberis_ and _Teesdalia_ have _zygomorphic_ - flowers. _Subularia_ (Fig. 403) is perigynous. The 2 external - sepals (Fig. 397) stand in the median plane; it may therefore - be supposed that there are two bracteoles outside these which, - however, are suppressed, and can only in a few instances be - traced in the young flower; the two lateral sepals are often - gibbous at the base, and serve as reservoirs for the nectar - secreted by the glands placed above them; they correspond in - position to the external petals of the Fumariaceæ. The 4 petals - which follow next arise simultaneously, and alternate with the - 4 sepals; if it could be shown that these are merely 2 median - petals, which have been deeply cleft and the two parts separated - from each other and displaced to the diagonal position, there - would be a perfect correspondence with the Fumariaceous flower; - then the petals would be followed in regular alternation by the - 2 lateral small stamens, the 2 median long stamens, which it - has been proved are split into 4 and placed in couples, and the - 2 laterally-placed carpels,--in all 6 dimerous whorls. But the - formation of the corolla by the splitting of 2 petals does not - agree with the development of the flower or bear comparison, and - hence the only fact in favour of this theory is the otherwise - prevailing correspondence with the Fumariaceæ. Yet it may - be observed that in special cases each pair of long stamens - clearly enough arises from one protuberance and even later - on may be considerably united or entirely undivided (_e.g._ - _Vella_); in other instances they are quite distinct from the - beginning, and it is possible that this latter condition has - become constant in the corolla. _Lepidium ruderale_ and others - have no corolla. _Senebiera didyma_ has only 2 median stamens. - _Megacarpæa_ has several stamens, no doubt by dédoublement, as - in Capparidaceæ.--The _number of carpels_ may also be abnormally - increased; _Tetrapoma barbareifolium_ has normally 4 carpels - with an equal number of placentæ and repla. It is supposed to - be a variety of _Nasturtium palustre_.--The 2–4–8–10 greenish - _glands_, which are found at the base of the stamens, are - nectaries, morphologically emergences, and not rudimentary - stamens. The forms of _fruits_ are of great systematic - significance, see the genera. In some species dimorphic fruits - are present, _e.g. Cardamine chenopodiifolia_ which has both - ordinary _Cardamine_-siliquas and 1-seeded siliculas. - - The _curved embryo_ appears in five forms, which have - systematic importance: 1. To the PLEURORHIZÆ belong those - genera whose radicle (with the hypocotyl) lies bent upwards - along the _edge_ of the _flat_ cotyledons (Fig. 399); to - this group belong _Cardamine_, _Nasturtium_, _Cheiranthus_, - _Matthiola_, _Cochlearia_, _Draba_, _Iberis_, _Thlaspi_, etc.; - diagrammatic transverse section: ◯=.--2. To NOTORHIZÆ belong - those whose radicle lies in an upward direction along the - _back_ of one of the _flat_ cotyledons (Figs. 400, 413); _e.g._ - _Hesperis_, _Sisymbrium_, _Lepidium_, _Capsella_, _Camelina_: - ◯‖.--3. ORTHOPLOCEÆ differ from the Notorhizeæ in having the - cotyledons folded (not flat) (Fig. 398 _E_, _F_); to this belong - _Brassica_, _Sinapis_, _Raphanus_, _Crambe_, etc.: ◯>>.--4. - SPIROLOBEÆ: the radicle lies as in the Notorhizæ, but the - cotyledons are so rolled together that a transverse section of - the seed cuts them twice; _Bunias_: ◯‖‖.--5. DIPLECOLOBEÆ: the - cotyledons are folded forward and backward so that a transverse - section cuts them several times; _Subularia_, _Senebiera_: ◯‖‖‖. - -On _germination_ the cotyledons appear above the ground as green -leaves; in the Orthoploceæ they are bilobed, in the _Lepidium_-species -divided. - -1. =Silicula, broad replum= (Siliculosæ latiseptæ), valves flat or -slightly vaulted, and the replum extends through the greatest width of -the silicula (Fig. 404). The seeds are situated in two rows. - -◯=: _Cochlearia_ (Horse-radish): the siliqua is nearly spheroid; -glabrous herbs, generally with fleshy, stalked leaves, and white -flowers.--_Draba_ has an oblong, lanceolate, somewhat compressed -silicula; herbs with small rosettes of leaves, most frequently with -stellate and long-stalked racemes.--_Alyssum_ and _Berteroa_ are -whitish, on account of the stellate hairs; they have a more compressed -and round or elliptical silicula. _Vesicaria_; _Aubrietia_. _Lunaria_ -(Honesty, Fig. 401): very broad and flat silicula with long stalk (the -receptacle as in Capparidaceæ). - -◯‖: _Camelina_ (Gold-of-pleasure) has a spheroid, pear-shaped siliqua -with a small rim passing right round (Fig. 402). _Subularia_ (Awlwort), -an aquatic plant with _perigynous_ flower (Fig. 403) and folded -cotyledons. - -2. =Silicula, narrow replum= (Siliculosæ angustiseptæ), _i.e._ the -replum is much shorter than the arched, more or less boat-shaped valves -(Figs. 405, 406, 407). - - [Illustration: FIG. 401.--_Lunaria biennis._ Fruit, the valves of - which have fallen off.] - - [Illustration: FIG. 402.--_Camelina sativa._ Fruit.] - - [Illustration: FIG. 403.--_Subularia aquatica._ Longitudinal - section through the flower.] - -◯=: _Thlaspi_ (Penny-Cress) has a flat, almost circular silicula, -emarginate or cordate, with a well-developed wing round the edge (Fig. -406). _Iberis_ and _Teesdalia_: the racemes during flowering are -especially corymbose, and the most external petals of the outer flowers -project radially and are much larger than the other two (the flower is -_zygomorphic_).--_Biscutella_, _Megacarpæa_. - -◯‖: _Capsella_ (Shepherd’s-Purse) has a wingless, obcordate or -triangular silicula (Fig. 407). _Lepidium_ (Pepperwort) has a few–(2–4) -seeded, slightly winged, oval silicula. _Senebiera_ has a silicula -splitting longitudinally into two nut-like portions; its cotyledons are -folded.--~_Anastatica hierochuntica_ (“Rose of Jericho”) is an annual, -silicula-fruited, desert plant (Arabia, Syria, N. Africa). After the -flowering all its then leafless branches bend together upwards, forming -a kind of ball; this spreads out again on coming in contact with water, -and the fruits then disseminate their seeds, which germinate very -quickly, often in the fruit.~ - -3. =Siliqua= (Siliquosæ). The fruit is a true siliqua, several times -longer than broad. The seeds in most are borne apparently in one row. - - [Illustration: FIG. 404.--Transverse section of a silicula with - broad replum: _s_ replum; _k_ the valves.] - - [Illustration: FIG. 405.--Transverse section of a silicula with - narrow replum.] - -◯>>: _Brassica_ (Cabbage). The seeds are placed apparently in one -row in each loculus (Fig. 398 _C_); the style is long and round; the -valves have only 1 strong, longitudinal rib.--_Melanosinapis_ (_M. -nigra_, Black-mustard); the style is compressed, two-edged; the valves -of the siliqua are one ribbed.--_Sinapis_ (Mustard); quadrangular or -flat style (in which in most cases there is a seed) and 3–5 strong, -longitudinal ribs on the valves.--_Eruca_ differs from _Brassica_ by -the shorter siliqua, broad, sword-like “beak” and seeds in two rows. - -◯= (Fig. 399): _Cardamine_ (Bitter Cress) has a long, linear siliqua, -with flat, unribbed, _elastic_ valves. The leaves are most frequently -pinnatifid or pinnate. ~_C. pratensis_ reproduces by buds formed -in the axils of the leaves.~--_Arabis_ (Rock Cress); _Matthiola_ -(Stock); _Cheiranthus cheiri_ (Wallflower); _Barbarea_ (Winter Cress) -(double-edged, quadrangular siliqua); _Nasturtium_ (_N. officinale_, -Water-cress); the siliqua of the latter genus is in some species short, -in others long. - - [Illustration: FIG. 406.--_Thlaspi arvense._] - - [Illustration: FIG. 407.--Silicula of _Capsella bursa-pastoris_.] - -◯‖ (Fig.400): _Sisymbrium_ (Hedge Mustard) the valves of the siliqua -are 3-ribbed.--_Erysimum_; _Hesperis_; _Schizopetalum_ (with fimbriate -petals). - -4. =Fruit jointed= (Lomentaceæ). The fruit is divided by transverse -walls into as many spaces as there are seeds, and dehisces at maturity, -generally _transversely_, into a corresponding number of nut-like -joints (“articulate-siliqua.”) - -◯=: _Crambe_ (Kale, Fig. 408). The fruit has only 2 joints. The lower -one resembles a short, thick stalk, and is barren, the upper one is -spherical, and has 1 seed.--_Cakile_ (_C. maritima_, Sea-kale); the -lower node is triangular, 1-locular, the upper one more ensiform, -1-locular (Fig. 409). - - [Illustration: FIG. 408.--Fruit of _Crambe maritima_.] - - [Illustration: FIG. 409.--_Cakile maritima._ Fruit (2/1).] - - [Illustration: FIG. 410.--_Raphanus raphanistrum._] - - [Illustration: FIG. 411.--_Raphanus sativus._] - -◯>>: _Raphanus_ has a long siliqua, which, in the garden Radish (_R. -sativus_), is spongy and slightly abstricted (Fig. 411), but neither -opens nor divides transversely (a kind of dry berry), and which in the -Wild Radish (_R. raphanistrum_) (Fig. 410) is abstricted in the form -of a string of pearls, and separates into many joints. ~_R. sativus_; -the “Radish” is formed by the hypocotyl, after the bursting of its -external, cortical portions (of which there are generally two patches -at the top of the Radish).~ - -5. =Siliqua indehiscent= (Nucumentaceæ). The fruit is a short, -_unjointed_, unilocular and 1-seeded nut, and the fruit-stalks are -often long, slender, and drooping. (Sometimes a thin endosperm is -present).--_Isatis_ (Woad) has most frequently an oblong, small-winged -nut; ◯‖ (Figs. 412, 413).--_Bunias_; _Neslia_. - - [The systematic division of this order given above is founded - upon that of A. P. de Candolle. Prantl (_Engler and Prantl, Nat. - Fam._), 1891, adopts a somewhat different system, which may - briefly be summarised as follows:-- - - _A._ Hairs unbranched or absent; no glandular hairs. - - 1. THELYPODIEÆ. Stigma equally developed on all sides; style - undivided or prolonged above the middle of the carpels, - or turned back.--_Stanleyinæ_; _Heliophilinæ_. - - 2. SINAPEÆ. Stigma strongly developed above the placenta; - style beaked or two-lobed. - - _a._ Cotyledons arising behind the bend of the - embryo.--_Lepidiinæ._ - - _b._ Cotyledons arising at the bend of the embryo. - - α. Only lateral nectaries. Generally a silicula or - indehiscent fruit.--_Cochleariinæ._ - - β. Generally a siliqua, more rarely a silicula or - transversely-divided or indehiscent fruit. - Nectaries generally lateral and - median.--_Alliariinæ_; _Sisymbriinæ_; _Vellinæ_; - _Brassicinæ_; _Cardamininæ_. - - _B._ Hairs collectively or partially branched, very rarely - entirely absent; glandular hairs are sometimes also present. - - 1. SCHIZOPETALEÆ. - - 2. HESPERIDEÆ. Stigma strongly developed above the placenta; - style undivided or prolonged above the placentæ into - shorter or longer lobes. - - _a._ Surface cells of the replum, not divided - diagonally.--_Capsellinæ_; _Turritinæ_; - _Erysiminæ_; _Alyssinæ_. - - _b._ Surface cells of the replum divided - diagonally.--_Malcolmiinæ_; _Hesperidinæ_; - _Moricandiinæ_.] - - [Illustration: FIG. 412.--_Isatis tinctoria._ Fruit (Fig. 412); - and in longitudinal section (Fig. 413). (Mag.)] - - POLLINATION. Honey is secreted by the nectaries mentioned - above; but the position of the stamens is not always the most - favourable for pollination by insects (in these flowers the - honey-seeking insect must touch the anthers with one of its - sides and the stigma with the other), and self-fertilisation - is common. In some species (_Cardamine pratensis_) the long - stamens turn their anthers outwards towards the small stamens, - so that 3 anthers surround each of the two large entrances to - the nectaries. - - 1200 species (180 genera), especially in the cold and - temperate parts of the Old World (Europe, W. Asia). Many - are _weeds_ in this country, _e.g._ Wild Cabbage (_Brassica - campestris_), Charlock (_Sinapis arvensis_), Wild Radish - (_Raphanus raphanistrum_) and others.--The order is acrid and - oleaginous. Oil is obtained from many of the oil-containing - seeds, especially of the Rape (_Brassica napus_), Summer-Rape - (the oil-yielding cultivated form of the Field-Cabbage) and - _Camelina_. Several are pot-herbs or fodder plants, _e.g._ - Cabbage - - (_Brassica oleracea_) with its numerous varieties: Cauliflower - (var. _botrytis_; the entire inflorescence is abnormally - branched and fleshy), Kohlrabi (var. _gongylodes_, with - swollen, tuberous stem), Kale, Red-Cabbage, White-Cabbage, - etc.; _B. campestris_, var. _rapifera_ (Turnip); _B. napus_, - var. _rapifera_ (Swede); _Raphanus sativus_ (Radish from W. - Asia), _R. caudatus_ (long Radish); _Nasturtium officinale_ - (Water Cress), _Lepidium sativum_ (Garden Cress), and _Barbarea - præcox_ (Early Cress); _Crambe maritima_ (Sea-Kkale). The - seeds of the following are especially used as spices: (the - flour of) _Melanosinapis_ (Black-mustard), and _Sinapis - alba_ (White-mustard), which are _officinal_ like the root - of _Cochlearia armoracia_ (Horse-radish, E. Eur.). The - herbaceous parts of _Cochlearia officinalis_ and _danica_ - are medicinal.--A blue dye (woad) is extracted from - _Isatis_.--Ornamental plants: _Cheiranthus cheiri_ (Wallflower), - _Matthiola_ (Stock), _Iberis_, _Hesperis_, _Lunaria_, and others - (especially from S. Eur.). Sweet-scented flowers are rare. - - [Illustration: FIG. 414.--_Gynandropsis pentaphylla._] - - [Illustration: FIG. 415.--_Capparis spinosa._] - - Order 4. =Capparidaceæ= (=Capers=). The relationship with the - Cruciferæ is so close that certain forms are with difficulty - distinguished from them. The diagram of the flower is the same - in the number and position of its parts, but it differs in the - modifications which occur in the development of the stamens. In - some genera all 4 stamens are undivided; in others both the 2 - median ones are divided as in the Cruciferæ (6 stamens, but _not - tetradynamous_) (Fig. 414); in other genera only 1 of these; in - other instances again they are divided into more than 2; and - finally the 2 lateral ones also may be found divided, so that - _indefinite stamens_ occur (Fig. 415). The bicarpellate gynœceum - is _unilocular_ (without replum), but more than 2 carpels may - occur. The ovary is elevated on a _stalk_ (sometimes as much - as 1 foot in length); also between the stamens and corolla a - similar stalk may be found (Fig. 414). The fruit is long and - siliquose (_Cleome_, _Polanisia_, _Gynandropsis_), or a berry - (_Capparis_). Endosperm absent. Some have zygomorphic flowers. - Gamosepalous calyx and perigynous flowers also occur.--350 - species; especially in the Tropics. The majority are trees - and shrubs, and they differ also from the Cruciferæ in having - distinct stipules present in some species. - - “Capers” are the flower buds of the climbing, thorny shrub, - _Capparis spinosa_ (Fig. 415), which grows in the Mediterranean. - - - Family 11. =Cistifloræ.= - -The flowers in this family are perfect, regular (except _Resedaceæ, -Violaceæ_), hypogynous, the perianth-leaves free (a few have them -slightly united), æstivation most frequently imbricate; they are -eucyclic in the andrœcium, and most frequently in the other parts, -and generally 5-merous with S5, P5, A5 + 5, G3, but other numbers -also occur; several have _indefinite stamens_, but the stamens arise -(where the development is known) in _centrifugal order_ and are -arranged, often very distinctly, _in bundles_; in other words, the -large number of stamens is formed by the splitting of a small number -(most frequently 5); a true spiral arrangement is never found. Gynœceum -syncarpous, multicarpellary (_Dilleniaceæ_ and a few _Resedaceæ_ are -apocarpous), most frequently the number of carpels is 3, forming a -_unilocular ovary_ with _parietal placentæ_, but parallel with this, -multilocular ovaries, with the ovules placed in the inner angle of the -loculi, are also found, and a few genera have a free, centrally-placed -placenta. The fruit is most frequently a capsule. The dehiscence is -never with a “replum,” _i.e._ the persistent frame of the placenta, -as in the family Rhœadinæ. One half of the orders has endosperm -(_Violaceæ_, _Cistaceæ_, _Droseraceæ_, _Bixaceæ_, _Ternstrœmiaceæ_, -etc.), the other has no endosperm (_Resedaceæ_, _Hypericaceæ_, -_Elatinaceæ_, _Tamaricaceæ_, etc.); some have a curved, the majority a -straight embryo. ~The family is scarcely quite natural; in the future -the orders will probably be arranged differently.~ - -Order 1. =Resedaceæ (Mignonettes).=--Herbs or small shrubs with -spirally-placed leaves and very small, gland-like stipules (as in -Cruciferæ); the ☿, hypogynous flowers are _zygomorphic_, and arranged -in racemes or spikes typically without bracteoles. The zygomorphic -structure is produced by the _greater development of the posterior side -of the flower_, especially the petals and the nectary (“disc,” in Fig. -416 _d_) which is situated between the petals and stamens; in general -there are 5–8 free sepals and petals, the latter consisting of a large -scale-like _sheath_ with a fimbriated blade (see Fig. 416); stamens -numerous; carpels 6–2 united together; ovary unilocular with parietal -placentæ, but _the cavity of the ovary is not closed_ at the top. In -_Astrocarpus_ the gynœceum is apocarpous. The fruit is most frequently -a capsule; the seeds are reniform, without endosperm, and the embryo is -_curved_. - - This order connects the Rhœadinæ with the Cistifloræ. It is - closely allied to the Rhœadinæ by its external appearance, even - by the smell and taste, the parietal placentation, structure of - the seeds, the inflorescences, etc., whilst by the irregular - flowers and the disc placed at the posterior side of the - flower, _it is allied to Capparidaceæ_, but differs from this - order in not having its characteristic number (2–4) and by - the very different mode of dehiscence of the fruit, etc. It - differs from the other orders of this family chiefly in the - fact that the number of the perianth-leaves is not constantly - 5. In _Reseda luteola_ both the calyx and corolla appear to - be 4-leaved, because the posterior sepal is suppressed, and - the 2 posterior petals are united. Where there are 10 stamens, - they stand in 2 whorls, _i.e._ in front of the sepals and - petals; if there are several, their position depends upon the - splitting.--_Astrocarpus_ is remarkable for its apocarpous fruit - and the position of the ovules on the _dorsal_ suture of the - carpel. - - The yellow, flat disc at the back of the flower serves as a - nectary, the honey being protected by the lobes of the petals. - If pollination by insects is not effected, then self-pollination - may take place, at all events in _R. odorata_. - - 45 species; the majority in the Mediterranean and in Persia. - _Reseda odorata_ (from Egypt) is cultivated on account of its - sweet scent; _R. luteola_ (“Dyer’s Weed”) yields a yellow dye. - - [Illustration: FIG. 416.--Diagram of _Reseda odorata_.] - -Order 2. =Droseraceæ (Sundews).= Herbs, chiefly living on moors or in -water, and whose leaves are adapted to catch and digest small animals. -With regard to the flower, they are closely allied to the Violaceæ, -especially to those with regular flowers. _Drosera_ (Sundew) has a -long-stalked scorpioid cyme with regular, ☿, hypogynous flowers, -5-merous as in _Viola_. S5, P5, A5, G3 (in a syncarpous gynœceum, -with free, bifid styles and basal or parietally-placed ovules in the -unilocular ovaries). The capsule opens also as in _Viola_, but, among -other differences, the styles are free, the seeds very small, and -surrounded by a loosely lying, thin shell. ~_Drosera_ has radical, -long-stalked leaves with the blade (Fig. 417) covered by numerous -strong glandular hairs, placed on the edge and in the middle; when -small animals are caught by these hairs, the latter and the entire -blade close slowly over them dissolving and absorbing all the -digestible matter as nourishment.~ - - [Illustration: FIG. 417.--Leaf-rosette of _Drosera rotundifolia_ - (nat. size), and a leaf (magnified).] - - _Dionæa muscipula_ (Fly-trap; N. Am.) has the same appearance - as _Drosera_, but the leaves are constructed as in Fig. 418. - The stalk is flat and winged, the blade small, circular, with - powerful, pointed teeth along the edge, and on its surface are 6 - small bristles (_A_), which are very sensitive. When these are - touched the blade quickly closes, folding along the midrib (_B_, - _C_) and imprisoning the irritating object, the teeth round the - edges fitting like the teeth of a trap. If it happens to be an - insect or similar body, a digestive fluid is secreted which, - like the gastric juice, dissolves the digestible portions. - _Aldrovandia vesiculosa_ (Central and S. Europe) captures small - aquatic animals in a similar manner; it is a floating, aquatic - plant, the two halves of its leaves also close together when - irritated (Fig. 419).--_Drosophyllum._ - - About 110 species; most of them in the temperate regions. - - [Illustration: FIG. 418.--_Dionæa muscipula._ Leaves (nat. size).] - - Orders 3 and 4. =Sarraceniaceæ and Nepenthaceæ.= These two - orders are perhaps most closely allied to the Droseraceæ and - agree with these, among other things, in the manner of taking - nourishment. Like the Droseraceæ they absorb nitrogenous food - from dissolved animal matter by means of their leaves, which are - specially constructed both to catch, to retain, and to digest - any small animals which may be caught. The SARRACENIACEÆ are - North American marsh-plants (10 species) which have pitcher-like - leaf-stalks, in the cavity of which a fluid (with properties - approaching those of gastric juice) is secreted, and which bear - at the apex a small, lid-like blade; these leaf-stalks are the - catching and digestive organs.--_Sarracenia, Darlingtonia._ - - [Illustration: FIG. 419.--_Aldrovandia vesiculosa_: _A_ a plant - (nat. size). _B_ Leaf (mag.); the blade is closed; the winged - stalk is prolonged into 4–6 irritable bristles.] - - [Illustration: FIG. 420.--_Nepenthes_ (reduced).] - - NEPENTHACEÆ has only 1 genus, _Nepenthes_ (the Pitcher-plant; - about 35 species), especially found in tropical E. Asia; the - majority are climbing shrubs. The leaf-stalks are twining - organs, and terminate either simply in a tendril, or in addition - to this, with a pitcher-shaped body (which in some species may - be as much as a foot in length) on whose upper edge a lid-like - structure is found (Fig. 420). In this pitcher, as among the - Sarraceniaceæ, a fluid is secreted which is able to digest the - animals captured (sometimes rather large) and which corresponds - in some degree to the gastric juice. - -Order 5. =Violaceæ (Violets).= The flowers are ☿, and generally -zygomorphic, hypogynous, with S5, P5, A5, G3 (Fig. 421). The stamens -are closely applied to the ovary, they have a very short filament, -and at their summit generally a membranous appendage formed by the -prolongation of the connective (Fig. 422 _g_). The ovary is unilocular -with 3 parietal placentæ; style undivided (Fig. 422 _B_). The fruit -is usually a 3-valved capsule, opening along the dorsal sutures -(Fig. 423). Embryo straight; endosperm fleshy (Fig. 425).--Many are -herbaceous plants (_e.g. Viola_), but in the Tropics shrubs are also -found (_e.g. Ionidium_); a few are lianes; the leaves are scattered, -with stipules, and involute in the bud. - - [Illustration: FIG. 421.--Diagram of _Viola_.] - - [Illustration: FIG. 422.--The large-flowered form of _Viola - tricolor_: _A_ the flower in median longitudinal section; _B_ the - gynœceum.] - -_Viola._ The sepals are prolonged backwards beyond the point of -insertion (appendiculate); the corolla is polypetalous, descending -imbricate, and zygomorphic, its anterior petal being larger than the -others and provided with a spur (Fig. 421). The 2 anterior of the 5 -almost sessile stamens are provided with a spur-like nectary, which -protrudes a considerable distance into the petaloid spur (Figs. 421, -422 _n_, _sp_). The style is club-like, and bears the stigma in a -groove on the anterior side (Fig. 422 _st_). ~Herbs with rhizomes, -or annuals; flowers solitary. _V. odorata_, _canina_, etc., have -cleistogamic flowers which produce fruit in addition to the large, -coloured (violet) flowers. The Pansy (_V. tricolor_) has large flowers -adapted for insect-pollination, and also smaller, less conspicuous -ones designed for self-pollination. The stigma, as in Fig. 422 _A_, -_st_, and _B_, is situated on the anterior side of the stylar-head, -immediately in front of the channel leading down to the spur (_sp_); -below it is situated a valve, easily covered with pollen when -the proboscis of an insect is introduced into the spur, but which -closes upon its withdrawal; cross-pollination is thus secured.--The -sweet-scented _V. odorata_ is visited by the honey-bee, which insures -cross-pollination, and in the absence of insect visits it effects -self-fertilisation by cleistogamic flowers. The conspicuous but -scentless _V. tricolor_, var. _vulgaris_, is less frequently visited by -insects (humble-bees). In _V. silvatica_ and _V. canina_ the pollen is -carried on the head or proboscis of the honey-sucking bee.--The fruits -of _V. odorata_ bury themselves slightly in the soil. In the others -the fruits are raised above the ground; the 3 boat-shaped valves close -together along the central line, and eject the seeds, one by one, with -much violence, so that they are thrown to a great distance.~ - - [Illustration: FIGS. 423–425.--_Viola Tricolor._ - - FIG. 423.--Capsule after dehiscence (nat. size). - - FIG. 424.--External view of the seed. - - FIG. 425.--Seed in longitudinal section.] - - The _Alsodeia_-group has regular or almost regular flowers. - Gamopetalous corollas are found in _Paypayroleæ_. _Sauvagesieæ_ - differs the most by its regular corolla, and 5–∞ free or united - staminodes. - - 250 species; especially in the Tropics.--The _Ionidium_-species - are used as ipecacuanha. A number of _Viola_-species are - cultivated as garden plants, especially _V. odorata_ - (sweet-scented Violet) and _V. tricolor_, which have a large - number of varieties. - - Order 6. =Frankeniaceæ.= A small order with doubtful - relationships. Perennial herbs or shrubs; beach plants with - nodose stem. Sepals united, petals free. Unilocular ovary, - with 3–4 parietal placentæ. Fruit a capsule. Embryo straight, - endospermous. Especially in S. Europe, Africa, on the shores of - the Mediterranean and Atlantic. - - Order 7. =Tamaricaceæ (Tamarisks).= To this order belong only - _Tamarix_ and _Myricaria_. They are shrubs of a cypress- or - heather-like appearance, as the scattered leaves are very small, - sessile, scale-like or linear, adpressed, entire, and usually - glaucous, and the branches are slender and whip-like. The - flowers are borne in small spikes or racemes, and are small, - reddish or whitish, regular, ☿, hypogynous and polypetalous; - formula S5, P5, A5 + 0 (_Tamarix_, which often has stipular - teeth at the base of the filaments), or A5 + 5 (_Myricaria_, - in which the stamens are united at the base); the number 4 may - appear instead of 5, but in either case there is usually a - tricarpellate gynœceum, which is _unilocular_ and has either - parietal placentæ (_Myricaria_) or a small basal placenta - (_Tamarix_); 1 trifid style, or 3 styles. Capsule dehiscing - along the dorsal suture, and resembling the Willows in having a - unilocular ovary with numerous _woolly_ seeds; but the seed-wool - in this case is borne on the chalaza, and may be attached to a - long stalk.--Some _Tamarix_-species shed part of their branches - in the winter.--40 species; North Temperate, on the sea-shores - or steppes, especially in Asia. Ornamental shrubs: _Myricaria - germanica_, and _Tamarix gallica_. - -Order 8. =Cistaceæ.= Shrubs or herbs, natives especially of the -Mediterranean region. Flowers generally in raceme-like scorpioid -cymes, regular, ☿, hypogynous; sepals 5, free, _twisted_ in the bud, -of which the two outer are generally much smaller than the others; -petals 5, free, _twisted_ in the bud (in the direction _opposite_ -to the sepals), fugacious; stamens _numerous_; gynœceum syncarpous, -carpels usually 3–5, style simple, ovary unilocular, with parietal -placentation (seldom divided into loculi, with axile placentation). The -ovules are _orthotropous_ in opposition to some of the other orders -of this family. The capsule dehisces along the dorsal sutures; embyro -_curved_. The leaves are simple, undivided, generally opposite and -stipulate.--~They are Violaceæ with regular flowers, numerous stamens, -and curved embryo. The numerous stamens are in reality only one or two -5-merous whorls, divided into a large number of stamens; these are -formed, therefore, in descending order, like the lobes of many compound -foliage-leaves.~ - -_Helianthemum_ (Rock-Rose), has 3 carpels.--_Cistus_ has 5 (-10) -carpels. - - About 70 species; temperate climates, especially about the - Mediterranean. The resin of the _Cistus_-species has been used - medicinally (ladanum). - - Order 9. =Bixaceæ.= This order is closely allied to the Cistaceæ - and Ternstrœmiaceæ; like these it has regular, 5-merous, - hypogynous flowers with numerous stamens, unilocular ovary and - _parietal_ placentæ; sometimes unisexual flowers; it differs in - having anatropous ovules, in the æstivation of the sepals, etc. - All species (about 180) are trees or shrubs, with scattered, - simple leaves, which usually have stipules, and are occasionally - dotted with pellucid oil-glands.--_Bixa orellana_ (Trop. Am.) - is the best known species; it has a 2-valved capsule; the seeds - are enclosed in a shiny _red, fleshy testa_, which contains the - well-known orange or yellow dye, annatto. - - Order 10. =Dilleniaceæ.= Gynœceum usually apocarpous, seed - arillate. The flower has most frequently S5, P5, and compound - stamens (one or more bundles); sometimes irregular. 200 species; - Tropical; woody plants, many lianes.--_Dillenia_, _Candollea_, - _Pleurandra_, _Davilla_, etc. - - Order 11. =Elatinaceæ= (=Water-worts=). About 25 species belong - to this order; especially in temperate climates. They are small, - creeping, rooted, aquatic plants, with opposite or verticillate - leaves and _stipules_. The flowers are solitary or situated in - small dichasia in the leaf-axils, they are small, regular, ☿, - hypogynous, with free petals, the same number in all 5 whorls - (Sn, Pn, An + n, Gn), 3-merous (_e.g. Elatine hexandra_), - 4-merous (_e.g. E. hydropiper_), or 5-merous (_Bergia_); the - corolla-stamens are sometimes suppressed; petals imbricate - without being twisted; the ovary is 3–4–5-locular, with 3–4–5 - _free styles_; the capsule dehisces septicidally. The seeds are - orthotropous or curved, often transversely ribbed, endosperm - wanting. The order is most nearly allied to Hypericaceæ, whose - primitive form it appears to represent. - - [Illustration: FIG. 426.--Diagram of _Hypericum quadrangulum_: - _S_ indicates the bud of the helicoid cyme in the axil of the - bracteole β.] - - [Illustration: FIG. 427.--_Hypericum._ Flower with three bundles - of stamens.] - -Order 12. =Hypericaceæ= (=St. John’s-worts=). This order is recognised -by its always _opposite_ or _verticillate_, _simple_, and entire, -penninerved leaves, without stipules, and usually dotted with -_pellucid_ glands; by the always ☿, regular, hypogynous flowers in a -cymose inflorescence; the generally 5-merous calyx and corolla, with -sepals and petals free; the stamens 3–5, numerously branched (Figs. -426, 427); and the gynœceum, 3–5-carpellate, styles usually _free_. The -ovary is 3–5-locular, or unilocular with 3–5 parietal placentæ. Fruit a -capsule (dehiscing septicidally) or berry. Endosperm absent. - - The inflorescence is a _dichasium_ or _helicoid cyme_. The - structure of the flowers is the same as that of the foregoing - orders: S5, P5; succeeding these in some cases are two 5-merous - whorls of stamens in regular alternation, of which the inner - is epipetalous; but the outer whorl is only represented by 5 - small scales (Fig. 427), or is altogether absent (_Hypericum - calycinum_, _H. hircinum_), and the inner divided into numerous - stamens, that is, these 5 stamens are so deeply divided that - 5 _epipetalous_ groups bearing anthers are found (as in the - Cistaceæ); in other cases the flower becomes _3-merous after - the petals_, stamens 3 + 3 following in regular alternation - (Figs. 426, 427), the outer whorl of stamens in these cases is - also present as staminodes (Fig. 427), or may be altogether - suppressed. Carpels 3–5. _The petals are often twisted_ in the - bud, and are then oblique. - -_Hypericum._ Some species have a square stem; in these cases the -leaves are placed opposite the edges. Fruit a capsule.--_Vismia_ has -a berry.--~The flowers of _Hypericum_ have no honey, and supply only -pollen; self-pollination often takes place.~ - - About 240 species; the tropical ones being often shrubs or - trees; the others generally perennial shrubs.--_Hypericum_, - St. John’s-wort, contains a resinous, red matter, which can be - extracted with alcohol. The American gamboge is the dried sap of - species of _Vismia_. - - Order 13. =Guttiferæ=, or =Clusiaceæ=. Closely allied to the - Hypericaceæ and Ternstrœmiaceæ. Leaves opposite or verticillate. - The flowers are often unisexual; stamens united; the gynœceum - has most frequently a sessile, radiating or shield-like stigma. - - 370 species; chiefly in the Tropics (Am.). They are principally - woody plants and their bark contains a yellow gum resin, - “gamboge,” which is extracted from _Garcinia morella_ (E. Ind.) - and others. Mangosteen (_Garcinia mangostana_ S.E. Asia), and - _Mammea americana_ (W. Ind.), have very delicious fruits. - To this order also belong _Platonia insignis_, _Pentadesma - butyracea_ (the Butter-tree), _Clusia_, _Calophyllum_, _Cataba_, - etc. - -Order 14. =Ternstrœmiaceæ.= Trees and shrubs with scattered, simple, -and often more or less leathery, evergreen, penninerved leaves, without -stipules (Fig. 428). The two most important genera are: _Camellia_ -and the closely allied _Thea_ (by some authorities these are united -into one genus). The flowers are regular, hypogynous, and situated -singly on very short stalks. A number of green floral-leaves are placed -below the calyx and gradually pass over into the sepals, and the -leaves (5–6) of the calyx again gradually pass over into the corolla -(this being especially marked in _Camellia_), of which the number of -leaves varies (5, 6, 7 and upwards); the calyx and the corolla are -_acyclic_ or _eucyclic_; the petals are slightly united at the base; -stamens _numerous_ in many whorls, the external ones are arranged in -bundles and united with the petals as in the Columniferæ; gynœceum -syncarpous; styles often _free_ nearly to the base; ovary 3–5-locular, -ovules numerous in each loculus. The fruit is a woody capsule.--~Other -genera show more distinctly than these the same structure as in the -preceding orders, namely: S5, P5, A5 + 5, of which the calyx-stamens -are often suppressed, and the petal-stamens divided into numerous -stamens.--_Kielmeyera_ (S. Am.)~ - - 260 species; especially in the Tropics (E. Asia, Am.) The - leaves of _Thea chinensis_ (or _Camellia thea_), the Tea-tree - (E. Asia), are cultivated for the well-known “tea,” and contain - theine: the best are the young, still hairy leaves, of greyish - colour; there are many varieties. Ornamental plants, _Camellia - japonica_ and _Actinidia_. - - [Illustration: FIG. 428.--_Thea chinensis_ (reduced).] - - Closely allied to this order are: Order 15. =Rhizoboleæ= (with - enormously large hypocotyl--hence the name), and Order 16. - =Marcgraviaceæ= (partly epiphytes, with dimorphic leaves and - cup- or helmet-like, coloured, honey-secreting floral-leaves, - which serve to attract insects). - - Order 17. =Dipterocarpaceæ.= This order has taken its name from - the large wings attached to the fruits in _Dipterocarpus_ (the - wings being largely developed sepals); trees and shrubs from - Trop. Asia. 180 species. Camphor ready prepared is found in the - stem of _Dryobalanops camphora_. _Hopea_; _Vateria_. - - - Family 12. =Gruinales.= - -The flowers are hypogynous, ☿, polypetalous, usually regular (except -_Pelargonium_, _Tropæolaceæ_, _Balsaminaceæ_) and _throughout -5-merous_: S5, P5, A5 + 5, or 5 + 0, G5 (_epipetalous_). The stamens -soon fall off and are _obdiplostemonous_, often united at the base -(_monadelphous_); the corolla-stamens are in some completely suppressed -(_e.g. Balsaminaceæ_, Fig. 438), in others reduced to teeth (_Linum_, -Fig. 431; _Erodium_). The _Tropæolaceæ_ have 3 carpels and only 8 -stamens (Fig. 437). Ring-like nectaries are not present, but at most -only glandular bodies, borne outside the base of the stamens. Ovaries -many-locular. The ovules as a rule are pendulous, with the micropyle -directed outwards (Fig. 431, B), and the radicle therefore also points -outwards. Usually _herbs_. Related to the Columniferæ. - -Order 1. =Oxalidaceæ.= Most of the species are herbs with rhizomes; -the leaves are stalked, _compound_, with entire leaflets which are -folded and bent backwards in the bud (and in the sleep position), -exstipulate; some species have sensitive leaves. The flowers (Fig. 429) -are regular, and have S5, P5, which are _twisted_ to the left or right -in æstivation, A5 + 5, all united at the base (monadelphous), gynœceum -5-carpellate, _styles 5 free_, stigmas capitate, ovary 5-locular, -ovules numerous. The fruit is a _capsule opening_ with clefts _on the -dorsal sutures_ through which the seeds are ejected, while the _fleshy, -external layer of the testa_ springs off elastically. Embryo straight. -Endosperm. - - [Illustration: FIG. 429.--Diagram of _Oxal’s acetosella_.] - - _Oxalis_ (Wood-Sorrel). Leaves digitate. Species also occur - with phyllodia, _i.e._ leaf-like petioles placed vertically - without lamina; a few have pinnate leaves. The flowers are - situated singly or in dichasia, and unipared scorpioid cymes. - The pollination is effected by insects. Some species are - trimorphic (long-, short-, medium-styled flowers) and some, - _e.g. O. acetosella_, have cleistogamic flowers in addition - to the ordinary ones. Glands are found on the outer side of - the corolla-stamens or of all the stamens. _O. tetraphylla_ - and others have adventitious edible roots, resembling - tap-roots.--_Averrhoa_ is a tropical tree, with berries and - pinnate leaves. - - 235 species (205 belong to _Oxalis_); chiefly in S. Africa and - Trop. America.--Oxalate of potash is contained in the leaves of - _Oxalis_. - -Order 2. =Linaceæ.= Herbs with scattered or opposite, sessile, -_simple_, small, entire leaves, without (rarely with small) stipules. -The flowers (Fig. 430) are regular, 5- or 4-merous. Petals are free, -_twisted_, quickly falling off. Stamens united at the base; the -petal-stamens _are either reduced to teeth_ (Fig. 431 _A_, _m_) _or -entirely suppressed_. _Styles free._ The (5–4) epipetalous loculi -of the ovary are incompletely halved by _false divisional walls_, -each half contains one ovule (Fig. 431 _C_). The fruit is a spherical -_capsule, dehiscing along the divisional wall_ (Fig. 432); the 10 (-8) -seeds have a straight embryo and very slight endosperm (Fig. 433). - - [Illustration: FIGS. 430–433.--_Linum usitatissimum._ - - Fig. 430.--The Flax plant. - - Fig. 431.--_A_ Flower after removal of sepals and petals; _m_ - petal-stamens reduced to teeth. _B_ Longitudinal section of - ovary. _C_ Transverse section of capsule. - - Fig. 432.--Capsule (nat. size). - - Fig. 433.--Transverse and longitudinal section of seed: _bl_ the - cotyledons; _k_ the plumule; _R_ the radicle; _fr_ the endosperm; - _sk_ the testa.] - -_Linum_ (Flax) has 5-merous flowers. ~The main axis terminates in a -flower; and the succeeding branching is cymose, or unipared scorpioid -branching by unilateral development, and the flowers in consequence of -the vigorous sympodial development of the lateral axis (and also by the -leaves being displaced and pushed aside), assume a position apparently -lateral (_i.e._ racemose) without bracts; each branch of the sympodium -generally has 2 leaves. The testa is shining and smooth when dry, but -its external cellular layer becomes mucilaginous in water.~--_Radiola_ -has a 4-merous flower. It is a small herb with opposite leaves, and -regular, dichasial branching. - - The anthers and stigmas in _L. catharticum_ and _usitatissimum_ - develop simultaneously, and cross-pollination as well as - self-pollination takes place. _L. grandiflorum_, _perenne_, - and others, are dimorphic (short-and long-styled). There are 5 - nectaries outside the stamens. - - 130 species; _Linum_ and _Radiola_ are native genera.--_L. - usitatissimum_ is extensively cultivated in Europe (especially - in Russia and Belgium), N. America and elsewhere (its home no - doubt being Asia), partly on account of the oil (linseed oil) - which is extracted from the seeds, and partly on account of - the bast of the stem, which has very thick-walled cells. The - seeds and oil are OFFICINAL. The species cultivated in ancient - times was _L. angustifolium_. Several species are cultivated as - ornamental plants. - -Order 3. =Geraniaceæ.= The majority are herbs with dichasial branching, -and scattered or opposite, stalked, _palminerved_ (rarely penninerved) -leaves with small _stipules_. The flowers are regular (except -_Pelargonium_) and 5-merous, with 10 or 5 stamens, which are slightly -united at the base. Nectaries alternate with the corolla-stamens. -The ovary is most frequently 5-locular, deeply 5-grooved, and bears -1 _well developed style_ (“beak”), which towards the apex divides -into 5 branches bearing stigmas; ovules 1 in each loculus, pendulous -or ascending. _The 5 carpels become detached from one another when -ripe_, and bend or _roll back_ (Fig. 434) or become _spirally twisted_ -in the upper “beak-like” part (Figs. 435, 436), whilst a _central -column_ (septal column) persists; each carpel, in consequence, remains -either closed, and the fruit is a 5-merous _schizocarp_ whose nut-like -lower portion, containing the seed, is forced into the ground, thus -burying the seed by the movements of the spirally-twisted, hygroscopic -“beak” (Figs. 435, 436); or it opens along the ventral suture, so -that the seeds may fall out, and it is then a 5-valved _capsule_, -with septicidal dehiscence (Fig. 434) and the rolling up often takes -place so suddenly and violently that the seeds are shot out to -considerable distances. The embryo is usually green and _curved_, and -the _cotyledons are folded_; endosperm is wanting. - -_Geranium_ (Crane’s-bill) has 5 + 5 stamens,and a septicidal capsule; -the carpels most frequently remain suspended from the apex of the -column (Fig. 434). The leaves are most frequently palminerved. The -flowers are situated solitarily or 2 together (2-flowered scorpioid -cyme).--_Erodium_ (Stork’s-bill); inflorescence a many-flowered -unipared scorpioid cyme, stamens 5 + 0 (petal-stamens are wanting), and -fruit a schizocarp whose carpels become detached; their beaks are hairy -on the internal surface and _twist themselves spirally_ (Fig. 436). -The umbellate inflorescences are composed of multiflowered scorpioid -cymes. The leaves are often penninerved.--~The most primitive type is -represented by _Biebersteinia_: S5, P5, A5 + 5, G5 (ovaries _free_, -and styles united above); fruit 5 small nuts. The most advanced type -is _Pelargonium_, which has _zygomorphic_ flowers, the posterior sepal -being prolonged into a spur which becomes adnate to the peduncle; -the petals are unequal in size; some of the petal-stamens are often -wanting. (_Erodium_ may be slightly zygomorphic).~ - - [Illustration: FIG. 434.--_Geranium sanguineum._ Fruit (3/1).] - - [Illustration: FIG. 435.--_Pelargonium._] - - [Illustration: FIG. 436.--_Erodium cicutarium_, detached carpel.] - - POLLINATION. The large-flowered _Geranium_-species are - protandrous, _e.g. G. pratense_ (one whorl of stamens opens - first, and then the other, and succeeding these the stigmas, - after shedding the pollen the stamens bend outwards); the - small-flowered are also adapted, with various modifications, - for self-pollination.--470 species; moderately hot climates, - especially S. Africa.--Several _Pelargonium_-species, with - numerous varieties, are ornamental plants (from S. Africa). - -Order 4. =Tropæolaceæ.= Herbaceous, juicy plants which have scattered, -long-stalked, peltate leaves without stipules, and often climb by their -sensitive petioles. The flowers are situated singly in the axils of the -foliage-leaves on long stalks, and are _zygomorphic_, the receptacle -under the posterior sepal being prolonged _into a spur_; there are also -differences between the posterior and anterior petals, the 2 posterior -petals situated on the border of the spur being _perigynous_, and the -edge of the anterior petals adjoining the claw fringed. After the 5 -sepals (which are more or less coloured) and the 5 petals, follow 8 -_stamens_ (as the 2 median ones are suppressed, one from each whorl) -and a gynœceum formed of 3 carpels; in each of the 3 loculi of the -3-grooved ovary is 1 ovule. The fruit is a _schizocarp_ and divides -into 3 1-seeded, _drupe-like_ fruitlets, which do not (as in the -Geraniaceæ) leave any pronounced column between them. Endosperm is -wanting. The cotyledons are thick and sometimes slightly coalescent. -~Tubers often occur.~ - - [Illustration: FIG. 437.--Diagram of _Tropæolum_: _sp_, spur.] - -_Tropæolum._--About 40 species; all from America. - - POLLINATION.--The spur is the receptacle for the nectar; the - flowers are protandrous; the anthers open first, and one by - one take up a position in front of the entrance to the spur, - resuming their original position when the pollen is shed; the - stigma finally takes their place after the filaments have bent - backwards.--These plants have an acrid taste (hence the name - “Nasturtium,” “Indian Cress”), on which account the flower-buds - and young fruits of _T. majus_ are used as capers. Some species - are ornamental plants. - -Order 5. =Balsaminaceæ.= Herbaceous, chiefly annual plants with -juicy, brittle stems, so transparent that the vascular bundles may be -distinctly seen. The leaves are simple, usually scattered, penninerved -and dentate; stipules are wanting, but sometimes large glands are -present in their place at the base of the petioles. The flowers are -strongly zygomorphic; of their five 5-merous whorls the petal-stamens -are suppressed (S5, P5, A5 + 0, G5); the sepals are _coloured_, the -2 _anterior ones_ (Fig. 438 _3_, _5_) _are very small_ or entirely -suppressed, _the posterior one_ is very large and _elongated into a -spur_, and the 2 lateral ones pushed forward; sometimes the weight -of the spur turns the flower completely round, so that the posterior -leaves assume an anterior position; apparently only 3 petals, since -the lateral and the posterior petals become united in pairs, and -the anterior is larger and differently shaped; the 5 stamens have -very short and thick filaments united at the base, and their anthers -finally adhere together and remain in this condition, covering over -the gynœceum; the filaments ultimately rupture at the base, and the -entire anthers are raised on the apex of the gynœceum as it grows -up. The gynœceum has a _sessile stigma_ and a 5-locular ovary. The -fruit is a capsule which, on maturity, opens suddenly when irritated, -dividing into valves from the base upwards, and as the 5 valves roll -up elastically, the seeds are shot out on all sides to considerable -distances; a central column persists (Fig. 439). The embryo is -straight, and without endosperm. - - [Illustration: FIG. 438.--Diagram of _Impatiens glanduligera_.] - - [Illustration: FIG. 439.--Fruit of _Impatiens_.] - - _Impatiens_; in Europe only _I. noli-me-tangere_. 225 species; - especially from Asia. Several species have two kinds of flowers: - small, cleistogamic, but fertile; and large, coloured flowers, - which in _I. balsamine_ (ornamental plant, E. Ind.) are - protandrous and pollinated by hive-and humble-bees, as they suck - the honey from the spur. - - Order 6. =Limnanthaceæ.= The flowers are regular and differ - from all the other orders in the family by having the carpels - not in front of the petals, but _in front of the sepals_ - (which are _valvate_), and further, the loculi are nearly - _free individually_, but with a _common gynobasic_ style; - the ovules are _ascending_ and _apotropous_ (anatropous with - ventral raphe). The fruit is a schizocarp, with nut-like - cocci.--_Limnanthes_ (4 species; N. Am.) perhaps belongs to - another family. - - Order 7. =Humiriaceæ.= Trees and shrubs; about 20 species; Trop. - Am. - - - Family 13. =Columniferæ.= - -The chief characteristics of the orders belonging to this family are -the ☿, regular, generally 5-merous, _hypogynous_ flowers with 5-merous -_calyx_, sepals united and _valvate_ in the bud; petals 5, free (often -_twisted_ in the bud); stamens ∞ _e.g._: 10, in two whorls, but one of -these is more or less suppressed, often altogether wanting, or replaced -by 5 staminodes, while _the other_ (inner whorl) _is generally divided -more or less deeply_ into a large number of anther-bearing filaments. -The filaments too (except _Tiliaceæ_) are _united into a tube_, which, -especially in the _Malvaceæ_, forms a long column in the centre of -the flower, surrounding the gynœceum (Figs. 445, 448); in this case, -which is the most pronounced, the filaments are united into one bundle -(_monadelphous_), in other instances, _polyadelphous_. The number of -carpels varies greatly (2 to about 50), but they are nearly always -united and form a syncarpous multilocular gynœceum.--The vegetative -characters also closely agree, the leaves _are always scattered and -generally stipulate_; all the green portions very often bear _stellate -hairs_, and the bark in all the 3 orders is _rich in tough bast_. -Mucilage is often present in cells or passages.--This family is -connected with the _Ternstrœmiaceæ_, from which it is very hard to draw -a sharp line of demarcation, and it is also allied to the _Cistaceæ_ -and to the _Gruinales_. - -Order 1. =Sterculiaceæ= (including Buettneriaceæ). This is, no -doubt, the least modified order, and one in which the stamens occur -undivided. Obdiplostemonous. The 10 stamens in two whorls are most -frequently united at the base into a short tube, and have _4-locular, -extrorse_ anthers. The calyx-stamens are nearly always simple, -tooth-like staminodes, situated on the edge of the tube, or are -entirely suppressed. The same relation is found, for instance, in the -Ampelidaceæ and Rhamnaceæ, namely _5 stamens in front of the 5 petals_; -not infrequently the 5 stamens are doubled (Fig. 441). Unisexual -flowers are found in _Sterculia_, _Cola_, _Heritiera_. The corolla -is often wanting, or developed in an unusual manner. Each loculus of -the ovary (generally 5) always contains more than one ovule. Fruit a -capsule. Androgynophore often present (_Helicteres_; _Sterculia_, etc.). - - _Hermannia_, _Mahernia_, _Melochia_, etc., have flat petals - with twisted æstivation; 5 undivided stamens, which usually - are but slightly united at the base, and most frequently, - without staminodes. _Thomasia_; _Helicteres_; _Sterculia_ - (free follicles).--_Theobroma_, _Rulingia_, _Buettneria_, - _Commersonia_, _Guazuma_, etc., have petals concave at the - base, and terminating in a limb abruptly bent back, and at the - boundary between them most frequently ligular outgrowths, as in - certain genera of the Caryophyllaceæ; stamens 5–15–∞, anthers - at the edge of a short tube and 5 linear staminodes (Fig. - 441).--The Cocoa-tree (_Theobroma_), (Fig. 440) bears large, - reddish-yellow, berry-like fruits, resembling short cucumbers, - but ultimately becoming leathery to woody; in each of the 5 - loculi are 2 (apparently only 1) rows of horizontal, oily seeds, - as large as almonds. Cotyledons large, thick, and irregularly - folded. Endosperm absent (Fig. 442). - - 49 genera, with about 750 species; almost entirely confined - to the Tropics; none in Europe or in N. Asia.--The seeds - of the Cocoa-tree (_T. cacao_, _bicolor_, _glaucum_, etc., - natives of Trop. Am., especially north of the Equator) are - used for chocolate and are also _officinal_ (“Cocoa-beans,” - “Cocoa-butter,” “Oil of Theobroma”). Theobromine. _Cola - acuminata_, Africa. - - [Illustration: FIG. 440.--_Theobroma cacao._ Branch with flowers - and fruits (⅙).] - - [Illustration: FIGS. 441–442.--_Theobroma cacao._ - - FIG. 441.--Diagram of the flower: _st_ barren stamens. - - FIG. 442.--_B_ Seed in transverse section: _n_ hilum. _A_ Embryo - after the removal of one of the cotyledons.] - -Order 2. =Tiliaceæ.= This differs from the other orders of the -Columniferæ chiefly in the stamens being entirely _free_ from each -other, and also _divided_ into many filaments, _as far as the base_, -or at all events very far down, so that the _flower appears to have -numerous stamens_ or to be _slightly_ polyadelphous (Fig. 443); in -addition to this, it may be observed that the anthers are _4-locular_ -and _introrse_. In _Luehea_ the groups of stamens alternate with the -petals. In a few genera (_Corchorus_, _Triumfetta_) 10 free and single -stamens are found in 2 whorls; but, in the majority, groups of free -stamens in separate bundles. The stamens are more or less united -in _Apeiba, Luehea_. Style simple. Ovary 2-locular. The ovules are -pendulous; raphe turned inwards. The calyx readily falls off; the -æstivation of the entirely free petals is slightly imbricate (_not -twisted_). - - [Illustration: FIG. 443.--Inflorescence of _Tilia_, with - its winged bracteole (_h_); _a_, _a_ axis of the shoot; the - vegetative bud is seen between the inflorescence and the axis of - the shoot; _b_ petiole of foliage-leaf.] - -_Tilia_ (Figs. 443, 444). Calyx and corolla 5-merous; the 5 staminal -leaves (opposite the petals) divided as far as the base into a large -number of stamens which are free or united into groups; gynœceum with -5 loculi in the ovary (opposite the sepals); there are 2 ovules in -each loculus, though the ovary ripens into a 1-seeded nut, which is -not detached from the axis of the inflorescence, but is carried away -by the wind, whirling round and round, its large-winged bracteole -serving as a parachute (Fig. 443).--~Only trees, with alternate, -obliquely heart-shaped and dentate leaves; stellate hairs, as in the -other Columniferæ, are often present. The terminal bud of the branch -always fails to develop, and the growth is then continued sympodially -by the uppermost axillary buds. The INFLORESCENCE (Figs. 443, 444) is -a 3–7-flowered dichasium (Fig. 444 _t_, _d_, _e_), which is developed -in the axil of a foliage-leaf (Fig. 444). The first of its 2 bracteoles -(_a_) is large, thin, leaf-like, and united with the inflorescence, -the lower portion of which forms a broad wing, its so-called “bract”; -the second bracteole (_b_), on the other hand, remains scale-like, -and supports a winter foliage-bud covered with bud-scales which thus -is situated at the base of the inflorescence, and is a bud of the -2nd order, in relation to the vegetative shoot. This bud is always -found beneath the inflorescence on the branch placed horizontally, -and the winged bracteole is always found above it, a relation which -is connected with the fact that the 2 rows of shoots on the sides -of a branch are _antidromous_ with regard to each other.--The -dichasium itself (Fig. 444) terminates with the flower (_t_); it has -3 floral-leaves (_c_, _d_, _e_), which soon fall off; _c_ is barren: -the other two bear flowers, or few-flowered dichasia, or unipared -scorpioid cymes (indicated in the figure).--The foliage-leaves are -folded in the bud upon the median line (1, 2, 3 in Fig. 444 are -foliage-leaves with their 2 stipules), the inner half is broader than -the outer, and after unfolding is turned away from the mother-axis (the -position of the new inflorescences and vegetative buds is indicated in -their axils on the figure).--The cotyledons on germination appear above -the ground as large, _lobed_ leaves.~ - - Of the other genera some have a bell-shaped, gamosepalous - calyx, some have no corolla, the anthers of some open at the - apex (_Aristotelia_, _Elæocarpus_, etc.), the majority have - a capsule, some have berries, or drupes, some separate into - fruitlets, etc.--_Corchorus_, _Triumfetta_ (nut, with hooked - bristles), _Luehea_, _Apeiba_, etc. _Sparmannia_ is an African - genus; 4-merous flowers; fruit a warted capsule; filaments - numerous and sensitive to touch, the external ones are without - anthers and moniliform above. The plant is covered with numerous - soft and stellate hairs, and at the apex of the branches bears - several cymose umbels. - - [Illustration: FIG. 444.--Diagram of the inflorescence of _Tilia_ - and the vegetative bud; the position of the leaves is indicated, - and also the position of the inflorescences, which develop from - their axils in the following year.] - - POLLINATION in _Tilia_ is effected by insects, especially - bees and Diptera, which swarm round the tree tops, allured - by the numerous strongly-scented flowers and the easily - accessible honey (formed in the hollow sepals). As the flowers - are pendulous, the nectar is protected from ruin; and, in - addition, the inflorescence is more or less concealed beneath - the foliage-leaf. Self-pollination is impossible, on account of - protandry.--About 470 species (nearly all trees and shrubs); - especially in the Tropics, only a few being found in the - temperate, none in the polar regions, or in high mountainous - districts.--The inflorescence of the native species of _Tilia_ - is medicinal. The wood is used for charcoal.--The majority are - used for timber, and for the sake of the bast (“Bast,” “Jute,” - the bast of _Corchorus textilis_, _Luehea_, and others). - -Order 3. =Malvaceæ= (=Mallows=). The plants are easily recognised by -the scattered, simple, _palminerved_, most frequently lobed, stipulate -_leaves_, folded in the bud; the perfect, regular, hypogynous flowers, -with _gamosepalous_, persistent, 5-merous calyx with _valvate_ -æstivation; the 5 _petals twisted_ in the bud and united with one -another at the base, and by the 5 _apparently numerous stamens_ (Figs. -445, 448), with the filaments _united into a tube_, with _reniform -bilocular anthers_ opening by a crescentic slit (in 2 valves). -Carpels 3–∞ united into one gynœceum; the _embryo is curved and the -cotyledons are folded_ (Figs. 447, 451); endosperm scanty, often -mucilaginous.--Most of the plants belonging to this order are herbs, -often closely studded with _stellate hairs_. The leaves are most -frequently palmatifid or palmatisect. - - [Illustration: FIG. 445.--Longitudinal section through the flower - of _Malva silvestris_.] - - [Illustration: FIG. 446.--Diagram of _Althæa rosea_: _i_ the - epicalyx.] - - An _epicalyx_ is often found formed by _floral-leaves_ placed - close beneath the calyx, in some 3, in others several. The - median sepal is posterior in the species without epicalyx, - often anterior in those which have an epicalyx.--The petals are - _twisted either to the right or to the left_ in accordance with - the spiral of the calyx; they are most frequently oblique, as - in the other plants with twisted corollas, so that the portion - covered in the æstivation is the most developed. The corolla - drops off as a whole, united with the staminal tube.--Only - the 5 petal-stamens are developed, but they are divided into - a number of stamens, placed in 2 rows, and provided only with - _half_-anthers (leaf-segments, see Fig. 446; the sepal-stamens - are completely suppressed); these 5 staminal leaves are then - united into a tube, frequently 5-dentate at the top, and - bearing the anthers on its external side. The pollen-grains - are specially large, spherical and spiny. There are from 3 to - about 50 carpels united into one gynœceum and placed round the - summit of the axis which most frequently projects between them. - There is only 1 style, which is generally divided into as many - stigma-bearing branches as there are carpels (Figs. 445, 448). - The fruit is a schizocarp or capsule. Endosperm (Figs. 447 A, - 451) scanty, often mucilaginous round the _embryo_, which is - rich in oil. - - The order is the most advanced type of Columniferæ; it stands - especially near to the Sterculiaceæ, but is separated from these - and from the Tiliaceæ, among other characters, by its 2-locular - (ultimately 1-chambered) anthers. - -The sub-orders may be arranged as follows:-- - -I. Carpels in one whorl. - -=A.= =The fruit a capsule=, ~most frequently with loculicidal -dehiscence, and many seeds in each loculus~. - -=1.= GOSSYPIEÆ. The staminal-column is naked at the apex, blunted, or -5-dentate.--_Gossypium_ (the Cotton plant) has an epicalyx of 3 large -ovate-cordate leaves, an almost entire, low and compressed calyx. -Solitary flowers. Large, most frequently yellow, corollas. A 3–5-valved -capsule with many spherical seeds. “Cotton” is the seed-hairs developed -upon the entire surface of the seeds (Fig. 447), and consists of long, -1-cellular hairs, filled with air (and therefore white); these are -thin-walled, with a large lumen, and during drying twist spirally, -and come together more or less in the form of bands. They consist -of cellulose, and have a cuticle.--_Hibiscus_ has several, most -frequently narrow, epicalyx-leaves, a distinct 5-toothed or 5-partite -calyx.--_Abutilon_; _Modiola_. - - [Illustration: FIG. 447.--_A_ Seed of _Gossypium_ with hairs; _B_ - the same in longitudinal section.] - - =2.= BOMBACEÆ. The staminal tube is more or less deeply cleft - into bundles, sometimes almost to the base; pollen smooth, - style simple with capitate, lobed stigma. Almost all plants - belonging to this group are trees, and in many instances have - large barrel-shaped stems, that is, swollen in the centre, and - sometimes covered with large warts. The wood is exceptionally - light and soft. The flowers are often enormously large, and have - beautiful petals; in some they unfold before the leaves. The - capsule-wall is sometimes closely covered on its inner service - with long, silky, woolly hairs, while the seeds themselves - are generally without hairs. These hairs, however, on account - of their brittle nature, cannot be used like those of the - Cotton-plant. Digitate leaves are found in the _Baobab-tree_ - (_Adansonia_) from Africa, noted for its enormously thick, but - short stem, and in the American _Silk-cotton trees_ (_Bombax_, - _Eriodendron_, _Chorisia_). _Ochroma_, _Cheirostemon_, _Durio_, - and others also belong to this group. _Durio_ is noted for its - delicious fruits, which have a most unpleasant smell. - - [_Bombax malabaricum_ is diplostemonous; the five sepal-stamens - repeatedly branch, and the filaments bear unilocular anthers; - the five petal-stamens bear bilocular anthers.] - -=B.= =Schizocarps=, with 1-seeded fruitlets, most frequently nut-like -and reniform (Figs. 449, 451). - -=3.= MALVEÆ, MALLOW GROUP. The carpels are arranged in one whorl -(Fig. 449); the number of stylar-branches equals that of the -carpels; fruitlets 1-seeded, reniform, indehiscent, but detaching -themselves from one another and from the persistent central column -(Figs. 450, 451).--~_Malva_ has an _epicalyx of 3 free leaves_. ~A -flower with 2 suppressed bracteoles is situated in the axil of the -foliage-leaves; one of these supports a homodromous foliage-shoot -which forms a repetition of the main axis, the other an antidromous -flower which continues the branching as a unipared scorpioid -cyme.~--_Althæa_, Rose Mallow, has an _epicalyx of 6–9 leaves united at -the base_.--~_Lavatera_, _Sida_, _Anoda_, _Bastardia_, etc., have no -epicalyx.~ - - [Illustration: FIGS. 448–451.--_Malva silvestris._] - - [Illustration: FIG. 448.--The flower after removal of the - perianth (5/1).] - - [Illustration: FIG. 449.--The fruit (5/1).] - - [Illustration: FIG. 450.--A fruitlet (5/1).] - - [Illustration: FIG. 451.--The same in longitudinal section.] - - =4.= URENEÆ, have always only 5 carpels arranged in 1 whorl, - with 1 ovule in each loculus, and the fruit a schizocarp, - generally with nut-like fruitlets provided with warts and - hooks; but in some they dehisce by 2 valves (capsule). They - differ principally from the other groups _in having twice as - many stylar-branches as carpels_; the staminal tube is naked at - the point, blunt or 5 toothed.--The genera _Urena_, _Pavonia_, - _Malachra_, _Malvaviscus_ (with _berry-like fruits_) belong to - this group. - -II. Carpels arranged in a spherical head in five groups opposite to the -petals. - - =5.= MALOPEÆ, differ from all the others in having a large - number of fruitlets arranged irregularly in a round head, and - separating considerably from each other even before maturity; - there is, however, only 1 style, divided into a corresponding - number of branches (this condition may be considered to have - arisen from the branching [dédoublement] of 5 _carpels_). - _Malope_ has 3 large, heart-shaped (_Kitaibelia_ 6–9) - epicalyx-leaves, united at the base. _Palava_ has no epicalyx. - - POLLINATION. The majority have protandrous flowers, and are - pollinated by insects. Between the basal portions of the 5 - petals, there are 5 nectaries, protected from the rain by - hairs, _e.g._ in _Malva silvestris_. When the flower first - opens the numerous anthers occupy the centre of the flower, and - the still undeveloped stigmas are concealed in the staminal - tube; in the next stage the anthers are withered and empty, - and the stigmas protrude and assume their places (Fig. 452). - The large-flowered forms, it appears, are pollinated only by - insects; but self-pollination takes place in small-flowered - forms, as, for example, in _Malva rotundifolia_, in which the - stylar-branches, twisting themselves, place the stigmas in - between the undeveloped anthers. - - [Illustration: FIG. 452.--_Anoda hastata_: _a_ the bud just - opened, the stigmas are concealed by the anthers; _b_ fully - opened flower in ♂-stage; the upper stamens are developed first, - and then the others in descending order; the stylar-branches - are now visible, and lie bent back on the staminal column; _c_ - all the stamens project upwards, and all the anthers are open, - but the stylar-branches are still bent back; d the anthers are - emptied and the filaments shrunk together, but the styles have - now straightened themselves upwards, and the stigmas are in the - receptive condition.] - - DISTRIBUTION. 800 species (63 genera), most of which are - natives of the Tropics, especially America. _Althæa_ and some - of the species of _Malva_ are natives of the temperate regions - of the Old World, the latter is also found in North America. - _Gossypium_ is tropical, no doubt especially Asiatic (_G. - herbaceum_ from India; _G. arboreum_ from Upper Egypt). Cotton - was introduced into Greece in the time of Herodotus, and was - cultivated in America before the arrival of the Europeans. - - USES. Pungent and poisonous properties are entirely wanting; - _mucilage_, on the other hand, is found in abundance in all - parts of the plant. Medicinal: the root of _Althæa officinalis_, - leaves and flowers of _Malva_-species (_M. silvestris vulgaris_ - and _borealis_) and _Gossypium_.--The seeds contain a large - quantity of _fatty oil_, which is in some cases extracted - (Cotton-seeds and others). _The seed-hairs of the Cotton - plant_ are the most important product of the order. The - cultivated forms of Cotton belong to several species: _G. - barbadense_, _herbaceum_, _religiosum_, _arboreum_ (Nankin), - _hirsutum_, and others. According to other botanists, there - are only 3 species. _Bast_ is obtained from _e.g. Hibiscus - cannabinus_ (Gambo-hemp, Africa), _Paritium tiliaceum_ and - _Sida retusa_. The fruits of certain species of _Hibiscus_ - (_e.g. H. esculentus_, from Tropical Africa) are used in - tropical countries as a vegetable before they are ripe.--_The - colouring matter_ in the flowers of _Althæa rosea_, var. - _nigra_, is used for colouring wines, and hence is extensively - cultivated in certain parts of Europe.--_Ethereal oils and - sweet-scented flowers_ are rare; but several species possess - a peculiar musk-like odour (_Malva moschata_, _Hibiscus - abelmoschus_, and others).--Many are cultivated as _ornamental - plants_ on account of the large flowers, _e.g._ Hollyhock (_A. - rosea_, etc.), _Lavatera trimestris_, _Malope grandiflora_ and - _trifida_, _Malva_-species, _Hibiscus rosa sinensis_, _syriaca_; - _Sphæralcea_, etc. - - - Family 14. =Tricoccæ.= - -The very large order _Euphorbiaceæ_ and three smaller ones belong to -this family. They have in common: _unisexual_, hypogynous, frequently -regular flowers, the perianth most frequently single, rarely double, or -entirely wanting; there is such a great variety in the structure and -parts of the flower that one only can be cited as the _rule_: viz. the -simple gynœceum composed of 3 carpels forming a 3-locular ovary, which -is frequently more or less deeply grooved (hence the name, _Tricoccæ_); -in the inner angles of the loculi are found 1 or 2 (never several) -pendulous (except _Empetraceæ_), anatropous ovules, with upward and -outwardly turned, frequently swollen, micropyle (Fig. 455). The seed -most frequently has a large endosperm and a straight embryo (Figs. -455 _B_, 464).--~The family approaches the nearest to the Gruinales -and Columniferæ; it may perhaps be regarded as an offshoot from the -Sterculiaceæ.~ - -Order 1. =Euphorbiaceæ.= Flowers unisexual. In each of the loculi of -the ovary, generally 3, there are 1 or 2 pendulous ovules with upward -and outwardly turned micropyle. The placenta protrudes above the ovules -(Figs. 454, 461 _B_). On the ripening of the capsule the 3 carpels -separate septicidally, frequently with great violence, ejecting the -seeds and leaving a central column. Endosperm copious.--For the rest, -the flowers present all stages, from genera with calyx and corolla, -to those which are the most reduced in Nature, namely the naked, -1-stamened flowers of _Euphorbia_. - -The same variety which is found in the flower is also present in the -vegetative parts. Some are herbs, as our Spurges, others are shrubs -and trees; some African _Euphorbia_-species even resemble the habit -of a Cactus. Leaf-like branches with rudimentary leaves are found in -_Phyllanthus_ (sub-genus _Xylophylla_) (Fig. 456). The leaves are -scattered or opposite, often stipulate; they are nearly always simple. -Large, highly-branched cells containing a great quantity of pungent -latex are found in many, and watery juice in others. Glands and -glandular hairs are general.--Only a few genera can be considered in -this book. - -As an example of the most perfect flowers (which partly reproduce -the Geraniaceous type) may be mentioned, _Croton_, _Manihot_, and -_Jatropha_; 5 sepals, 5 petals, sometimes gamopetalous, andrœcium -diplostemonous, or many-stamened, often monodelphous. - - [Illustration: FIGS. 453–455.--_Ricinus communis._ - - FIG. 453.--♂-flower (magnified). - - FIG. 454.--♀-flower in longitudinal section. - - FIG. 455.--_A_ seed entire; _B_ in longitudinal section.] - -_Ricinus_ (Castor-oil) (Figs. 453–455); monœcious; the ♂-flowers, -situated in the lower portion of the inflorescence, have 5 -perianth-leaves and a large number of branched stamens; the ♀-flower -has 3–5 perianth-leaves; 3 bifid styles. Leaves peltate, palmately -lobed. The seeds (Fig. 455) contain an abundance of fatty oil and -large aleurone grains.--_Mercurialis_ (Mercury): the perianth is most -frequently 3-merous; in the ♂-flowers 9–12 stamens; in the ♀-flowers -most frequently a _2-locular_ gynœceum.--_Phyllanthus_: Pr3 + 3, A3, -united in some and forming a column in the centre of the flower (Figs. -457, 458); _Xylophylla_ is a section of this genus.-- _Hura crepitans_ -(Sand-box tree) has a many-carpellate gynœceum, which separates with -great violence when ripe.--A drupe is found in _Hippomane mancinella_ -(the Mancinil-tree, W. Ind.)--_Alchornea (Coelebogyne) ilicifolia_ is -well known on account of its “parthenogenesis”; only the ♀-plant has -been introduced into Europe, but it nevertheless produces seeds capable -of germination; these have generally several embryos. - - [Illustration: FIGS. 456–458.--_Phyllanthus (Xylophylla) - angustifolius._ - - FIG. 456.--Leaf-like branch with flowers (nat. size). - - FIG. 457.--♂-flower; and FIG. 458, ♀-flower (mag.).] - -_Euphorbia_ (Spurge) has the most reduced flowers, which are borne -in a very complicated inflorescence. Each ♂-flower (Fig. 460 _B_) is -naked, and consists of one stamen only (terminal on the axis). In the -closely allied genus _Anthostema_, a small perianth is situated at -the place where, in _Euphorbia_, there is a joint in the “filament,” -(Fig. 461 _A_). The ♀-flowers (Fig. 460) are naked, with a 3-locular -ovary and 3 bifid styles. (_Anthostema_ has a distinct perianth (Fig. -461 _B_); in a few Euphorbias traces of a perianth are present). -In _Euphorbia_ the ♂-and ♀-flowers are grouped into flower-like -inflorescences termed “cyathia.” Each cyathium consists of a centrally -placed ♀-flower which is first developed, surrounded by 5 groups of -♂-flowers (stamens) placed in a zig-zag, with a centrifugal order -of development (Figs. 459, 460 _B_), that is, in unipared scorpioid -cymes; these flowers are surrounded by an _involucre_ of 5 leaves -united into a _bell-shaped structure_ (Fig. 459, 1–5) (resembling a -calyx); on its edge are placed 4, generally crescent-like, yellow -glands, one in each of the intervals, except one, between the lobes of -the involucre (shaded in Fig. 459; see also Fig. 460 _A_). Scale-like -thin structures (floral-leaves?) are situated between the ♂-flowers. -The ♀-flower has a long stalk, and finally bends down on one side, -namely to the place on the edge of the involucre where the gland is not -developed. These cyathia are again arranged in an inflorescence which -commences as a 3–5-rayed umbellate cyme (pleiochasium), the branches -of which ramify dichasially and finally as scorpioid cymes.--Latex, -with peculiar-shaped starch-grains, is found in laticiferous _cells_ -(especially in the Cactus-like, leafless species.) - - [Illustration: FIG. 459.--Diagram of an inflorescence (cyathium) - of _Euphorbia_ with 3 floral-leaves, _m_, _n_, _o_, supporting - other cyathia which are subtended by 2 floral-leaves (bracteoles; - _m_, _n_). 1–5, the involucral leaves in their order of - development; the shaded portions are the crescentic glands.] - - [Illustration: FIG. 460.--_Euphorbia lathyris_: _A_ an (entire) - inflorescence (cyathium); _B_ the same after the removal of the - involucre.] - - [Illustration: FIG. 461.--_Anthostema_: ♂- (_A_) and ♀-(_B_) - flowers; _p_ the perianth; _ar_ the node; _o_ the ovule.] - - 205 genera; more than 3,000 species; especially in the - Tropics.--Many are used on account of the oil, and of the - pungent (aperient, poisonous, anthelmintic, etc.) properties in - the latex or the seeds. OFFICINAL: “Cascarilla-bark” of _Croton - eluteria_; the fatty oil of the seeds of _Croton tiglium_ - (Trop. Asia); “Castor oil” from _Ricinus communis_ (Africa, - and cultivated in all warm climates throughout the world); - the glandular hairs of _Mallotus philippinensis_ (“Kamala”); - this also yields a red dye. Gum “Euphorbium” is the hardened - (resinous) latex of the _Cactus_-like _Euphorbia resinifera_ - (Morocco).--NUTRITIVE plants: _Manihot utilissima_ and other - species (Maniok, Am.). Their large, farinaceous roots form a - very important article of food in the Tropics (Cassava-flour, - Tapioca or Brazilian arrowroot). The fresh latex of the root in - some species is a powerful poison; but the poisonous properties - are diminished by roasting or cooking. _Caoutchouc_ is obtained - from _Siphonia elastica_ (Trop. S. Am.). The vegetable - tallow of the Chinese tallow-tree (_Stillingia sebifera_) is - used in large quantities in soap factories. An indigo-like - _dye_ is obtained from _Crozophora tinctoria_, and is also - found in _Mercurialis perennis_. Shellac is obtained from - _Aleurites laccifera_. ORNAMENTAL plants: _Acalypha_, _Croton_, - _Dalechampia_.--_Hippomane_ is poisonous. - - Order 2. =Buxaceæ.= This order differs from the Euphorbiaceæ - in having the micropyle turned inwards; the ♂-flower has a - 4-partite perianth and 4 stamens; the ♀-flower a 6-partite - perianth and 3 carpels. Capsule with loculicidal dehiscence, - the inner layer being detached elastically from the outer.--30 - species. Shrubs without latex and with evergreen leaves.--_Buxus - sempervirens_ (Box) is an ornamental shrub (poisonous); it has a - very hard and valuable wood which is used for wood-engraving and - carving. - - [Illustration: FIGS. 462–464. _Callitriche stagnalis._ - - FIG. 462.--♂-flower with the 2 bracteoles and the solitary stamen. - - FIG. 463.--♀-flower. - - FIG. 464.--Longitudinal section of the ripe fruit.] - - Order 3. =Callitrichaceæ.= Aquatic plants, growing at the bottom - of shallow water, with opposite, simple, undivided, entire, - exstipulate leaves, which are generally crowded and form a - rosette in the apex of the branches. The flowers are unisexual - (monœcious) and borne singly in the leaf-axils; they have no - perianth, but are provided with two delicate bracteoles; the - ♂-flowers consist of only _1 terminal stamen_ (Fig. 462); - the ♀-flowers of a bicarpellate gynœceum (Fig. 463) which is - originally 2-locular, but later on becomes 4-locular, as in the - case of the gynœceum of the Labiatæ, by the formation of a false - partition-wall; in each loculus there is 1 pendulous ovule with - the micropyle turned outwards. Fruit a _4-partite schizocarp_ - (Fig. 464). 25 species.--_Callitriche._ - - Order 4 (?). =Empetraceæ.= 4 species. _Empetrum_; _E. nigrum_ - (Crowberry) is a heather-like, moorland, evergreen undershrub - with linear leaves, having a deep groove closed with hairs, on - the under side. The _erect ovules_ show the greatest deviation - from the Euphorbiaceæ. Diœcious (and ☿); S3, P3; in the - ♂-flower, 3 stamens; in the ♀-flower, a 6–9-locular ovary. Fruit - a _drupe_. - - - Family 15. =Terebinthinæ.= - -The diagram of the flower (Figs. 465–467) is the same as in the -Gruinales, namely S, P, A2 and G in whorls of 5 (less frequently 3, 4, -6, 8), and the same modifications also occur with the suppression of -the petal-stamens, etc. But a _ring_ or sometimes _cup-like glandular -structure_ (_disc_) is found _between_ the andrœcium and the gynœceum -(Figs. 465, 466). The flowers similarly are regular, _hypogynous_, ☿ -and polypetalous, though exceptions are found to all these characters: -thus, for example, united sepals and petals frequently occur, and, -in some orders, unisexual flowers by the suppression of one sex. In -most cases the flowers are small, greenish-yellow, and arranged in -paniculate inflorescences. The carpels (most frequently 5) are free in -a few, but generally united into a multilocular gynœceum; rarely more -than 1 or 2 ovules in each loculus. The gynœceum in the Anacardiaceæ -is so reduced that it has only 1 fertile loculus with 1 ovule.--The -_ovules are epitropous_, _i.e._ anatropous with outward-turned raphe -(except the Anacardiaceæ).--The majority of the species are trees -and shrubs with scattered, often _compound (pinnate) leaves_ without -stipules, and as in addition they frequently contain _aromatic, -especially turpentine-like substances_, they assume a certain -resemblance to the Walnut trees, and were formerly classed with them -mainly on this account. In a series of genera the volatile, scented -oils are found in special glands in the bark of the branches and in the -leaves, in the latter case appearing as _pellucid dots_. This family -includes several orders which are somewhat difficult to distinguish -from each other. - - Order 1. =Connaraceæ.= This order forms the connecting link - between Terebinthinæ and Rosifloræ (_Spiræa_) as well as - Leguminosæ, with which they are sometimes classed. The flowers - have 5 5-merous whorls; 2 ovules in each loculus; micropyle - turned upwards. Fruit a _follicle_, rarely a collection - of follicles. Seed with aril. Shrubs with scattered (most - frequently pinnate) leaves, without stipules. 170 species. - Tropical. - - Order 2. =Meliaceæ.= Trees and shrubs with scattered, often - pinnate leaves without pellucid dots and exstipulate; the - leaflets are nearly always entire. Flowers small in paniculate - inflorescences. Calyx and corolla 4–5-merous; 2 whorls of - stamens; 3–5 carpels in the gynœceum. A very characteristic - feature is the union of the filaments into a tube, on the - edge of which stipule-like teeth are often found. There are - most frequently 2 ovules in the loculi; fruit a capsule with - many winged seeds in _Swietenia_ (Mahogany tree; Trop. Am.), - _Cedrela_, etc.; berries in others. The wood of _Cedrela_ is - used for making cigar boxes. 550 species; tropical. - -Order 3. =Rutaceæ.= Leaves glandular with pellucid dots. The type -is the same as that of the family. Flowers 4–5-merous. The ovary is -most frequently 4–5-grooved. Disc well pronounced, often appearing as -a “gynophore.” The majority are shrubs with alternate or opposite, -compound, more rarely simple, leaves. - -=A.= The ovary is deeply 2–5-cleft with basal styles which are more or -less united; the carpels in some genera are entirely free (groups 1, -2). The fruit is capsular and most frequently dehisces like follicles -along the ventral suture or septicidally, so that a horn-like internal -layer (endocarp) separates elastically from the external layer. - - =1.= ZANTHOXYLEÆ. _Zanthoxylum_; _Choisya_; _Evodia_. - - =2.= BORONIEÆ. Australia.--_Correa._ - - =3.= DIOSMEÆ. Heather-like shrubs; Africa.--_Diosma_, - _Coleonema_, _Empleurum_ and _Barosma_. OFFICINAL: _Barosma - crenulata_ and _betulina_, “broad Buchu leaves” (_B. - serratifolia_ and _Empleurum serrulatum_, “narrow Buchu-leaves”). - - [Illustration: FIG. 465.--_Ruta._ Flower (mag.).] - - [Illustration: FIG. 466.--_Ruta._ Longitudinal section of flower.] - - [Illustration: FIG. 467.--_Ruta._ Floral diagram.] - -=4.= RUTEÆ. _Ruta_ (Figs. 465–467) _graveolens_ is an herbaceous, -glaucous, strongly smelling plant with bipinnate leaves and yellow -flowers; the terminal flower is 5-merous, the others 4-merous (S. -Eur.).--_Dictamnus_; zygomorphic flower. ~The individual carpels of the -fruit separate from each other, and dehisce like follicles, upon which -the internal layer is detached elastically and springs out, carrying -the seeds with it. Several species are ornamental plants.~ - - =5.= CUSPARIEÆ. American. Flowers often zygomorphic with - gamopetalous corolla; stamens 5.--_Ticorea_; _Galipea_ (_G. - officinalis_; S. Am.; “Cortex angosturæ”); _Cusparia_; - _Almeidea_. - -=B.= The ovary is entire or only slightly grooved; the style is -terminal, undivided. The fruit is most frequently a drupe or berry. - - =6.= TODDALIEÆ. _Ptelea_; winged fruit. The buds are enclosed in - the leaf-sheath. _Skimmia_; _Phellodendron_. - - [Illustration: FIGS. 468–470.--_Citrus vulgaris._ - - FIG. 468.--Branch with compound leaves. - - FIG. 469.--Transverse section of fruit. - - FIG. 470.--Flowers (after the removal of the petals).] - -=7.= AURANTIEÆ, ORANGE GROUP. Fruit a berry with a leathery external -layer.--The most typical flower is found for example in _Limonia_: -S5, P5, A5 + 5, G5 (2–5).--_Citrus_ has 4–5–8-merous flowers, a -gamosepalous, dentate calyx, free petals, one whorl of stamens which -are split irregularly into several bundles (Fig. 470). The fruit is a -_multilocular berry_ provided with a thick, tough, outer layer. The -juicy pulp, which fills up the loculi and envelopes the seeds, is -formed from many large-celled, juicy hair-structures which arise on the -inner side of the walls of the loculi and by degrees entirely fill them -up; the dissepiments remain thin, and form the partitions so easily -separating from each other (Fig. 469). The seeds in many instances are -remarkable for containing several embryos. The blade of the leaf is -separated from the frequently winged stalk by a _node_ (and hence is a -compound leaf with only the terminal leaflet developed?) (Fig. 468); -in other genera, as _Triphasia_, there is a fully developed trifoliate -leaf. Thorns are frequently developed.--~The species of this genus, -which is a native of the warmer parts of S. E. Asia, are very hard to -separate. The differences are found in the forms of the fruit, the -leaves and the leaf-stalks, and in the number of stamens. _Citrus -medica_, “Cedrat” (Ind.); _C. limonum_, “Citron,” “Lemon” (introduced -into Italy in the 3rd to 4th century). OFFICINAL: the fruits and -essential oil of Lemon. _C. aurantium_ from E. Asia, the Orange -(introduced into Italy in the 14th century). _C. vulgaris_ (Fig. 468), -Bitter Orange (introduced into Europe at the time of the Crusades); -the unripe Bitter Oranges, and peel of the Bitter Orange is officinal; -it is from the flowers of this species especially that the essence -of Neroli is made. _C. limetta_, _C. bergamia_, Bergamot; essence of -Bergamot is officinal. _C. decumana_, Pomalo, a native of the Islands -of the Pacific. About 780 species; chiefly tropical.~ - - Order 4. =Burseraceæ.= Fruit a drupe; 1–5 stones. The bark, - as well as the other parts, contain strong aromatic resins - and balsams, and hence several species are used: the Myrrh - tree, _Commiphora_ (_Balsamodendron_) from Arabia and Africa; - OFFICINAL: Myrrha (_Commiphora myrrha_). Mecca-balsam from _C. - opobalsamum_, Arabia; E. Africa. The Incense-tree (_Boswellia_) - from the same parts of the globe and E. India. The incense of - _B. carteri_ is medicinal (Frankincense). The resin (Elemi) of - _Protium_-species is officinal, and is used technically for - varnish (S. Am.). Takamahaka-resin from _Elaphrium_ (S. Am.) - _Protium_ (_Icica_); _Amyris_ (1 carpel). 270 species; tropical. - - Order 5. =Zygophyllaceæ.= The majority have opposite, pinnate - leaves with stipules. _Leaves without pellucid dots._ The - filaments have a scale on the inner side. The most important is - _Guaiacum officinale_ (West India), the wood (Lignum Vitæ) of - which is very hard and heavy, this wood and Gum-guaiacum are - officinal. Others have a peculiar repulsive smell and taste: the - Creosote shrub (_Larrea mexicana_) and _Zygophyllum simplex_. - _Tribulus terrester_ is a common weed in S. Europe. _Fagonia._ - _Peganum harmala_ (South of Russia) yields a red dye.--110 - species; especially in the Tropics; several species in sandy - deserts. _Nitraria._ - - Order 6. =Simarubaceæ.= This order is distinguished by the - abundance of _bitter_ substances which it contains (Quassine) - especially in the bark and the wood. The wood of _Quassia amara_ - (Guiana, Antilles) is officinal; _Picraena excelsa_ yields - Jamaica Quassia; the bark of _Simaruba_, _Simaba_-species - and others is used. _Ailanthus glandulosa_ is a garden plant - (pinnate leaves, winged fruit).--110 species. Tropical. - - Order 7. =Ochnaceæ.= Flowers diplostemonous, 5-merous. The - unilocular ovaries, which are individually free, project - considerably into the air around the gynobasic style; 1 ovule - in each loculus; the fruitlets are drupes. Shrubs; leaves - alternate, with stipules. _Ochna_; _Ouratea_.--160 species; - tropical; especially American. - - Order 8. =Anacardiaceæ.= The ovary rarely contains more than 1 - ovule, even though there be several loculi and several carpels; - in _Anacardium_ all the 10 stamens except one become suppressed. - Resin passages.--_Anacardium._ The most peculiar feature is the - development of the flower-stalk into a fleshy body about the - form and size of a pear (_A. occidentale_ from Trop. Am. and - _A. orientale_ from E. Ind.) which bears the kidney-shaped nut - (the so-called “Cashew-nut”) on its apex. _Mangifera indica_ - (the Mango-tree, from E. Ind.) is cultivated in several tropical - countries on account of its delicious drupe. Similarly, species - of _Spondias_ (_S. dulcis_, Pacific Islands, _S. lutea_). - Several species of _Rhus_ are ornamental shrubs in this country, - for instance, _R. typhina_ (N. Am.), _R. cotinus_ (the Wig-tree, - the _barren_ flower-stalks of the panicles being feather-like - and hairy); _R. toxicodendron_ (Poisonous Sumach, from N. Am.) - is poisonous. Chinese galls are produced by the sting of a - leaf-louse (_Aphis chinensis_) on _R. semialata_ (China), and - Japanese wax is from the seeds of _R. succedanea_ (Japan). - Considerable quantities of Sumach (_R. coriaria_) are used in - tanning and as a black dye. OFFICINAL: the mastic resin of - _Pistacia lentiscus_ (the Mastic-tree, from the Mediterranean). - The fruits of _Pistacia vera_ (Syria) are edible; _P. - terebinthus_ and others yield turpentine.--450 species; tropical. - - Order 9. =Icacinaceæ.= Flowers 4–5-merous; haplostemonous; - receptacle convex or cup-like surrounding the gynœceum; in - the (single) loculus of the ovary, 2 anatropous, pendulous - ovules.--200 species; tropical. - - Family 16. =Aesculinæ.= - -The essential characters of this family are in the main the same as -those of the Terebinthinæ and Gruinales. The flowers are hypogynous, -perfect, with free petals, 5-merous (S5, P5, typically A5 + 5, all -of which, however, are not generally developed; in our native orders -there are only 7–8 stamens), and most frequently a _3-merous, 3-locular -gynœceum_ (less frequently 2 or 5 carpels with as many loculi). In -each loculus there are usually only 1–2 ovules. A deviation from the -preceding families is the frequent _zygomorphy_ of the flower, with, -as a rule an _oblique_ plane of symmetry (Fig. 471). When a _disc_ is -developed it is placed _outside_ the stamens. The majority have no -endosperm (Fig. 473).--The members of the family are nearly all trees. - - The family is closely allied to the Terebinthinæ, but unlike - this it never has aromatic properties, and differs also - in the position of the nectary, in the flowers, which are - often irregular with a reduction in the number of stamens, - and in the ovule which is usually ascending with micropyle - pointing downwards (the Terebinthinæ having the micropyle - turned upwards), etc. It is also related to Frangulinæ, the - Staphyleaceæ being the chief connecting link; but the Æsculinæ - generally have compound leaves. - - Order 1. =Staphyleaceæ.= Leaves opposite, often compound. - Flowers regular, ☿, 5-merous in calyx and corolla, 5-stamened. - The stamens are placed _outside_ the nectary. Ovary syncarpous - or 2–3-partite with free styles. The capsule is thin, - bladder-like, 2–3-locular, opening at the apex, and has several - very hard seeds with a shining testa without aril. Endosperm. - _Staphylea pinnata_ (S. Europe) and _trifoliata_ (N. Am.) are - cultivated in gardens; they have white flowers in pendulous, - axillary racemes or panicles.--16 species.--_Staphylea_ is found - in the Tertiary of N. America. - - Order 2. =Melianthaceæ.= Glaucous shrubs with scattered, pinnate - leaves, and large stipules. _Melianthus._--8 species; S. Africa. - -Order 3. =Sapindaceæ.= Trees or shrubs, often climbing by tendrils -(lianes with anomalous structure of the stem) and with compound leaves. -The flowers, in most cases, are small, insignificant, and without -scent, and in some polygamous and zygomorphic. S4–5, P4–5, A8 (less -frequently 5–10) inside the nectary (disc); ovary generally 3-locular, -with 1–2 ovules in each loculus (raphe ventral, micropyle turned -downwards). Seed without endosperm, often with an aril. The embryo is -often thick and curved (Fig. 473). - - [Illustration: FIGS. 471–473.--_Æsculus hippocastanum._ - - FIG. 471.--Diagram of the flower and of a scorpioid cyme. - - FIG. 472.--Flower in longitudinal section. - - FIG. 473.--Seed in longitudinal section.] - -_Æsculus_ (Horse-Chestnut). Trees with opposite, digitate, dentate -leaves without stipules; the inflorescence is composed of unipared -scorpioid cymes arranged in a pyramidal panicle (termed a thyrsus). The -flowers are irregular, with an _oblique plane of symmetry_ (through the -4th sepal, Fig. 471); there are 5 sepals, 5 free petals, of which the -one lying between S^3 and S^5 is the smallest (see Fig. 471) and may -be absent; stamens 7 (5 + 2), three being suppressed; gynœceum simple, -3-carpellary and 3-locular, with single style; of the two ovules one is -ascending, the other descending (Fig. 472).--The fruit is a 3-valvate, -sometimes spiny, capsule, with loculicidal dehiscence, the seed having -a large hilum, a curved embryo without endosperm and united cotyledons -(the radicle lies in a fold of the testa, Fig. 473). _Æ. hippocastanum_ -(Greece, Asia), introduced into cultivation about 300 years ago; -the majority of the other species, _e.g. Æ. pavia_, etc., several -of which are frequently cultivated in gardens, are from N. America. -~The flower of the Horse-Chestnut is adapted for bees, whose abdomen -touches the anthers or style when visiting the flower. The flowers are -protogynous.~ - - The other Sapindaceæ have most frequently 4 sepals, 8 stamens, - various fruits (septicidal capsule, nuts with or without wings, - schizocarp), etc. _Serjania_, _Cardiospermum_, _Sapindus_, - _Koelreuteria_, etc. (about 118 genera, 970 species). The seeds - of _Paullinia sorbilis_ contain caffeine, and are used as “Pasta - guaranà,” in the North Western Brazils in the manufacture of a - common drink. _Nephelium_ (or _Euphoria_) _litchi_ (with edible - aril), and other species, from Asia. - - [Illustration: FIG. 474.--Samara of _Acer platanoides_.] - -Order 4. =Aceraceæ.= This order is so closely allied to the Sapindaceæ, -that some authorities have classed it with them. The main difference -is in the _regularity_ of the flowers, and the =2=-merous gynœceum -(in abnormal cases several carpels occur).--They are trees, and, like -the Horse-Chestnuts, have opposite leaves without stipules; in _Acer_ -the leaves are palminerved, but imparipinnate in _Negundo_, a plant -frequently cultivated in gardens. The flowers are often unisexual, -polygamous (some species have ☿-, ♂-and ♀-flowers); sepals 5, petals -5 free, =stamens 8= (that is, 5 + 5, but the two median ones are -absent) inside a large disc. Fruit a samara (schizocarp) with 2 -_winged, nut-like_ fruitlets (Fig. 474). In each of the 2 loculi of the -ovary are 2 ovules. Embryo _curved_, with thin, _folded_ cotyledons. -Endosperm absent.--~The inflorescences are racemes with a more or -less elongated main axis and terminal flower (which sometimes has 10 -stamens); when the lateral branches are developed they are similar -to the main axis. In some species both corolla and petal-stamens are -suppressed. _Acer_ is pollinated by insects, _Negundo_ by the wind.--88 -species; North Temperate zone. _Acer_ in the Tertiary from the -Oligocene. The following are native plants: Maple (_Acer campestre_), -Sycamore (_A. pseudoplatanus_, doubtful native). Important as avenue -trees and timber. Sugar is obtained from the spring sap of the Sugar -Maple (N. Am.).~ - - Order 5. =Malpighiaceæ.= A tropical (especially American) order - closely related to the Aceraceæ, having often the same form of - fruit (but 3-partite). Some species are lianes with anomalous - stem-structure. Leaves opposite. The flowers are regular or - obliquely zygomorphic (the plane of symmetry passing through - sepal 3), with S5, P5, A5 + 5, G3; 1 pendulous ovule in each - loculus. Important characteristics for identification are the - numerous grandular structures on the sepals. Peculiar 2-spined - hairs are found in some. _Malpighia_, _Bunchosia_, _Galphimia_, - _Tetrapterys_, _Heteropterys_, etc.--About 600 species. - - Order 6. =Erythroxylaceæ.= Sepals 5, petals 5 (with a ligular - corona), 10 stamens in one bundle. Gynœceum 3-locular. Fruit - a drupe. Tropical (especially American) trees and shrubs, the - _Coca-plant_ (_Erythroxylon coca_) being best known. Its leaves - are considered by the inhabitants of Chile and Peru to be one - of the indispensable necessaries of life; they are chewed, and - possess intoxicating, exhilarating properties, and contain - the alkaloid cocaine, which is frequently employed as a local - anæsthetic.--103 species; chiefly in America. - - Order 7. =Vochysiaceæ.= Trees; Trop. Am. 1 stamen.--140 species. - - Order 8. =Trigoniaceæ.= Shrubs; Trop. Am.--30 species. - - Order 9. =Tremandraceæ.= Polygalaceæ with regular flowers.--27 - species. Australia. - - [Illustration: FIG. 475.--Diagram of _Polygala_: _d_ a gland - in the posterior side of the flower; α and β the two caducous - bracteoles.] - -Order 10. =Polygalaceæ.= Herbs or shrubs (some tropical species are -lianes) with scattered (rarely opposite), simple and most frequently -quite entire leaves, without stipules. The flowers are usually borne in -terminal spikes or racemes, and are strongly zygomorphic (_the plane -of symmetry being median_); they have 5 free sepals, the 2 _lateral -ones_ of which (4 and 5 in Figs. 475, 476) are very large, _petaloid_, -and frequently project on each side like the “wings” of a Pea-flower; -petals 5, of which the two lateral ones are wanting or rudimentary -(dotted on Fig. 475), and the _anterior_ “the _keel_” (Fig. 476 _c_) -is large, hollow and boat-shaped, and frequently with a lobed or -fimbriated edge (Fig. 476 _A_ and _B_, _c_); stamens 8, the two median -ones being absent, all _united_ into a tube split along the back, which -is also slightly united to the keel (the anthers, often 2 locular, -_open by pores_, Fig. 476 _B_, _st_); the 2 median carpels form a -bilocular ovary. 1 pendulous ovule in each loculus (Figs. 476 _C_, -475); capsule compressed with loculicidal dehiscence, rarely a nut. -_Polygala_ (Milk-wort). - - 470 species; distributed over the whole globe (none Arctic). - OFFICINAL: the root of _P. senega_, from N. Am. Some are used as - ornamental plants. - - POLLINATION. The flowers of _Polygala_ are pollinated by insects - (chiefly bees). The fimbriated processes of the anterior petal - support the insect when it alights. The anthers lie on each - side of the stigma in the pouch of the anterior petal; the apex - of the style is spoon-shaped, and immediately behind it is a - viscid stigmatic lobe. In reaching the honey the proboscis of - the insect must come in contact with the pollen and the viscid - stigma, by which it is rendered sticky; this ensures the pollen - adhering to the proboscis and so being carried to other flowers. - - [Illustration: FIG. 476.--_Polygala amara._ Parts of the flower - (mag.) _A_ Flower from side, 1-5 sepals: _c_ keel; _B_ flower - from above spread out: _st_ the 8 stamens; _c_ fimbriated edge of - “keel”; _C_ ovary with style and stigma.] - - - Family 17. =Frangulinæ.= - -The plants belonging to this family, with very few exceptions, are -trees or shrubs. The leaves are usually simple; stipules may be -absent or present. The flowers in almost all the orders are _small, -green or whitish_; they are _always regular_, 4-_or_ 5-_merous_ with -2–5 _carpels_, but never have more than 1 _whorl of stamens_, which -in _Rhamnaceæ_ and _Ampelidaceæ_ are placed _opposite_ the petals -(typically 5 + 5 or 4 + 4 stamens, of which however either the -external or internal whorl is always wanting); hypogynous or slightly -perigynous, in _Rhamnaceæ_ only strongly perigynous or epigynous; -generally ☿; the calyx is inconspicuous; petals free or slightly -united. Gynœceum simple; _ovary generally multilocular_; style short or -entirely wanting. A _disc_ is nearly always developed in the flower, -but is found sometimes inside the staminal whorl, sometimes outside -it or between the stamens. The ovules are apotropous (anatropous with -dorsal or ventral raphe). - -Order 1. =Celastraceæ.= _Euonymus europæa_ (Spindle-tree) may be -chosen as a type. It is a shrub with simple, opposite leaves and -small caducous stipules. The small, greenish-yellow flowers, borne -in regularly-branched dichasia, are regular, ☿, with 4 whorls, 4-(or -5-) merous in regular alternation. There is a _thick disc_ upon which -the polypetalous corolla (imbricate in the bud) and the stamens are -borne, with a slightly perigynous insertion. The style is short and -thick; the ovary has 2 _erect_ ovules in each loculus. The fruit is -a red, 4-valvate capsule with loculicidal dehiscence; the seeds are -few in number, and have a large, red-yellow _aril_ (developed from -the micropyle). Embryo green, in a large, fleshy, white endosperm. -~The dingy yellow flowers are generally visited only by flies and ants -for the sake of the honey secreted by the disc, and while they run -about on the flowers they touch the anthers and stigmas, now with one -part of the body, now with another. The flower is protandrous. The -stigmas are not developed till several days after the opening of the -anthers.--_Celastrus_, _Cassine_, _Catha_, etc.~ - - 38 genera; 300 species. Distributed over the entire globe, with - the exception of the colder districts, and especially in the - Tropics. Some are ornamental bushes (_Euonymus japonica_). The - leaves of _Catha edulis_ are used by the Arabs and Abyssinians - in the same way as those of _Coca_ by the Peruvians. - - Order 2. =Hippocrateaceæ.= 150 species; tropical; chiefly - lianes. S5, P5, A3, G3. Anthers extrorse. - - [Illustration: FIG. 477.--_Ilex aquifolium_: magnified flower.] - -Order 3. =Aquifoliaceæ (Hollies).= The genus _Ilex_ forms almost the -entire order. (175 species out of 180; especially from S. Am.) They -are shrubs or trees with scattered, leathery, simple leaves (in _Ilex -aquifolium_, spiny) with very small stipules. The flowers are small, -white, and borne in few-flowered inflorescences in the axils of the -foliage-leaves; they are most frequently unisexual and diœcious. There -are 4–5 sepals, petals, stamens and carpels in regular alternation; -the calyx and _corolla_ have their leaves _slightly_ connate; stamens -slightly adnate to the corolla; the ovary is generally almost spherical -with a thick, sessile stigma (Fig. 477). This order deviates especially -from _Celastraceæ_ in the _absence of the disc_ and in having only -1 (_pendulous_) ovule in each of the 4 loculi of the ovary, and in -having a _drupe_ with generally 4 stones. Embryo extremely small, at -the apex of the large endosperm, with the radicle directed upwards.--~3 -genera.--_I. aquifolium_ (Holly) principally on the coasts of European -countries; from Norway to W. Denmark, and further westward. It is a -common garden shrub with stiff, shining leaves and red fruits. Several -South American species contain so much _caffeine_ that they may be used -as a beverage in the place of tea (_I. paraguayensis_, Paraguay tea, or -Maté). The Holly does not contain caffeine.~ - -Order 4. =Ampelidaceæ (Vines).= Shrubs with the stem swollen at the -insertion of the petioles and climbing by _tendrils borne opposite -the leaves_ (Figs. 478, 479). The leaves are scattered (generally -1/2), stalked, stipulate, frequently palminerved and lobed, divided or -compound. The small, greenish flowers are generally borne in paniculate -_inflorescences, whose position is the same as that of the tendrils_ -(Fig. 478); they are hypogynous or slightly perigynous, ☿, with 4–5 -sepals, petals, stamens (which, as in the Rhamneæ, are _opposite the -petals_; Fig. 480 _A_, _B_) and 2 carpels. The calyx is very small, -entire, or slightly dentate; corolla _valvate_, and in some falling off -as a hood, since the individual parts remain united at the summit (Fig. -480 _A_). Between the stamens and gynœceum is situated an hypogynous -_disc_, with 5 lobes alternating with the stamens (Fig. 480 _A_, _B_, -_E_). In each loculus of the 2-locular ovary there are 2 _erect_ -ovules (_E_); the style is short or wanting. The fruit is a _berry_. -The embryo is small and lies in a horny, sometimes slightly folded -(ruminate) endosperm (Fig. 480 _C_, _D_). - - [Illustration: FIGS. 478–481.--_Vitis vinifera._ - - FIG. 478.--Branch with bunch of grapes. - - FIG. 479.--Diagram of the position of leaf and tendrils. The - branch is divided into sections on the sympodial theory (the - successive generations, I, II, III, IV, are alternately white and - shaded); _k_ buds. - - FIG. 480.--A Flower throwing off the corolla; _B_ flower after - the removal of the corolla; _C_, _D_ longitudinal and transverse - section of seed; _E_ longitudinal section of gynœceum; _s_ calyx. - - FIG. 481.--Diagram of branch and position of leaves; _sl_ - tendril; _lt_ the main axis; _ax_ stipules of the foliage-leaf - shown below; _g_ axillary-bud (the dwarf-branch); _v_ its - fore-leaf; _l_{1} l_{2}_ its first two foliage-leaves with - their stipules; _lt_{1}_ long-branch in the axil of _v_ - (everything appertaining to this branch is entirely black); - _v_{1}_ the first leaf of this branch.] - - _Vitis_ and _Ampelopsis_ (5-merous flowers); _Cissus_ (4-merous - flower); _Leea_ (without stipules, corolla gamopetalous). The - inflorescence in _Pterisanthes_ (E. Ind.) has a peculiar, flat, - leaf-like axis, on the edges of which ♂-flowers are borne, and - on the surface ♀-flowers. - - The TENDRILS in Ampelidaceæ are modified branches, since they - bear leaves and may be abnormally developed as branches with - foliage-leaves, and finally the inflorescences are borne in - the position of the tendrils, and tendrils are met with which - are partly inflorescences. The explanation of the position - of the tendril, namely, right opposite the foliage-leaf but - without a subtending-leaf, has been much disputed. The relative - positions are as follows: in _Vitis vinifera_ the following - two kinds of shoots and relative positions are found (the - other species deviate in one or other particular), (_a_) - LONG-BRANCHES, which have 2 scale-leaves and a large number of - foliage-leaves with a divergence of 1/2; opposite the lowest - 3–5 foliage-leaves no tendrils are found, then follow: 2 - foliage-leaves with tendrils, 1 without a tendril, 2 with and - 1 without, etc., with great regularity. Buds are developed in - the axils of the foliage-leaves (Fig. 479): these develop into - (_b_) DWARF-BRANCHES, which commence with 1 laterally-placed - scale-leaf (fore-leaf; Fig. 481 _v_) succeeded by several - foliage-leaves with a divergence of 1/2 (in a plane at right - angles to that of the mother-shoot), but the whole shoot is - extremely small, and often dries up and drops off in the - autumn, so that only the scale-leaf, _v_, with the bud (Fig. - 481 _lt_{1}_) in its axil remains. This bud in the following - year developes into a new long-branch, and since its leaves - lie in a plane at right angles to that of the dwarf-branch, - their plane coincides with that of the long-branch from which - it is developed (the grandmother axis).--The tendrils no doubt - may most correctly be regarded as the modified main axis which - has been pushed aside by a lateral branch. The branches are - then sympodia, whose successive shoots bear alternately 1 - and 2 foliage-leaves: thus, on the figure there are portions - altogether of 5 shoots (I.-V.), the 1-leaved ones are shaded, - the 2-leaved ones are white. The following facts however are - adverse to this theory: (1) the first leaf on an axillary bud - is then situated 180° from the subtending leaf (_e.g._ the - lowermost shaded leaf, Fig. 479, 180° from the lowermost white - leaf), whilst the rule in the Dicotyledons is that it is placed - only about 90° to one side. (2) The buds (Fig. 479 _K_) from - which the dwarf-branches develop, must then be accessory and - sister-buds to the sympodial shoots, but their first leaves have - a different relative position to this, which is very peculiar, - and a still more remarkable fact is that the buds, _K_, etc. are - similar in structure and present in _all the axils_; thus we - _only_ find accessory buds in the cases where no tendrils are - opposite to the leaves, and the main bud must then be considered - to be suppressed. (3) The development proves that the tendrils - arise on the side of a vigorous growing-point of the stem or by - its division, and do not develop, as might be expected, from - the apex of the shoot. But these relations however, find their - analogues and are all capable of explanation, whereas other less - natural modes of explanation are opposed to them. - - 435 species; especially in the Tropics; they are rarer in - America. In N. Am. some _Vitis_-species and _Ampelopsis - quinquefolia_ are found. _Vitis vinifera_ is supposed to have - originated in the districts East and South of the Caspian Sea. - Wine is obtained from _Vitis_-species, especially _V. vinifera_, - and “raisins,”--(the name “currants,” given to a special variety - with small, seedless fruits, is derived from Corinth).--The - species of _Ampelopsis_ (Virginian Creeper) are cultivated as - ornamental plants. - -Order 5. =Rhamnaceæ.= _The stamens are placed opposite the petals_ -as in the Ampelidaceæ (Fig. 482), but the flowers are _much more -perigynous or entirely epigynous_. The trees and shrubs belonging -to this order have simple, most frequently penninerved leaves with -stipules; frequently thorny (modified branches). The flowers are -inconspicuous, sometimes unisexual (Fig. 482), and have 5 (-4) sepals, -petals, stamens, and generally 3 (2–5) carpels. The calyx has _valvate_ -æstivation. The petals are very _small_ (generally less than the -sepals), often spoon-like, hollow, and embracing the stamens; _a disc -covers the inner surface of the thalamus_ or the base of the style in -the epigynous flower; gynœceum simple, with one style and one _erect -ovule in each loculus_. The fruit is most frequently a _drupe_. The -embryo is large, often green or yellow, with endosperm. - -_Rhamnus_ (Buckthorn) has a juicy drupe with 3 (2–4) stones, surrounded -at the base by the persistent portion of the receptacle; the disc is -thin. _R. cathartica_ (common Buckthorn): diœcious, with opposite, -serrate leaves. _R. frangula_ (Alder Buckthorn): flowers ☿, with -scattered, entire leaves.--~_Ceanothus_ (N. Am., with richly-flowered -inflorescences and a fruit closely resembling that of the Euphorbias). -_Phylica_, _Pomaderris_ (Austr., fruit a capsule). _Zizyphus_, -_Paliurus_, _Colletia_ (S. Am.) are thorny shrubs; _C. spinosa_ has -thorny shoots with small, caducous leaves; the seedling has normal -foliage-leaves. Others climb by tendrils as in the Ampelidaceæ, _e.g._ -_Gouania_.~ - - [Illustration: FIG. 482.--_Rhamnus cathartica_: _A_ long-styled - ♂-flower; _pet_ petals; _B_ short-styled ♂-flower; _C_ - long-styled ♀-flower; _D_ short-styled ♀-flower (after Darwin).] - - 475 species, 40 genera; chiefly in temperate and tropical - climes. Some are medicinal plants, the bark and fruit - having purgative properties (the bark of _Rhamnus frangula_ - and “Cascara Sagrada” from the bark of _R. purshiana_ are - officinal). The fruits and seeds of others are edible, for - example, the fruits of _Zizyphus lotus_, _Z. vulgaris_, _Z. - spina Christi_, etc. Green and yellow _dyes_ are obtained from - the fruit of _R. cathartica_, _infectoria_ and others (Avignon - grain). _Ceanothus-_, _Rhamnus-_ and evergreen _Phylica_-species - are ornamental shrubs. - - - Family 18. =Thymelæinæ.= - -Exclusively trees or shrubs with simple, entire, scattered leaves -without stipules. They have a _strongly perigynous_, regular, -_4-merous_ flower. The receptacle (often coloured) envelopes a simple -gynœceum formed of =1= _carpel_ and with, in most cases, =1= ovule, -bearing on its edge 4 (or 5) petaloid sepals and, but rarely at the -same time, small, scale-like petals. The corolla is most frequently -entirely wanting (and hence these plants were formerly reckoned among -the Monochlamydeæ); frequently only one of the 2 whorls of stamens, -which are situated on the inner side of the edge of the receptacle, is -developed. The fruit is most frequently a _1-seeded_ berry or drupe, or -a nut which may be falsely berry-like, the partly persistent receptacle -being fleshy and enveloping it. - - This family appears the most nearly allied to the Frangulinæ, - especially the Rhamnaceæ, and may be considered as a further - development of these in the direction of the petaloid - development of the receptacle and reduction of the corolla and - gynœceum, which in this instance only consists of one carpel. - Another deviation is that both the whorls of stamens are - present, while one of these is always wanting in Frangulinæ. - They also appear to be related to the Lauraceæ (see page 391). - -Order 1. =Thymelæaceæ.= The flowers are most frequently ☿ (Fig. 483). -The receptacle is high, generally tubular, coloured, and bears on its -edge the 4-(or 5)-merous calyx, with imbricate æstivation. The corolla -is wanting or is represented by small scales. The stamens are situated -on the inside of the receptacle, and number 4 + 4 (or 5 + 5); stigma -capitate. 1 _pendulous ovule_ (Fig. 483 _B_), the _radicle pointing -upwards_. The fruit is most frequently a berry. ~A disc is sometimes -developed. Endosperm wanting or very slight.~ - - [Illustration: FIG. 483.--_Daphne mezereum_: _A_ flower; _B_ - longitudinal section of pistil.] - -_Daphne_ (Spurge-Laurel, Fig. 483) has a deciduous receptacle, often -coloured; sepals 4; petals absent; stamens 4 + 4. Berry.--_Gnidia_ -(corolla); _Pimelea_ (2 stamens); _Thymelæa_; _Passerina_ and others. - - 400 species; chiefly in the warm, sub-tropical zone, especially - the Cape and Australia. Only _Daphne_ and _Thymelæa_ in - Europe. In the fruit and bark of some, for example _Daphne_, - pungent, burning and poisonous properties are found. The bark - of _D. mezereum_ (native and cultivated) and _D. laureola_ is - officinal. A specially tough bast is found in some species, for - example _Lagetta lintearia_ (Lace-tree, Jamaica), which is used - in weaving. Some are cultivated in gardens as ornamental shrubs, - especially species of _Daphne_. - -Order 2. =Elæagnaceæ.= Shrubs or trees, which are easily recognised -by the covering of _peltate hairs_ found upon almost all parts of the -plant, causing them to assume a _silvery_ or rusty-brown appearance. -Stipules are absent; the leaves are simple, most frequently scattered. -Flowers (Figs. 484, 485) frequently unisexual. The sepals are -valvate, 2-4; the _corolla is wanting_; _stamens_ 4 + 4 or 0 + 4. -The ovule is _erect_ and _the radicle turned downwards_ (Fig. 486). -The fruit is a _nut_, but becomes _a false fruit_, being surrounded -by the persistent receptacle or the lower part of it, and thus -assuming a berry- or drupe-like appearance (Fig. 486). Endosperm -insignificant.--_Shepherdia_ (opposite leaves) has 4 sepals, 4+4 -stamens, as in _Daphne_. Diœcious.--_Elæagnus_ (Silver-leaf) is ☿, -has 4–6 sepals, and 4–6 stamens alternating with them. _Hippophaë_ -is diœcious; it has 2 sepals and 4 stamens in the ♂-flower (perhaps -properly speaking 2+2 stamens); thorny (stem-structures). - - 16 species; especially ornamental shrubs, _e.g. Elæagnus - argentea_, _angustifolia_; _Hippophaë rhamnoides_ and - _Shepherdia canadensis_. Northern Temp. - - [Illustration: FIGS. 484–486.--_Elæagnus angustifolia._ - - FIG. 484.--Floral diagram. - - FIG. 485.--Longitudinal section through the flower. - - FIG. 486.--Longitudinal section through the fruit.] - -Order 3 (?). =Proteaceæ.= This order has its chief centre in the dry -regions of Australia (6/10–7/10 of about 1,000 species), a smaller -number in S. Africa (2/10–3/10). a few species in S. Am. Trees or -shrubs, leaves generally scattered, without stipules, and more or -less dry, leathery, evergreen, and often of very different forms on -the same plant (undivided, compound, etc.) The flowers are ☿ (rarely -unisexual), and _4-merous_ in the single, petaloid perianth and in the -staminal whorl; 1 carpel; sometimes zygomorphic. The perianth-leaves -are generally almost free, with _valvate_, æstivation, often leathery. -Small scales alternating with the perianth are often found at the -base of the ovary. The stamens generally have extremely short -filaments, and are situated opposite, sometimes quite on the tip of the -perianth-leaves, in a spoon-like groove. The gynœceum is 1-locular, has -1–several ovules, and is often raised on a stalk-like internode. The -fruit is a follicle or nut. The seeds, most frequently winged, have no -endosperm.--_Protea_, _Manglesia_, _Hakea_, _Banksia_, _Grevillea_, -etc. 50 genera; about 1,000 species. Several species are cultivated in -our conservatories for the sake of the flowers, which are beautifully -coloured and arranged in crowded inflorescences. Protandrous. It is -doubtful whether they were existent in Europe in the Tertiary Period. -The true systematic position of the order is doubtful. They are related -to the Leguminosæ and Rosifloræ, but more closely no doubt to the two -preceding orders. - - - Family 19. =Saxifraginæ.= - -The flower is generally perfect, regular and polypetalous, usually -_perigynous_ or _epigynous_, _eucyclic_ and 5-merous; most frequently -S5, P5, A5 + 5 or 5 + 0 and G=2=-5, but other numbers are found, -especially 4; the flowers are very frequently obdiplostemonous. The -calyx is sometimes large and the corolla small; the carpels in some -are entirely free, in others more or less united. Endosperm is found -in the majority. ~The hypogynous forms approach the Cistifloræ, the -others the following families, especially the Rosifloræ. This family -is not, upon the whole, so well defined and natural as most of the -others. The Saxifragaceæ proper, approach very near to the Rosaceæ, -especially _Spiræa_, and form a transition to it. The forms with -opposite leaves, as _Philadelphus_, etc., approach the Myrtifloræ, just -as the Escalloniæ appear to be closely allied to Bicornes, especially -_Vacciniaceæ_. Finally through _Pittosporaceæ_, they pass over to the -Frangulinæ. The family terminates in very reduced forms, on the one -hand in the arborescent orders with crowded inflorescences, on the -other perhaps in the very remarkable order _Podostemaceæ_.~ - - [Illustration: FIG. 487.--Diagram of a 6-merous flower (_Sedum - hispanicum_): _w_ branch of scorpioid cyme in the axil of the - bracteole β.] - -Order 1. =Crassulaceæ.= Nearly all are herbs or small shrubs with -round, succulent branches and scattered, _fleshy_, often more or less -round leaves, which are very rarely incised, and never have stipules. -The flowers are generally borne in dichasia or unipared scorpioid -cymes, which again may be arranged in racemes, umbels, etc.; they are -regular, ☿, hypogynous or perigynous, and most frequently have free -sepals and petals (gamopetalous corollas with sessile stamens are found -in _Cotyledon_, _Bryophyllum_, _Echeveria_, and others); the floral -formula is Sn, Pn, An + n, Gn, where n may have very different values, -partly depending upon the size of the flower (_e.g._ 4–7 in _Sedum_, -Fig. 487; 6–30 in _Sempervivum_; 4 in _Rhodiola_, _Bryophyllum_, -and _Kalanchoë_; 5 in _Echeveria_, _Umbilicus_, _Cotyledon_). The -carpels are _free_ and are _placed opposite the petals_ (Fig. 487). -Fruit a _syncarp composed of follicles_ containing many, small seeds -without endosperm. Outside each carpel is found a small, nectariferous -scale (Fig. 487). ~The northern genus, _Rhodiola_, is diœcious. The -petal-stamens are wanting in some (_Crassula_, _Bulliarda_, and -others). The floral-leaves are very often displaced upon their axillary -branches. A multicarpellary gynœceum also occurs.~ - -_Sedum_ (Stonecrop) is generally 5-merous with 10 stamens; _Sempervivum -tectorum_ (House-leek), 12-merous, and with 24 stamens. ~The leaves -of _Bryophyllum calycinum_ very readily form buds, and also frequently -exude water from the edges.~ - - 485 species; especially Temp. (Cape, Europe). Principally used - as ornamental plants. - -Order 2. =Saxifragaceæ.= The flowers are 4–5-merous with =2= (-3) -carpels, most frequently: S5, P5, A5 + 5 (obdiplostemonous), G2. They -are regular, ☿, polypetalous, hypogynous, perigynous or most frequently -_more or less epigynous_ (Fig. 488). The carpels may be individually -quite free, but are more frequently united at the base, or the entire -portion enclosing the ovules is united into a 1- or 2-locular ovary, the -styles, however, are always free. _Fruit a capsule_ with many seeds; -endosperm present.--They are herbs, most frequently with _scattered_ -leaves without stipules; but the leaf-base is broad. The inflorescences -are most frequently cymose, and a displacement of the floral-leaves is -frequent (_e.g._ _Chrysosplenium_).--~Some _Saxifraga_-species, _e.g._ -_S. sarmentosa_, have irregular flower with an _oblique_ plane of -symmetry. The petal-stamens in some may be wanting: _Heuchera_, species -of _Saxifraga_ and _Mitella_. The corolla is wanting in others.~ - -_Saxifraga_ (Saxifrage): S5, P5, A5 + 5, G2 (Fig. 488); capsule -bilocular, opening along the ventral suture between the 2 persistent -styles. ~_S. granulata_ has small tubers at the base of the -stem.~--_Chrysosplenium_ (Golden Saxifrage): 4 sepals, _no corolla_, 4 -+ 4 stamens; 1-locular capsule. - - Protandry is most frequently found in _Saxifraga_, with the - stamens successively bending towards the gynœceum; protogyny - is more rare. In other genera there is protogyny without any - movement of the stamens; _Chrysosplenium_ is homogamous.--About - 300 species; mostly in temperate climates. _Saxifraga_ is - especially Alpine. _S. crassifolia_ and other species, _Hoteia - japonica_, _Tellima_, etc., are ornamental plants. - - [Illustration: FIG. 488.--_Saxifraga granulata._ Longitudinal - section of flower.] - -The following genera are allied to the Saxifragaceæ:-- - -=1.= _Parnassia_ (about 14 species; _P. palustris_, Grass of -Parnassus). The flower is slightly perigynous, and has S5, P5, 5 -fertile sepal-stamens, and 5 petal-stamens, which are developed as -barren staminodes, palmately-lobed, and (3–) 4 carpels united in a -1-locular ovary with (3–) 4 parietal placentæ. Capsule.--~Protandrous. -The flower has a slightly oblique plane of symmetry, which is -especially shown during its development and in the order of sequence -in which the anthers dehisce: originally they lie closely round the -gynœceum; the anthers dehisce extrorsely, first the one which is placed -opposite the most external sepal (the 2/5 arrangement is very distinct -in the calyx), the filament elongating so that the anther lies over -the ovary, and this is followed successively by the 4 others in a -zig-zag line; the filaments bend backwards after the pollen is shed -and the anthers drop off, and the stigmas are not developed until this -is completed. The barren stamens are palmately divided into an uneven -number (7, 9, 11) of lobes, tapering from the centre towards the edge, -and bearing apparently glandular tips; their gland-like appearance is -supposed to allure flies to visit the flower, or they may act as a kind -of fence which compels the insects to enter the flower in a certain -way, and thus effect pollination; the honey is secreted on their inner -side, and not by the gland-like tips.~ - - [Illustration: FIG. 489.--Portion of _Cephalotus follicularis_: - _k_ pitcher-like leaf with thick corrugated edge (_m_) and lid - (_l_); _b_ foliage-leaf of the ordinary form.] - -=2.= _Adoxa moschatellina_ (Moschatel). This is a perennial, creeping -herb; the horizontal rhizome has an unlimited growth, and bears, in -a _scattered_ arrangement, both foliage-leaves, and white, fleshy -scale-leaves. The aerial stem bears 2 opposite foliage-leaves and a -capitate inflorescence of 5 flowers, 4 placed laterally (in opposite -pairs) and 1 terminally. The flower is semi-epigynous, the calyx -gamosepalous, corolla absent. The stamens are divided to the base, so -that each filament bears a bilocular anther. The style is free, deeply -cleft. The _terminal_ flower has 2 bracteoles, 4 sepals, 4 stamens, -cleft to the base, and a 4-locular ovary. The bracts of the _lateral_ -flowers are displaced on the flower-stalk, as in _Chrysosplenium_, and -united with the 2 bracteoles into a kind of 3-leaved involucre; these -flowers have 5 sepals, 5 split stamens with 2-locular anthers, and a -5-locular ovary. 1 pendulous ovule in each loculus. Fruit a _drupe_, -green-coloured, with 1–5 stones.--This plant, which would perhaps -be best placed in a special order, has also been classed with the -Araliaceæ and Caprifoliaceæ. - - The following are also allied to this order: _Escalloniaceæ_ - (arborescent plants with simple, scattered, leathery leaves), - _Cunoniaceæ_ (arborescent with opposite leaves), _Cephalotaceæ_ - (with pitcher-like, insect-catching leaves; Australia; Fig. - 489) and _Francoaceæ_. These have respectively 85, 107, 1 and 3 - species. - - [Illustration: FIGS. 490–492.--_Ribes rubrum._ - - FIG. 490.--Floral diagram. - - FIG. 491.--Flower in longitudinal section. - - FIG. 492.--Seeds in longitudinal section.] - -Order 3. =Ribesiaceæ= (=Currants=). 5-stamened Saxifragaceæ with -epigynous flowers.--Moderately sized shrubs with _scattered_, stalked -and palminerved, and generally palmilobed leaves, with a large -leaf-sheath. The flowers (Figs. 490, 491), most frequently borne in -_racemes_, are regular, _epigynous_, and have often, _above the ovary_, -a cup- or bell-shaped, or tubular prolongation of the receptacle, on -which the sepals, petals and stamens are situated; they have 5 sepals -(often large, coloured), 5 _small_, free petals, only =5= stamens -(opposite the sepals) and a =2=-carpellate gynœceum with a _unilocular_ -ovary and 2 _parietal_ placentæ bearing many ovules. The fruit is a -_berry_, whose seeds have a fleshy and juicy outer covering (Fig. 492). -~In some species, for example _Ribes grossularia_, there is found an -unbranched, or a 3–5-branched spine, very closely resembling the spiny -leaves of the _Berberis_, but which, however, are emergences springing -from the base of the petiole. _Ribes_ has two kinds of branches: -long-branches and dwarf-branches, the latter alone bearing the -flowers.~--_Ribes_ (Figs. 490–492). The blades of the leaf are folded -or rolled together in vernation. _R. alpinum_ is diœcious. - - 75 species; especially from the N. Temp. regions (especially - N. Am.).--The receptacle secretes honey on its inner surface. - The Gooseberry-flower is slightly protandrous, others are - homogamous; insect-and self-pollination are found. The following - are FRUIT BUSHES: _R. nigrum_ (Black Currant), _R. rubrum_ - (Red Currant), _R. grossularia_ (Gooseberry), originating in - Northern Europe and Asia. ORNAMENTAL BUSHES: the North American - _R. aureum_ (Golden Currant) and _R. sanguineum_ (Blood-red - Currant), etc. - - [Illustration: FIG. 493.--_Deutzia crenata._ Longitudinal section - of flower.] - -Order 4. =Hydrangeaceæ.= Shrubs, with simple, opposite leaves, -without stipules; flowers generally epigynous, 4–5-merous (Fig. -493).--_Hydrangea_ (_H. hortensia_, etc.). Shrubs from N. Am. and E. -Asia; corolla often valvate. The inflorescence, as in the case of the -inflorescence of _Viburnum opulus_ (Guelder Rose), has often irregular, -large, but barren flowers at the circumference, whilst the others are -much smaller, regular and ☿; the barren flowers are mostly 4-merous; -in these cases it is the calyx which is large and petaloid, while the -other parts of the flower are more or less suppressed. The branches of -the inflorescence appear to be partially devoid of floral-leaves, since -they are displaced upon the main axis.--_Philadelphus_; racemes (with -terminal flower), sepals 4 (valvate), petals 4 (twisted), stamens many, -and carpels 4 (opposite the petals), forming a 4-locular ovary. The -numerous stamens (20–30) occur by the splitting of the sepal-stamens -and are often therefore placed in distinct bundles. Fruit a capsule. -_Ph. coronaria_ (Syringa, Mock Orange-blossom), from S. Eur., is a -common ornamental shrub, as also is _Deutzia_ (Fig. 493) from N. Am. -and E. Asia. The latter has S5, P5, A5 + 5, G3.--About 70 species. - -Order 5 (?). =Pittosporaceæ.= This order has its home especially in -Australia (90 species). The flower has S5, P5, A5 (episepalous), G2 -(3–5), most frequently a unilocular ovary with many ovules in 2 rows, -borne on 2 parietal placentæ, or a bilocular ovary. Some have berries, -others capsules. _Pittosporum, Citriobatus, Sollya, Billardiera._ - -Order 6. =Hamamelidaceæ.= Flowers more or less epigynous, with S4, P0 -or 4, 4 fertile sepal-stamens, and 4 barren petal-stamens, bilocular -ovary with 1–2 ovules in each loculus. Fruit a capsule. _Hamamelis_: -one species in Japan and one in N. Am. _Fothergilla._ _Liquidambar_: -monœcious; flowers in capitula or spikes; ♂-flowers without perianth, -stamens indefinite; ♀-flower: slight perianth, 2-locular ovary with -many ovules. OFFICINAL: “Styrax-balsam,” which is obtained by boiling -the bark of _Liq. orientalis_, from Asia Minor. _Liquidambar_ and -_Parrotia_ are found as fossils in the Upper Oligocene; _Hamamelis_ -perhaps in the Chalk. - -Finally two orders with very reduced flowers are included in this -family. - -Order 7. =Platanaceæ.= Trees, with large, scattered, palminerved and -lobed leaves, and ochreate stipules; the buds are concealed in a hollow -at the base of the petiole. The bark falls off in large scales. ♂-and -♀-flowers (monœcious) in crowded, spherical inflorescences which are -placed at wide intervals on a terminal, thin, and pendulous axis. The -flowers have an insignificant calyx and corolla; the ♂-flower has few -stamens; ♀-flower, perigynous, with 4 free carpels, 1 _pendulous_, -_orthotropous_ ovule in each. Fruit a nut; endosperm absent. 5 species; -frequently grown in avenues and parks. _P. occidentalis_ (N. Am.); _P. -orientalis_ (W. Asia.). - -Order 8. =Podostemaceæ.= Aquatic plants, especially in swiftly -running water, with somewhat of an Alga-like, Moss-like, or thalloid -appearance; they show themselves in many ways to be adapted to their -mode of life and situations (having a dorsiventral creeping stem, the -flowers sunk in hollows, a formation of haptera upon the roots, and -thalloid assimilating roots and thalloid stems, etc.). Tropical; 100 -species. - - - Family 20. =Rosifloræ.= - -The leaves are scattered, stipulate, or have at least a well developed -sheath, which is generally prolonged on each side into a free -portion (“adnate stipules”). The flowers are regular, _perigynous_ -or _epigynous_. Calyx and corolla 5 (-4)-_merous_ with the usual -position. The corolla is always polypetalous. The stamens are present -in very varying numbers (5–∞) and position, but _always_ placed in -5-_or_ 10-_merous whorls_; they _are frequently_ 20 in 3 whorls (10 -+ 5 + 5; see Figs. 494, 502, 505); the nearer they are placed to the -circumference, the longer they are; they are generally _incurved in the -bud, or even rolled up_. The number of the carpels is from 1–∞; in most -cases all are _individually free_ (syncarp), and when they are united -it is in every case with the ovaries only, whilst the _styles_ remain -more or less _free_ (_Pomaceæ_, species of _Spiræa_). The _seeds_ have -a straight embryo, and usually no endosperm. - - The perianth and stamens are most frequently _perigynous_ on - the edge of the widened receptacle; its form varies between a - flat cupule and a long tube or a cup (Figs. 495, 496, 498, 499, - 500); the carpels are situated on its base or inner surface, in - some instances on a central conical elongation of the floral - axis (Fig. 496). The carpels in _Pomaceæ_ also unite more or - less with the hollow receptacle, or this grows in and fills up - the space between the carpels, so that a more or less epigynous - flower is formed (Fig. 504).--The following numbers of _stamens_ - occur: 5, 10 (in 1 whorl), 15 (10 + 5), 20 (10 + 5 + 5), 25 (10 - + 10 + 5), 30-50 (in 10-merous whorls)--compare the diagrams. - The theoretical explanation of this relation of the 10-merous - whorls and their alternation with the 5-merous whorls is not - definitely determined; a splitting of the members of the - 5-merous whorls may be supposed, but the development shows no - indication of this, and it is not supported in any other way. - Several genera have “_gynobasic_” styles, that is, the style - springs from the base of the ovary (Fig. 497 _A_, _B_). - - The Rosifloræ are on one side closely related to the - Saxifragaceæ (especially through _Spiræa_) from which it is - difficult to separate them, and to the Myrtifloræ; on the other - side they are allied, through the Mimosaceæ with the large - number of stamens, and through the Amygdalaceæ with its single - carpel, to the Leguminosæ. The family begins with forms which - have many-seeded follicles, and passes on the one side to forms - with nuts and drupes in perigynous flowers, and on the other - side to the Pomaceæ. - -Order 1. =Rosaceæ.= Herbs or shrubs, generally with compound leaves and -persistent (adnate) stipules, flower _perigynous_, _gynœceum formed of -many free_ (therefore oblique) _carpels, syncarps_ with fruitlets of -various kinds. The exceptions are noted under the genera. - - [Illustration: FIG. 494.--Diagram of _Comarum palustre_.] - - [Illustration: FIG. 495.--Flower of _Spiræa lanceolata_.] - -=1.= SPIRÆEÆ (Fig. 495) has 2–many ovules in each ovary, while in the -other groups there is generally only 1, and never more than 2 ovules in -each loculus. There are generally 5 _cyclic_ carpels and the fruit is -5 _follicles_, which are not enclosed by the receptacle. The majority -are shrubs. Stipules are often wanting.--_Spiræa_ (Meadow-Sweet). -The flowers are generally borne in richly flowered inflorescences -of various forms. The carpels, in some species, unite together -and form a _simple_ gynœceum with free styles (an approach to the -_Pomaceæ_).--~Closely allied to _Spiræa_ are the East Asiatic shrubs: -_Kerria japonica_, which has solitary flowers, in this country nearly -always double (the fruit a nut), and _Rhodotypos kerrioides_ which -has opposite leaves, a remarkable feature among the Rosifloræ; it has -a 4-merous flower, a well developed disc inside the andrœcium, and a -drupe. Closely allied also is _Gillenia_ (N. Am.) differing chiefly -in the ascending ovules, _Spiræa_ having pendulous ovules, and a more -tubular receptacle.~ - - The groups _Quillajeæ_ and _Neuradeæ_ form a transition from - _Spiræa_ to _Pomaceæ_. In the first group, which contains only - trees or shrubs with generally simple leaves, the carpels are - either free or united (into a capsule); in the second the - receptacle unites with the carpels, which are themselves often - united together; in this case, too, the fruit is a capsule. - _Quillaja_ (S. Am.); _Exochorda_ (China). - -=2.= POTENTILLEÆ (Figs. 494, 496, 497). The flower has an “_epicalyx_” -(Fig. 494 _C_) alternating with the sepals and formed by their -stipules which are united in pairs, and hence its leaves are often -more or less deeply bifid. The receptacle is cupular and often quite -insignificant. The sepals are valvate in the bud. The large number of -fruitlets are _achenes_, borne on a well-developed convex portion of -the receptacle (~the Ranunculeæ resemble the Potentilleæ, but have -no epicalyx, no enlarged receptacle, and spirally-placed stamens~). -Most of the species are herbs with dichasial inflorescences, often -arranged in racemes.--_Potentilla_ (Cinquefoil). The achenes are -borne on a _dry_, hairy receptacle; the style is situated towards -the apex of the ovary, and is not prolonged after flowering. Herbs -with digitate, in some, however, pinnate leaves, and generally yellow -flowers.--_Comarum_ (Fig. 494) (Marsh Cinquefoil) forms, by its -fleshy-spongy receptacle, a transition to the next genus.--_Fragaria_ -(Strawberry) (Fig. 496). The receptacle becomes finally fleshy, -coloured, and falls off (biologically it is a berry); the numerous -fruitlets (drupes with thin pericarp) have basal styles (Fig. 497); -leaves trifoliate; long, creeping runners.--_Geum_ (Avens) has a -terminal style which after flowering elongates into a long beak, with -the apex (after the uppermost part has been thrown off) bent back into -a hook, thus furnishing a means of distribution for the fruits. Leaves -pinnate.--~_Dryas_ comprises 3 Arctic or Alpine species with simple -leaves and solitary flowers, the calyx and corolla 8–9-merous, the -fruit resembles that of _Geum_, but the styles become still longer and -feather-like (a flying apparatus).~ - - [Illustration: FIGS. 496, 497.--_Fragaria vesca._ - - FIG. 496.--Longitudinal section of flower. - - FIG. 497.--A carpel, entire, and in longitudinal section.] - -=3.= RUBEÆ. _Rubus_ (Bramble) has the same form of receptacle as the -_Potentilleæ_, but _no epicalyx_; _the fruitlets are drupes_, not -enclosed by the persistent calyx. Most frequently shrubs or undershrubs -with prickles (emergences), glandular bristles and compound leaves. -In the Raspberry (_R. idæus_) the fruitlets unite together and detach -themselves from the receptacle. - -=4.= ROSEÆ. _Rosa_; the receptacle is hollow, ovoid and contracted -beneath the insertion of the calyx (Fig. 498), ultimately _fleshy_ -and _coloured_; it encloses a large number of fruitlets which are -achenes as hard as stones (“hip,” biologically a berry).--Shrubs with -imparipinnate leaves and adnate stipules. ~The sepals show clearly the -order of their development (a divergence of 2/5), the two outer ones on -both sides are lobed, the third one on one side only, and the two last, -whose edges are covered by the others, are not lobed at all. _Prickles_ -(emergences) are generally present and in some species are placed in -regular order, being found immediately below each leaf (usually two) -although at somewhat varying heights.~ - - [Illustration: FIG. 498.--Longitudinal section of flower of - _Rosa_.] - - [Illustration: FIGS. 499, 500.--_Agrimonia eupatoria._ - - FIG. 499.--Flower in longitudinal section. - - FIG. 500.--Fruit and receptacle in longitudinal section.] - -=5.= AGRIMONIEÆ. The receptacle is more or less cup- or bell-shaped, -and almost closed at the mouth; it is persistent and envelopes the -_nut-like fruitlets_, but is _dry_, and in some species hard, the -fruitlets being firmly attached to it. In biological connection -with this the number of the carpels is generally only 1 or 2, and -the whole becomes a _false nut_ (Fig. 500). Herbs.--_Agrimonia_ -(Agrimony; Figs. 499, 500); the perianth is 5-merous, stamens 5–20. -The receptacle bears externally, on the upper surface, a number of -hooked bristles which serve as a means of distribution for the 1–2 -achenes which are enclosed in it, and hence the entire flower finally -falls off. The inflorescence is a long upright raceme. ~These bristles -are arranged in whorls of 5 and 10, of which the uppermost alternate -with the sepals.~--_Alchemilla_ (Ladies-mantle; Fig. 501) has 8 green -perianth-leaves in two whorls (some authorities consider the four outer -as an epicalyx, and the flower therefore apetalous), and 4 stamens -_alternating with the innermost whorl_. There is only one carpel with a -_basal_ style and capitate stigma. The flowers are small and greenish, -the filaments jointed. The anthers open by one extrorse cleft. The -leaf-sheath entirely envelops the stem; the leaves are palminerved. -_A. aphanes_ has often only 1–2 stamens. ~The following genera, with -4-merous flowers borne in short spikes or capitula, are allied to this -group. _Sanguisorba_ has entomophilous, ☿-flowers with 4(-20) stamens, -1 carpel; stigma papillose.--_Poterium_; spike or capitulum, the -uppermost flowers are ♀, the lowermost ♂, and some intermediate ones ☿ -(the order of opening is not always centripetal); S4, P0, A20–30, G2, -the long styles having brush-like stigmas (wind-pollination). Leaves -imparipinnate.~ - - [Illustration: FIG. 501.--Flower of _Alchemilla_ in longitudinal - section.] - - POLLINATION. A yellow ring on the inner side of the receptacle, - inside the stamens, serves as a nectary when any honey - is formed; this, for instance, is not the case in _Rosa, - Agrimonia_, _Spiræa ulmaria_, _S. filipendula_, _S. aruncus_, - etc., to which the insects (especially flies and bees) are - allured by the quantity of pollen. Homogamy and slight - protogyny are frequent, in many instances self-pollination - also is finally possible. _Poterium_, with the long-haired - stigma, is wind-pollinated.--About 550 (1100?) species, - especially in northern temperate regions.--USES. OFFICINAL: - the petals of _Rosa centifolia_ and _gallica_, the fruits of - the Raspberry (_Rubus idæus_), the rhizome of _Geum urbanum_, - the flowers of the Koso-tree (_Hagenia abyssinica_ or _Brayera - anthelmintica_).--The bark of _Quillaja saponaria_ (Chili) is - used as soap and contains _saponin_. “Attar of Roses” from - _Rosa damascena_, _centifolia_ and other species, especially - from the southern slopes of the Balkans. Many species and - varieties of Roses are ORNAMENTAL plants: from S. Europe, _Rosa - lutea_ (the Yellow Rose), _R. gallica_ (the French Rose) and - _R. rubrifolia_; from W. Asia, _R. centifolia_, of which the - Moss Roses (_R. muscosa_ and _cristata_) are varieties, and _R. - damascena_; from India and N. Africa, _R. moschata_ (the Musk - Rose); from China, _R. indica_ (Tea Rose) etc., besides the - native species and the varieties which have been derived from - them. In addition, _Kerria japonica_, species of _Potentilla_, - _Rubus odoratus_ from N. Am., and many species of _Spiræa_ from - South-eastern Europe and N. Am. ESCULENT: the “hips” of _R. - mollissima_, _R. pomifera_, etc.; the fruits of _Rubus_-species: - Raspberry (_R. idæus_), Cloudberry (_R. chamæmorus_), Blackberry - (_R. fruticosus_), etc.; of _Fragaria_-species (_F. vesca_, - _collina_, _grandiflora_, etc). - -Order 2. =Amygdalaceæ.= Trees or shrubs with rosaceous flowers; -leaves simple with caducous stipules; a regular, _perigynous_ flower, -the receptacle being partly thrown off by a circular slit; sepals -5, petals 5, stamens 20–30; _gynœceum simple, formed of 1 carpel_ -(hence oblique, Fig. 502), with terminal style and 2 pendulous ovules, -ripening into a _drupe_ (Fig. 503).--The leaves are penninerved and -frequently have _glands_ on the stalks and edges; _thorns_ (modified -branches) often occur, _i.e._ dwarf-branches, which, after producing -a few leaves, terminate their growth in a thorn (_e.g._ _Prunus -spinosa_). ~The vernation of the _foliage-leaves_ varies in the -different genera; in the Almond, Peach, Cherry, and Bird-Cherry they -are folded; in the Apricot, Plum, Sloe and Bullace, rolled together. In -some the flowers unfold before the leaves (_Amygdalus_, _Armeniaca_). -That the gynœceum is formed of 1 carpel is evident in this as in other -instances (_e.g._ in the Leguminosæ, which are closely related to this -order), from the fact that the carpel is oblique, and has only one -plane of symmetry, and similarly in the fruit there is a longitudinal -groove on one side which indicates the ventral suture. It is only -exceptionally that both ovules are developed. In abnormal instances -more than 1 carpel is developed.~ - - [Illustration: FIG. 502.--Diagram of _Prunus virginiana_.] - -=A.= FRUIT HAIRY: _Amygdalus_ (_A. communis_, Almond-tree) has a dry -pulp which is detached irregularly, when ripe, from the wrinkled, -grooved, ovoid and somewhat compressed stone.--_Persica_ (_P. -vulgaris_, Peach-tree) differs from the Almond in having a juicy pulp, -not detachable from the stone, which is deeply grooved and has pits -in the grooves (Fig. 503). (~The name of the genus is derived from -Persia, though it is a native of China.~).--_Armeniaca_ (_A. vulgaris_, -Apricot) has a hairy, velvety fruit, but the stone is smooth and has -two ribs along one of the edges; the pulp is juicy. (~The generic name -has been given on the incorrect assumption that it was a native of -Armenia; its home is China.~) - - [Illustration: FIG. 503.--Fruit of the Peach. The pulp is cut - through so that the stone is visible.] - -=B.= FRUIT GLABROUS (_i.e._ without hairs): _Prunus_ (Plum) has a -glabrous fruit with bluish bloom; the stone is compressed, smooth or -wrinkled. The flowers are borne solitarily or in couples, and open -before or at the same time as the leaves; they are borne on shoots -without foliage-leaves.--_Cerasus_ (Cherry) has a glabrous, spherical -fruit, without bloom, and a spherical stone. The flowers are situated -in 2–many-flowered umbels or racemes, and open at the same time as the -leaves or a little before them. ~_Long-stalked_ flowers in _umbels_ -are found in _C. avium_ (Wild Cherry), _C. vulgaris_ (the cultivated -Cherry, from Western Asia); _racemes_ at the apex of leaf-bearing -branches and small spherical fruits are found in _C. padus_ (Bird -Cherry), _C. virginiana_, _C. laurocerasus_ (Cherry-laurel), _C. -mahaleb_.~ - - POLLINATION. _Prunus spinosa_ (Sloe, Blackthorn) is protogynous, - but the stamens are developed before the stigma withers. Honey - is secreted by the receptacle. _Cerasus padus_ (Bird-Cherry) - agrees in some measure with _P. spinosa_. In the flowers of - the Plum and Cherry the stamens and stigma are developed - simultaneously and self pollination seems general; the - stigma, however, overtops the inner stamens and thus promotes - cross-pollination.--DISTRIBUTION. 114 species in the N. Temp, - zone; few in the warmer regions; the majority from W. Asia. _C. - vulgaris_, from the regions of the Caspian; _Prunus spinosa_, - _insititia_ (Bullace), _domestica_ (Plum, from the Caucasus, - Persia).--USES, principally as fruit-trees: Cherry, Plum, - Apricot, etc.; “Almonds” are the seeds of _Amygdalus communis_ - (W. Mediterranean), “bitter,” “sweet,” and “shell” almonds are - from different varieties, the latter being remarkable for the - thin, brittle stone. In the majority of species and in almost - all parts of the plant (especially the bark, seed and leaves) - is found the glycoside, _amygdalin_, which forms prussic acid. - Many form _gum_, and the seeds have _fatty oils_ (“Almond - oil”). OFFICINAL: the seeds and oil of _Amygdalus communis_, - and the fruit of the Cherry; in other countries also the leaves - of _C. laurocerasus_.--The stems of _Cerasus mahaleb_ are - used for pipes. Ornamental Shrubs: _Amygdalus nana_, _Cerasus - laurocerasus_. - - Order 3. _Chrysobalanaceæ._ Tropical Amygdalaceæ with - zygomorphic flower and gynobasic style. 200 species; especially - Am. and Asia. _Chrysobalanus icaco_ (Cocoa-plum) is cultivated - on account of its fruit (Am.) - -Order 4. =Pomaceæ.= Trees and shrubs, most frequently with simple -leaves and caducous stipules. The flowers (Fig. 505) have 5 sepals, 5 -petals and generally 20 stamens (10 + 5 + 5, or 10 + 10 + 5). There are -from 1–5 _carpels_, which unite entirely or to some extent with each -other, and with the hollow, fleshy receptacle (the _flower_ becoming -_epigynous_), (Figs. 505, 506, 507). The carpels are nearly always -free on the ventral sutures, rarely free at the sides also. The whole -outer portion of the fruit becomes fleshy, but the portions of the -pericarp surrounding the loculi (endocarp) are most frequently formed -of sclerenchymatous cells, and are more or less firm (the “core”). The -nature of the fruit varies, according to the thickness and hardness -of the endocarp, being either a “berry” or a “drupe” (see _A_ and -_B_). When the endocarp is thin and parchment-like, the fruit has the -characteristics of a berry, each of the 5 loculi generally present -containing several seeds; but when this is hard the fruit resembles a -drupe, only one seed is developed in each loculus, and the number of -the loculi is reduced to one or two. There are nearly always 2 ovules -in the loculi of the ovary, but in _Cydonia_ there are a large number -in 2 rows. In the genera which have stones, only one seed is developed -in each stone. The genera are distinguished mainly in accordance with -the kind of fruit and the number of ovules and seeds. - - [Illustration: FIG. 504.--Longitudinal and transverse section - through the flowers of _A_, _B_ _Cotoneaster_; _C_ _Cydonia_; - _D_ _Malus communis_; _E_ _Raphiolepis_; _F_ _Cydonia_; _G_ - _Mespilus_.] - - [Illustration: FIG. 505.--Floral diagram of _Mespilus germanica_.] - -=A.= SORBEÆ. THE ENDOCARP IS PARCHMENT-LIKE OR PAPERY (drupe, with thin -stone or berry). - -1. _Pyrus_ and _Cydonia_; carpels completely embedded in the cup-like -receptacle, styles always free.--_Pyrus_: the fruit is glabrous, -and has only a small calyx, withering or deciduous, and a 5-locular -ovary with at most 2 ascending ovules in each loculus (Fig. 504 -_D_). The large flowers are situated in few-flowered umbels or -corymbs. ~_P. communis_ (Pear; free styles, Fig. 507; it has the -well-known pear-shaped fruit; the core is reduced to several groups -of sclerenchymatous cells embedded in the pulp, the leaf-stalk is as -long as the blade).~--_Cydonia_ (Quince) has a hairy fruit with _many -seeds in 2 rows_ in each loculus of the endocarp (Figs. 504 _C_, _F_; -506); the testa of these seeds is mucilaginous. _C. vulgaris_, large, -terminal flowers on lateral branches, and large leaf-like, persistent -sepals. - - [Illustration: FIG. 506.--_Cydonia vulgaris._ Longitudinal - section of fruit.] - - [Illustration: FIG. 507.--Longitudinal section of Pear flower.] - -2. _Malus_ and _Amelanchier_ (_Aronia_); carpels free on the ventral -edge; styles united. _Malus communis_ (Apple) the fruit is “umbilicate” -at the base; no sclerenchymatous cells in the pulp; styles united at -the base (Fig. 504 _D_); leaf-stalk shorter than the blade. _Sorbus_ -(Mountain-ash) differs only in having a 2–3-locular fruit with -extremely thin endocarp. Cymose inflorescences in umbellate cymes. -~_S. aucuparia_ has pinnate leaves, _S. aria_ (White-beam) and other -species have simple leaves.--_Amelanchier_ (the Service-tree) has a -false divisional wall springing from the dorsal suture, and more or -less projecting into each of the loculi of the ovary; _Raphiolepis_ -(Fig. 504 _E_) has racemes and a juicy berry; _Eriobotrya japonica_ -(Loquat).~ - -=B.= CRATÆGEÆ. THE ENDOCARP IS HARD AND BONY (“drupes,” generally -with several, sometimes, however, with only 1–2 stones, rarely one -multilocular stone; only 1 seed in each of the loculi).--_Cratægus_ -(Hawthorn, May). There are 1–5 stones in the spherical or ovoid fruit. -The disc, found on the apex of the fruit, inside the small, withered -calyx, is small (much less than the transverse section of the fruit). -Shrubs with thorns (branches) and moderately large flowers borne in -corymbs.--_Mespilus_ (Medlar) differs from the last-named only in -having a _large disc_ at the apex of the fruit, inside the large, -_leaf-like sepals_, _i.e._ almost equal to the greatest diameter of the -fruit. The flowers are solitary and terminal.--_Cotoneaster_ is chiefly -distinguished from the others by its syncarps, the 2–5 carpels (and -stones) being free from one another, and only united to the receptacle -by a larger or smaller portion of their dorsal surface (Figs. 504 _A_, -_B_). Small shrubs with leathery leaves, generally covered with white, -felted hairs on the lower surface, and with small flowers; the fruit is -red or black. - - Pear, Apple, Mountain Ash and Hawthorn have protogynous - flowers which secrete honey, and are conspicuous to ensure - insect pollination.--180 species; in the northern temperate - regions.--Pear and Apple are especially cultivated as fruit - trees in a number of varieties; the Paradise Apple (_Pyrus - baccata_); especially in southern countries also the Quince - (from N. Persia and the Caucasian districts), Medlar and - _Amelanchier vulgaris_. _Malus pumila_ (Caucasus, - Altai) and _M. dasyphylla_ (Orient, S. Eur.) are regarded - as primitive forms of the Apple-tree; _M. sylvestris_, - which grows wild in European forests, appears to have been less - used. The early Lake-dwellers in Switzerland had the apple-tree - both wild and cultivated.--The original form of the Pear is - supposed to be _Pyrus achras_ (Central Asia).--Many of - the species of _Cratægus_, some with double flowers, and - _Pyrus (Chænomeles) japonica_, with brilliant red flowers, - are cultivated as ornamental shrubs. OFFICINAL: Quince - pips, on account of the mucilaginous testa.--The fruits contain - free organic acids and sugar; prussic acid may be obtained from - the seeds. The wood of the Pear-tree is used in manufactures. - - - Family 21. =Leguminosæ.= - -The most characteristic feature is, that the _gynœceum is 1-locular_ -and formed of _1 carpel, the ventral suture of which is turned -posteriorly_. The fruit, in most instances, is a _pod_ (legume), -which opens generally along both sutures, the two valves twisting -more or less in opposite directions. ~In other instances it opens -along one suture only, or as a pyxidium (Red Clover), or it is -indehiscent, in which case it is more or less berry-like (_e.g._ the -Tamarind, Carob-bean), or it is a drupe (_e.g._ the Tonquin-bean), or -a 1–few-seeded nut (_e.g._ _Melilotus_), or a lomentum, which divides -transversely into as many joints as there are seeds (_Ornithopus_, see -Fig. 513).~ - -The inflorescences belong to the _centripetal_ type (_i.e._ -indefinite); cymes do not occur. The flowers are _zygomorphic_, with -vertical plane of symmetry, seldom regular; _5-merous_ with but a few -exceptions, ☿, and slightly _perigynous_. The following diagram is the -most general (Fig. 511): 5 sepals, with the _unpaired sepal median -and anterior_, 5 petals, 5 + 5 stamens, all in alternating whorls, 1 -carpel. The calyx is most frequently gamosepalous, the gynœceum is -narrowed down at the base to a short stalk and, in the majority, is -more or less bent. The seed is most frequently kidney-shaped, with -a smooth, hard and shining testa, the hilum being very distinct. -_Endosperm is wanting_, or is reduced to a thin layer, which is of -service when the seed swells during germination. The vegetative parts -have these features in common, namely, the _leaves are scattered, -stipulate_, and almost always _compound_. Peculiar _sleep-movements_ -and _sensitiveness_ are found in some, chiefly in the Mimosas. Many, -probably all, Leguminosæ have _small tubercles on their roots_ which -are produced by a kind of bacterium, and assist in the assimilation -of free nitrogen. Spontaneous movements are exhibited by _Desmodium -gyrans_ (Telegraph-plant). - - This family is closely allied to the Rosifloræ, with which it - agrees in the scattered leaves, the presence of stipules, the - generally 5-merous and most frequently perigynous flowers with - eucyclic stamens, and the absence of endosperm. _Amygdalaceæ_ - and _Chrysobalanaceæ_, with solitary carpels, approach on one - side to the Leguminosæ, among which genera with drupes are also - found; _Mimosaceæ_, with their many stamens, form a connecting - link on the other side. In this respect the Mimosa-genus - _Affonsea_, and certain Cæsalpineæ and Swartzieæ, are of special - interest in having more than one carpel (syncarp), a condition - which is sometimes met with abnormally in other Leguminosæ, as - well as in Amygdalaceæ. About 7,000 species of the Leguminosæ - are known. - -Order 1. =Cæsalpiniaceæ.= These are _leguminous plants with straight -embryo and a flower which is not papilionaceous and has not the -same æstivation_ (Figs. 508–510); but in reality there is not a -single characteristic which absolutely distinguishes them from the -Papilionaceæ.--The majority are arborescent; the leaves as a rule -are pinnate or bipinnate. The flower is 5-merous, most frequently -perigynous and slightly zygomorphic; the calyx is free or gamosepalous, -the corolla polypetalous with _ascending imbricate æstivation_ (_i.e._ -the two lowest petals envelop the lateral ones, and these again the -posterior; Fig. 508); 10 _free stamens_; fruit various. - - [Illustration: FIGS. 508–510.--_Cassia floribunda._ - - FIG. 508.--Floral diagram. - - FIG. 509.--Flower. - - FIG. 510.--The same in long. sect.] - -_Cassia_ (Figs. 508–510) is the largest genus (about 200 species); it -has an almost hypogynous, zygomorphic flower with 5 free sepals and -petals; of the 10 stamens the 3 posterior are generally barren, the -others are of very unequal length and open at the apex by _pores_ (Fig. -509). In some (the _Senna_ group) the fruit is a flat, short, thin, -dehiscing pod; in others (_Cathartocarpus_) it is round, long, woody -or fleshy, indehiscent, and divided internally by more or less fleshy -transverse walls into as many cells as there are seeds.--The following -also have DEHISCENT FRUITS: _Bauhinia_ (often lianes, tropical climbers -with tendrils [stem-structures] and anomalous stems), _Copaifera_, -_Hæmatoxylon_ (whose pod does not dehisce along the suture, but -laterally), _Cercis_ (simple leaves; the corolla resembles that of -the Papilionaceæ, but the posterior petal is the smallest, and is -enveloped by the 2 lateral ones, which are enveloped in their turn by -the 2 anterior).--FRUIT INDEHISCENT: _Tamarindus indica_; the pod is -almost round, often a little abstricted between the seeds; the wall -is formed by a thin, brittle external layer, enclosing an acid pulp; -well-developed septa are present, between the seeds; the most internal -layer is parchment-like. Calyx 4-merous by the coalescence of 2 sepals. -Only 3 fertile stamens.--_Ceratonia siliqua_ (Carob-bean, Locusts); -the pod is long, compressed, with thick sutures, and has a wall, the -central part of which is more or less leathery, fleshy and sweet; -there are transverse septa between the seeds, as in the Tamarind. -Embryo greenish in endosperm. The flower is without a corolla, 5 -stamens.--_Pterogyne_ (winged fruit), etc.--KRAMERIEÆ with _Krameria_ -is an anomalous group. - - DISTRIBUTION. 80 genera, with 740 species; almost exclusively - in the Tropics. The Carob-tree and _Cercis_ grow in the - Mediterranean basin. The largest and most widely distributed - genus is _Cassia_, which is found as trees, shrubs, and weeds - in all tropical countries. The order has many important - uses to mankind. MEDICINAL: the leaves and pods of _Cassia - acutifolia_ and _angustifolia_ (officinal, Senna-leaves), - the fruit-pulp of the _Cassia_-sub-genus, _Cathartocarpus_. - Rhatany root from _Krameria triandra_ (Peru, officinal). - _Balsam_ is extracted from a number of _Copaifera_-species - (Balsam of Copaiba) from S. Am. (officinal), and from _Hymenæa_ - (Copal balsam), _Trachylobium_ and others. _Edible fruits_ are - obtained especially from the Carob-tree (from the East) and - the Tamarind (officinal). The heart-wood of several species of - _Cæsalpinia_, such as _C. brasiliensis_ (the Pernambuco-tree), - _echinata_ (Red-tree), and _sappan_, yield _dyes_; _Hæmatoxylon_ - (_H. campechianum_, Logwood), _Copaifera bracteata_ - (Amarant-tree).--_Timber_ is obtained from many (_Melanoxylon_ - and others). In Europe they are of little importance as - ornamental plants, these being confined principally to the - species of _Gleditschia_ (_G. triacantha_, from N. Am.) and - _Cercis_ (the Judas-tree, _C. siliquastrum_, S. Eur.), which - are cultivated in gardens; but in tropical gardens beautiful - flowering species, _e.g._ of _Cassia_, _Poinciana_, _Brownea_, - are found, and the most beautiful of all ornamental plants, the - Indian _Amherstia nobilis_. - - [Illustration: FIG. 511.--Diagram of _Faba vulgaris_: _f_ the - standard; _v_ the wings; _k_ the keel.] - -Order 2. =Papilionaceæ.= The flower (Figs. 511, 512) is _strongly -zygomorphic_ and somewhat perigynous (Fig. 512 _B_; most frequently -more on one side than the other). The calyx is _gamosepalous_ and -persistent. The polypetalous corolla has _descending_ imbricate -æstivation, the posterior, large leaf, the _standard_ (Figs. 511 _f_; -512 _B’_, _e_), _covering in the bud_ the two lateral ones, the _wings_ -(Figs. 511 _v_; 512 _B’_, _a_), which again cover the two anterior; -these are united in the form of a boat, the _keel_ (_k_ and _c_); the -wings and the two petals of the keel are very unsymmetrical. That the -keel is formed of two petals is seen by its position (in front of one -sepal) and by the two often more or less free claws. The 10 (5 + 5) -_stamens_ (monadelphous) _are either all united into one bundle, or -into two bundles_ (diadelphous), the posterior one being free (Fig. 512 -_C_). The ovules are _curved_ and _also the embryo_ (Fig. 512 _G_), -especially the hypocotyl, so that the radicle assumes a position close -to the edge of the thick, fleshy cotyledons. Endosperm wanting; the -cotyledons are very rich in proteid reserve material. The forms of the -fruit and exceptions are described under the genera. - - [Illustration: FIG. 512.--_Pisum sativum_: _A_ entire flower; _B_ - in longitudinal section; _C_ gynœceum and stamens; _D_ gynœceum; - _B’_ corolla dissected, _e_ standard, _a_, _a_ wings, _c_ keel; - _D_ seed opened to show the cotyledons (_c_), the radicle (_r_), - the plumule (_g_); _E_ fruit (legume); _F_ seed.] - - _Geocarpic_ fruits, _i.e._ those which penetrate the soil during - their development and ripen underground, are found in _e.g._ - _Arachis hypogæa_ (see page 472), _Trifolium subterraneum_, - _Vicia amphicarpæa_. _Germination_ takes place in various ways. - In the majority the cotyledons are raised above the ground as - green, leaf-like bodies; in the Vicieæ they remain thick and - white, and are always enclosed in the testa, and are therefore - never able to take part in the work of assimilation; in species - of _Phaseolus_, on the other hand, they are raised well above - the ground and become green, but remain however thick and fleshy. - - =1, 2.= The two groups PODALYRIEÆ (the majority of the genera - are Australian) and SOPHOREÆ (_Sophora_, _Edwardsia_, etc.), - represent the oldest type, as they have 10 _free stamens_ and so - form the transition to the Cæsalpiniaceæ. Nearly all are trees - and shrubs. - -=3.= ASTRAGALEÆ. Herbs or shrubs, less frequently trees, with -_imparipinnate_ leaves (without tendrils). The flowers are -generally borne in racemes or spikes. Stamens monadelphous or -diadelphous.--_Astragalus_ (Milk-Vetch) has the legume incompletely -divided longitudinally into 2 loculi by a septum formed by the incurved -dorsal suture. Diadelphous.--_Glycyrrhiza_ (Liquorice); _Colutea_ -(Bladder-Senna) from S. Europe; _Robinia_ (the false Acacia) with -thorny stipules; _Indigofera_ (the Indigo plant); _Amorpha_ (which has -only one petal, namely the standard, and the fruit a nut), _Caragana_, -_Wistaria_ (a climbing shrub), _Galega_. _Carmichælia australis_, when -old, produces flat branches with scale-like leaves. - -=4.= VICIEÆ. _Climbing herbs_ with _paripinnate_ leaves, the midrib -ending in a point or frequently in a _tendril_, which generally is -branched, representing lateral veins without mesophyll; stamens -diadelphous; the cotyledons remain underground on germination.--_Vicia_ -(Vetch) has a filamentous style, hairy towards the tip, and a -pod with many seeds; climbing by means of tendrils; the leaves -have many leaflets.--_Faba_ (_F. vulgaris_, Horse-bean) is erect, -without tendrils; its pod is thick with spongy septa between the -seeds.--_Ervum_ (Lentil) has a pod with only 1–2 seeds, and sweeping -hairs (stylar-brush) on the inner side of the style.--_Pisum_ (Pea; -Fig. 512) has very large stipules, the bent style has a hollow groove -on the anterior side. _P. sativum_ (Common Pea), _P. arvense_ (Grey -Pea).--_Lathyrus_ (Sweet Pea) generally has an angular, winged stem and -most frequently only a few pairs of leaflets. The style is flattened, -with sweeping hairs on the back. ~In _L. aphaca_ the stipules alone -are developed into foliage-leaves, while the remainder of the leaf is -modified into a tendril.~--_Cicer_ has a nearly straight embryo and -imparipinnate leaves with dentate or incised leaflets. _C. arietinus_ -(Chick-pea).--~_Abrus_ (_precatorius_, etc.); the seeds (“Crab’s eyes,” -“Paternoster peas,” “Jequirity”) are scarlet with a black spot round -the hilum.~ - -=5.= PHASEOLEÆ. Herbs, twining or erect, but not climbing by tendrils; -the leaves are imparipinnate, generally _ternate_, and bear small, -linear bodies resembling stipules at the base of the stalks of the -leaflets. The inflorescences are most frequently compound, groups of -few flowers being situated on short, nodose, lateral axes borne on a -longer stem. On germination the cotyledons are raised a considerable -distance above the ground, and become greenish, but do not become -leaf-like; in _P. multiflorus_ they remain underground. Stamens as -in the Vetches.--_Phaseolus_ (Kidney-bean): the keel with the stamen -and style is spirally _twisted_ (to the right). Herbs, twining to the -left.--~The “Calabar-bean” (_Physostigma venenosum_), _Erythrina_, -_Clitoria_, _Glycine_, _Soja_, _Mucuna_, _Apios_, _Canavalia_, _Vigna_, -_Dolichos_, _Cajanus_, _Rhynchosia_, etc.~ - -=6.= TRIFOLIEÆ (CLOVERS). Herbs with _ternate_ leaves, the leaflets -are often dentate with the veins prolonged into the teeth; stamens -diadelphous; fruit 1-locular, 1–few-seeded, pyxidium-like, irregularly -dehiscent, or more frequently a _nut_. The flowers are generally borne -in capitula, racemes, or spikes.--_Trifolium_ (Clover). The corolla -is gamopetalous. The calyx persists, together with the corolla, round -the ripe fruit. The inflorescence is a spike, capitulum or capitate -umbel; the leaves are ternate, and have adnate stipules.--_Medicago_ -(Medick). The corolla falls off after flowering; fruit curved like a -sickle or spirally twisted; it is a nut, and opens with difficulty. -Leaves ternate.--_Melilotus_ (Melilot) has a small, spherical or -lanceolate, thick and wrinkled fruit, which as a rule is indehiscent. -The inflorescence is a raceme, often long, or a spike, sometimes a -capitulum. Leaves ternate.--_Ononis_ (Rest-harrow) differs in having -monadelphous stamens and in being more shrub-like and bushy, and in -having a normal, 2-valved pod, by which characteristic it approaches -the Genisteæ. The flowers are generally rose-coloured, solitary, or in -few-flowered racemes in the leaf-axils. Thorns (branches) are often -present; the leaves are compound with only one small leaflet (the -terminal one), or ternate with adnate stipules. - -=7.= LOTEÆ. Herbs with ternate or imparipinnate leaves, with entire -leaflets. In the latter case, when the lowest pair of leaflets is -placed quite close to the sheath, the stalk is wanting, and apparently -a trifoliate leaf with large stipules is developed. Flowers in -an umbel or capitulum. Stamens monadelphous or diadelphous, the -filaments (either all of them, or only the 5 sepal-stamens) are -widened at the top.--_Lotus_ (Bird’s-foot-trefoil) has a long, round -pod.--_Tetragonolobus._--_Anthyllis_ (Lady’s-finger); the fruit is -a nut, which is distributed by the wind by means of the membranous, -bladder-like calyx, which completely encloses and falls off with it. - -=8.= GENISTEÆ. The majority are shrubs or trees with apparently simple -leaves, _i.e._ compound leaves with only one leaflet (the terminal -leaflet), or ternate leaves; the stipules in most instances are very -small or are entirely wanting; stamens monadelphous.--_Genista_ -(Dyer’s-weed) has apparently simple leaves; the branches often -terminate in a thorn. ~The strongly-winged stems in _G. sagittalis_ -are its most important organs of assimilation. _Bossiæa rufa_ -has flat branches, its leaves being reduced to small, pointed -stipules.~--_Sarothamnus_ (Broom) has switch-like, angular branches -and often both the apparently simple and ternate leaves on the same -shoot; style spirally rolled.--_Cytisus_ (Laburnum). _Ulex_ (Furze; -~in _U. europæus_, the seedlings bear a few foliage leaves, but -the leaves succeeding these are modified into thorns~); _Spartium_; -_Crotalaria_, etc.--_Lupinus_ (Lupin) is allied to this group; it has -a thick, often somewhat fleshy pod, and digitate leaves with adnate -stipules.--_Retama._ - -=9.= HEDYSAREÆ are especially recognised by having the ovary divided -by transverse septa into as many cells as there are seeds, the fruit -thus becomes a _lomentum_, dehiscing transversely into nut-like joints -(Fig. 513).--_Ornithopus_ (Bird’s-foot); _Coronilla_; _Hippocrepis_; -_Onobrychis_ (Sainfoin) has a fruit with only 1 joint (_i.e._ a -1-seeded nut); _Desmodium_; _Alhagi_; _Hedysarum_, etc.--_Arachis -hypogæa_ (Earth-nut) has a pod which is abstricted between the seeds, -and is indehiscent, but is not multilocular nor a true lomentum; it is -reticulately wrinkled externally, and ripens underground; the basal -part of the ovary is prolonged after flowering, attaining a length of -several inches, and buries the young fruit in the soil. The embryo is -straight.--~_Desmodium gyrans_ is well-known for its motile leaflets.~ - - [Illustration: FIG. 513.--_Hedysarum coronarium._] - -=10.= DALBERGIEÆ. 25 genera; especially in Tropical America; the -majority are trees, a few shrubs or lianes; the leaves are simple -or imparipinnate. The fruit is _indehiscent_ in all; in some it is -a winged, in others a wingless _nut_ (_Machærium_, _Dalbergia_, -_Centrolobium_, etc.), in others, again, a drupe, _e.g._ in _Dipteryx_ -(Tonquin-bean) and _Andira_. In some genera the embryo is straight. - - POLLINATION. Especially effected by Bees. The nectar is secreted - by a ring or disc-like portion round the base of the gynœceum or - the inner surface of the receptacle. The flower is constructed - with a peculiar mechanism to ensure cross-pollination by - insects. The pollen is shed just before the flower opens, and - is retained in a pouch formed by the keel. An insect visiting - the flower uses the wings and keel for a landing-stage, and - in attempting to reach the honey presses down the wings and - the keel which are locked together near the standard; the - stylar-brush by this means is forced through the apical opening - of the keel and a little pollen is thus swept out and deposited - upon the abdomen of the visiting insect as it presses against - the apex of the keel; the insect thus carries away pollen and - may effect cross-pollination. In the different flowers this - arrangement is modified in various ways to promote pollination. - 5000 species (319 genera); especially in the Tropics, where - many are important forest trees.--The following plants are used - FOR FOOD: _Pisum sativum_ (W. Asia?) and _arvense_ (Italy); - _Phaseolus vulgaris_ (Kidney-bean, American; _Dolichos sinensis_ - was known to the Greeks and Romans under the name “φασηλος,” - “phaseolus”), _P. compressus_ (French-bean), etc.; _Faba_ - _vulgaris_ (Field-bean, Horse-bean; from the Old World); - _Ervum lens_ (Lentil, Eastern Mediterranean); in tropical - countries the oil-containing seeds of _Arachis hypogæa_.--The - following are FODDER plants: _Vicia sativa_, _Faba vulgaris_, - _Onobrychis sativa_ (Sainfoin), _Medicago sativa_ (Lucerne), - and _lupulina_ (Medick), species of _Trifolium_, _Hedysarum - coronarium_. OFFICINAL: “Liquorice root,” from _Glycyrrhiza - glabra_ (S. Europe); “Red Sandalwood,” from _Pterocarpus - santalinus_ (Tropical E. Asia); Gum Tragacanth, from - _Astragalus_-species (E. Mediterranean); Balsam of Peru, from - _Toluifera pereiræ_, and Balsam of Tolu, from _Toluifera - balsamum_. Calabar-beans, from _Physostigma venenosum_; Kino, - from _Pterocarpus marsupium_; the pith of _Andira araroba_ is - used under the name of “Chrysarobin.”--Of use TECHNICALLY: - _Genista tinctoria_ (yellow dye) and _Indigofera-species_ - (Indigo), the bast of _Crotalaria juncea_ (Sunn Hemp); the - seeds of _Dipteryx_, which contain Coumarin, and are highly - scented, and Balsam of _Myroxylon_. POISONOUS: the seeds of - _Laburnum_ (_Cytisus laburnum_), various species of _Lathyrus_, - and _Abrus precatorius_; the latter contain two poisonous - proteids, paraglobulin and albumose, which resemble snake-poison - in their effects. The following are ORNAMENTAL plants: - _Phaseolus multiflorus_ (Scarlet runner, from America), _Robinia - pseudacacia_, _Amorpha_, _Colutea_, _Coronilla_, _Indigofera - dosua_, _Wistaria polystachya_, _Cytisus laburnum_ (Laburnum, S. - Europe, Orient.) and other species. - -Order 3. =Mimosaceæ.= The flowers are most frequently hypogynous -and _regular_, the æstivation of the corolla is _valvate_ and, in -the majority of instances, that of the calyx also. The flower is -4-merous, less frequently 5- or 3-merous.--The flowers are generally -small, but are always borne in compact, round _capitula_ or spikes -(Fig. 514); they are hypogynous or perigynous. The calyx is generally -_gamosepalous_ and the corolla _gamopetalous_, the latter being -frequently wanting. The stamens are equal or double the number of the -petals (_Mimosa_, etc., in _M. pudica_, _e.g._ S4, P4, A4, G1) or -(in _Acacia_, _Inga_, etc.) in a large, indefinite number, free or -monadelphous, often united to the corolla (Fig. 514 _b_). The colour of -the flower in most cases is due to the long and numerous stamens. The -_fruit_ is various. The embryo is _straight_ as in the Cæsalpiniaceæ. -_Entada_ and many species of _Mimosa_ have a flat, straight, or -somewhat sickle-like pod, which resembles the siliqua of the Cruciferæ -in that the sutures (in this instance, however, dorsal and ventral -suture) persist as a frame, but the intermediate portion divides, as -in the transversely divided siliqua, into as many nut-like portions as -there are seeds. Some species have a pod of enormous dimensions. The -seeds of _Entada gigalobium_ are often carried from the West Indies to -the N. W. coasts of Europe by the Gulf Stream.--The fruit of _Acacia_ -in some species is an ordinary pod, in others it is transversely -divided, or remains an undivided fruit, a nut.--This order includes -both trees and herbaceous plants, which are often thorny; the leaves -are usually bipinnate (Fig. 514) and are sensitive, and also possess -sleep-movements.--Many Australian Acacias have compound leaves only -when young, but when old have _phyllodia_, _i.e._ leaf-like petioles -without blades, placed vertically. A large number have thorny stipules, -which in some (_Acacia sphærocephala_) attain an enormous size, and -serve as a home for ants, which in return protect their host-plant -against the attacks of other, leaf-cutting ants. - - [Illustration: FIG. 514.--_Acacia farnesiana_: _a_ - inflorescence; _b_ flower.] - -Other genera besides those mentioned are: _Adenanthera_, _Desmanthus_, -_Parkia_, _Inga_ (with rather fleshy, indehiscent fruit), _Calliandra_, -etc. - - 1350 species (30 genera); none natives of Europe, their home - being the Tropics and sub-tropical regions, especially - Australia and Africa.--Fossils in Tertiary.--Gums are found in - many species of _Acacia_, especially the African (Gum arabic) - and Australian, of which some are _officinal_. The bark, and - also the fruits, contain a large amount of _tannic acid_ and - are used as astringents and in tanning (“Bablah” is the fruits - of several species of _Acacia_). Catechu is a valuable tanning - material extracted from the wood of _Acacia catechu_ (E. Ind). - The flowers of _Acacia farnesiana_ (Fig. 514) are used in - the manufacture of perfumes. With us they are cultivated as - ornamental plants, _e.g._ _A. lophantha_ and many others, in - conservatories. - - - Family 22. =Passiflorinæ.= - -The flowers are most frequently regular, 5-merous in the three -most external whorls, eucyclic and perigynous or epigynous, less -frequently hypogynous. A characteristic feature is that the ovary is -_tricarpellary_, _unilocular_, and with 3 _parietal_ placentæ which -sometimes meet in the central line (_Cucurbitaceæ_). The styles are -generally free and _bifid_. To all these characteristics, however, -there are exceptions. ~The Cucurbitaceæ are sometimes placed among the -Sympetalæ, close to the Campanulinæ, but they are not allied to the -Sympetalæ, from which they differ especially, for instance, in the -structure of the ovule. The position of the Begoniaceæ in this family -is also open to doubt.~ - - [Illustration: FIG. 515.--_Passiflora cœrulea_ (reduced).] - -Order 1. =Passifloraceæ= (=Passion-flowers=). The majority are -herbs which climb by means of tendrils (modified branches) and have -scattered, stipulate leaves, often palminerved and lobed (Fig. 515). -The flowers, which are often large and beautiful, are regular, ☿, with -S5, P5, A5, G3; the calyx and corolla are _perigynous_, and immediately -inside the corolla is the “corona,” consisting of numerous, tapering, -filamentous bodies, or sometimes united in rings, most frequently -petaloid and coloured; the stamens are raised on a long, round -internode above the _cup-like receptacle_; immediately above these is -the gynœceum with its 3 free styles and capitate stigmas; the ovary is -unilocular with 3 parietal placentæ. Fruit most frequently a _berry_. -The seeds have an aril. - - 210 species; especially in Tropical America. Several - _Passiflora_-species are ornamental plants, and the fruits of - some species are edible. - -Order 2. =Papayaceæ.= The best known representative is the Papaw -(_Carica papaya_), a Tropical American tree whose stem is usually -unbranched, and bears at its summit several large, palmilobed leaves -on long stalks. The stem and leaves have latex. The large, Melon-like -berries are edible, and for this reason it is cultivated in the -Tropics. Flowers unisexual, with slightly different structure in -the ♂-and ♀-flowers, besides intermediate forms. The ♂-flower has a -gamopetalous, the ♀-flower a polypetalous corolla.--The milky juice -contains a substance with similar action to pepsine. 10 stamens. 5 -carpels. - - Order 3. =Turneraceæ.= 85 species; especially in America. - - Order 4. =Samydaceæ.= 160 species; tropical. - -Order 5. =Loasaceæ.= Herbaceous plants seldom shrubs, sometimes -climbing, and nearly always studded with _stiff hairs_, in some -instances stinging or hooked. The leaves are most frequently palmilobed -and without stipules. The flowers are regular, ☿, polypetalous, -entirely _epigynous_, with 4–5 sepals, petals and stamens, or more -frequently (by splitting) many stamens, those which are placed before -the sepals being generally barren and more or less petaloid; carpels -most frequently 3, united into an inferior, unilocular ovary with 3 -parietal placentæ, above which the receptacle is generally more or less -prolonged. Fruit a capsule; in _Gronovia_ an ovary with 1 ovule and -fruit a nut. - - 115 species; principally from S. Am. A number of annuals are - often grown in our gardens: _Bartonia aurea_ (California); - _Mentzelia_; _Cajophora_; _Gronovia_. - -Order 6. =Datiscaceæ.= 4 species, especially in the Tropics.--_Datisca -cannabina_ (Asia Minor) resembles the Hemp in external appearance. The -flowers are diœcious, insignificant; ♂-flowers: a low, gamosepalous -calyx, no corolla, and an indefinite number of stamens; ♀-flowers; -_epigynous_; ovary unilocular with free, mostly bifid, styles, and -generally 3 parietal placentæ. In most cases the ovary is not entirely -closed at the top (as in _Reseda_). - - [Illustration: FIG. 516.--_Begonia rex_ (reduced).] - -Order 7. =Begoniaceæ.= This order principally comprises herbs or -under-shrubs with succulent stems (having scattered vascular bundles -in the pith); the leaves are arranged in two rows (a divergence of -1/2) and _are asymmetrical_, as a rule more or less obliquely cordate, -or ovate with cordate base (Fig. 516); large, caducous stipules are -present. Inflorescences dichasial, or unipared scorpioid cymes; the -flowers are unisexual; the first ones (the oldest) are ♂-flowers, while -♀-flowers are found especially on the younger axes. The ♂-flowers -have most frequently 2 + 2 coloured perianth-leaves, and many stamens -collected into a head in the centre of the flower; the ♀-flowers are -_epigynous_ with 5 coloured perianth-leaves (placed spirally with a -divergence of 2/5) and a trilocular ovary, bearing 3 bifid styles and -3 wings (the wings usually of unequal size); in the inner angle of -each loculus there is one large projecting placenta, or two plate-like -placentæ (the bent back edges of the carpels) studded with ovules. -Fruit a capsule, with many extremely small seeds.--_Begonia._ - - 420 species; almost all from the Tropics (Am., Asia).--Many - species, with varieties and hybrids, are ornamental plants in - houses and conservatories, chiefly on account of the form, - colour and markings of their leaves; but also for their very - beautiful flowers. They reproduce easily by adventitious buds - from leaves and portions of leaves placed on damp soil; some - have bulbils. Like the Oxalideæ they contain an acid sap. - - [Illustration: FIG. 517.--_Ecballium agreste._ Diagram of a ♂-and - a ♀-flower.] - -Order 8. =Cucurbitaceæ.= The flower is _epigynous_, and, as a rule, -is also provided with a leaf-like, cup- or bell-shaped receptacle -above the ovary, to which the perianth and stamens are attached; the -flowers are regular, _unisexual_, with rudiments of the other sex, -and 5-merous: sepals 5, narrow and pointed, with the median sepal -posterior (Fig. 517), petals 5, stamens 5, and carpels 3 (rarely 4–5); -the corolla is _gamopetalous_ in the majority, polypetalous in some; -generally plicate-valvate in the bud. _The anthers in the ♂-flowers are -extrorse, and monothecious, i.e. only one half of each of the anthers -of the 5 stamens is developed_, the _pollen-sac_ having frequently a -peculiar [tilde]-shaped curve (Fig. 518 _A_, _B_); the stamens are -_either all united_ into a column (_e.g._ in _Cucurbita_), or they -are _united in pairs_, so that only one remains free (Figs. 517 _A_; -518 _A_); in the latter case there appears to be one small stamen -with a [tilde]-shaped, curved pollen-sac and two larger ones, each -with two curved pollen-sacs placed as in Fig. 517 _A_. The original -form appears to be _Fevillea_ with free petals and 5 free stamens. -Sometimes the rudiment of a gynœceum is present. The carpels are united -into an _ovary_ with 3 (4–5) placentæ formed by their united edges. -These are thick, fleshy, and _bifid_, bearing a number of ovules on -each side (Figs. 517 _B_; 518 _C_, _D_); in general the placentæ are -so large that they not only meet in the centre, but also fill up the -ovary as far as the wall of the pericarp. The whole interior of the -fruit thus becomes a juicy mass in which three lines may be seen, -meeting in the centre (the boundaries of the individual placentæ), -and near the circumference 6 groups of seeds (Fig. 518 _D_). When the -carpels are equal in number to the petals they alternate with them. -The _style_ is short and thick, and generally divided into 3 (4–5) -branches, with a horse-shoe shaped stigma on each branch (Fig. 518 -_C_). The _fruit_ is most frequently a many-seeded _berry_; in some it -attains a considerable size and has a firm external layer (_Cucurbita_, -_Lagenaria_, etc.). _The embryo is straight_, has _no endosperm_, -but contains a large quantity of _oil_. The exceptions to the above -characters will be found under the genera. - - [Illustration: FIG. 518.--_Citrullus colocynthis_: _A_ ♂-flower, - cut open and spread out; _B_ stamen; _C_ ♀-flower in long - section; _h_ receptacle; _ca_ calyx; _D_ transverse section of - ovary.] - -Exclusively herbs, generally with stiff hairs and yellow flowers. Many -species are annuals, others are perennial, having tuberous roots or -hypocotyls. The leaves are scattered, long-stalked, in most cases more -or less heart-shaped, palminerved, palmilobed, and exstipulate; in -their axils are found both flowers (singly, or in an inflorescence) -and a vegetative bud, and outside the axil, _on the anodic[37] side of -the leaf, a simple or branched tendril_, by which the plant _climbs_ -(exceptions: _e.g._ _Ecballium_). - - The position of the flowers, branches and tendrils situated - in and near the leaf-axils is as follows. In the leaf-axils, - a flower is borne (as a branch of the first order), ♂ or ♀, - according to the conditions of the various genera. This branch - is not situated in the centre of the axil, but is removed - slightly towards the anodic side of the leaf. Of its two - bracteoles as a rule only the one lying on the anodic side is - developed, namely as a tendril, which is displaced to a position - outside the axil. The branch of the first order bears on its - catodic side an inflorescence (in the axil of the suppressed - bracteole), on the anodic side a vegetative bud which grows out - into a branch like the main axis. The subtending leaf of this - branch is thus the tendril; but when it has several arms the - condition is complicated by the appearance of an accessory bud - which unites with its subtending leaf, the tendril, its leaves - also becoming tendrils (situated on an undeveloped internode); - the many-branched tendril is thus a branch, and the tendril-arms - are its leaves, except the main arm which is its subtending - leaf. Other explanations of these difficult relations have - been given.--The _germination_ is somewhat peculiar, owing to - the fact that a heel-like prolongation is formed at the base - of the hypocotyl to assist in separating the two halves of the - testa from each other, and to facilitate the unfolding of the - cotyledons. - -_Cucurbita_ (Pumpkin, Marrow) has branched tendrils; the flowers are -monœcious, and are borne singly; the corolla is bell-shaped, and -divided almost as far as the middle. The stamens are all united into -a tube; the compressed seeds have a thick, blunt edge.--_Cucumis_ has -(generally) unbranched tendrils; the ♀-flowers are borne singly, whilst -the ♂-flowers are borne in groups: the corolla is divided nearly as -far as the base, and the stamens are united 2-2-1. The connective is -elongated above the anthers. The seeds have a sharp edge.--_Citrullus_ -(Fig. 518) has a corolla similar to _Cucumis_, but ☿-and ♂-flowers are -borne singly; the stigma is only 3-lobed, the fruit most frequently -spherical.--_Ecballium_ (Squirting Cucumber, only 1 species, E. -_elaterium_) has no tendrils, and is therefore not a climber. The -oblong fruit is pendulous from the apex of its stalk, and when ripe is -distended with an acrid, watery fluid; on being touched the fruit is -detached, and the seeds, together with the watery fluid, are violently -ejected through the aperture formed at the base of the fruit. The -♂-flowers are borne in racemes near the solitary ♀-flowers (Fig. -517).--_Bryonia_ (White Bryony) has chiefly unbranched tendrils and -small, greenish-yellow, usually diœcious flowers with rotate corolla, -in many-flowered inflorescences; the small, spherical berry has no -specially firm outer layer, and generally only few seeds. The tap-root -and a few of the other roots are tuberous. _B. alba_ (berry black; -monœcious) and _dioica_ (berry red; diœcious). ~Among other genera may -be mentioned: _Lagenaria_ (Gourd); the fruit has a woody external -layer which, after the removal of the pulpy integument, may be used -as a gourd. _Luffa_ has a polypetalous corolla; the fruit is dry, and -consists internally of a network of vascular bundles; it opens by an -aperture at the summit. _Benincasa_; the fruit has a close, bluish -coating of wax. _Trichosanthes_ (Snake Cucumber) has a thin, round, -long and curved fruit. _Momordica_; the fleshy fruit opens and ejects -the seeds. _Cyclanthera_ takes its name from the staminal column which -is found in the centre of the ♂-flower, bearing a bilocular, ring-like -anther which opens by a horizontal cleft. The fruit is unilocular by -suppression, has 1 placenta, and when touched opens and ejects the -seeds. _Sicyos_ and _Sechium_ have only unilocular ovaries with one -pendulous ovule. _Sechium_ has, moreover, 5 free stamens, of which only -one is halved, the other 4 having both halves of the anther. _Fevillea_ -and _Thladiantha_ also have 5 free stamens. _Dimorphochlamys_ has -dimorphic flowers.~ - - POLLINATION is effected by insects, chiefly bees or wasps, - the nectar being secreted by the inner, yellow portion of the - receptacle; in the ♂-flower access is gained to the nectar - through the slits between the stamens, which arch over the - nectary.--85 genera; about 637 species; especially in the - Tropics. Only two are found in the whole of N. Europe, _Bryonia - alba_ and _dioica_; in S. Europe, _Ecballium_ also. Most of - the cultivated species have been obtained from Asia, such as - the Cucumber, Melon, Colocynth, several _Luffa_-species (the - “Gourds” mentioned in Scripture are _Cucumis chate_); from - Africa, the Water-melon, _Cucurbita maxima_, and others; from - S. Am., no doubt, the Pumpkin (_C. pepo_ and _melopepo_). USES. - Many species are used in medicine or for domestic purposes. - _Bitter_, _poisonous properties_ are found; the fruits of the - two _officinal_ ones are purgative: _Citrullus colocynthis_ - (Mediterranean, E. India, Ceylon) and _Ecballium elaterium_, - as well as various tropical species, the roots of Bryonia, - etc.--The following are cultivated AS ARTICLES OF FOOD: Pumpkin - (_Cucurbita pepo_, etc.), Cucumber (_Cucumis sativus_), Melon - (_Cucumis melo_), the Water-melon (_Citrullus vulgaris_), - _Sechium edule_ (Chocho), certain species of _Luffa_ (the - young fruit). The Bottle Gourd is cultivated in tropical - countries for the sake of its hard pericarp, which is useful - for bowls, bottles, etc. The fruits of _Luffa_ have a number - of reticulately felted, tolerably firm vascular bundles, which - render them serviceable in various ways (as a kind of “sponge”). - The Cucurbits are of no use in the manufactures. Only a few are - cultivated as ornamental plants, chiefly as curiosities. - - - Family 23. =Myrtifloræ.= - -The leaves are most frequently _opposite_, _simple_, _entire_ (rarely -dentate), and _exstipulate_. The flowers are _regular_ and _epigynous_ -(perigynous in _Lythraceæ_ and a few others), ☿, polypetalous; the -number of members in a whorl is generally 4 or 5 (S, P, A, or most -frequently A 2, G), but sometimes it becomes (_e.g._ Myrtles and -_Lythraceæ_) very large in the andrœcium by splitting, and in the -gynœceum also is often different. (When suppression takes place it is -principally in the corolla and petal-stamens.) In nearly all instances -the calyx is _valvate_. Gyncœceum multicarpellary, multilocular, -with only one _style_ (except _Haloragidaceæ_). In the majority the -ovules are situated on an axile placenta in the multilocular ovary. -_Endosperm is wanting_ in the majority.--~Less important exceptions: -_Rhizophoraceæ_ and _Gunnera_ have stipules. _Haloragidaceæ_ have -several styles and endosperm. _Rhizophora_ also has endosperm.~ - -Order 1. =Lythraceæ.= _Hermaphrodite_, _perigynous_ flowers which are -_most frequently =6=-merous_, viz. S 6 (often with a _commissural_ -“_epicalyx_,” Fig. 519 _c_), one segment posterior, P 6, A 6 + 6 or -6 + 0 and G =2–6=, forming a 2–6-locular ovary with many ovules in -the loculi, style single, and capitate stigma. The _gynœceum is free_ -at the base of the tubular, or bell-shaped, _thin_, strongly veined -receptacle, which bears the other leaf-whorls on its edge and inner -side. Fruit a capsule. No endosperm.--To this order belong both herbs, -shrubs and trees. The branches are frequently square, the leaves always -_undivided_, _entire_, and without stipules, or with several very -small stipules, and often opposite. The calyx is valvate. The flower -is regular (except _Cuphea_) and frequently large and beautiful. The -stamens are generally incurved in the bud, and the petals irregularly -folded. - - [Illustration: FIG. 519.--_Lythrum salicaria._ _c_ the - “epicalyx.”] - -_Lythrum_ (Loose-strife). The flower is diplostemonous and 6-merous, -with a long, tubular receptacle with epicalyx-teeth (Fig. 519 _c_). -The 12 stamens are arranged in two tiers on the inner side of the -receptacle. The gynœceum is bicarpellary. ~The flowers are borne -in small dichasia in the leaf-axils, and their number is increased -by accessory inflorescences beneath the main inflorescence.--The -native species, _L. salicaria_, is trimorphic (long-styled, mid-and -short-styled forms, Fig. 520). Cross-pollination is chiefly -effected by humble-bees and bees, which seek the nectar formed at -the bottom of the receptacle. Other species are only dimorphic, -or even monomorphic.~--Closely allied are, _Nesæa_, _Diplusodon_, -_Lagerstrœmia_, and _Cuphea_, whose flower resembles that of _Lythrum_, -but is zygomorphic. In _Cuphea_ the receptacle is oblique and at the -back prolonged into a _spur_, in which the nectar, secreted by a -gland situated behind the ovary, is collected; the calyx and corolla -gradually become reduced in size toward the anterior side of the -flower; the reverse, however, is the case with the 11 stamens (the -posterior one is absent); the posterior loculus in the bilocular ovary -is sometimes barren; the fruit, when ripe, dehisces along the posterior -side, the ovary as well as the wall of the receptacle being ruptured -by the placenta, which expands and projects freely. ~The flowers stand -singly in the centre of the stem, between the pairs of leaves. This -may be explained as follows: of the two foliage-leaves in each pair, -one supports a foliage-shoot, the other a flower; the foliage-shoot -remains in the axil, but the flower is displaced through the length -of an entire internode to the next pair of leaves, and then assumes -a position between these two leaves. All foliage-shoots stand in two -rows, the flowers in two other rows.~ - - [Illustration: FIG. 520.--_Lythrum salicaria._ One side of the - perianth is removed from all three flowers. _A_ is long-styled, - _B_ mid-styled, and _C_ short-styled. The direction of the arrows - and dotted lines indicates the best (legitimate) methods of - crossing.] - - _Peplis_ (Water-purslane), a small, annual plant, with thin, - bell-shaped receptacle without projecting nerves. The small - flowers have no petal-stamens, and often also no corolla; fruit - indehiscent.--_Ammannia_ is closely allied to it. - - 365 species; 30 genera; mostly in the Tropics, and more - especially S. Am.--Some yield _dyes_, _e.g._ _Lawsonia inermis_ - (cultivated in Africa and Asia) and _Lagerstrœmeria indica_; - some contain tannin; others are ornamental plants, especially in - gardens in warm countries. - - Order 2. =Blattiaceæ.= 12 species. Tropical Asia and Africa. - Trees. Formerly included with _Punica_, but best placed as an - independent order. - - Order 3. =Melastomaceæ.= A very natural and very large order - (150 genera; 2,500 species), its home being chiefly in tropical - S. America, especially the Brazils (termed by Schouw “The - kingdom of Palms and Melastomaceæ”). There are both herbaceous - and arborescent species, which are easily recognized by the - opposite or verticillate, simple leaves which have (with the - exception of a few heather-like species) 3–5–7–9 curved veins - proceeding from the base of the leaf, and connected very - regularly by closely parallel, transverse veins. The flower - is perigynous or epigynous; its type is that of the Onagraceæ - (4–5-merous; 1 whorl of sepals, petals and carpels, 2 of - stamens); the calyx is valvate, the corolla is twisted (to - the left) in æstivation; the stamens are very characteristic; - in the bud they are geniculate; the anther opens in the often - long, beak-like, prolonged point, with 1, less frequently with - 2 pores, and has generally ear-like appendages at its base. - The fruit is a berry or capsule. These large and beautiful - flowering-plants play a very important part in South American - landscapes; otherwise they are of slight importance (a few are - cultivated in conservatories, _e.g._ _Centradenia_, _Medinilla_, - _Lasiandra_, _Tibouchina_, _Miconia_, etc.). - -Order 4. =Œnotheraceæ= (or =Onagraceæ=). The flowers are arranged in -racemes or spikes, ☿, epigynous, regular, polypetalous, _=4=-merous in -all 5 whorls_ (1 whorl of sepals, petals and carpels, 2 of stamens); -2–3–5–6-merous flowers are less frequent; _the calyx is valvate_, the -_corolla twisted_ in æstivation (the left edge being covered). Gynœceum -simple with multilocular ovary; the _style is undivided_, filiform, -and bears a capitate or 4-partite stigma; endosperm wanting; embryo -straight.--The majority are herbs, especially water- and marsh-plants; -several are shrubs. No essential oils. The leaves are alternate or -opposite, always single, and without (or with very small) stipules. -~The odourless flowers sometimes have a coloured calyx. In some -instances (_e.g._ _Œnothera_, _Fuchsia_) the receptacle is prolonged -more or less beyond the inferior ovary, and finally falls off. The -stamens are obdiplostemonous (carpels epipetalous); the petal-stamens -are sometimes suppressed. The anthers in some genera are divided into -storeys. The well-pronounced, triangular pollen-grains are connected -together by viscous threads. Small stipules are sometimes found, _e.g._ -_Fuchsia_, _Lopezia_.~ - - [Illustration: FIG. 521.--Flower of _Lopezia_.] - -=A.= =Fruit a capsule.= _Œnothera_ (Evening Primrose) is 4-merous, -has 8 stamens, a tubular receptacle, and an oblong capsule with -loculicidal dehiscence leaving a centrally placed column, bearing -the seeds.--_Epilobium_ (Willow-herb) deviates from _Œnothera_ -especially in the seeds being hairy (at the chalazal end of the -seed).--_Chamænerium_ is a Willow-herb with zygomorphic flowers.--~The -following may be included here: _Clarkia_, _Eucharidium_ (an _Œnothera_ -with 4 stamens and 3-lobed petals), _Godetia_ and _Boisduvalia_, -_Jussiæa_ (dehiscence septicidal), _Isnardia_ (petal-stamens absent, -sometimes the petals also).--_Lopezia_ has a peculiar, zygomorphic -flower (Fig. 521); one of the four sepals is bent forwards and the -other 3 backwards; the posterior petals are narrower than the 2 -anterior ones which are turned obliquely backwards and bent like -a knee, with a greenish nectary at the bend; 2 stamens, one only -fertile (the posterior), while the anterior is barren, petaloid, and -spoon-shaped; both are sensitive, which is essential for pollination. -In Fig. 521, _a_ represents an early stage, in which the stamen and -style lie concealed in the staminode; _b_ is the ♂ stage, the stamen -projects from the centre of the flower; _c_, the ♀ stage, the style -occupies the place of the stamen.~ - -=B.= =Fruit a berry.= _Fuchsia_ generally has a coloured calyx and -tubular receptacle; the corolla may be wanting. - -=C.= =Fruit a nut.= _Circæa_ (Enchanter’s Nightshade) has a 2-merous -flower (S2, P2, A2 + 0 [petal-stamens are wanting], G2). The flowers -are borne in racemes without bracts.--_Gaura._ - -=D.= =Fruit a drupe.= _Trapa_ (Horn-nut); a peculiar aquatic plant; -the submerged stem has long internodes and lanceolate leaves, falling -off at an early period, but at each node are found 4 long roots with -thin, lateral roots (sometimes erroneously regarded as leaves) borne -pinnately; the stem reaching the surface of the water, bears a rosette -of rhombic foliage-leaves, with large, inflated stalks containing air, -and forming the floating apparatus of the plants. In the axils of the -leaves (as in _Gunnera_) 8 small, stipular structures are present. The -flowers are solitary in the axils of the foliage-leaves (S4, P4, A4 + -0, G2), _semi_-epigynous. There is an 8-lobed, crenate disc on the free -portion of the ovary; one ovule in each loculus. The fruit is a _drupe_ -with 4 (or 2) prominent horns (the persistent sepals), which after the -pulp has decayed away bear a series of hooks turned downwards on each -side, _i.e._ sclerenchymatous bundles which formerly lay concealed -in the pulp of the sepals. ~The germination is peculiar: one of the -cotyledons is large, and its thick extremity remains in the fruit, -the other however is small and is pushed out at the apex of the fruit -together with the radicle and plumule; the development of the root soon -ceases, and the plumule usually grows into a stem entirely without -branches, similar to the one described above, only that 1–2 precisely -similar shoots arise in the axil of each cotyledon, so that each embryo -produces 3–5 shoots.--_Trapa_, by its mode of life, its 1-seeded fruit, -etc., forms a transition to _Haloragidaceæ_.~ - - The large-flowered forms are adapted for insect-pollination and - are often protandrous, the small-flowered ones are homogamous - and may pollinate themselves. _Œnothera_ is adapted for - hawk-moths and bees.--330 species; especially in temperate - climates, chiefly in the Northern Hemisphere. _Epilobium_, - _Circæa_ are natives of this country; _Trapa_ is extinct in this - country, it has been found in a semi-fossilized condition near - Cromer and in bogs in Denmark, and existed in Sweden until a few - years ago; _Œnothera_ has been introduced from N. Am.--A number - of N. Am. species are grown as ornamental plants in our gardens. - The seeds of _Trapa natans_ are edible, and used as food in - China. - -Order 5. =Haloragidaceæ.= This is a reduced form of the Œnotheraceæ, -and principally differs from these in the presence of _endosperm_ -and _free styles_. _Only 1 ovule in each loculus._--84 species -distributed over the entire globe; the majority are aquatic -plants. The most advanced type is _Myriophyllum_ (Water-Milfoil), -with a regular, epigynous flower (S4, P4, A4 + 4, G4), most -frequently _diclinous_ (monœcious); the fruit is a _2–4-partite -schizocarp_. Aquatic plants, most frequently with pectinate, pinnate -leaves.--_Haloragis._--~_Gunnera_ (a dozen species from the Southern -Hemisphere) forms the next step in the reduction. Large, scattered, -rough-haired, and softly-spined leaves, with small flowers in crowded -inflorescences. The flower, when most complete, has S2, P2, A2 -(petal-stamens) and G2, forming an inferior, unilocular ovary with -1 ovule. It is remarkable for the great number of stipules placed -in transverse rows in the leaf-axils, for the peculiar glandular -organs, and for the colonies of _Nostoc_, which are found embedded in -the cortex as a kind of parasite.~--The simplest form is _Hippuris_ -(Mare’s-tail) with an extremely small, crenate or entire calyx, without -corolla, and with only one stamen and one carpel, forming an inferior, -unilocular ovary with only one ovule. Fruit a drupe with thin pulp. -~It is an aquatic plant with creeping, sympodial rhizome, and erect -unbranched shoots, bearing numerous small, verticillate leaves. The -small flowers are situated singly in the leaf-axils.~ - - Order 6. =Rhizophoraceæ.= Tropical trees or shrubs (50 species, - the best known being _Rhizophora mangle_, Mangrove) which grow - gregariously, especially along the banks of rivers and by - sea-coasts, where the water is quiet and brackish, and where - they form the so-called Mangrove-swamps. Aerial roots are formed - on the stems and branches (Fig. 522 _A_). The seeds germinate - in the fruit, which by arrest contains only one seed (Fig. 522 - _B_), before it is detached from the tree. The radicle projects - considerably from the seed, and hangs down freely in the air; - when the embryo is finally detached from the mother-plant, - the separation is effected by the hood-like cotyledon, which - entirely envelops the plumule, becoming detached from the rest - of the embryo, which falls down, while the hood-like cotyledon - remains enclosed in the fruit. The embryo, after it has fallen, - strikes root, and continues growing in the undisturbed mud - under the trees, or perhaps it may first be drifted about by - the water, being well adapted for this by its peculiar, tough - nature, and large, intercellular spaces.--It may also further - be remarked that the anther is divided into a number of small - loculi. The leaves are stipulate. The endosperm projects from - the micropyle, growing out from the base of the seed, and thus - serves as an organ of suction to convey nutriment to the embryo - from the mother-plant. - - Order 7. =Combretaceæ.= Trees and shrubs, partly lianes. - An inferior, unilocular ovary with few pendulous ovules. - _Conocarpus_ and _Laguncularia_ form, in conjunction with - the species of Rhizophoraceæ, the tropical Mangrove-swamps. - _Terminalia._--280 species; Tropics. - - [Illustration: FIG. 522.--_Rhizophora mangle_ with the germinating - fruit (much reduced).] - -Order 8. =Myrtaceæ (Myrtles).= The plants belonging to this order are -shrubs or trees, the majority being easily recognised by the vegetative -characters. The leaves, for instance, are most frequently opposite, -without stipules, undivided and entire, parchment-like or leathery, -evergreen, _aromatic_, finely dotted by _pellucid glands containing -essential oils_; the venation is penninerved with a nerve just inside -and running parallel to the edge of the leaf. The flowers are regular, -epigynous (Figs. 523, 524, 525) and ☿, most frequently =4-= or 5-merous -in the calyx and corolla, with _many_ stamens (by splitting, so that -they are often in several distinct bundles) and an ovary with one -style, formed of 2–5–many carpels; the receptacle is most frequently -united for its entire length with the ovary. The fruit varies, but is -_most frequently a berry_. The embryo is thick, often curved, with -united cotyledons; no endosperm. - -=1.= MYRTEÆ, MYRTLE GROUP. Chiefly American, though some are found also -in Africa and Asia. The fruit is a _berry_ with generally 2–5 loculi in -the ovary, and many ovules in each.--_Myrtus_; _Eugenia_ (the petals -fall off together as a hood in the Clove, _E. caryophyllata_, Figs. -523, 524); _Myrcia_; _Jambosa_; _Amomis_; _Psidium_, etc. - -=2.= PUNICEÆ, POMEGRANATE GROUP. Only 2 species (_Punica granatum_; -from Persia, Afghanistan), differing in several respects from the -typical form of the Myrtaceæ. The leaves are generally _opposite_, -without glands and marginal veins. The receptacle, calyx and corolla -are red; the latter 5–8–(generally 6-) merous. Calyx valvate and -corolla folded as in Lythraceæ, stamens also and epicalyx as in this -order. The most characteristic feature is the inferior, spherical -berry, with dry pericarp, formed from two whorls of carpels in two -tiers (Fig. 525); the interior whorl, which is also the lower, has -3 carpels, and the placentæ are situated in the inner angles of the -3 loculi; the external whorl is 5-merous, and the placentæ have -originally the same position in the inner angles of the loculi, but -their position is changed to the outer side of the loculi owing to the -growth of the wall of the ovary, which takes place early, causing the -carpels to become, as it were, turned inside out, so that the part -which was turned downwards is turned upwards, and the part which was -turned inwards becomes turned outwards (as in _Mesembrianthemum_). The -edible part of the fruit is the _fleshy testa_, as in _Ribes_. The -cotyledons are rolled together spirally. - - [Illustration: FIGS. 523, 524.--_Eugenia caryophyllata._ - - FIG. 523.--Flowers (nat. size). - - FIG. 524.--A bud (“clove”), long. sec. (mag.).] - - [Illustration: FIG. 525.--_Punica granatum._ Flower, long. sec. - (nat. size).] - -=3.= LECYTHIDEÆ. The majority are South American. The leaves are -scattered, without pellucid glands, and frequently dentate. The flowers -are zygomorphic. The woody fruits are either indehiscent, or open by -a lid. To this belong: _Bertholletia_ (_B. excelsa_), the seeds well -known as “Brazil-nuts,” _Lecythis_ (Sapucaia-nuts from _L. ollaria_), -_Barringtonia_. - -=4.= LEPTOSPERMEÆ. Almost entirely from Australia and the East -Asian and Pacific Islands. The fruit is a _capsule_. The leaves -are scattered, and in some placed edgewise by the twisting of the -leaf-stalks.--_Eucalyptus_, the Australian Gum-tree; the calyx falls -off like a lid (Figs. 526, 527). Some of the species attain gigantic -heights, _E. amygdalina_ 140–150 m. with a diameter of 8 m. The leaves -in _E. globulus_ are opposite and dorsiventral on the young plant; on -the older scattered, placed edgewise by the twisting of the leaf-stalk, -and isolateral; _Metrosideros_, _Calothamnus_ (stamens distinctly -polyadelphous), _Melaleuca_, _Leptospermum_, _Callistemon_ (the flowers -are borne in spikes whose axis continues to grow after flowering, thus -several zones of fruits may be seen on the same branch). - - [Illustration: FIGS. 526, 527.--_Eucalyptus globulus._ - - FIG. 526.--Long. sect. of flower. - - FIG. 527.--Flower opening.] - - -=5.= CHAMÆLAUCIEÆ. Australian shrubs with heath-like appearance; they -differ from the other Myrtaceæ in having a unilocular ovary with few, -basal ovules, and a 1-seeded _nut_. The sepals are often pappus-like, -and divided into many bristles.--_Chamælaucium_, _Darwinia_, etc. - - This large order (2,100 species) is confined almost entirely to - the Tropics, being found principally in America and Australia. - In Europe, only _Myrtus communis_.--Several are useful on - account of the large quantity of _volatile oils_ (contained - in internal glands): the flower-buds (“Cloves”) of _Eugenia - caryophyllata_ (the Moluccas, cultivated in the Tropics, Figs. - 523, 524); the unripe, dry berries (“Pimento”) of _Myrtus - pimenta_ (_Pimenta officinalis_, W. Indies); Cajeput oil is - extracted from _Melaleuca minor_ and _leucadendron_ (East - Asian Islands). _Eucalyptus globulus_ (Australia) has of late - years become well known on account of its rapid growth, its - hard wood, and its antipyretic qualities; it is cultivated on - swampy soils, which it helps to drain.--OFFICINAL: “Cloves,” - and the cork of both stem and root of _Punica granatum_. - Several have EDIBLE FRUITS, such as _Psidium guyava_ (Guava, - var. _pomiferum_ and _pyriferum_, Am.), _Eugenia cauliflora_ - and others, _E. jambosa_, _Punica granatum_ (the Pomegranate), - etc. EDIBLE SEEDS (with abundance of _fatty oil_): “Brazil - nuts” from _Bertholletia excelsa_ (Trop. S. Am.). “Bay-rum” - is extracted from the leaves and fruits of the Bayberry-tree - (_Pimenta acris_, W. Ind.); Guava-rum from the berries of - _Eugenia floribunda_. _Tannin_ is found in large quantities - _e.g._ in _Punica_. _Gum_ is formed by many Australian Eucalypti - (“Gum-trees”). ORNAMENTAL PLANTS cultivated in this country are: - _Myrtus communis_ (Mediterranean), several in conservatories, - especially the Australian Leptospermeæ, Eucalyptæ and others. - - - Family 24. =Umbellifloræ.= - -The flower is regular, ☿, and _completely epigynous_, 5- or 4-merous, -with =1= whorl of stamens and 5–2 carpels. _Sepals very small, -tooth-like._ The _corolla is polypetalous, most frequently valvate in -æstivation_ (least pronounced in the Umbelliferous plants). Round the -base of the styles, which are generally free, there is an _epigynous_ -(undivided, or divided) _nectar-disc_ (“stylar-foot”: Figs. 528 _B_, -_C_, _D_; 539); the number of loculi in the ovary equals that of the -carpels; _only =1= pendulous (anatropous) ovule_ (Fig. 528 _C_) _in -each loculus_. Endosperm copious (Fig. 528 _D_). To this must be added -that the inflorescence in the majority of cases is an _umbel_ or a -capitulum, especially in the _Umbelliferæ_ and _Araliaceæ_. Stipules -are absent, but most frequently the base of the petiole forms a large -sheath. - - The Umbellifloræ are on one side so closely allied to the - Frangulinæ, especially Rhamnaceæ, that they may perhaps be - regarded as the epigynous continuation of this family. On - the other hand, the similarities to the Rubiales, especially - those between Cornaceæ and Sambuceæ, are so great that there - is scarcely any character to distinguish them except the - polypetalous corolla of the former and the gamopetalous corolla - of the latter. Whether this is more than a merely analogous - resemblance, and if not, whether the Cornaceæ at least should - not be included in the Rubiales, must be left in abeyance.--The - sepals are very small, as is generally the case in epigynous - flowers. - -Order 1. =Cornaceæ.= The majority of the species are shrubs with solid -internodes, _opposite_ (rarely scattered) leaves, which are _simple_, -_entire_ (rarely incised), penninerved, _without_ stipules or large -sheaths; flowers _=4=-merous_ (most frequently S4, P4, A4, G2), borne -in dichasia which are either collected into corymbs (_e.g._ _Cornus -sanguinea_), or in closely crowded umbels or capitula (_Cornus mas_, -_C. suecica_), in which latter case there is often a _large_, leafy, or -coloured, most frequently 4-leaved _involucre_ round the base of the -inflorescence; the _style is undivided_, with lobed stigma; the raphe -of the ovule is turned _outwards_. The fruit is a _berry_ or a _drupe_, -with a 1–4-locular stone or 2 free stones. - -_Cornus_ (Dogwood, Cornel) has S4, P4, A4, G2. Leaves opposite. - -_Drupe_ with a bilocular, 2-seeded stone.--_Aucuba_, diœcious; -unilocular ovary; 1 ovule; 1-seeded berry.--_Garrya._--_Helwingia._ - - 80 species; N. Temp. The fruits of _Cornus mas_ are edible; - the wood is very hard; gum is found in some. Several species - of _Cornus_ and _Aucuba japonica_ (Japan) are cultivated as - ornamental shrubs. - -Order 2. =Araliaceæ (Ivies).= Principally _trees_ or _shrubs_ with -_solid stems_. The leaves are _scattered_, simple or compound, with -a sheath more or less developed. The flowers are most frequently -situated in umbels or capitula which are either borne singly or in -racemes, or in paniculate inflorescences. The small, most frequently -yellowish-green flowers are =5=-_merous_, in the calyx, corolla, and -andrœcium; the gynœceum may be 5-merous or may have some other number -(=2=-∞). The styles are most frequently several, free; the _raphe_ -of the ovules is turned _inwards_ as in the Umbelliferous plants. -The fruit is a _drupe_ or _berry_.--~Stellate hairs often occur. The -petals generally have a broad base, and a thick apex which is slightly -incurved, and a distinctly valvate æstivation.~ - -_Hedera helix_ (Ivy) climbs by adventitious roots. The leaves are -palminerved and lobed on the sterile branches, but often ovate and not -lobed on the flowering branches. ~The flowers are yellowish-green and -open in the autumn; they are slightly protandrous, and are visited by -flies and wasps. Berries black. Endosperm ruminate.--_Panax._ _Aralia_ -(with _Dimorphanthus_).~ - - 375 species, 51 genera; especially in the Tropics (E. - Asia).--The Ivy, several species of _Aralia_, _e.g._ _A. - japonica_ (_Fatsia_), _Gastonia palmata_, are cultivated as - ornamental plants. Paper is manufactured from the pith of - _Aralia papyrifera_ (China). - -Order 3. =Umbelliferæ.= _The stem is herbaceous_ with _hollow -internodes_; the leaves are _scattered_, and have a broad, amplexicaul -base, a _large, most frequently inflated sheath_, and generally a -pinnate (often very much dissected) blade. ~Entire leaves are found in -_Hydrocotyle vulgaris_; _Bupleurum_.~ - -The flowers are ☿, regular, small, but collected in _compound umbels_, -that is, in “simple umbels,” which again are borne in umbels (for -exceptions see _Hydrocotyleæ_); the external flowers in the simple -umbel have often subtending bracts, which surround the base as an -_involucre_, and may be termed the _small involucre_; the internal ones -have no bracts; when involucral leaves are present at the base of the -compound umbel, they may be termed the _large involucre_. - - [Illustration: FIG. 528.--_Daucus carota_ with flower and fruit.] - -The _flower_ has =5= sepals (the median, as usual, posterior), =5= -petals, =5= stamens and =2= carpels (in the median line) (Fig. 528). -The calyx is often scarcely indicated. The petals have a short claw -are most frequently obcordate, or have an incurved apex (Fig. 528 _B_, -_C_), being incurved in the bud; they are white, rarely yellow (Fennel -and Parsnips), blue or red. The flowers are sometimes zygomorphic, -especially those on the circumference of the umbel, and in that case -it is the petal which is directed outside (anterior) which is the -largest, and the two posterior are the smallest (_e.g. Heracleum_). -The stamens are _incurved_ in the bud. The 2 _free styles_ unite at -the base into the “stylar-foot” (_stylopod_), a swollen nectary (Fig. -528 _B_, _C_); the ovary is bilocular, the raphe of the ovules being -directed inwards. _The fruit is a schizocarp_, _dividing into two -mericarps_; the plane in which these separate coincides with that of -the union of the carpels, and the two _nut-like mericarps_ are in -most genera kept together for awhile at the top of a thin, bifid, or -undivided stalk (_carpophore_) which is in direct continuation with -the flower-stalk (Fig. 537). Each mericarp has most frequently 5 more -or less strongly projecting ridges, the _primary ridges_ (Figs. 530, -532, 534, 535, etc.), of which 3 lie on the back of the mericarp, the -_dorsal ridges_, and 2 on its edge near the plane of division, the -_marginal ridges_; five of these (10 ridges in all in the entire fruit) -are placed opposite the calyx-teeth and the others between them. In -some genera there are in addition 4 _secondary ridges_ to each mericarp -between the primary ones (Fig. 528 _E_: the secondary ridges bear the -long bristles). Inside these secondary ridges, or inside the grooves -between the primary ridges, when the secondary ridges are absent, _oil -ducts_ (vittæ, schizogenous ducts) are found in the pericarp, most -frequently one in each groove; two are also often found on the ventral -side of each mericarp (Figs. 528 _E_, 530 _ol_, etc.). The seed is -most frequently united with the pericarp. The _embryo_ is _small_ and -lies high up in the large, most frequently horny endosperm (Fig. 528 -_D_).--The endosperm _does not contain starch, but oil_, and presents -three different forms, of important systematic value: (=a=) those which -are quite flat on the ventral side (_i.e._ the side turned towards the -plane of splitting) (Figs. 528 _E_, 530, 531, 534, etc.): the majority -of the genera, ORTHOSPERMEÆ (_e.g._ _Carum_, _Pastinaca_); (=b=) -those in which the endosperm on the ventral side is provided with a -longitudinal groove, often deep: CAMPYLOSPERMEÆ (_e.g._ _Anthriscus_); -the transverse section is nearly a crescent (Fig. 532); (=c=) those -in which the endosperm is concave on the ventral side (hollow in -both longitudinal and transverse sections): CŒLOSPERMEÆ (_e.g._ -_Coriandrum_) (Fig. 538). - - The genera are distinguished first of all by the endosperm and - forms of fruit, the ridges and oil-ducts; then by the form of - the umbel, the calyx and corolla, by the absence or presence of - an involucre, etc. - - [Illustration: FIG. 529.--_Hydrocotyle vulgaris._ Transverse - section of fruit.] - -1. HYDROCOTYLEÆ, PENNY-WORT GROUP. _Capitula_ or _simple umbels_ -(all the other groups have compound umbels). No oil-ducts. -Orthospermous.--_Hydrocotyle_ (Penny-wort). The fruit is _considerably -compressed_ laterally (Fig. 529). The calyx-teeth are small. The leaves -are peltate.--_Didiscus._--_Sanicula_ (Sannicle). The umbels are small, -capitate, generally collected in a raceme; calyx-teeth distinct. ♂-and -♀-flowers in the same umbel. The fruits are round, studded with hooked -bristles. No carpophore.--_Astrantia_ has an umbel surrounded by a -large, often coloured involucre, with this exception it is the same -as the preceding, but the fruit is slightly compressed, with 5 equal -ridges. _Hacquetia_ (_Dondia_).--_Eryngium_ (Sea Holly): leaves often -thorny. The flowers _are all sessile_, the inflorescence is thus a -capitulum; each flower is often subtended by a bract, which is thorny -like the involucre, resembling the burrs of the Teasel. The sepals are -large.--~_Lagœcia_: one of the loculi of the ovary is suppressed.~ - - [Illustration: FIG. 530.--Fruit of _Carum petroselinum_: _fr_ - endosperm; _ol_ oil-ducts.] - - [Illustration: FIG. 531.--_Pimpinella._ Transverse section of - fruit.] - -=2.= AMMIEÆ, CARAWAY GROUP (Figs. 530–532). The fruit has only the 10 -primary ridges; it is usually short, almost spherical or broadly ovate -and distinctly _compressed_ laterally. Oil-canals are most frequently -present. Orthospermous (except _Conium_).--_Cicuta_ (Cow-bane). -Pointed calyx-teeth. Glabrous herbs with pinnate or bipinnate leaves. -~_C. virosa_ has a thick, vertical rhizome, divided by transverse -septa into many compartments; the leaflets are narrow, lanceolate, -and dentate; the large involucre is wanting.~--_Apium_ (Celery). No -calyx-teeth. _A. graveolens_, a maritime plant, has neither large nor -small involucre; the umbels are short-stalked or sessile.--_Carum_ -(Caraway). Calyx-teeth small; the large involucre is wanting or is only -few-leaved. _C. carvi_ (Caraway). _C. petroselinum_, (Parsley) (Fig. -530). _Falcaria_; _Ammi_; _Helosciadium_; _Bupleurum_ (Hare’s-ear) with -simple leaves and yellow corolla; _Pimpinella_ (Fig. 531); _Sium_; -_Ægopodium_ (_A. podagraria_, Gout-weed) has bi- or tri-ternate leaves, -with ovate, dentate leaflets; the large involucre is wanting.--_Conium_ -is campylospermous (Fig. 532); the short, broadly ovate fruit has -distinctly projecting, often wavy crenulate ridges. _C. maculatum_ -(Hemlock) has a round, smooth stem with purplish spots. - - [Illustration: FIG. 532.--_Conium maculatum._ Fruit entire and - in transverse section.] - -=3.= SCANDICEÆ. This group has a distinctly oblong or linear fruit -which is _slightly compressed laterally_, and generally prolonged -upwards into a “beak”; wings absent. _Campylospermous._ Otherwise -as in the Ammieæ.--_Anthriscus_ (Beaked Parsley) has a lanceolate -fruit, round on the dorsal side, without ridges, but with a ten-ridged -beak.--_Scandix_ (Shepherd’s-needle).--_Chærophyllum_ (Chervil): fruit -lanceolate or linear with low, blunt ridges; beak absent or very short. -_C. temulum_ has a red-spotted, hairy stem.--_Myrrhis_ (Cicely) has a -short beak and sharp, almost winged ridges. _M. odorata_ (Sweet Cicely) -has very long fruits. - - [Illustration: FIG. 533.--_Œnanthe phellandrium._ Fruit entire - and in transverse section. _emb_ The embryo; _ol_ the oil-ducts; - _fr_ endosperm.] - - [Illustration: FIG. 534.--_Fœniculum vulgare._ Fruit in - transverse section.] - -=4.= SESELINEÆ, FENNEL GROUP (Figs. 533, 534). The fruit is slightly -elliptical or oblong, in transverse section circular or nearly so, -without grooves in the dividing plane; only primary ridges are -present. Orthospermous.--_Fœniculum_ (Fennel) has yellow petals; both -involucres are wanting; the fruit is oblong. The ridges are thick, all -equally developed, or the lateral ridges are slightly larger (Fig. -534).--_Æthusa_ (_A. cynapium_, Fool’s Parsley); the large involucre -is wanting or is reduced to one leaf, the small involucre is composed -of three linear leaves which hang downwards on the outer side of the -umbels. The fruit is spherical-ovate, with thick, sharp, keeled ridges, -the lateral ones of which are the broadest.--_Œnanthe_ (Dropwort); the -fruit (Fig. 533) has usually an ovate, lanceolate form, with distinct, -pointed sepals and long, erect styles; the ridges are very blunt, the -marginal ones a trifle broader than the others.--_Seseli_, _Libanotis_, -_Cnidium_, _Silex_, _Silaus_, _Meum_, etc. - -=5.= PEUCEDANEÆ, PARSNIP GROUP (Figs. 535–537). The fruit is most -frequently very strongly _compressed_ dorsally, with broad, mostly -_winged_, lateral ridges. Only primary ridges. The dorsal ridges may -project considerably, but are not winged. Orthospermous. - - [Illustration: FIG. 535.--_Archangelica officinalis._ - - Transverse section of fruit.] - - [Illustration: FIG. 536.--_Scorodosma fœtidum._ - - Transverse section of fruit.] - - [Illustration: FIG. 537.--_Heracleum sphondylium._ Fruit.] - -=a.= The winged lateral ridges stand _out from each other_, so that the -fruit appears to be 4-winged (Fig. 535).--_Angelica_; _Archangelica_ -(Fig. 535); _Levisticum_ (Lovage). - -=b.= The winged lateral ridges lie _close together_, and form one -wing on each side of the fruit (Fig. 536).--_Pastinaca_ (Parsnip). -Corolla yellow. The dorsal ridges are very weak; the oil-ducts do not -reach quite as far as the base of the fruit. Both large and small -involucres are wanting; leaflets ovate. _Anethum_ (Dill) is a Parsnip -with more distinct dorsal ridges and filamentous leaflets. _Peucedanum_ -(Hog’s-fennel); _Ferula_ (with _Scorodosma_, Fig. 536, and _Narthex_); -_Dorema_.--_Heracleum_ (Cow-parsnip); the flowers in the margin of the -umbels are often very large, zygomorphic, and project like rays, _e.g._ -in _H. sibiricum_. The fruit is very flat, with very small dorsal -ridges; the oil-ducts are more or less club-like and _do not reach as -far as_ the base of the fruit (Fig. 537). _Imperatoria_; _Tordylium_. - -=6.= DAUCEÆ, CARROT GROUP (Fig. 528). The fruit has 18 ridges, _i.e._ -each fruitlet has 5 primary and 4 secondary ridges, the latter being -often more prominent and projecting further than the primary ones. The -oil-ducts are situated under the secondary ridges (Fig. 528). - -=a.= ORTHOSPERMOUS: _Daucus_ (Carrot). The secondary ridges project -much further than the primary, and bear on their crests a series of -hooked spines (Fig. 528 _D_, _E_); these are much longer than the -small bristles on the primary ridges. ~The involucral leaves of _D. -carota_ (Carrot) are numerous and deeply pinnate; the inflorescence -contracts during the ripening of the fruit, and since the external -umbels have longer stalks than the central ones, they arch over them, -and the inflorescence becomes hollow. For the terminal flower, see -below.~--_Cuminum_; _Laserpitium_; _Melanoselinum_. - -=b.= CAMPYLOSPERMOUS: _Torilis_ (Hedge Parsley). The primary ridges -are covered with bristles; the secondary ridges are not. very distinct -on account of the spines, which entirely fill up the grooves. -_Caucalis_ (Bur Parsley). - - [Illustration: FIG. 538.--_Coriandrum sativum_: _b_ secondary - ridges; _d_ primary ridges; _f_ endosperm; _l_ embryo.] - -=c.= CŒLOSPERMOUS: _Coriandrum_ (Coriander) has a smooth, spherical -fruit (Fig. 538) with a distinct, 5-dentate calyx, the two anterior -(_i.e._ turned outward) teeth being generally longer than the others; -the two fruitlets scarcely separate from each other naturally; all the -ridges project only very slightly, the curved primary ones least, the -secondary ridges most. - - POLLINATION. The flowers are adapted for insect-pollination; - they secrete nectar at the base of the styles; individually - they are rather small and insignificant, but yet are rendered - conspicuous by being always crowded in many-flowered - inflorescences. _Protandry_ is common, sometimes to such - an extent that the stamens have already fallen off before - the styles begin to develop (Fig 539, 2). Insect visits are - more frequent and numerous as the inflorescences are more - conspicuous. The flowers as a rule are ☿, but ♂-flowers are - often found interspersed among the others (Fig. 539), and the - number of these becomes greater on the umbels developed at the - latest period. A terminal flower, which differs from the others - in form, and in _Daucus carota_ often in colour also (purple), - is sometimes found in the umbel. The nectar lies so exposed and - flat that the flowers are principally visited by insects with - short probosces, especially Diptera; bees are less frequent - visitors, and butterflies rare.--1400 species (175 genera); - especially from temperate climates in Europe, Asia, N. Am. About - 68 species in this country. - - [Illustration: FIG. 539.--_Anthriscus silvester_: 1 ♂-flower; 2 - ☿-flower.] - - USES. A few are cultivated as ornamental plants. They are, - however, useful in medicine,[38] and for culinary purposes - on account of the _essential oils_ and _gum-resins_ which - in many are formed in root, stem, and fruit. The FRUITS of - the following are used: _Carum carvi_ [+] (Caraway), _Carum - petroselinum_ (Parsley; also the leaves and root; its home - is the Eastern Mediterranean); _Fœniculum capillaceum_ [+] - (Fennel; S. Europe); _Pimpinella anisum_ [+] (Anise; E. - Mediterranean); _Coriandrum sativum_ [+] (Coriander; S. Eur.); - _Œnanthe phellandrium_ (Water Dropwort); _Cuminum cyminum_ - (Point Caraway; Africa; cultivated in S. Europe); _Anethum - graveolens_ (Dill). The LEAVES of the following are used as - pot-herbs: _Anthriscus cerefolium_ (Chervil); _Myrrhis odorata_ - (Sweet Cicely; Orient.); _Conium maculatum_ [+] (the green - portions; Hemlock). Besides Parsley, the ROOTS of the following - are used: Carrot, Parsnip, _Sium sisarum_ (Sugar-root; E. Asia); - _Chærophyllum bulbosum_ (Chervil-root); _Levisticum officinale_ - (foliage-shoots; S. Europe); _Imperatoria ostruthium_; - _Apium graveolens_ (Celery, the root in conjunction with the - internodes); _Pimpinella saxifraga_ and _magna_ (Pimpinell); - _Archangelica_ (Angelica, the root of _A. norvegica_ was - formerly an article of food in Norway). _Poisonous alkaloids_ - are found in a few, such as Fool’s Parsley (_Æthusa cynapium_), - Hemlock (_Conium maculatum_), Cow-bane (_Cicuta virosa_) - and species of _Œnanthe_.--_Gum-resin_ is extracted from - various species: “Galbanum” from _Ferula galbaniflua_ [+] and - _rubricalis_ [+] (Persia); Asafœtida from _Ferula scorodosma_ - [+] and _F. narthex_ [+]; Ammoniac-gum from _Dorema ammoniacum_ - [+], all from Central and S. W. Asia. “_Silphium_” was an - Umbelliferous plant which grew in ancient times in Cyrene, and - from which the Romans extracted a valued condiment. - - - Family 25. =Hysterophyta.= - -This family (with the exception of Aristolochiaceæ) includes only -parasitic plants. Partly on this ground, and partly because they -all have _epigynous_ flowers, they are considered to belong to the -youngest type (which is expressed in the name ὕστερος, the one that -comes after). It is not certain to which of the preceding families they -are most nearly allied. ~Again, it is a matter of doubt whether the -Aristolochiaceæ are related to the others; they are by Engler united -with Rafflesiaceæ into one family, _Aristolochiales_.~ - - [Illustration: FIG. 540.--Flower of _Aristolochia clematitis_ - (long. sect.). _A_ Before pollination, and _B_ after: _n_ stigma; - _a_ anthers; _t_ an insect; _kf_ ovary.] - -Order 1. _Aristolochiaceæ._ The majority are perennial herbs or -twining shrubs, whose stalked, simple, and generally more or less -cordate or reniform leaves are borne in 2 rows and are exstipulate. -The flowers are _hermaphrodite_, _epigynous_, regular or zygomorphic; -perianth-leaves united, _simple_ but most frequently _petaloid_ and -3-merous; 6 or 12 (in _Thottea_ as many as 36) stamens with _extrorse_ -anthers. The ovary is more or less completely 4–6-locular with ovules -attached in the inner angles of the loculi (Fig. 540 _kf_). The style -is short, and has a large, radiating stigma (Fig. 540 _n_). Fruit a -capsule. Seeds rich in endosperm. - -_Asarum europæum._ Each shoot has 2 reniform foliage-leaves, between -which the terminal flower is borne (the rhizome becomes a sympodium -by development of the bud in the axil of the upper foliage-leaf). -The flower is _regular_ and has a bell-shaped perianth with 3 outer -valvate, and 3 inner small segments (which may be wanting). =12= (2 -× 6) free, extrorse stamens, 6 carpels.--_Aristolochia clematitis_ -(Birth-wort) has an erect, unbranched stem, bearing many flowers in the -leaf-axils, in a zig-zag row (accessory buds in a unipared scorpioid -cyme). The flowers are zygomorphic (Fig. 540), formed by 3 alternating, -6-merous whorls. The perianth has a lower, much-distended part (_k_), -succeeded by a narrow, bent tube (_r_), which passes over into an -oblique, almost tongue-like projection (6 vascular bundles indicate -that the number 6 is prevalent here, as in _Asarum_); =6= stamens (Fig. -540 _a_), with the dorsal portion turned upwards, are united with the -short style to form a _stylar column_; they are placed quite beneath -the 6 commissural stigmatic rays, which arch over them as short, thick -lobes. ~Protogynous; POLLINATION is effected in _Arist. clematitis_ -by small flies; these enter the erect unfertilised flower through -the tube (Fig. 540 _A_, _l_) without being prevented by the stiff, -downwardly-turned hairs which line the tube and prevent their escape; -they find the stigma (_n_) fully developed, and may pollinate it with -the pollen they have brought with them. The stigmas then straighten -and wither (_B_, _n_), the anthers open, and the flies may again be -covered with pollen; but the hairs which blocked up the tube do not -wither until the anthers have shed their pollen, and only then allow -the imprisoned flies to escape and effect cross-pollination. Prior to -pollination, the flowers stand erect, but after this has taken place -they become pendulous, and the perianth soon withers.--_A. sipho_ -(Pipe-flower), another species, is a climber, and often grown in -gardens; it has only one row of accessory buds in the leaf-axils.--200 -species; chiefly in S. Am. OFFICINAL: the rhizome of _Aristolochia -serpentaria_ (N. Am.).~ - - [Illustration: FIG. 541.--A fruit of _Myzodendron brachystachyum_ - (slightly mag.) germinating on a branch.] - -Order 2. =Santalaceæ.= Parasites containing chlorophyll, which, by -the help of peculiar organs of suction (haustoria) on their roots, -live principally on the roots of other plants. Some are herbs, -others under-shrubs. The regular, most frequently ☿-flowers have -a simple perianth, which is gamophyllous, 3- or 5 partite with the -segments valvate in the bud, and a corresponding number of stamens -opposite the perianth-leaves. In the inferior ovary there is a -_free, centrally placed_, often long and curved _placenta_ with -three ovules (one opposite each carpel); these are naked, or in any -case have an extremely insignificant integument. Fruit a nut or -drupe. Seed without testa. Endosperm fleshy. 225 species; chiefly -in the Tropics.--_Thesium_, a native, is a herb with scattered, -linear leaves and small 5-merous flowers (P5, A5, G3) in erect -racemes; the subtending bracts are displaced on the flower-stalks. -Fruit a nut.--_Osyris_ (diœcious shrub; 3-merous flowers) is -another European genus.--_Santalum album_, which grows in E. Ind., -yields the valuable, scented Sandalwood, the oil of which is used -medicinally.--_Quinchamalium._ - - _Myzodendron_ is a reduced form of the Santalaceæ; the ♂-flowers - are without perianth; the perianth of the ♀-flower is 3-merous. - About 7 species; S. Am.; parasitic on a Beech (_Nothofagus_). - The fruit has 3 feathery brushes, alternating with the lobes - of the stigma, which serve as flying organs and to attach the - fruits to a branch (Fig. 541), the brushes twining round as - soon as they come in contact with it. There is only 1 seed in - the fruit, which germinates by a long, negatively heliotropic - hypocotyl, and is attached by a radicle modified into an - haustorium. - -Order 3. =Loranthaceæ= (=Mistletoes=). Plants containing chlorophyll -which are parasites on trees, and most frequently have opposite, -simple, entire leaves and regular, epigynous, often unisexual, 2- or -3-merous flowers, with single or double perianth. Stamens equal in -number and opposite to the perianth-leaves, free, or in varying degrees -united to one another. The inferior ovary is constructed as in the -Santalaceæ, the ovules being situated on a low, free, centrally-placed -placenta, but the placenta and ovules unite with the wall of the ovary -into _one connected, parenchymatous mass_, in which _the embryo-sacs -are imbedded_. Only 1 (less frequently 2–3) of the 1–6 embryo-sacs -is fertile. The number of the carpels however varies. The fruit is a -_1-seeded berry_, whose inner layer is changed into a _tough slimy -mass_ (bird-lime), which serves to attach the fruits to other plants. - - The two groups, _Loranthoideæ_ and _Viscoideæ_, are - distinguished by the fact that the former has a distinct - “calyculus,” _i.e._ an entire or lobed, or dentate swelling - on the receptacle below the perianth. The majority of the - Loranthoideæ have a petaloid perianth; in all the Viscoideæ, on - the other hand, it is sepaloid. - - [Illustration: FIG. 542.--_Viscum album_: _A_ branch with leaves - and berries: _a_ scale-leaves; _b_ foliage-leaves; _n_ _m_ _n_ - flowers; _B_ seedling, the bark of the branch being removed; _C_ - an older embryo which still retains the cotyledons.] - - [Illustration: FIG. 543.--To the left the Rafflesiaceous _Cytinus - hypocistus_, parasitic on the roots of _Cistus_. To the right the - Balanophoraceous _Cynomorium coccineum_, parasitic on the roots - of _Salicornia_.] - -The Mistletoe (_Viscum album_, Fig. 542) is a native, evergreen plant -which may be found growing on almost any of our trees (sometimes on -the Oak), and, like other Loranthaceæ, it produces swellings of the -affected branches. ~Its spherical white berries (Fig. 542 _A_) enclose -(1–) 2–3 green embryos; they are eaten by birds (especially Thrushes), -and are partly sown with their excrement, partly struck or brushed -off the branches of the trees, the seed being enclosed, at maturity, -by viscin, _i.e._ “bird-lime.” The seeds may also germinate on the -branches, without having first passed through the alimentary canal -of the birds. On germination, the hypocotyl-axis first appears, as -in Fig. 541, and bends towards the branch; the apex of the root then -broadens, and forms at the end a disc-like haustorium, from the centre -of which a root-like body grows through the bark into the wood, and -ramifies between the bark and wood. Suckers are developed on the root -like strands which are formed in this manner, without, however, having -a rootcap; they are green, and penetrate the wood by the medullary -rays (Fig. 542 _C_). Adventitious buds may also be developed from the -root-like strands which break through the bark and emerge as young -plants. The young stem quickly ceases its longitudinal growth, and -lateral shoots are developed from the axils of its foliage-leaves. -These and all following shoots have a similar structure; each of -them bears a pair of scale-leaves (Fig. 542 _A_, _a_) and a pair -of foliage-leaves (Fig. 542 _A_, _b_), and then terminates its -growth, if it does not produce an inflorescence; new lateral shoots -proceed from the axils of the foliage-leaves, and the branching, in -consequence, is extremely regular and falsely dichotomous. Only one -internode (shoot-generation) is formed each year, so that each fork -indicates one year. The foliage-leaves fall off in the second year. -The inflorescence is a 3(-5)-flowered dichasium (Fig. 542 _A_, _m_ is -the central flower, _n_ the lateral). The plants are _diœcious_; the -♂-flower as a rule is 2-merous: perianth 2 + 2, each leaf of which -bears on its inner side 6–20 pollen-sacs, each of which opens by a -pore; this relationship may be considered to have arisen from the union -of the perianth-leaves with the multilocular stamens (2 + 2) placed -opposite them. The ♀-flowers always have Pr 2 + 2, G2.--_Loranthus_ -is also found in Europe (it has a 3-merous flower), especially in -the central and south-eastern districts, on _Quercus cerris_ and _Q. -pubescens_; but the great majority of the 520 species grow in the -Tropics on trees which they ornament with their often brightly-coloured -flowers, and ultimately kill when present in too great numbers. The -pollination in the numerous Loranthaceæ with unisexual flowers, is -effected by the wind. In _Viscum album_ this takes place in autumn, -the actual fertilisation in the following spring, and the maturity in -November or December; in the succeeding month of May the berry is ready -to germinate, and falls off.~ - - USES. Birdlime from _Viscum album_. - - Order 4. =Rafflesiaceæ= and Order 5. =Balanophoraceæ=. - These orders comprise _root-parasites_, almost entirely - devoid of chlorophyll; they are reddish or yellow, without - foliage-leaves (Fig. 543). As far as our knowledge of these - rare tropical plants extends, they have thalloid organs of - vegetation resembling the root-like strands of _Viscum_, or - they are filamentous and branched like Fungus-hyphæ; they live - in and on the tissues of the host-plant, from which their - flowering-shoots, often of mushroom-like form, are subsequently - developed (Fig. 543). In order to unfold they must often break - through the tissues of the host-plant. - - Of the RAFFLESIACEÆ, _Cytinus hypocistus_ is found in S. Europe - living on roots of _Cistus_-plants and to some extent resembling - _Monotropa_ (Fig. 543). _Rafflesia_ is the best known; it lives - on roots of _Cissus_-species (belonging to the Ampelidaceæ) in - Java; its yellowish-red, stinking flowers attain a gigantic - size (one metre or more in diameter), and are borne almost - directly on the roots of the host-plant. Besides these there - are other genera: _Brugmansia_, _Pilostyles_, _Hydnora_.--To - BALANOPHORACEÆ (Fig. 543) belong: _Balanophora_, _Langsdorffia_, - _Scybalium_, _Sarcophyte_, _Helosis_, etc., and in S. Europe, - _Cynomorium coccineum_. - - - Sub-Class 2. =Sympetalæ.= - -The characters which separate this from the first Sub-class, the -Choripetalæ, have been described on page 336. They consist in the -following: the flower is always verticillate, generally with =5= -sepals, =5= petals, =5= stamens, and =2= carpels (in the median plane), -the calyx is generally persistent and gamosepalous, the corolla is -gamopetalous and united to the stamens, which are therefore adnate to -it, the ovules have only _one_ thick integument and a small nucellus. -(The exceptions are noted later.) - - This Sub-class is no doubt more recent than the Choripetalæ; it - is also peculiar in including fewer trees and shrubby forms than - the latter. - -The Sympetalæ may be separated into 2 sections:-- - -=A.= PENTACYCLICÆ (FIVE-WHORLED). The flowers in this section have -5 _whorls equal in number_, namely, 2 staminal whorls in addition -to the calyx, corolla, and carpels; in some instances, one of the -staminal whorls is rudimentary or entirely suppressed, but in this -case it is frequently the sepal-stamens which are suppressed, and -the whorl which is present stands opposite the petals. The flowers -are regular. The _number of carpels equals that of the sepals_, but -in one of the orders (_Bicornes_) they are opposite the petals (the -flower being obdiplostemonous); in the other two orders (_Primulinæ_ -and _Diospyrinæ_) they are placed opposite the sepals (the flower -being diplostemonous). This section is the most closely allied to the -Choripetalæ, since the petals may sometimes be found entirely free, -and the stamens inserted directly on the receptacle (Ericaceæ); ovules -with two integuments are also found. ~It is very doubtful, whether the -orders included under this head have any relationship with the other -Sympetalæ. They appear in any case to represent older types.~ - -=B.= TETRACYCLICÆ (FOUR-WHORLED). The flowers have only 4 whorls, -namely, beside sepals, petals, and carpels, only one whorl of stamens, -which alternates with the petals; there is no trace of the second -staminal whorl, and when the number of carpels is the same as that of -the preceding whorls (“isomerous”) they alternate with the stamens; but -in most cases there are 2 _carpels placed in the median plane_ (see the -diagrams, _e.g._ Figs. 559, 567, 583, 590, etc.). This section is the -largest, and the one which shows the characteristics of the Sympetalæ -best. Very irregular flowers are met with. - -The following families belong to the =Pentacyclicæ=: 26, _Bicornes_; -27, _Diospyrinæ_; 28, _Primulinæ_. - -The remaining families belonging to the =Tetracyclicæ= are:-- - -=a.= HYPOGYNOUS flowers (with a few exceptions): 29, _Tubifloræ_; 30, -_Personatæ_; 31, _Nuculiferæ_; 32, _Contortæ_. - -=b.= EPIGYNOUS flowers: 33, _Rubiales_; 34, _Dipsacales_; 35, -_Campanulinæ_; 36, _Aggregatæ_. The ovaries and ovules in the last -family are always reduced to one; and at the same time the fruits -become nuts, and the flowers are united into crowded inflorescences. - - - - - A. Pentacyclicæ. - - - Family 26. =Bicornes.= - -This family is chiefly composed of shrubs, less frequently of small -trees, or perennial herbs; their leaves are undivided, most frequently -evergreen, stiff and leathery, and always without stipules. The flowers -are ☿ and _regular_, rarely slightly zygomorphic, most frequently -obdiplostemonous, and 4- or 5-merous through all the 5 whorls. _The -stamens are attached to the receptacle_, and as a rule are quite -free from the petals, an attachment which is very rare among the -Gamopetalæ. They have a simple gynœceum with _one_ undivided style, a -commissural stigma, and a _multilocular_ ovary, whose axile placentæ -project considerably into the loculi, and bear a large number of -ovules. ~The placentæ are sometimes not united, and in consequence, the -ovary is 1-locular with incomplete partition-walls, _e.g._ _Pyrola_, -_Monotropa_.~ Embryo straight, with endosperm. _The carpels are placed -opposite the petals._ - -The _diagram_ is generally Sn, Pn, An + n, Gn, in which n is 4 or 5. To -this may be added, that the _corolla is in most cases gamopetalous_, -but in some (especially _Pyrolaceæ_) perfectly polypetalous; and that -the _anthers usually open by pores_, and often have _two horn-like_ -appendages (hence the name “Bicornes”) (Figs. 545, 546); frequently -the two halves of the anther are also widely separated from each other -at the upper end, so that the pores are placed each one at the end of -its own tube (Fig. 546); the pollen-grains in the majority are united -into _tetrads_ (Fig. 542 _D_).--The flowers, as a rule, are pendulous -and borne in racemes, coloured (red or white), but odourless. When the -fruit is a capsule, the placenta with the seeds attached persists as a -central column. A _mycorhiza_ occurs on many. - -The majority of plants belonging to this family inhabit cold and -temperate countries, or high mountains in tropical regions; they prefer -cold and dry or damp places (bogs, heaths, etc.). Plentiful in N. -America. - -Order 1. =Pyrolaceæ.= Perennial _herbs_; _petals most frequently -quite free from each other_, and falling off singly after flowering; -_the anthers are without appendages_, and open by pores (Fig. 544), -or by a transverse slit. The placentæ are thick. The seeds in the -_capsule-like_ fruit (loculicidal dehiscence) are exceedingly small and -light, they have a sac-like testa which loosely envelops them, an oily -endosperm, and an _extremely simple embryo_, which consists only of an -ellipsoidal, cellular mass, without cotyledons or differentiation into -plumule and radicle. - -_Pyrola_ (Winter-green) is green, and has also large evergreen -foliage-leaves. The flowers, 5-merous, are most frequently borne in -racemes without a terminal flower; the anthers are extrorse in the bud -with the pores in the lower portion (Fig. 544 _A_), but they become -inverted at a later period, so that the pores open at the top (Fig. -544 _C_). ~_P. uniflora_ has a single, terminal flower; it winters by -its roots, producing from these in the spring aerial, quite unbranched -shoots. _Chimaphila umbellata._~ - - [Illustration: FIG. 544.--_Pyrola minor_: _A_ portions of a - young flower; _B_ the stigma; _C_ portions of an older flower - (longitudinal section).] - -_Monotropa_ (Yellow Bird’s-nest) is very pale yellow, without -chlorophyll, succulent, and has only scale-like leaves closely pressed -upon the stem; it is a saprophyte. The raceme has a terminal flower, -and is pendulous before flowering. The anthers open by a semicircular, -transverse cleft. ~_M. hypopitys_ reproduces chiefly by root-shoots.~ - - About 30 species, especially N. Europe, N. America, and N. Asia. - -Order 2. =Ericaceæ.= The flower (Fig. 545) is _hypogynous_, the median -sepal posterior; corolla, _gamopetalous_; the stamens are generally -_2-horned_, and the fruit is a _capsule_, less frequently a berry or -drupe. At the base of the ovary is a nectar-secreting disc (Fig. 545 -_B_). This order comprises shrubs or undershrubs (rarely small trees), -which are evergreen, and as a rule have densely crowded leaves. - -=1.= ERICEÆ, HEATH GROUP. Flowers most frequently _4-merous_ (S4, -P4, A4 + 4, G4, united in a 4-locular gynœceum), rarely 5-merous. -The withered corolla _persists_ after flowering. The leaves are most -frequently acicular, opposite or verticillate; the buds are without -scales. The fruit is a capsule.--_Calluna_ (_C. vulgaris_, Ling) has -a deeply 4-cleft corolla, which is less than the coloured calyx; -capsule with septicidal dehiscence.--_Erica_ (about 420 species; _E. -tetralix_, Cross-leaved Heath) has a tubular or bell-shaped, 4-dentate -corolla, which is much longer than the calyx. Capsule with loculicidal -dehiscence.--_Pentapera._ - -=2.= ANDROMEDEÆ. The flowers are 5-merous (S5, P5, A5 + 5, G5), -with _deciduous_ corolla. Capsule with loculicidal dehiscence. The -leaves are scattered, and incline more to the ordinary broad-leaved -forms.--_Andromeda_; _Gaultheria_; _Cassandra (Lyonia)_; _Cassiope_. - - [Illustration: FIG. 545.--_Arctostaphylos uva-ursi._] - -=3.= ARBUTEÆ. The flowers as in the preceding group (Fig. 545), but the -fruit is a berry or drupe. _Arctostaphylos_ (_A. uva-ursi_, Bear-berry) -has a drupe with 5 stones in a dry, farinaceous pulp; in other -species there is 1 stone with several loculi. _Arbutus_ (_A. unedo_, -Strawberry-tree) has a spherical berry. - - _Pollination_ is effected by means of insects, especially by - bees. The pollen is light and dry, and is shaken out through - the pores of the anthers when the insects agitate the horn-like - appendages during their visits. Self-pollination takes place, - no doubt, in many cases.--800 species; the very large genus, - _Erica_, especially in S. Africa (the Cape).--OFFICINAL: the - leaves of _Arctostaphylos uva ursi_. _Arbutus unedo_ (S. Europe) - has an edible, peculiarly warted (strawberry-like) fruit. Many - _Erica_-species are cultivated as ornamental plants. - -Order 3. =Rhodoraceæ= (=Rhododendrons=). This differs from the -preceding order in the _median sepal being anterior_, and hence the -position of the other floral whorls is also reversed. The flower is -_hypogynous_, in most cases 5-merous; the corolla is most frequently -deeply cleft or polypetalous, and falls off after flowering; the -anthers open by pores, and have _no horn-like appendages_. _Capsule_ -with _septicidal_ dehiscence.--The shrubs or small trees belonging to -this order have, like the Vaccineæ, ordinary foliage-leaves, and the -buds are generally provided with _large bud-scales_. - -_Rhododendron_ has 10 stamens, and a slightly zygomorphic flower with -deeply 5-cleft corolla (the section _Azalea_ has frequently only 5 -stamens, the petal-stamens being absent). They are Alpine plants (200 -species) in the mountains of Asia, especially the Himalayas; some in -S. Europe.--_Menziesia._--_Ledum_; small, rusty-brown, hairy shrubs -with polypetalous, expanded, star-like corolla.--_Kalmia_ (N. Am.) has -a cupular corolla, with 10 small, pocket-like depressions in which -the anthers are concealed until the arched, elastic filaments are -freed from this position by means of the insects, when they quickly -straighten themselves in the centre of the flower.--_Phyllodoce_; -_Loiseleuria_ (5 stamens); (_Clethra_ (?); also placed among the -Ternstrœmiaceæ). - - About 270 species. Several species are ornamental plants. - Several plants of the order are more or less _narcotic_. _Ledum - palustre_ has been used as a substitute for hops. - - Order 4. =Diapensiaceæ.= Hypogynous flower. 3 floral-leaves - beneath the flower (S5, P5, A5 + 0, G3). Stamens on the throat - of the corolla. Pollen-grains single. Disc absent. Capsule - loculicidal.--9 species from the Arctic regions. It is doubtful - whether this order should be included in the Bicornes; perhaps - it would be more correctly assigned to the _Polemoniaceæ_. - - Order 5. =Epacridaceæ.= This order comprises those species of - the family which are confined to Australia and the South Sea - Islands. They are shrub-like plants, resembling the Ericaceæ in - habit, in the inflorescence, and in the structure, form, and - colour of the flower. They differ especially in having only - 1 _whorl of stamens_ (placed opposite the sepals) and in the - anthers having only 2 loculi, and opening by a longitudinal - slit. Fruit most frequently a drupe (or loculicidal capsule). - _Epacris_-and _Styphelia_-species are ornamental plants. About - 325 species. - -Order 6. =Vacciniaceæ= (=Bilberries=). _The flower_ (Fig. 546) _is -epigynous, the corolla gamopetalous_, and _the fruit a berry_. The -latter is most frequently spherical, and bears on its apex the calyx, -which is generally very low, almost entire, and with a _disc-like -expansion_ inside. The flower is 4- or 5-merous (Fig. 546 _B_, _D_). The -anthers have 2 pores, and are most frequently 2-horned (Fig. 546 _F_, -_G_). Small shrubs; the leaves are scattered, not needle-like. - -_Vaccinium_ (Bilberry, Whortleberry) has an urceolate, gamopetalous, -only slightly dentate corolla, and horn-like appendages to the anthers -(Fig. 546). ~_V. vitis idæa_ (Cowberry) is evergreen, with flowers in -racemes, and bright red berries; _V. myrtillus_ (Bilberry) and _V. -uliginosum_ (Bog Whortleberry) both have black berries with a blue -bloom, leaves deciduous.~--_Oxycoccus_ has a _polypetalous_ corolla -with the petals projecting backwards. Anthers without appendages. ~_O. -palustris_ (Cranberry) has a slender, creeping stem, and is evergreen. -Dark red berry.~ - - Pollination essentially the same as the preceding order.--320 - species; especially in N. Am. Some are useful on account of - their edible fruits, especially _Vaccinium myrtillus_ and _V. - vitis-idæa_, and in a less degree _Oxycoccus_, etc. The fruits - of _V. myrtillus_ are _officinal_. - - [Illustration: FIG. 546.--_Vaccinium uliginosum_ (var. - _microphyllum_). The parts of the flower _A-E_ are enlarged 5–6 - times; _C_ and _E_ are longitudinal sections; _B_ and _D_ the - flower seen from above; _F_ and _G_ a stamen seen from the back - and front; _H_ the style and stigma.] - - - Family 27. =Diospyrinæ.= - -The flowers are _regular_, gamopetalous, typically diplostemonous, -with the same number throughout all 5 whorls, thus: Sn, Pn, An + n, -Gn, where n most frequently =5 (4–6), rarely 3, 7 or 8. Of the two -whorls of stamens the one opposite the sepals is often present only -as rudiments or is entirely suppressed, and the completely developed -_stamens are thus placed opposite the petals_. The carpels are -generally placed opposite the sepals. The _ovary is multilocular_ with -the ovules attached in the inner angles. The fruit is most frequently -a _berry_. The seeds are large, generally solitary, or a few in each -loculus.--All plants belonging to this family are _trees_ or shrubs -with _scattered_, _single_, _most frequently entire_, _penninerved_ and -_leathery_ leaves without stipules; the majority are tropical (America, -Asia), some are found in N. Am. and the Mediterranean. - - Order 1. =Sapotaceæ.= Plants with latex; anthers extrorse, 1 - _erect_ ovule in each loculus; fruit a berry; the seeds with - bony, shiny brown testa have a large, lateral hilum. The leaves - are frequently covered with silky hairs.--A useful order in - several respects (400 tropical species). The wood of some - genera, such as _Sideroxylon_ (Iron wood) and _Bumelia_, is as - hard as iron. The latex of _Palaquium_ (_P. oblongifolium_, _P. - gutta_, and other species), _Mimusops_ and _Payena_ (Sumatra, - E. Ind.), is the raw material of _gutta percha_. The following - have very delicious fruits: _Lucuma mammosa_, _Achras sapota_, - _Chrysophyllum cainito_ (Star-apple), etc. The seeds of _Bassia_ - (E. Ind.) contain a large quantity of a fatty oil. _Isonandra_, - _Mimusops schimperi_ are often found in the Egyptian royal tombs. - - Order 2. =Ebenaceæ.= Plants without latex, often diœcious; - flowers with a more or less leathery perianth. The number of - stamens is sometimes increased (by splitting?); ovules 1–2, - _pendulous_ in each loculus. Fruit a berry.--250 species; - chiefly tropical. Some are well known on account of their - hard and black-coloured heart-wood, _e.g._ _Maba ebenus_ (the - Moluccas) and _Diospyros ebenum_ (Ebony-wood, from Tropical - Asia) and others.--The fruits are edible _e.g._ of _Diospyros - lotus_ (Date-plum, Asia), which is also cultivated as an - ornamental shrub, together with several other species. - - Order 3. =Styracaceæ.= The flower is more or less _epigynous_, - and the corolla is almost _polypetalous_. The stamens (by - splitting?) are more than double the number of the petals, and - often united at the base. Stellate hairs are frequent.--235 - species; Tropical Asia and America, a few for example in the - East.--OFFICINAL: Gum-benzoin from _Styrax benzoin_ and perhaps - other species (Sumatra and Siam). _Halesia tetraptera_ (N. Am.) - is an ornamental shrub with 4-winged fruits. - - [Illustration: FIG. 547.--Diagram of _Primula_.] - - - Family 28. =Primulinæ.= - -The flowers are _regular_, ☿, _hypogynous_, and gamopetalous. The -_stamens_ are _equal in number_ to the petals (Fig. 547) and _are -placed opposite to them_. The ovary is _unilocular_, with _a free, -central_ placenta with 1–many ovules.--The flower is a further -development of the Diospyrinæ; the suppression of the calyx-stamens, -which commenced in this family, is carried further in the Primulinæ, -so that in the majority of cases no trace of them is present, but -in certain species and genera (_Samolus_, _Lysimachia thyrsiflora_, -_Soldanella_, certain Myrsineæ) some small bodies (scales, teeth, -etc.) are found in the position of the suppressed stamens. Again, the -lateral portions of the carpels are suppressed, so that the _ventral -placentæ_ with the ovules are separated from the dorsal portions, and -_are united into a free central placenta_; this theory is supported by -the branching of the vascular bundles, the development, and various -comparative considerations.--Sn, Pn, A0 + n, Gn; where n = 4–8, -generally 5. The carpels are placed opposite the sepals (Fig. 547). - -Order 1. =Primulaceæ= (=Primroses=). This order has _many ovules_ -attached to a _thick, free, central placenta_ (Fig. 547); _style -undivided_ with a _capitate_ stigma; ovules semi-anatropous; fruit a -_capsule_ with many seeds. - -All the plants belonging to this order are _herbs_; stipules wanting; -the flower is most frequently 5-merous (S5, P5, A0 + 5, G5; except -_Centunculus_ and _Trientalis_). The corolla and capsule have various -forms, but the capsule generally opens by teeth at the apex. The ovules -are semi-anatropous (in _Hottonia_ they are anatropous), and the seeds -are therefore _peltate_, with the hilum situated in the centre of one -side. The endosperm is fleshy or horny. The flowers are borne either in -racemes or in umbels; as _bracteoles are typically_ absent (Fig. 547), -cymose branching does not occur. - - [Illustration: FIG. 548.--_Primula_: dimorphic flowers. _A_ - short-styled; _B_ long-styled.] - - [Illustration: FIG. 549.--_Cyclamen persicum._] - -_Primula_ (Primrose) has most frequently a vertical rhizome, bearing -a rosette of leaves at its summit, and long-stalked umbels; corolla -_rotate_ or slightly funnel-shaped; the capsule opens at the apex by 5 -_teeth_. The flowers in some species are heterostyled (long-styled or -short-styled; Fig. 548). Closely allied are _Androsace_ (with ovate, -cup-shaped corolla-tube and ligular scales, alternating with the -corolla-lobes) and _Soldanella_ (funnel-shaped corolla with laciniate -lobes and most frequently ligular scales).--_Hottonia_ (Water-Violet) -is an aquatic plant with pectinate leaves and heterostyled -flowers.--_Cortusa._ _Dodecatheon._ _Cyclamen_ (Fig. 549) has solitary, -long-stalked flowers, and a rotate corolla with the lobes reflexed; the -stalk of the capsule rolls up spirally; the tuberous rhizome is formed -by the hypocotyledonary internode. Only 1 cotyledon.--_Lysimachia_ -(Money-wort); stem-internodes well developed, leaves opposite or -verticillate, calyx almost polysepalous, corolla deeply 5-partite (Fig. -550). The flowers are solitary or in racemes.--_Anagallis_ (Pimpernel), -leaves opposite, flowers solitary; the fruit a pyxidium (Fig. 551); -similarly in _Centunculus_, which is 4-merous.--_Trientalis_, the -flowers are most frequently 7-merous.--_Glaux_ (Sea Milk-wort) is a -creeping maritime plant with opposite leaves; flowers solitary in the -leaf-axils, _corolla absent_, but with coloured calyx. ~The petals are -usually developed later than the stamens in the Primulaceæ; but in -this instance they are entirely suppressed.~--_Samolus_ (Brookweed) -differs from all the others in having an _epigynous_ flower; -barren sepal-stamens are also present. The bracts in the racemose -inflorescences are displaced along the flower-stalks. - - [Illustration: FIG. 550.--_Lysimachia thyrsiflora._] - - [Illustration: FIG. 551.--_Anagallis arvensis._ Fruit dehiscing.] - - POLLINATION. Insect-pollination in the majority; - cross-pollination is promoted in some by heterostyly (Fig. - 548).--300 species; especially in northern temperate zones; - the majority on mountains (_Soldanella_, _Androsace_, etc.); - almost absent in the Tropics. A large number are ORNAMENTAL - PLANTS, _e.g._ _Primula auricula_ (from the Alps), _P. sinensis_ - (China), _P. elatior_ (Oxslip, a native) and _grandiflora_, etc. - _Cyclamen europæum_ (Alpine Violet); the tubers are poisonous. - - Order 2. =Myrsinaceæ.= Trees or shrubs; evergreen, tropical - Primulaceæ with fleshy fruits and few seeds, embedded in the - placenta. The leaves are nearly always dotted with yellow - glands (schizogenous resin-receptacles).--550 species; - especially Am.--ORNAMENTAL PLANTS: _Ardisia crenulata_ (W. - Ind.); other genera: _Clavija_, _Maesa_, _Theophrasta_ (barren - sepal-stamens), _Myrsine_, _Jacquinia_ (barren sepal-stamens), - etc.--_Ægiceras_, allied to this order, comprises arborescent - plants, often growing with _Rhizophora_ in tropical forests, - along the shore. The embryo germinates while still in the fruit. - -Order 3. =Plumbaginaceæ.= This order has a position of the stamens -similar to that in Primulaceæ (S5, P5, A0 + 5, G5), but it differs -from these in the flower, which has generally a _membranous_, dry, -thin, coloured, folded, almost entire calyx and an _almost entirely -polypetalous corolla_, which, as a rule, has twisted æstivation and is -_only united_ with the stamens _at its base_; but more especially it -differs in the ovary, which bears 5 _free_ or almost free _styles_ and -only 1 _basal_ ovule with a _long_, twisted funicle (the placenta of -the Primulaceæ is here so much reduced that it bears only 1 ovule). -The fruit is a _nut_ or _capsule_. The radicle is turned outwards. -Endosperm mealy.--To this order belong herbs or under-shrubs, which -are especially natives of the sea-coast and of salt-steppes; they also -resemble the Primulaceæ in the scattered, undivided, entire leaves -(without stipules), often in rosettes, and the inflorescence borne -on a long stalk. In opposition to the Primulaceæ, the _bracteoles -are typically present, and hence the branching is generally cymose_ -(scorpioid). - -_Armeria_ (Thrift) has a round _capitulum_, composed of closely-packed -dichasia, surrounded at its base by an involucre with peculiar -prolongations, directed downwards, and united into a sheath protecting -the intercalary zone of growth. The pericarp is finally ruptured at -the base, and drops off like a hood.--In _Statice_ (Sea-lavender), the -unipared scorpioid cymes are prolonged and collected into panicle-like -inflorescences.--~_Plumbago_ is the genus which approaches nearest to -the Primulaceæ, and differs most from the characters given above. It -has capitate or spike-like inflorescences, a salver-shaped corolla, and -the stamens are not attached to the corolla. The style is only divided -at the extremity; the calyx is not membranous, but is covered with -sticky, glandular hairs.~ - - 250 species; chiefly in the Mediterranean and about the Caspian - Sea, on salt-steppes and beaches. Some are Tropical; a few are - ornamental plants. - - - - - B. Tetracyclicæ. - - - a. Tetracyclicæ with hypogynous flowers. - - - Family 29. =Tubifloræ.= - -The flower is regular, ☿, and _hypogynous_. The gamopetalous type is -present in this family with great uniformity, without suppression -or splitting; S5, P5, A5, G2 (3–5). The stamens are all fertile, -alternating with the lobes of the corolla. Gynœceum with 2, more -seldom 3–5 syncarpous carpels. Style nearly always simple; 2 dorsal -stigmas. In each carpel 2–∞ ovules. At the base of the ovary is found -a yellowish ring-like nectary (Fig. 552 C), sometimes 5-sinuate or -5-partite.--The leaves are nearly always scattered; stipules are -absent.--~The Solanaceæ, which formerly were classed here, are so -closely allied to the Personatæ, that it would be unnatural not to -place them first in this family; and the Boraginaceæ (which were also -placed in the Tubifloræ) appear to be best united, with the Labiatæ and -others, into one family Nuculiferæ.~ - - Order 1. =Polemoniaceæ.= The flowers are regular; S5, P5, - A5, G3. The calyx and corolla have united leaves, the petals - _twisted_ to the right in _æstivation_ (all the left edges - being covered). The ovary is 3-locular with 2–∞ ovules in - each loculus; the style is trifid at the apex; the fruit - is a 3-valved capsule. Embryo straight; endosperm fleshy. - The inflorescences are dichasia passing over into unipared - helicoid cymes (the shoot of the _lower_ bracteole being the - more strongly developed).--Herbs without latex. 150 species; - especially Western N. Am.--_Phlox_ (salver-shaped corolla; - entire, opposite leaves), _Polemonium_ (campanulate or almost - rotate corolla; scattered, pinnate leaves), _Leptosiphon_, - _Gilia_, _Collomia_, _Cobæa_ (climbing, like the Vetches, by - tendrils at the ends of the leaves), etc. They are frequently - ornamental plants. - - Order 2. =Hydrophyllaceæ.= This order approaches very closely to - the Boraginaceæ. Herbs with pinnate or palmate leaves; S5, P5, - A5, G2. The lobes of the corolla are imbricate in æstivation. - Generally 2 median carpels. The ovary is _most frequently - unilocular_, and the seeds are situated on 2 _parietal - placentæ_; capsule 2-valved; embryo straight; endosperm fleshy. - In the corolla-tube, opposite the corolla-lobes, there are - frequently appendages of various forms, which resemble those of - _Cuscuta_. The inflorescences correspond exactly with those of - the Boraginaceæ, being _unipared scorpioid cymes_, which, prior - to opening, _are tightly rolled up_.--130 species, especially in - N. Am. (California, etc.). Many annual species of _Phacelia_, - _Nemophila_, _Whitlavia_, _Eutoca_, _Cosmanthus_, etc., are - cultivated in gardens as ornamental plants. _Hydrolea_ (has a - bilocular ovary, and two free styles). - -Order 3. =Convolvulaceæ= (=Bindweeds=). The flower is regular, -hypogynous, with 5 almost free sepals (quincuncial æstivation), P5, -A5, G2 (rarely 3–5). The _corolla_ is very characteristic; it is -(with various forms) almost entire, or slightly 5-lobed, and _folded_ -longitudinally _in the bud_ in such a way that 5 projecting, flat -portions, tapering towards the top and frequently differing in colour -and hairiness from the rest, are visible externally and applied close -together, while the remainder of the corolla is folded inwards (Fig. -552 A); and hence the whole corolla is _strongly twisted to the right_ -in the bud. The gynœceum most frequently has a bilocular ovary; _in -each loculus_ there are _only_ 2 (erect) _anatropous ovules_ on the -placenta, which is not especially thickened (Fig. 552 _D_, _E_); each -loculus is sometimes divided into two by a false septum (a relationship -with the _Boraginaceæ_, etc.); style simple with most frequently a -bilobed stigma, or a bipartite style. The fruit is nearly spherical, -most frequently a _capsule_. The seeds are erect, and have a large -hilum at the base. The embryo is _curved_, with leaf-like, thin, -bilobed, most frequently folded cotyledons; _endosperm absent or -mucilaginous_. - -=1.= CONVOLVULEÆ, BINDWEED GROUP. The majority are _twining_ (to -the left) _herbs_, with _latex_. The leaves are scattered, without -stipules, often long stalked, and nearly always with cordate base; -some are palmately lobed. The flowers are most frequently solitary -in the leaf-axils, large, quickly withering.--_Convolvulus_ (Fig. -552), _Calystegia_ (unilocular ovary, 2 large bracteoles), _Ipomœa_, -_Batatas_, _Evolvulus_ (with a doubly bifid style), _Calonyction_, -_Pharbitis_, etc. - - [Illustration: FIG. 552.--_Convolvulus scammonia._] - -=2.= DICHONDREÆ. This group is a more primitive form, not twining, -and without latex. It has 2 _free_ carpels with basal style (as in -Boraginaceæ) and valvate corolla. - -=3.= CUSCUTEÆ, DODDER GROUP (Fig. 553). Parasites, with round, -filamentous stems, bearing only scale-like leaves and almost destitute -of chlorophyll (they are reddish or yellowish); they are parasitic -upon other plants, around which they twine, first with narrow, compact -coils from which haustoria (Fig. 553 _A_) are developed which enter the -host-plant, and then with wider coils by which they raise themselves -to other portions of their host or try to reach other plants. On -germination a very temporary primary root is developed, which bears -root-hairs as far as the tip (rootcap is wanting); it only serves as a -kind of reservoir for water, and perishes very soon after the seedling -has fastened on to a host. The embryo is filamentous and rolled up -_spirally_ (Fig. 553 _C_), and is sometimes destitute of cotyledons. -The flowers are crowded into capitulate inflorescences, complicated -by accessory shoots (Fig. 553 _A_); they have S5, P5 (_imbricate_ -æstivation), A5 (and beneath the stamens 5 scales on the corolla-tube), -G2. Fruit a capsule opening by a lid.--_Cuscuta europœa_, _C. -epilinum_ (Flax-Dodder), _C. epithymum_ (Lesser-Dodder), _C. trifolii_ -(Clover-Dodder), etc., are parasitic on different hosts, or parasitic -each on its own particular host. - - [Illustration: FIG. 553.--_Cuscuta trifolii_, parasitic on Red - Clover. _A_ A portion of the stem with an inflorescence and - haustoria (mag.); _B_ seed (nat. size); _C_ seed (mag.); _D_ - embryo (nat. size).] - - 840 species; the majority in the Tropics, especially Am. Many - are ornamental plants. OFFICINAL: some on account of their - purgative properties: the tuberous roots of _Ipomæa purga_ - (Jalap, from Mexico) and the dried latex (“Scammony”) of - _Convolvulus scammonia_ (from the East). The tuberous roots of - _Batatas edulis_ (Trop. S. Am.) are used as a common vegetable - (Sweet Potato) in the Tropics. - - - Family 30. =Personatæ.= - -The type of the flower is: S5, P5, A5 (of which one, or in some cases -several, are suppressed), and G2. The flowers are _hypogynous_, ☿, -perfect with gamopetalous corolla, but most frequently irregular -(medianly zygomorphic, except _Solanaceæ_), the _corolla_ being -_bilabiate_ (divided into a posterior part of two lobes and an anterior -part of three lobes), and the _stamens_ 4, _didynamous_ (the posterior -being suppressed). The ovary has 2 loculi (only 1 in _Utriculariaceæ_, -_Gesneriaceæ_, _Orobanche_); the placenta in the first-named orders -(1–7) is most frequently very thick, and bears a _great many ovules_ -(Figs. 554, 555, 557, 562); the number of ovules in the last orders -(8–9) is considerably reduced (Fig. 570). - -Special mention may be made of the apparently 4-merous flower which -is found, _e.g._ in _Veronica_ and _Plantago_ (Figs. 567, 562 _C_, -570, 571), and which arises from the typical 5-merous flower by the -suppression of the posterior sepal and the posterior stamen, and by -the union of the two posterior petals into one.--Terminal flowers -very seldom occur on the main axis, and would not harmonise well -with the very irregular form of the flower. When they do occur, they -are, as a rule, “peloric,” _i.e._ regular (in _Linaria vulgaris_ two -kinds of peloric flowers occur,--one with 5 spurs, and one without -spurs). The halves of the anthers are often divided as far as the -base, and laterally so widely separated from each other as to assume -an almost straight line (Figs. 563, 564). There is generally a nectary -(“disc”) round the base of the ovary, often 5-lobed (or divided into -free glands).--A common vegetative characteristic is the _absence of -stipules_. - - The 9 orders of the Personatæ are: 1, Solanaceæ; 2, Nolanaceæ; - 3, Scrophulariaceæ; 4, Utriculariaceæ; 5, Gesneriaceæ; 6, - Bignoniaceæ; 7, Pedaliaceæ; 8, Acanthaceæ; 9, Plantaginaceæ. - - [Illustration: FIG. 554.--Diagram of _Petunia_.] - -Order 1. =Solanaceæ.= The flower (Figs. 554, 555, 559) is hypogynous, -regular (zygomorphic in _Hyoscyamus_), ☿, and gamopetalous, with -S5, P5 (most frequently _imbricate_ or _valvate_), A5, G2, the 2 -carpels being placed obliquely (Fig. 554); the bilocular ovary has a -very _thick axile placenta_ (Figs. 554, 555 _H_, 557), which extends -almost as far as the wall of the ovary. The fruit is a capsule -or berry; the seeds are more or less reniform, and the embryo is -_curved_ (rarely straight), in a fleshy endosperm (Figs. 555 _F_, _G_; -561).--Both arborescent and herbaceous forms are found in the order; -leaves scattered without stipules, but with variously formed laminæ -(always penninerved). _A peculiar leaf-arrangement_ is found in many -species, viz. the leaves are borne _in pairs, a large and a smaller -one together_; these pairs stand in 2 rows, and the flowers are then -situated _between_ the individual leaves in each pair, apparently _not_ -in a leaf axil. The inflorescences are frequently unipared scorpioid -cymes without floral-leaves. - - [Illustration: FIG. 555.--_Atropa belladonna_: _A_ is reduced.] - - Zygomorphic flowers occur, and thus form a transition to the - closely allied Scrophulariaceæ; the zygomorphy sometimes - shows itself only in the relative length of the stamens, - sometimes also in the corolla (_Hyoscyamus_).--_Nicandra_ is - 5-merous throughout all the whorls.--The peculiar relative - _leaf-arrangement_ in this order occurs from sympodial branching - and displacement. The most simple is, _e.g._ _Datura_ (Fig. 556 - _A_); each shoot-generation in the floral parts of the plant has - only 2 foliage-leaves (_f^1_ and _f^2_), and then terminates - in a flower; the axillary buds of both the foliage-leaves - are developed and form a dichasium, but since the leaves are - displaced on their axillary-shoots as far, or almost as far, as - the first leaf of these axillary-shoots, the flowers are borne - singly on the dichasial branches, and all the branches appear to - be without subtending leaves (Shoot I is white, II shaded, III - white, etc., diagram _A_). _Scopolia_ and others (Fig. 556 _B_) - differ in that the lowest and smallest (_f^1_) of the two leaves - on each shoot is barren, and is therefore not displaced; but the - upper one (the second bracteole, _f^2_) is displaced as in the - first instance, and consequently it assumes a position near the - first leaf (the shaded leaf _f^2_ of shoot I being placed near - the white leaf _f^1_ of shoot II, etc.,) of the next youngest - shoot-generation, and hence the leaves are borne in pairs; the - flower placed between the two leaves of a pair is therefore the - terminal flower of the shoot to which the smaller of the two - leaves belongs, and the larger leaf is the subtending leaf for - the floral shoot itself. - - [Illustration: FIG. 556.--Diagrammatic representation of the - branching in Solanaceæ. The various shoot-generations are white - or shaded.] - - [Illustration: FIG. 557.--Fruit of _Hyoscyamus niger_ after - removal of calyx.] - - [Illustration: FIG. 558.--Fruit of _Datura stramonium_.] - -=A.= FRUIT A CAPSULE. _Nicotiana_ (Tobacco) has a 2-valved capsule with -septifragal dehiscence; the valves separate at the apex; the corolla is -funnel-shaped, tubular, salver-shaped or campanulate. The flowers in -panicles.--_Datura_ (_D. stramonium_, Thorn-apple) has a (frequently -spiny) capsule (Fig. 558), which is _falsely 4-locular_ (at the top, -bilocular) and opens septifragally with 4 valves. The lower part of -the calyx persists as a thick collar (see Fig. 558). The corolla -is funnel-shaped. The flowers are solitary, large.--_Hyoscyamus_ -(_H. niger_, Henbane) has a pyxidium (Fig. 557) enclosed in the -campanulate, completely persistent, thick-walled calyx. The flowers -are slightly _zygomorphic_, and borne in unipared scorpioid cymes. -~_Scopolia_ (pyxidium); _Fabiana_ (Heather-like shrub); _Petunia_ -(slightly zygomorphic flower; funnel-shaped corolla); _Nierembergia_; -_Brunfelsia_ (almost a drupe); _Franciscea_; _Browallia_.~--Among -those with capsular fruits are found the most anomalous forms, which -by their zygomorphic flowers and often didynamous stamens present the -transition to the Scrophulariaceæ: _Salpiglossis_; _Schizanthus_ (lobed -petals; 2 perfect, and 3 rudimentary stamens). - - [Illustration: FIGS. 559–561.--_Solanum tuberosum._ - - FIG. 559.--Flower (1/1). - - FIG. 560.--Stamen, ejecting pollen. - - FIG. 561.--Longitudinal section of seed.] - -=B.= FRUIT A BERRY. _Solanum_ (Nightshade); rotate corolla (Fig. -559). The stamens have short filaments, the anthers stand erect, -close together round the style, like a cone in the centre of the -flower, and open by pores at the apex (Fig. 560). ~_S. tuberosum_ -(the Potato-plant); the Potato-tuber is a swollen, underground -stem; the “eyes” are buds, situated in the axils of its scale-like, -quickly-perishing leaves.~--_Lycopersicum_ resembles _Solanum_ in -the flower, but the united anthers open by longitudinal clefts and -have an apical appendage. The cultivated species, _L. esculentum_ -(Tomato), has often a higher number than 5 in the flower, and in the -fruit several loculi of unequal size.--_Physalis_ (Winter Cherry); -the calyx ultimately swells out in the form of a bladder, becomes -coloured, and loosely envelopes the spherical berry.--_Capsicum_ -(Guinea Pepper-plant); some species have very large, irregular, -rather dry (red, yellow, black) berries, which are unilocular -in the upper part.--_Lycium_ (false Tea-plant); the corolla is -salver- or funnel-shaped; shrubs; often thorny.--_Atropa_ (_A. -belladonna_, Deadly Nightshade, Fig. 555); corolla campanulate; -the calyx projects beneath the spherical, black berry. The flowers -are borne singly.--_Mandragora_; (Mandrake); _Nicandra_ (ovary -often 5-locular).--~A small tropical group: CESTREÆ (_Cestrum_, -_Habrothamnus_, etc.) has an almost _straight_ embryo, which may -also be found _e.g_. in species of _Nicotiana_. Related to the -Scrophulariaceæ.~ - - About 1,500 species; the majority within the Tropics, outside - these limits especially in America. _Solanum nigrum_ is a common - weed.--_The Potato-plant_ (_Solanum tuberosum_), from Peru - and Chili, was introduced into Europe in 1584 by Sir Walter - Raleigh. (Potatoes = Batatos). The fruits of several serve as - _condiments_: Chilies or Pod-pepper (_Capsicum annuum_ and - _longum_), and the Cayenne-pepper (_C. baccatum_ and others), - whose fruits also are officinal, were brought to Europe from S. - America by Columbus, and are commonly cultivated in Tropical - America; _Lycopersicum esculentum_ (Tomato) and others from - Peru; _Solanum ovigerum_ (Egg-plant); _Solanum melongena_, - etc. _Poisonous_, _acrid_, _narcotic_ properties (alkaloids, - etc., solanine, nicotine, atropine, hyoscyamine) are found in - many: _Atropa belladonna_ (from S. Europe; the roots and leaves - are officinal); _Solanum dulcamara_ (Bitter-sweet; formerly - officinal), _S. toxicarium_ (Guiana); _Datura stramonium_ from - Asia (leaves and seeds officinal), _D. sanguinea_, _metel_, - _tatula_, and others; _Hyoscyamus_ (officinal: the leaves - and seeds of _H. niger_); _Nicotiana tabacum_ (Virginian - tobacco, officinal: the leaves), _N. rustica_ and others from - Trop. America (_Tobacco_ was introduced into Europe in 1560); - _Cestrum_-species. _Duboisia myoporoides_ (Australia); the - leaves contain _hyoscyamine_ and are used in medicine. A number - of species of these genera are ornamental plants. - - Order 2. =Nolanaceæ.= These most resemble the Convolvulaceæ - in the corolla, but the Solanaceæ in their branching, and - leaf-arrangement (in pairs, etc.). The diagram is the same as - in _Nicandra_ with 5 carpels, but the fruits of this order - most frequently form, by invaginations in various directions, - an ovary (with 1 style) consisting of numerous and irregularly - grouped, 1-ovuled cells; the fruit is a schizocarp with many - 1-seeded fruitlets.--_Nolana_ (Western S. America): a few are - ornamental plants. - -Order 3. =Scrophulariaceæ.= The flower is hypogynous, ☿, _zygomorphic_, -with the usual type: S5, P5, A5, and G2, the latter placed _in the -median plane_; some genera have all 5 stamens developed (Fig. 562 -_A_), but most frequently the posterior one is suppressed and the -flower becomes _didynamous_ (Fig. 562 _B_). The fruit, as in the -capsular-fruited Solanaceæ, is a bilocular, 2-valved _capsule_, with -a _thick, axile placenta_, and most often septicidal dehiscence -(Fig. 563 _C_). The _numerous seeds_ are not reniform as in many -Solanaceæ, and have a _straight, or only slightly curved embryo_, with -abundant endosperm (Fig. 563 _D_).--The majority are herbs; some are -arborescent; the leaves are opposite or scattered, but stipules are -wanting as in the whole family. - - The Scrophulariaceæ are closely allied to the Solanaceæ, and - there is, properly speaking, no characteristic feature which - absolutely separates them. The somewhat irregular corolla, with - five stamens of unequal length in _Verbascum_, is also found - in _Hyoscyamus_; curved and straight embryos are found in both - orders. The activation of the corolla in the Scrophulariaceæ is - _simple imbricate_, in the Solanaceæ most frequently _folded - imbricate_ (in _Atropa_ and those allied to it, imbricate - without folding). The genera (about 164) are distinguished - according to the form of the corolla, number of stamens, - inflorescence, arrangement of the leaves, etc. _Verbascum_ - belongs to the most primitive 5-stamened forms, and from it - proceed a long series down to _Veronica_, with only two stamens - and most frequently the posterior sepal suppressed. - - [Illustration: FIG. 562.--Diagrams. _A_ _Verbascum_; _B_ - _Linaria_; _C_ _Veronica_.] - -=1.= ANTIRRHINEÆ, SNAPDRAGON GROUP. This has most frequently a -descending æstivation of the petals (the posterior petals are outside -the lateral ones, which again enclose the anterior; Fig. 562 _A_, _B_). -The plants belonging to this group are not parasites. - -=a.= =5-stamened.=--_Verbascum_ (Mullein, Fig. 563 _A_) has a slightly -irregular, rotate corolla; five stamens (frequently covered with woolly -hairs), of which the two anterior ones are the longer and differ -often also in other respects. ~The inflorescences are racemose, often -with several series of accessory dichasia in the axil of each primary -floral-leaf. The leaves are scattered and, together with the stems, are -often covered with a grey felt of branched hairs.~ - - [Illustration: FIG. 563.--_Verbascum thapsiforme._] - - [Illustration: FIG. 564.--_Antirrhinum majus._ A flower, and the - upper lip of a flower with the stamens.] - - [Illustration: FIG. 565.--_Scrophularia nodosa._ Protogynous - flower in various stages: _A_ ♀ stage; _g_ the stigma projecting - from the throat of the corolla; _B_ the same in longitudinal - section; _C_ ♂ stage, the stigma is bent down and its former - position occupied by the stamens; _s_ staminode; _g_ stigma; _d_ - nectary.] - - [Illustration: FIG. 566.--_Digitalis purpurea._] - -=b.= =4-stamened, didynamous= (Fig. 564).--_Scrophularia_ (Fig-wort, -Fig. 565) has cymose inflorescences in a panicle; the corolla (Fig. -565) is urceolate, short two-lipped; the posterior stamens are present -as a scale below the upper lip of the corolla (Fig 565 _s_). ~_S. -nodosa_ has a tuberous rhizome.--_Pentstemon_; the posterior stamen is -barren and very long.~--_Antirrhinum_ (Snapdragon). The corolla (Fig. -564) is personate, _i.e._ bilabiate, but with the under lip arched -to such an extent that it meets the upper lip, closes the corolla -throat, and entirely conceals the stamens and style; the corolla-tube -is produced into a short pouch at the base on the anterior side. The -capsule is oblique and opens by 2–3 pores, formed by small, dentate -valves. In _Linaria_ (Toad-flax) the pouch is produced into a spur. -Sometimes there are traces of the posterior stamens. The capsule opens -by large pores (one for each loculus), produced by large, many-partite -valves. _L. vulgaris_ reproduces by suckers.--_Digitalis_ (Foxglove, -Fig. 566) has long racemes with drooping flowers; the posterior sepal -is small (a step towards complete suppression, as in _Veronica_); the -corolla is obliquely campanulate, and generally nearly 4-lobed, the -two posterior petals coalescing.--_Alonsoa_; _Nemesia_; _Chelone_; -_Herpestis_; _Mimulus_; _Torenia_; _Vandellia_; _Limosella_ (_L. -aquatica_, Mud-wort, native); _Scoparia_; _Capraria_; _Erinus_ (found -on the Roman Camp at Chesters, Northumberland, and supposed to have -been introduced from Spain by the Roman soldiers); _Celsia_ (near -_Verbascum_); _Maurandia_; _Lophospermum_; _Rhodochiton_; _Collinsia_; -_Nycterinia_, etc. - - [Illustration: FIG. 567.-Flower of _Veronica_.] - -=c.= =2-stamened.=--_Gratiola_ (Water-hyssop). 5-partite calyx. -The upper lip of the corolla is undivided or slightly bifid; the -two anterior stamens are either entirely absent or are reduced to -staminodes (a transition to _Veronica_).--_Veronica_ (Speedwell), most -frequently 4-partite calyx; 4-lobed, rotate, zygomorphic corolla with -2 perfect stamens and no trace of the others (Figs. 567, 562 _c_); -capsule with loculicidal dehiscence. _Calceolaria_; the corolla has two -slipper-like lips. - -=2.= RHINANTHEÆ, YELLOW-RATTLE GROUP. Herbs, all of which (with -the exception of _Lathræa_) are annual _parasites_ with green -foliage-leaves. They attach themselves by haustoria to the roots of -other plants and draw nourishment from them. The majority turn black -when dried. Racemose inflorescences. In many the calyx is 4-partite, -the posterior sepal being absent, or very small. The corolla is -distinctly bilabiate (Fig. 568), with _most frequently ascending -æstiration_; in the majority it does not become detached at the -base, but by means of a ring-like cut some distance up the tube; 4 -didynamous stamens; pollen-grains dry, easily falling out; the anthers -are often furnished at the base with bristles or hairs (Fig. 568) -which play a part in the pollination, the probosces of the insects, -being forcibly pushed against them, agitate the anthers and shake out -the pollen-grains. Capsule with loculicidal dehiscence.--_Euphrasia_ -(Eye-bright), _Melampyrum_ (Cow-wheat), _Rhinanthus_ (Yellow-rattle), -_Odontites_ (Bartsia), _Pedicularis_ (Louse-wort), and _Lathrœa_ -(Tooth-wort) all have native species. The last named is pale yellow, -or reddish (without chlorophyll); ~it is a parasite on the roots of -the Hazel, Beech and other shrubs, having an aerial stem, and an -underground, perennial rhizome, covered with opposite, scale-like, -more or less fleshy leaves with a number of internal glandular, -labyrinthine cavities. The inflorescence is a unilateral raceme. It -approaches _Gesneriaceæ_ in having a _unilocular_ ovary with two -parietal placentæ.~ - - [Illustration: FIG. 568.--_Euphrasia officinalis._ Flower of - the large and the small-flowered forms; showing the anthers and - stigmas.] - - The mechanical contrivances for POLLINATION are so numerous - that no general principle can be laid down. Personate flowers, - like those of _Antirrhinum_ are only accessible to strong - insects, such as humble-bees, which can force themselves - between the two lips, and so become dusted with pollen on - the back. In _Euphrasia_ and other _Rhinantheæ_ the insects - become covered with smooth, powdery pollen when they shake - the anther-apparatus in touching the hairs and bristles - mentioned above. _Scrophularia nodosa_ is protogynous (Fig. - 565). _Digitalis purpurea_, however, is protandrous. _Mimulus - luteus_ and some others have sensitive stigmatic lobes, which - shut up on being touched. The _Veronica_-species constitute - a series, from large-flowered down to small-flowered forms, - and parallel with them are found various gradations from - insect-to self-pollination. In some (as _Euphrasia officinalis_, - _Rhinanthus crista galli_) there are two kinds of flowers: - large, which are pollinated by insects, and small, which are - self-pollinated (Fig. 568). _Lathræa squamaria_ (Tooth-wort) - is a protogynous spring-flowering plant, largely visited by - humble-bees. Others have cleistogamic flowers. _Nycterinia - capensis_ opens its flowers at night. - - 2,000 species; chiefly from the Temp. OFFICINAL: _Digitalis - purpurea_ (the leaves; Europe), a poisonous plant. _Verbascum - thapsus_ and _thapsiforme_, _Veronica officinalis_ (“Herba V.”), - _Gratiola officinalis_ (“Herba”) have medicinal uses. The whole - of the Scrophulariaceæ are more or less suspicious, if not - actually poisonous, and none serve as food. Many are ORNAMENTAL - PLANTS: _Mimulus luteus_ (N. America), _Paulownia imperialis_ - (the only species; in Japan; a tree), _Antirrhinum vulgare_ (S. - Eur.), _Linaria_, _Pentstemon_, _Veronica_, _Calceolaria_ (Peru, - Chili, etc.). - - [Illustration: FIG. 569.--Leaf of _Utricularia vulgaris_, with - bladder. Median longitudinal section through a bladder containing - a _Cyclops_. At a a hair of the upper-lip, at _i_ 2 bristles - of the under-lip of the entrance (_a_, _b_); in the latter are - placed 4 bristles _h_; _k_ stalk of the bladder, in which is seen - a vascular bundle. (After Cohn.)] - -Order 4. =Utriculariaceæ.= To this order belong only perennial, -_insectivorous_, _aquatic_, and _marsh-plants_ (200 species) with -a more or less characteristic appearance. They differ from the -Scrophulariaceæ, especially in having =2= stamens (the anterior) and -a _unilocular ovary_, with _free, central placenta_ (like that of the -Primulaceæ). For the rest the flower is distinctly bilabiate, both in -the calyx and corolla. Two-valved capsule; no endosperm. - -_Pinguicula_ (Butter-wort) has a rosette of leaves close to the ground; -these are sticky, covered with glandular hairs, and roll round any -small insects which may be caught upon them; flowers solitary, terminal -on a long scape; calyx, 5-partite; corolla with spur. The embryo -germinates with 1 cotyledon.--_Utricularia_ (Bladder-wort). Our native -species are floating, _without roots_, with hair-like, divided leaves, -studded with peculiar bladders (in the Tropics there are terrestrial -species, with ordinary foliage). The bladders (Fig. 569) have an -aperture, closed by a valve opening inwards, so that small aquatic -animals are allowed to enter, but are not able to escape; they are -thus entrapped in the bladders, and are probably used as food. Calyx -bipartite; corolla personate with spur. - - The _embryo_ of _Utricularia_ is very imperfect, scarcely - more than a spherical, cellular mass, with a few slight - leaf-rudiments. On the germination of _U. vulgaris_, several - bristle-like leaves develop into a compact rosette; the stem - then develops, and also the finely-divided, bladder-bearing - leaves. A primary root is not developed. The stems branch - copiously and in a very peculiar manner. The growing-point of - the stem is rolled spirally.--The stigmatic lobes are sensitive - and close on being touched; self-pollination often takes place, - however, in _Pinguicula_. - - Order 5. =Gesneriaceæ.= The flower in this order may be both - _epigynous_ (_Gesnerieæ_) and _hypogynous_ (_Cyrtandreæ_), - but otherwise is nearly the same as in Scrophulariaceæ, - only that _the ovary is unilocular_, with 2 _parietal_, - often bifid, _placentæ_. Of the 5 stamens the posterior is - rudimentary, or (more rarely) entirely wanting, and the others - are didynamous (Cyrtandreæ have often only 2 stamens); their - anthers are generally glued into a quadrangular mass. The - majority are herbs with juicy stems, opposite, verticillate - or scattered leaves without stipules, often, like the stems, - thick and juicy, soft-haired or glabrous. The corollas are - often highly-coloured (scarlet, red-yellow, etc., and spotted - internally), large and magnificent, so that many species are - ornamental plants. GESNERIEÆ (often epigynous) have endosperm; - S. Am.--CYRTANDREÆ, hypogynous, without endosperm; Asia, S. - Africa.--_Streptocarpus_, neither the primary root nor primary - shoot attains development; one of the cotyledons dies, while the - other grows and becomes a very large foliage-leaf, from which - spring adventitious roots and adventitious inflorescences. - - 500 species. _Gloxinia_, _Achimenes_, _Gesneria_, _Alloplectus_, - _Tydæa_, _Columnea_, _Nægelia_, _Æschynanthus_, and others, - especially in the forests of tropical America. Some are - epiphytes on trees, others prefer the leaf-mould of the - forest and crevices of cliffs. Several genera have peculiar, - catkin-like, underground shoots, with scale-like compact leaves; - others have tubers. - - _Orobanche_ (Broom-rape) is allied to this order as a - _parasitic_ form. It is a parasite on the roots of other - plants, not like _Lathræa_ by means of thin rootbranches with - haustoria, but growing with the base of its stem in close - contact with its host, and probably even often protruding a kind - of thallus into it, in a manner similar to the Loranthaceæ. Its - aerial shoots are not entirely destitute of chlorophyll, but - are not green; they only bear scale-leaves and terminate in a - raceme or spike-like inflorescence.--Some _Orobanche_-species - are detrimental to various cultivated plants (Hemp, Lucerne, - Tobacco, etc.). The flowers are strongly zygomorphic; the - posterior sepal is often wanting, and the anterior are united - to the two lateral ones. Ovary unilocular, as in Gesneraceæ, - with 2 or 4 parietal placentæ.--The exceedingly small seeds have - a very rudimentary embryo, formed of an ellipsoidal, cellular - mass, without indication of cotyledons or other organs.--About - 100 species; especially in the Mediterranean region. - - Order 6. =Bignoniaceæ.= 500 species; nearly all trees and - shrubs, and to a great extent lianes, climbing by tendrils - (modified leaves), which are sometimes terminated by a - special clasping apparatus. These lianes have, as a rule, an - _anomalous stem structure_, the wood being either divided - into four wedges at right angles to each other, separated - by four grooves filled with secondary wood-parenchyma, or a - greater number of wedges occur, by the cambium ceasing to - form wood in several places. The leaves are most frequently - opposite and compound; the flowers in the main are similar - to the didynamous Scrophulariaceæ, and especially resemble - those of _Digitalis purpurea_; they are bilabiate, large, - and beautiful, campanulate or trumpet-shaped, many of the - prettiest ornamental plants in the Tropics belonging to this - order. The fruit is most frequently a large, woody, 2-valved, - siliqua-like, septifragal capsule, whose valves separate from - the flat and broad partition-wall, which bears the large, - generally winged seeds: _Tecoma_; _Bignonia_.--In gardens: - _Catalpa syringæfolia_ (Trumpet-wood); _Tecoma radicans_ - (from S. Am.).--“Palisander”-wood is from _Jacaranda_ (S. - Am.).--_Eccremocarpus_ (N. Am.) forms, by its unilocular - capsule, a transition to the Gesneriaceæ (_E. scaber_; - herbaceous). - - _Crescentia_ is allied to this order; _C. cujete_ (Calabash) is - its best known species. The fruit (unilocular with 2 parietal - placentæ) is a very large, spherical or ellipsoidal berry, with - a firm, finally woody outer layer. After the removal of the - juicy interior, these are commonly used as drinking vessels in - Tropical America. - - Order 7. =Pedaliaceæ.= _Sesamum_ (_orientale_ and _indicum_); - very important oil-plants, which from olden times have been - cultivated in tropical Asia and Africa for food and as medicinal - plants, and are now cultivated in America also. The seeds are - used as a raw material in the manufacture of soap in Europe.--To - this order also belong _Martynia_ and _Craniolaria_, which have - a long horned capsule and sensitive stigmas.--46 species. - - Order 8. =Acanthaceæ.= 1,500 species; mostly erect, slender, - branched herbs or shrubs, rarely arborescent, especially in - S. Am. and Ind. The branches frequently have swollen nodes; - the leaves are _opposite_, penninerved, undivided, more or - less lanceolate or elliptical, and generally leave a distinct - scar when they fall off. Stipules are wanting. The flowers are - solitary or in dichasia, which are arranged in 4-rowed spikes - or racemes, each flower with its subtending bract, which may be - brightly coloured, and most frequently also with two bracteoles. - With regard to the corolla (which is often labiate, in any - case irregular, and frequently prettily coloured), the 2 or - 4 didynamous stamens (of whose anthers one half is inserted - lower than the other, or suppressed) and the gynœceum, the - Acanthaceæ are true Personatæ, approaching most nearly to the - Scrophulariaceæ: they differ from the other orders especially in - the _fruit_, which is a bilocular, 2-valved, often elastically - dehiscing capsule, which never has more than 2 rows, and in some - only 2 seeds in each loculus, the seeds being often compressed - and borne on _strong_, _curved_ or _hook-like funicles_ - (_retinacula_) which persist after dehiscence. _Embryo curved - without endosperm_; radicle pointed downwards.--Cleistogamic - flowers are found in several species. Cystoliths are common. - - The following grow wild in Europe: _Acanthus_ (_spinosus_ - and _mollis_, whose pinnatifid leaves served as models for - the capitals of the Corinthian columns). The posterior sepal - is the largest of all the leaves of the flower, and covers - the other parts like a helmet; the 2 anterior sepals are - united, and the two lateral ones are small and greenish; the - corolla has no upper-lip, but only a 3-lobed under-lip. The - anthers are bilocular; the filaments ultimately become very - firm.--_Justicia_, _Eranthemum_, _Goldfussia_, _Thunbergia_ (a - twiner), _Ruellia_, _Dicliptera_, etc.--Ornamental plants in - conservatories. - -Order 9. =Plantaginaceæ= (=Plantains=). The flowers (Figs. 570, 571) -are regular, ☿, hypogynous, with a =4=-partite, persistent calyx, -a gamopetalous, _scarious_ corolla with =4= projecting lobes, =4= -stamens, incurved in the bud, later on projecting considerably, about -equal in length, and a bilocular ovary with _one_ long, filamentous, -_undivided_, _feathery_, papillose style (see Fig. 571). The ovary -is most frequently bilocular with 1–few ovules in each loculus. An -hypogynous disc is wanting. The fruit is a _pyxidium_ with 1–few -peltate seeds attached in each loculus (_Littorella_ is in several -respects an exception). All species are herbs, the majority with -leaf-rosettes near the ground, and the flowers in spikes or capitula. - - The labiate-like flowers are in this case entirely concealed - under a regular, apparently 4-merous exterior. The structure of - the flower, however, is the same as in the _Scrophulariaceæ_, - only the reduction, which is found in _Veronica_ (compare Figs. - 562 _C_, 567 with 570, 571), is also present in this instance - and the lobes are also more equally developed; the posterior - petal corresponds to the bilobed upper-lip; the posterior stamen - and the posterior sepal also are entirely wanting. In the - development of the flower there is no trace of posterior sepal - or stamen, and the posterior petal arises from one primordium, - but the two anterior sepals arise before the lateral ones. The - position of sepals and petals does not agree with that of a - true 4-merous flower, which is represented in Fig. 361 _E._ The - bracteoles are always suppressed in _Plantago_. - -_Plantago_ (Plantain, Rib-grass). The foliage-leaves are most -frequently scattered, entire, with curved veins, arranged in a -rosette close to the ground on an unlimited rhizome; the spike-like -inflorescence is borne on a long scape; in some (_P. psyllium_) the -leaves are opposite on a stem with well-developed internodes, and -the inflorescences are borne in their axils. The order also presents -a transition from insect-pollinated to wind-pollinated flowers. -~The flowers are protogynous, wind-pollinated in _P. major_ and _P. -lanceolata_, partly also in the other species, but insect pollination -also occurs, and _P. media_ has three kinds of flowers, some of which -are adapted for wind-pollination (Fig. 571), others, with short -filaments, for insects.~ _Littorella lacustris_ (Shore-weed) is the -most reduced of the Plantaginaceæ: an aquatic plant with rosettes -of round, awl-like leaves and diclinous (monœcious) flowers. ~In the -axils of the foliage-leaves is a very short 3-flowered spike, formed by -2 sessile ♀-flowers, and above them a long-stalked ♂-flower; all the -flowers are lateral, the terminal one being absent, as in _Plantago_. -The ♂-flower is essentially the same as in _Plantago_, but the ♀-flower -has a scarious corolla, with a narrow, 3–4-dentate mouth, which closes -tightly round the nut-like fruit.~ - - [Illustration: FIGS. 570, 571.--_Plantago media._ - - FIG. 570.--Diagram of _Plantago media_. - - FIG. 571.--Two different forms of the flower (magnified): - 1, chiefly adapted for pollination by wind; 2, for - insect-pollination. _a_ The stigma; _b_ the calyx; _k_ the - corolla.] - - The genus _Plantago_ constitutes nearly the entire - order (200 species). Some are widely distributed weeds - (_e.g._ _P. major_, “The white man’s footstep”). In - _P. psyllium_ (S. Eur.) the integument of the seeds is - mucilaginous, and swells considerably in water. - - - Family 31. =Nuculiferæ.= - -The flowers are _hypogynous_ and _zygomorphic_ (in _Boraginaceæ_ and -_Cordiaceæ_, however, they are regular, except _Echium_ and _Anchusa -arvensis_). The calyx is gamosepalous, the corolla _bilabiate_ (except -in the two orders mentioned), mostly after 2/3, _i.e._ divided into -a 2-leaved posterior portion, and a 3-leaved anterior portion. -The æstivation of the corolla is nearly always descending.--In -_Boraginaceæ_ and _Cordiaceæ_ there are 5 stamens of equal length; in -the other orders 4 didynamous ones, or only 2 fertile; the posterior -stamen is sometimes developed as a staminode, sometimes fertile (in -_Stilbaceæ_). The ovary is formed of 2 median carpels (except some -_Verbenaceæ_), with (1-) =2= ovules on each carpel; in the majority of -the orders it is, however, divided by a false partition-wall between -the dorsal and ventral sutures, into =4= _loculi_, each of which is -often raised independently, causing the style to be situated in the -depression between the four lobes (“gynobasic” style, Figs. 572, -573, 575, 579). The fruit in these orders most frequently becomes a -_4-partite schizocarp_ with _nut-like fruitlets_. The other orders have -a 1(-2)-locular ovary.--The leaves are _simple, without stipules_. - - The family is related to (and proceeds from) the _Tubifloræ_, - especially _Convolvulaceæ_, which has an almost similar - construction of the ovary. It is doubtful whether the - _Cordiaceæ_ and _Boraginaceæ_ should be classed with the others. - - The orders are: 1, Cordiaceæ; 2. Boraginaceæ; 3, Verbenaceæ; 4, - Labiatæ; 5, Selaginaceæ; 6. Globulariaceæ; 7, Stilbaceæ. - - Order 1. =Cordiaceæ= unites Convolvulaceæ and Boraginaceæ. - Tree-like plants with 5-(4–10) merous flowers, doubly bifid - style, and drupe with 4 or less loculi. No endosperm; cotyledons - folded.--185 species; tropical. - -Order 2. =Boraginaceæ.= The vegetative parts are very characteristic: -_herbs_ with _cylindrical_ stems and _scattered_, undivided, nearly -always sessile, entire leaves, without stipules, and generally, -together with the other green portions of the plant, covered with -stiff hairs, consequently rough and often even stinging (hence -the other name for the order _Asperifoliæ_). The inflorescences -are _unipared scorpioid cymes_ with the branches coiled spirally -(“helicoid,” Fig. 573) before the flowers open. The flower is perfect, -_regular_ (obliquely zygomorphic in _Echium_ and _Anchusa arvensis_), -hypogynous, gamopetalous: S5, P5 (often with ligular outgrowths), -A5, G2, but each of the two loculi of the ovary becomes divided by a -false partition-wall into two, each of which contains one _pendulous_ -anatropous ovule with the micropyle turned upwards; the four loculi -arch upwards, so that the ovary becomes 4-lobed, and the style is -then, as in the _Borageæ_, placed _at the base_ (“gynobasic”) between -the four projections (Figs. 572, 573). The fruit is a _4-partite -schizocarp_ with four nut-like fruitlets (Fig. 572).--_Endosperm is -wanting_ (except in _Heliotropium_); the radicle is turned _upwards_. - - The INFLORESCENCES are often double unipared scorpioid cymes; - the bud of the second bracteole is developed, that of the first - suppressed; in some cases both the bracteoles are suppressed - (_Myosotis_, _Omphalodes_, etc.), but in other instances all - the first bracteoles (_a_) only are suppressed, and the others - are then situated in two rows towards the under side of the - coiled axis, while the flowers are situated on the upper side. - Displacement of the branches or of the floral-leaves sometimes - takes place. The flowers are often red at first, and later on - become blue or violet; they hardly ever have any smell. The - fruit entirely resembles that of the Labiatæ, but the radicle - of the latter is turned downwards. The fruitlets present small - differences which have systematic importance; they are hollow or - flat at the base, attached to a flat or columnar receptacle, etc. - -=1.= HELIOTROPIEÆ. This group deviates from the characteristics -mentioned above in the undivided ovary and terminal (“apical”) style. -In this, as well as in the fact that in some genera (_Tournefortia_, -_Ehretia_, etc.) the fruit is a drupe, it connects this order with the -Cordiaceæ. _Heliotropium_, _Tiaridium_, and others have schizocarps. - -=2.= BORAGEÆ, BORAGE GROUP. Style gynobasic; fruit a schizocarp. - -=A.= The throat of the corolla is without ligules, or with very small -ones.--_Pulmonaria_ (Lung-wort); funnel-shaped corolla; a whorl -of hairs in the corolla-throat.--_Echium_ (Viper’s-bugloss) has -zygomorphic flowers, the plane of symmetry almost coinciding with that -of the very well-developed inflorescence (through the fourth sepal); -the corolla is obliquely funnel-shaped, the style is more deeply cleft -at the apex than in the others; stamens 2 longer, 2 shorter, and 1 -still shorter.--_Cerinthe_ has a tubular corolla with five small -teeth and two bilocular fruitlets. The bracts are large and leafy, -and, like all the rest of the plant, are _almost glabrous_.--A few -_Lithospermum_-species have a naked corolla-throat; others have small -hairy ligules, which do not close the corolla-throat. The fruitlets -are as hard as stone, owing to the presence of carbonate of lime and -silica.--_Mertensia_ (_Steenhammera_); _Arnebia_; _Nonnea_ (small -ligules). - -=B.= The corolla-throat is closed by, or in any case provided with -_ligules_, _i.e._ scale-like bodies or small protuberances, situated -in the throat of the corolla _opposite_ the petals, and which are -invaginations or _internal_ spurs of the petals (Fig. 572 _D_).--The -nuts in _Cynoglossum_ (Hound’s-tongue) bear _hooked bristles_ over the -entire surface, or, in _Echinospermum_, only on the edge. The following -have smooth nuts:--_Symphytum_ (Comfrey) has a cylindrical, campanulate -corolla, and prolonged-triangular, pointed ligules.--_Borago_ -(Borage) has a rotate corolla with projecting, emarginate ligules; -the stamens have a horn-like appendage, projecting upwards from the -back of the filament. The fruitlets are hollow below.--_Anchusa_ -(Alkanet, Fig. 572). The corolla is salver-shaped; the ligules -small, hairy protuberances. _A. (Lycopsis) arvensis_ has an S-curved -corolla-tube.--_Myosotis_ (Forget-me-not, Fig. 573); rotate corolla -with small (yellow) protuberances in the throat; scorpioid cyme without -floral-leaves; fruitlets flat.--_Omphalodes_; fruitlets hollow at the -back, with a scarious, turned-in, toothed edge.--_Asperugo_ (Mad-wort); -the calyx grows after flowering, becoming large, compressed, and -deeply bifid. - - [Illustration: FIG. 572.--_Anchusa officinalis_: _A_ diagram; - the brocteole _a_ is suppressed (dotted); β supports a flower. - _B_, _C_ _Myosotis_, the fruit, entire and with the calyx in - longitudinal section. _D_, _F_ _Alkanna tinctoria_: D the corolla - opened (4/1); _e_ the ligule; _f_, _g_ the anthers; _E_ gyncœceum - (3/1); _F_ fruit, with three fruitlets; _i_ an aborted loculus; - _h_ disc.] - - CROSS-POLLINATION is most commonly effected by insects - (especially bees). There are a great many contrivances for - pollination; some flowers are protandrous (_Echium vulgare_, - _Borago officin._), others are heterostylous (long-and - short-styled: _Pulmonaria officin._); the corona (ligules) is - a protection against rain, and excludes certain insects. Some - are barren when self-pollinated (_Pulmonaria officinalis_, - _Echium vulgare_); others which have but little honey, may, - failing insect-pollination, fertilise themselves, and in - _Myosotis versicolor_ this regularly occurs by the growth of the - corolla during flowering, so that the anthers are brought into - contact with the stigma. Honey is secreted on the hypogynous - disc.--About 1,150 species, growing especially in the northern - temperate zone, _Mucilage_ is found (_e.g._ in the _officinal_ - root of _Cynoglossum officinale_, in the root of _Symphytum_): - red _dyes_ are found in some roots (_e.g._ Alkanet-root, the - root of _Alkanna tinctoria_, which is also medicinal; S. E. - Europe, Asia Minor); some are _poisonous_: _Cynoglossum_, - _Echium_, _Anchusa_, etc. Several species are ornamental plants. - _Heliotropium_ (Peru) is cultivated chiefly on account of its - pleasant scent; essential oils are otherwise very rare. - - [Illustration: FIG. 573.-_Myosotis._ Inflorescence and gynœceum.] - -Order 3. =Verbenaceæ.= The majority are shrubs; a few are herbs or -trees (Teak-tree); some are lianes. The branches are often square. -The leaves are opposite or verticillate, without stipules; in some -compound. The inflorescences are racemes, spikes, capitula, or -dichasia. Five sepals; five petals in a gamopetalous, zygomorphic -corolla, which is often bilabiate, but rarely to such an extent as in -the Labiatæ, and the upper lip in some is larger than the under, in -others smaller; stamens four didynamous, or two; the ovary is entire -(not grooved or divided), 1- or 2-locular, or, as in the Labiatæ, -divided into four loculi with an _erect_ ovule in each, but in some -the anterior carpel is suppressed. One _terminal_ style. The fruit is, -_e.g._ in _Verbena_, a 4 partite schizocarp with nut-like fruitlets; -in _Vitex_ (digitate leaves) a drupe with a 4-locular stone; in -_Clerodendron_ a similar fruit, with four free stones; in _Lantana_ -a bilocular stone, or two unilocular stones. The radicle is _turned -downwards_. Endosperm small or absent.--_Lippia_, _Stachytarpheta_, -_Bouchea_, _Priva_, _Citharexylon_, _Callicarpa_, etc.--The Verbenaceæ -are closely allied to the Labiatæ; they differ especially in the ovary -not being 4-lobed with gynobasic style, but undivided, almost spherical -or ovoid with a terminal style. Again, the leaves are not so constantly -opposite, and the inflorescences are various. - - 730 species; especially in the Tropics; there are several in - America, especially _Lantana-species_; shrubby weeds.--Many of - those mentioned are ORNAMENTAL PLANTS, especially _Verbena_; - _Vitex agnus castus_ is a S. European shrub. _Lippia citriodora_ - (S. Am.) etc., have strongly-scented leaves; the Teak tree - (_Tectona grandis_) is one of the largest trees in East India, - and has a very hard wood. - - _Avicennia_ is allied to this order; it inhabits the Mangrove - swamps on tropical coasts. The endosperm emerges from the ovule, - carrying the embryo with it; the embryo ultimately bursts the - endosperm and lies free in the loculus of the fruit; this is - then filled by the embryo with its large, green cotyledons, - which are borne on an already hairy or rooted stem. The seedling - thus developed falls from the tree, together with the fruit, and - strikes root in the mud. One special cell of the endosperm at - an earlier period becomes a highly-developed organ of suction, - growing into a much-branched sac, very rich in protoplasm. - -Order 4. =Labiatæ.= The special characteristics are: the _square_ stem, -the _opposite leaves_ (without stipules), the inflorescences which are -formed by _two double unipared scorpioid cymes_, the _labiate_ corolla, -the 4 _didynamous_ stamens (the posterior being entirely suppressed) -(Fig. 574), and the _4-partite schizocarp_ with _nut-like fruitlets_. -The floral formula is S5, P5, A5 (the posterior stamen is generally -absent), G2. - - [Illustration: FIG. 574.--Diagram of _Lamium album_: _sv_ - dichasia.] - -They are chiefly aromatic plants (herbs, shrubs, _e.g._ Lavender, -or trees), volatile oil being formed in internal cells or in the -glandular hairs, which cover all green parts. The stem is always more -or less markedly square; the leaves are borne upon the flat sides, -and are simple and penninerved, but vary in the other characters. -The inflorescences are double unipared scorpioid cymes, which may -be situated at some distance from one another in the axils of the -foliage-leaves (Fig. 575 _A_), but frequently when the subtending -leaves are bract-like, they are crowded into spike-like inflorescences -(_Lavandula_, _Mentha_, _Salvia_, etc.), each of the so-called “whorls” -(verticillaster, glomerulus) being a double unipared scorpioid cyme -(Fig. 574). (Solitary flowers are found in _e.g._ _Scutellaria_, and -_Origanum_). The calyx is strongly gamosepalous, 5-toothed, often -bilabiate (Fig. 575 _B_). The corolla is strongly bilabiate (Figs. 575, -576, etc.), with 2 lobes in the upper lip and 3 lobes in the under lip -(an approach to regularity occurs only when the upper lip is small, -and thus resembles one lobe, as in _Mentha_ (Fig. 578) and _Lycopus_, -so that the corolla approaches the 4-merous corolla of _Veronica_ -and _Plantago_). The posterior stamen in the diagram (Fig. 574*) -is entirely suppressed; in most of the genera the posterior lateral -stamens are the smaller (Fig. 575 _D_), and are entirely suppressed in -some (see below); in others, _e.g._ _Nepeta_, they are the longer. 2 -stamens are found in _Salvia_, _Rosmarinus_, _Lycopus_, etc. The two -halves of the anthers are often separated from one another, and are -placed at an angle with each other. The gynœceum has 1 style with a -bifid extremity (Fig. 575 _C_) bearing the stigma; the true bilocular -ovary is divided by a false partition-wall into 4 loculi, each with 1 -erect ovule (Fig. 575 _H_). These 4 loculi project so strongly that the -ovary becomes deeply 4-lobed with the style situated in the centre of -the lobes and at their base, “gynobasic” (Figs. 575, 579). A ring-like, -often crenate, nectary surrounds the base of the ovary (Fig. 575 _G_, -_H_). The embryo in this order, as in the _Verbenaceæ_, is directed -downwards (Fig. 575 _J_) (it is directed upwards in the _Boraginaceæ_, -which have an entirely similar fruit). _Endosperm absent._ - - [Illustration: FIG. 575.--_Thymus vulgaris._] - - The 142 genera are mainly distinguished according to the form of - the calyx and corolla, the number, direction, and length of the - stamens, the forms of the nuts, etc. - -=1.= AJUGEÆ, BUGLE GROUP. Calyx 10-nerved; the upper lip is small; 4 -stamens. The ovary is not so strongly lobed as in the following group, -so that it is most nearly allied to the _Verbenaceæ_. The nuts are -reticulately wrinkled. _Ajuga_ (Bugle) has a very small upper lip. The -upper lip of _Teucrium_ (Germander) is deeply cleft, and the two lobes -are bent on their respective sides towards the under lip, which in -consequence appears to be 5-lobed, and the upper lip to be wanting. - - [Illustration: FIG. 576.--_Lamium album_: _A_ lateral view of - flower; _B_ longitudinal section; _C_ ovary with nectaries (_a_); - _D_ the apex of the style; _e_, upper lip of corolla; _c_, _b_, - _c_ the three petals of the lower lip; _f_ anthers; _g_ stigma.] - -=2.= STACHYDEÆ, BETONY GROUP. The calyx is 5- or 10-nerved. The -upper lip of the corolla is most frequently _strongly arched_ or -helmet-shaped; 4 stamens, the _anterior pair the longer_ (Fig. 576). - -=a.= A somewhat regular and 5–10-dentate calyx with _projecting_ -stamens.--_Stachys_ (Betony, Woundwort); the lobes of the under -lip are rounded off. The anterior filaments, after pollination, -_bend outwards_. _Betonica_--_Ballota_ (Horehound); the calyx -is funnel-shaped, and has triangular, long, pointed, awn-like -teeth.--_Galeopsis_ (Hemp-nettle) has two conical protuberances on the -under lip between the lateral and the central lobes. The anthers open -by 2 _unequal_ valves. _Lamium_ (Dead-nettle, Fig. 576) has dentate, -lateral lobes on the under lip. _L. album_ (White Dead-nettle), _L. -rubrum_, etc. _Galeobdolon._--_Leonurus_; _Phlomis_. - -=b.= Tubular, regular, often 10-toothed calyx and _concealed_ -stamens.--_Marrubium vulgare_ (Fig. 577); 10 calyx-teeth, hooked at -the apex; many almost spherical whorls of flowers in the axils of the -foliage-leaves, at some distance from one another.--_Sideritis._ - - [Illustration: FIG. 577.--_Marrubium vulgare._] - -=c.= Strongly bilabiate calyx, the lips _closing together_ after -flowering.--_Scutellaria_ (Skull-cap); the two lips of the calyx are -entire, the upper lip has a large spur, and drops off on the ripening -of the fruit. The flowers are generally solitary and turned to one -side.--_Prunella_ (Heal-all); the calyx is compressed, its two lips are -strongly dentate, the upper lips closing slightly round the under. The -stamens have a tooth-like projection beneath the anthers. - -=3.= NEPETEÆ, CATMINT GROUP. 13–15 nerves in the calyx; this deviates -from the other groups in the _posterior stamens being the longer_. -The upper lip is slightly arched. _Nepeta_ (Catmint), also _Glechoma_ -(Ground Ivy), with regular, and _Dracocephalum_ with irregular calyx. - - [Illustration: FIG. 578.--_Mentha aquatica_, var. _crispa_.] - -=4.= SATUREIEÆ, MINT GROUP. The upper lip is _flat_, most frequently -ovate, or almost spherical, and emarginate (Fig. 578). The calyx -is most frequently 5–10-nerved. 4 stamens, _the anterior being the -longer_; rarely, 2 stamens only.--_Mentha_ (Mint, Fig. 578) has a -regular, 5-dentate calyx, a small, almost regular, 4-partite corolla, -and 4 erect stamens of nearly equal size. The verticillasters are -many-flowered, and are often collected into cylindrical inflorescences. -Herbs.--_Lycopus_ (Gipsy-wort); corolla almost regular. 2 stamens, -the posterior lateral ones are wanting. _Preslia_: 4-dentate calyx, -4-partite, regular corolla; 4 stamens of equal size.--_Thymus_ (Thyme, -Fig. 575) has a strongly bilabiate calyx, the throat being closed by -a whorl of hairs (Fig. 575 B). The corolla is distinctly labiate. -Under-shrubs, with small entire leaves; verticillasters few-flowered -and separate.--_Origanum_ (Marjoram); spike or capitate inflorescences -with the flowers solitary in the axils of the rather large and -distinctly 4-rowed (often slightly coloured) floral-leaves. _Melissa._ -_Calamintha._ _Clinopodium_ (Wild Basil). _Satureia._ _Hyssopus_ -(Hyssop); small, entire leaves; the verticillasters are situated -unilaterally in a slender, spike-like inflorescence. _Lavandula_ -(Lavender); shrubs with verticillasters collected in cylindrical, -long-stalked inflorescences; the calyx is tubular, has 13–15 nerves, -the posterior tooth is much larger than the others. Stamens and style -do _not_ project. ~_Coleus_ differs, among other characters, in having -united filaments; the stamens and style are bent down and concealed in -the boat-shaped under lip.~ - - [Illustration: FIG. 579.--_Salvia officinalis._] - -=5.= MONARDEÆ, SALVIA GROUP. _Only the 2 anterior stamens are -developed._--_Salvia_ (Fig. 579); calyx deeply bilabiate; the upper -lip of the corolla is generally strongly compressed. Rudiments of -the two lateral stamens are present. The connective in the two -fertile stamens is long and filamentous, and bears at the upper end -a normal half-anther, but at the lower one a barren, often broader -portion, against which the insect is obliged to push its proboscis -during its visits to the flowers, causing the pollen-bearing -half-anther to be pressed down against its back. Floral-leaves often -coloured.--_Rosmarinus_ (Rosemary); a shrub with leathery linear -leaves, with rolled back edge. A small tooth on the filament represents -the barren half of the anther. _Monarda._ - - The POLLINATION is generally effected by insects, especially - bees; the under-lip is the landing-stage and the pollen is - deposited on their backs. Cross-fertilisation is promoted by - dichogamy; honey is secreted by an hypogynous disc and collected - in the corolla-tube. Some genera are homogamous (_Lamium_, - _Galeopsis_, etc.); others are dichogamous (protandrous); a - few are _gynodiœcious_: ♀-and ☿-flowers in various relative - sizes (_Glechoma hederaceum_, _Thymus_, _Salvia pratensis_, - and others). The entrance of uninvited guests to the honey is - often rendered difficult by whorls of hairs, etc. In numerous - instances the upper lip protects the pollen from rain. - _Cleistogamy_ is found _e.g._ in _Lamium amplexicaule_. - - 2,700 species; distributed over the entire globe, but the - greater number in Mediterranean countries (especially in the - Eastern regions), where many are shrub-like.--Poisonous and - acrid properties are absent. On account of their _volatile oils_ - they are principally used as _condiments_, for _perfumery_ - and in _medicine_ (the officinal parts are therefore nearly - always “folia” and “herba,” in _Lavandula_ the flowers, and - the volatile oils extracted from them). Such are:[39]_Mentha - piperita_ [+] (Peppermint)--menthol is obtained from this - species and from _M. arvensis_--_M. viridis_ [+] (Spearmint), - _M. crispa_ (Curly-mint), _Thymus vulgaris_ (Garden Thyme), - _Melissa officinalis_ (S. Eur.), _Hyssopus officinalis_ - (Hyssop, S. Eur.), _Origanum majorana_ (Marjoram, from the - Mediterranean), _O. vulgare_ (Wild Marjoram), _creticum_, - _smyrnæum_, etc., _Salvia officinalis_ (S. Eur.), _Rosmarinus - officinalis_ (oil of Rosemary, S. Eur.), _Lavandula vera_ [+] - (oil of Lavender, S. Eur.). Also: _Satureia hortensis_ (S. - Eur.), _Ocimum basilicum_ (E. India), _Pogostemon patchouli_ - (E. India), etc.--As _ornamental_ plants, _e.g._ _Monarda_, - _Plectranthus_, and _Coleus_ (foliage-plants, often with red - stems and leaves), _Stachys lanata_ (white, woolly), _Phlomis_, - _Salvia_-species, _Perilla_, etc. - - Order 5. =Selaginaceæ.= 130 species; small, most frequently - heath-like shrubs or herbs, mainly from S. Africa. They - differ from the other Nuculiferæ especially in the bilocular, - transversely-placed anthers of the 4 stamens (2 stamens - divided as far as the base (?)). The ovary has 2, or by - suppression only 1 loculus, each with 1 ovule, and the fruit - is a schizocarp dividing into two, or is a 1-seeded nut. - Radicle turned upwards.--A few are ornamental plants (_Selago_, - _Hebenstreitia_). - - Order 6. =Globulariaceæ.= 12 species; especially in the - Mediterranean. They form an analogy to the Compositæ, and in the - main resemble _Jasione montana_ in appearance, the flowers being - crowded into a spherical head (hence their name) and supported - by bracts, but _without_ involucre; the ovary is _unilocular_ - with 1 pendulous ovule. The _1-seeded nut_ is enveloped by the - persistent calyx. The corolla is more or less labiate, the - upper-lip is often absent as in the ligulate corollas of the - Astereæ; stamens 4, didynamous, with transversely placed anthers - opening by one transverse cleft. The leaves are scattered, - simple, entire, and generally form a rosette. _Globularia._ - - Order 7. =Stilbaceæ.= Heath-like shrubs. The ovary is bilocular; - 1 erect seed in each loculus, or the posterior cell is empty. - _Stilbe._ 7 species. S. Africa. - - - Family 32. =Contortæ.= - -_Hypogynous_, regular, ☿, gamopetalous flowers (Figs. 581, 582), -which are generally 5- or 4-merous, with 5 or 4 stamens (with the -exception of _Oleaceæ_ and _Jasminaceæ_ which have _only_ 2 stamens, -alternating with the carpels). The gynœceum is formed of 2 (nearly -always median) carpels. The corolla _very frequently has twisted -æstivation_ (the upper edges of the petals being free; Fig. 581 _A_), -and hence the individual lobes of the corolla are oblique, but the -flower as a whole is regularly actinomorphic. A nectary, in the form of -a honey-secreting ring or glands, is often found round the base of the -ovary.--The leaves, with a few exceptions, are _opposite_ and _without -stipules_. Endosperm large (Fig. 581 _C_), except in _Jasminaceæ_ and -_Asclepiadaceæ_. - - The Apocynaceæ and the Asclepiadaceæ, on account of the free - ovaries, without doubt represent a more primitive form, but the - Asclepiadaceæ on the other hand form an offshoot on account of - their peculiar pollen-masses. The Loganiaceæ form a transition - to the Rubiaceæ. - - The orders are:-- - - A. STAMENS 5. 1, Gentianaceæ; 2, Apocynaceæ; 3, Asclepiadaceæ; - 4, Loganiaceæ. - - B. STAMENS 2. 5, Oleaceæ; 6, Jasminaceæ; 7, Salvadoraceæ. - -Order 1. =Gentianaceæ= (=Gentians=). _Glabrous_ herbs, without latex; -the opposite, undivided and _entire_ leaves are often slightly united -at the base; many have rosette-like radical leaves. _Stipules absent_. -The flowers are generally borne in regular, dichotomously-branched -_dichasia_ (Figs. 580, 581 _A_), which finally become transformed into -unipared scorpioid cymes; the parts of the flower are 4–5-merous as -far as the gynœceum, which is 2-merous; the calyx frequently is almost -polysepalous; the corolla has distinctly twisted æstivation (the upper -edges being free) (Fig. 581 _A_), except _Menyantheæ_. The carpels are -_entirely_ united, and most frequently form a _1-locular_ ovary with 2 -_parietal placentæ_ bearing many ovules (often in several rows, Fig. -581 _D_, _F_). _Capsule_, 2-valved, with septicidal dehiscence, the -incurved edges bearing the seeds (Fig. 581 _D_, _F_). - - [Illustration: FIG. 580.--_Erythræa._ Inflorescence. 1, 2, 3, - etc., the successive shoot-generations.] - -=1.= GENTIANEÆ.--_Gentiana_ (Gentian) has most frequently a tubular, -campanulate or funnel-shaped corolla, sometimes with teeth between the -corolla-lobes and fringed in the throat of the corolla; _G. lutea_ has -a rotate, yellow corolla.--~_Swertia_: rotate corolla; each lobe has at -its base 1–2 nectaries, with fringed edges.~ - -_Erythræa_ (Centaury, Fig. 581); corolla most frequently salver-shaped. -The anthers ultimately become spirally twisted (_E_). The style -prolonged, deciduous. The flower has the _Lobelia_-arrangement, -_i.e._ the median sepal is anterior; the corolla is rose-coloured (in -the native species). The capsule is semi-bilocular (Fig. 581 _F_, -_G_).--~_Cicendia_ has a low creeping stem, fine as a thread, and -small, yellow flowers, 4-merous (without twisted anther).--_Chlora_ -(Yellow-wort) 6–8-merous.~ - - [Illustration: FIG. 581.--_Erythræa centaurium._ Inflorescence, - flower and fruit: _br^1_, _br^2_ floral-leaves of the 1st and 2nd - order; _G_ a valve of the capsule separated from its fellow.] - -=2.= MENYANTHEÆ. _Menyanthes_ (Buck-bean) deviates in several respects -from the type of the order. The leaves are _scattered_ and, in _M. -trifoliata_, trifoliate; the corolla has _valvate_ æstivation; the -testa is also very hard (thin in the true Gentians). They are aquatic -plants with creeping rhizome; the flowers borne in racemes, with -terminal flower, heterostylous. The corolla is funnel-shaped with a -very hairy throat.--~_Limnanthemum_ with floating leaves, like the -Water-lilies.~ - - 575 species; distributed over the entire globe, but most - numerous in _Alpine_ districts. Neither poisonous nor nutritive - plants are found, but several are used in medicine on account of - the _bitter_ properties so prevalent amongst them. OFFICINAL: - the roots of _Gentiana lutea_. The roots of other species, - _e.g._ _G. purpurea_, _punctata_ and _pannonica_ (Europe) and - the leaves of _Menyanthes trifoliata_ are medicinal. Some are - grown as ornamental plants on account of the pure (often deep - blue) colour of the flowers. - -Order 2. =Apocynaceæ= (=Periwinkles=). Trees and shrubs (also lianes), -less frequently herbs, generally _with latex_. The leaves are -opposite, simple, entire, _without stipules_; the flowers are regular; -corolla-lobes oblique, æstivation twisted. The stamens are individually -free, and the _pollen-grains are free_ or at most united in fours (see -Asclepiadaceæ). The two carpels have 2–∞ ovules, in all cases there is -only 1 style and a capitate stigma, which towards the base is widened -out into a disc-like table (stigma-disc) abstricted in the centre; -but the carpels in most of the genera (_e.g._ those mentioned below) -are entirely separate, and the fruit consists of two _follicles_, the -seeds of which often have a tuft of _woolly hairs_ projecting from the -micropyle, less frequently of two drupes. In some other genera there -is a 1-locular (provided with 2 parietal placentæ) or a 2-locular ovary -becoming a 2-valved capsule or a berry. Endosperm abundant. - -_Vinca_ (Periwinkle) has a salver-shaped corolla, which is twisted -to the left in æstivation (_i.e._ the left edge of the petals is -free); nectaries 2, alternating with the carpels; the summit of the -style is hairy. Follicles; seeds without hairs. ~Mostly creeping, -perennial, evergreen plants, whose large flowers are apparently -axillary; in reality they are terminal, but by the development of -the bud in the axil of one of the two uppermost leaves, they are -thus displaced over the other leaf of the pair (a helicoid sympodium -being formed).--_Plumeria_, _Tabernæmontana_, _Cerbera_ (drupe). -_Aspidosperma._~ - -_Nerium_ (Oleander). The leaves are in whorls of 3. Corolla -funnel-shaped, in æstivation twisted to the right, and with a corona -resembling that of _Lychnis_. The anthers are prolonged at the base -and each also bears at the apex a long, linear, hairy appendage; these -finally become spirally twisted. Follicles; seeds hairy. _Apocynum_, -_Echites_, etc. _Epigynum_ is epigynous. - - 124 genera, 1,000 species; principally in the Tropics. Only 2 - species of _Vinca_ are natives of this country; the following - are cultivated as ornamental plants:--_Vinca minor_, _V. major_, - _V. (Lochnera) rosea_, _Amsonia salicifolia_, _Nerium oleander_ - (Eastern Mediterranean). The _latex_ of some is _poisonous_ - (_Tanghinia venenifera_, _Cerbera_). Caoutchouc is obtained from - others (_Hankornia_, _Landolphia_, _Vahea_, etc.). Tough bast is - frequently developed. The bark of _Aspidosperma quebracho_ and - the seeds of _Strophanthus hispidus_ are used in medicine (also - for African arrow-poison), the latter is officinal. - -Order 3. =Asclepiadaceæ.= A natural and easily recognised order, -closely allied to the Apocynaceæ, having, like it, frequently a -poisonous latex, opposite, single, entire leaves and fundamentally the -same floral diagram and floral structure (S5, P5, A5, G2); but in some -the æstivation of the corolla is valvate. The carpels here also have -_free ovaries_, but are united for some distance above into a _large, -shield-like, 5-angular head_, having on its underside the true stigmas, -and the fruit always consists of 2 _follicles_; seeds most frequently -numerous and _hairy_ at the micropyle (“vegetable silk”); endosperm -scanty.--The order is distinguished from the Apocynaceæ and from all -other plants also, except the Orchids, by having all the pollen-grains -in each of the =2= loculi of the anthers (true 2-locular anthers) -united into _one waxy, club-shaped pollen-mass_ (“pollinium”), for the -purpose of pollination by insects. These heavy masses, in order to -secure pollination (as in the case of the Orchids), must be attached to -sticky discs (corpuscula); there are 5 corpuscula, one at each of the -corners of the 5-angular stylar-head (alternating with the anthers), -and to each of these are attached 2 pollinia, one from each of the -anthers situated on either side (thus each anther gives its right -pollinium to one corpusculum and its left to another). The stamens are -frequently united at the base, and each bears on the back a variously -formed, petaloid appendage, termed a “cucullus.” - - [Illustration: FIG. 582.--_Asclepias cornuti._ _A_ An open flower - with the calyx (_k_) and corolla (_c_) turned down; the stamens - are bent together and surround the gynœceum. _B_ The andrœcium - after removal of the sterile part (cucullus) of the anther, which - functions as a nectary: _e_ the lateral expansions of the fertile - portion of the anthers; _f_ the slit between the expansions of - two contiguous anthers, through which the insect’s foot, and - later a pollinium which is caught by it, is dragged, and behind - which the only receptive part (stigma) is hidden; above the slit - _f_ is the gland (_r_), which secretes the horny corpusculum, - which is split at its base and joined on either side with a - pollinium (this is more distinctly seen in _D_ and _E_). When - the foot of the insect is caught in the slit (_f_) and is drawn - upwards, it becomes entrapped in the slit of the corpusculum, - which is then pulled out together with the pollinia firmly - attached to it. In walking over the flowers the insect will draw - its foot through other slits (_f_) and so leave the pollinia on - the stigmas. _C_, _D_ The gynœceum with the pollinia hanging - freely. _E_ A corpusculum and two pollinia.] - -A peculiar relative position (and therefore a good, distinctive -characteristic) is often found in the _inflorescence_, which is cymose; -it is placed _between_ the two leaves of a whorl, nearer to one than to -the other. ~The leaf-pairs are placed obliquely in the floral region, -at acute and obtuse angles, and not at right angles (as in the purely -vegetative parts); the inflorescences are placed in two rows only which -are nearly 90° from each other, and the two contiguous to one another -are antidromous; they are in reality terminal, each on its own axis, -and the entire floral portion of the shoot is a unipared scorpioid -cymose sympodium; in addition, complications also arise through -individual parts becoming united.--Herbs and shrubs, some twining or -climbing.~ - -In _Asclepias_ the corolla is bent back and there is a cup-like -cucullus, from the base of which protrudes a horn-shaped body, bent -inwards.--_Vincetoxicum_ has a rotate corolla and a ring-like, 5-lobed -cucullus, without internal prominences.--~_Stapelia_ (especially from -S. Africa) is remarkable on account of its Cactus-like, leafless stems -and large, brownish flowers, often with carrion-like smell. _Periploca_ -has more powdery pollinia (S. Eur., etc.); _Hoya carnosa_ (Wax-flower; -Trop. Asia) is a climber, and has small, annual, flower-bearing -dwarf-branches. _Ceropegia._~ - - 201 genera with 1700 species, distributed over all tropical - countries; few outside these limits: no native species. Several - are used in medicine on account of the pungent properties of the - latex. Condurango-bark of _Gonolobus condurango_ is medicinal. - Caoutchouc is obtained from the latex of some (_e.g._ from - _Cynanchum_). The seed-hairs, which are most frequently shining, - silk-like, and white, are not sufficiently pliant to be of much - value. Ornamental plants in our gardens: _Asclepias_-species, - etc. - - Order 4. =Loganiaceæ.= Ovary single, with two loculi, in - structure resembling the Rubiaceæ, but superior. 360 species - are included in this order; the majority are tree-like, some - lianes which climb by tendril-like branches. The _interpetiolar - stipules_ of some species are very characteristic (as in - Rubiaceæ, to which they maybe considered to be closely related). - The fruit is a capsule or berry. The most familiar genus - is _Strychnos_, which has spherical berries with an often - firm external layer, and compressed seeds with shield-like - attachments; endosperm abundant. The leaves have 3–5 strong, - curved nerves proceeding from the base.--_Spigelia._--They - have _no latex_, as in the two preceding orders, but many are - _very poisonous_ (containing the alkaloid “strychnine,” etc.); - the South American arrow-poison, urare or curare, is made from - various species of _Strychnos_, also an arrow-poison in the East - Indian Islands (Java, etc.). OFFICINAL, the seeds of _Strychnos - nux vomica_ (“Vomic nut,” Ind.). The seeds of _Strychnos - ignatii_ (Ignatius-beans, medicinal), and others are poisonous. - -Order 5. =Oleaceæ.= The leaves are always opposite. The inflorescences -are racemes or panicles. The calyx and corolla are _4-merous_, -more or less united, free in some species; the corolla has most -frequently _valvate_ æstivation. All four forms of fruit occur (see -the genera). _Ovules pendulous_, 2 in each loculus (Fig. 583 _C_). -Endosperm oily.--_Syringa_ (Lilac) and _Forsythia_ (anthers somewhat -extrose) have _capsules_ with loculicidal dehiscence and winged -seeds.--_Fraxinus_ (Ash) has _winged nuts_ (samara) (Fig. 583 _D_); -trees with most frequently imparipinnate leaves; the flowers are -_naked_ and sometimes unisexual (polygamous), the Manna Ash (_F. -ornus_) has however a double perianth with 4 free petals (Fig. 583 -_a_); in the native species, _F. excelsior_, the flowers open before -the foliage appears.--_Ligustrum_ (Privet) has _berries_.--_Olea_ (_O. -europæa_; Olive) has _drupes_; the pulp and seeds of the ellipsoidal -fruits are rich in oil. The lanceolate leaves are grey on the under -surface, being covered with stellate hairs. In the wild state it is -thorny (modified branches).--_Phillyrea_; _Chionanthus_.--Few species -of _Linociera_ have 4 stamens. - - [Illustration: FIG. 583.--_Fraxinus ornus_: _A_ flower; _ca_ - calyx; co corolla; _B_ gynœceum and calyx; _C_ longitudinal - median section of gynœceum; _D_ fruit.] - - 180 species; chiefly in the northern temperate zone. The - _Olive-tree_ (_Olea europæa_) has been an important cultivated - plant from ancient times (Olive oil, Provence oil, “Sweet oil”). - The best oil is extracted from the fruit-pulp. The fruits are - edible. Home: Western Asia, Eastern Mediterranean. TIMBER: - the Ash (_Fr. excelsior_). OFFICINAL: the Manna Ash (_Fr. - ornus_), cultivated in the Mediterranean countries for the - sake of its saccharine juice, which flows out and coagulates - into “Manna.”--The following are ornamental plants: species of - _Ligustrum_ and _Syringa_ (introduced in the 16th century, from - S.E. Europe and Asia), _Forsythia_ (China, Japan; the large, - yellow flowers are borne on dwarf-branches with scale-like - leaves, before the opening of the foliage-leaves), _Chionanthus_. - - Order 6. =Jasminaceæ.= The æstivation of the corolla is - _imbricate_; the _ovules are erect_; seeds almost without - endosperm; radicle directed downwards. The number of lobes - in the calyx and corolla is not 4, but _e.g._ 5, 8, 10, - and variations are sometimes found in the same individual. - The fruit is a berry or capsule. Many species are twiners, - and their scattered or opposite leaves are most frequently - imparipinnate.--120 species; especially in Trop. Asia (E. - India). Some _Jasminum_-species are cultivated as ornamental - shrubs in the warmer districts on account of their elegant - foliage, and beautiful, sweet-scented flowers, the essential - oil of which is also used in perfumery; the best known are: _J. - sambac_ and _grandiflorum_. _Nyctanthes arbor-tristis_ opens its - sweet-scented flowers only at night (E. India). - - Order 7 (?). _Salvadoraceæ._ 8–9 species; Asia, - Africa.--_Salvadora._ - - - - - b. Tetracyclicæ with epigynous flowers. - - - Family 33. =Rubiales.= - -_The leaves are always opposite or verticillate. The flower is -epigynous_, ☿, 5-(or 4-) merous, with the usual sympetalous diagram; -2–5 carpels. The inflorescences are frequently dichasial. The sepals -are small, reduced to teeth, and become almost entirely suppressed -in the higher forms.--The flower is regular in _Rubiaceæ_ and some -_Caprifoliaceæ_, but in other genera of this latter order (especially -of _Lonicereæ_) it is unsymmetrical. In several genera of the order -first mentioned the loculi of the ovary contain many ovules, but in -the last the number of loculi and ovules becomes reduced. This is to -some extent connected with the nature of the fruit which is many-seeded -in most instances, namely a capsule or berry, but in others nut-like. -Endosperm is present. - - The family on one side is allied to the Contortæ (not only - through the _Loganiaceæ_ but also through the _Apocynaceæ_), and - may be regarded as an epigynous continuation of this family; on - the other side it is allied to the Valerianaceæ and Dipsacaceæ. - Many points of agreement with the _Cornaceæ_ and _Araliaceæ_ are - also found, and in fact several Caprifoliaceæ are distinguished - from these by hardly any other feature than the gamopetalous - corolla. - - [Illustration: FIG. 584.--_Cinchona calisaya._ Flowering branch.] - -Order 1. =Rubiaceæ.= Leaves opposite (or verticillate), undivided and -entire, with _interpetiolar stipules_ (Fig. 586). Flowers epigynous -and hermaphrodite, _regular_, 4- or 5-merous with the usual arrangement -(Figs. 585, 588–590); corolla gamopetalous, in æstivation often -valvate; ovary _frequently 2-locular_. - - [Illustration: FIG. 585.--_Cinchona calisaya._ _A_ entire flower; - _B_ after removal of the corolla; _C_ longitudinal section of - ovary; _D_ fruit; _E_ seed.] - - There are no external characters which at once distinguish - this exceedingly large order, as in many other natural orders - (Compositæ, Umbelliferæ, etc.), but the _opposite_ leaves with - _interpetiolar stipules_ form an excellent mark of recognition. - It is divided into many sub-orders and groups, especially - characterised by the nature of the ovary (1 or several ovules - in each loculus), and of the fruit (schizocarp, berry, drupe, - capsule).--The corolla is bilabiate in 4 genera; its æstivation - in some is twisted; in _Capirona_, etc., the filaments are of - unequal size. The ovary is semi-epigynous in _Henriquezia_, etc. - In _Morinda_ all the fleshy fruits coalesce into one multiple - fruit. - -=1.= CINCHONEÆ. The fruit is a 2-valved _capsule_, with many winged -seeds (Fig. 585). _Cinchona_ (Quinine, Fig. 584). Trees and shrubs -with the foliage and inflorescence somewhat resembling _Syringa_; -the corolla also being of a lilac colour, more or less salver- or -funnel-shaped, and frequently edged with a fringe of hairs (Fig. 585), -is somewhat similar to that of _Menyanthes_. Their home is the Andes -from Bolivia to Venezuela, varying in altitude from 1–3000 metres. -There are now large plantations in Java and E. India. ~(The name -“quinine” is of Indian origin; that of the genus “_Cinchona_,” is from -the Spanish Duchess Cinchon, who in 1638 first introduced the bark into -Europe.) The following are closely allied: _Cascarilla_, _Remijia_, -_Ladenbergia_, _Manettia_, _Bouvardia_, etc.~ - -=2.= GARDENIEÆ. Trees and shrubs, frequently having a many-locular -berry. _Randia_, _Gardenia_, _Genipa_, _Hamelia_, etc. - -=3.= COFFEEÆ. Only 1 seed in each of the two loculi of the ovary; -_the fruit is a drupe with 2 stones_. _Coffea_ has an ellipsoidal -fruit about the size and colour of a cherry; the two thin-shelled, -parchment-like stones are enclosed by a thin layer of pulp; the two -seeds are flat on the side turned to one another, which has also a -deep, longitudinal groove curving to the sides. The endosperm is hard, -horny and greyish (without starch); the small embryo lies in the lower -end near the circumference. The Coffee-plant (_C. arabica_) is a small -tree, or more frequently, and especially in plantations, a shrub with -large dark-green leaves and scented, white flowers. Its home is in -Tropical Africa; it is now cultivated in many tropical countries. -_C. liberica_, W. Africa.--_Cephaëlis_ (_C. ipecacuanha_, Fig. 586; -the roots are officinal).--~_Psychotria_, _Chiococca_, _Ixora_, -_Hydnophytum_, _Myrmecodia_, etc.~ - - [Illustration: FIG. 586.--_Cephaëlis ipecacuanha._ Portion of a - branch: _st_ stipules.] - -=4.= SPERMACOCEÆ. Chiefly small shrubs and herbs, many of which -are weeds in tropical countries. The stipular sheaths bear -numerous bristles at the edge. _Spermacoce_, _Borreria_, _Diodia_, -_Richardsonia_, etc. - -=5.= STELLATÆ. _Herbaceous plants with_ verticillate leaves (Figs. -587, 588–590); _the stipules are large, leaf-like_, and resemble the -lamina of the leaves, so that _the leaves appear to be placed several -in a whorl_, while in reality there are only two opposite leaves, the -stipules of which project _freely_, and are not erect (Fig. 587). - - [Illustration: FIG. 587.--_Rubia tinctorum._] - -In some cases there are apparently 4 leaves in the whorl, and then 2 of -these are leaves, and the other two are their interpetiolar stipules. -When there are apparently 6 leaves, then the two of these which are -opposite each other are leaves, and the other four are stipules; -if there are several members in the whorl, then a division of the -stipules has taken place. The proof of this theory is founded upon -the fact that not more than 2 of the leaves of the whorl ever support -buds (which, in addition, are seldom of equal vigour), and also that -the whorls do not alternate with each other, which, according to the -rules of the position of the leaves, they should do if all the members -of a whorl had equal value. If there are, for instance, 4 members in -two successive whorls, they stand right above one another, and do not -alternate. The development and anatomical relations (the branching of -the vascular bundles) also point to the same conclusion.~--All the -other groups of the order have only 2 small scale-like interpetiolar -stipules, or they form at the base of the leaf-stalks an interpetiolar -sheath, having often a toothed edge (Fig. 586).--Another characteristic -feature in this group is that the calyx is rudimentary, the corolla -_valvate_ (Fig. 588), and that each of the two loculi of the ovary has -only 1 ovule. The fruit is a _schizocarp dividing into 2 fruitlets_ -(Fig. 590). ~The forms of the fruit, as well as many other characters, -as, for example, the epigynous flower, the rudimentary calyx, the two -free or almost free styles, present interesting analogous resemblances -to the polypetalous order of the Umbelliferæ.~ This group has its home -chiefly in the temperate regions of the northern hemisphere, especially -about the Mediterranean; it is the only group which occurs in this -country, represented by 4 genera. - - [Illustration: FIGS. 588–590.--_Rubia tinctorum._ - - FIG. 588.--Diagram. - - FIG. 589.--Longitudinal section of flower. - - FIG. 590.--Longitudinal section of fruit (3/1).] - -_Galium_ (Cleavers) is almost destitute of a calyx; it has a -small _4-partite, rotate corolla_, 4 stamens, and 2 free styles. -The fruitlets are _nut-like_. The inflorescence is a paniculate -dichasium passing into helicoid cymes.--_Asperula_ (Woodruff) is -distinguished from the above by its salver- or funnel-shaped corolla. -1 style.--_Rubia_ (Madder, Figs. 587–590) has almost the same form of -corolla as _Galium_, but (most frequently) a _5-merous flower_, and the -fruitlets are “_drupes_.” ~_Sherardia_ (Field Madder); the flowers are -clustered in closely arranged cymes surrounded by _an involucre_; _the -calyx has 6 distinct teeth_, while the number of petals and stamens is -4. The corolla is funnel-shaped.--_Vaillantia._ _Crucianella._~ - - The DISTRIBUTION OF SEEDS, in some instances, is promoted by - hooked appendages on the fruitlets (_e.g._ _Galium aparine_). - - The small flowers of the Stellatæ are frequently collected - in compact inflorescences, and are therefore rendered more - conspicuous; slight protandry is found in some, self-pollination - in the species which are less conspicuous. Many species are - heterostylous. _Myrmecodia_, _Hydnophytum_, and other genera - have large tubers (hypocotyledonous stems), whose labyrinthine - cavities and passages are inhabited by ants. - - About 4,500 species; tropical or sub-tropical except the - Stellatæ; especially American. The tropical ones are mostly - trees.--Several are ~OFFICINAL~ on account of the large - amount of _alkaloids_ and _glycosides_ which they contain. The - most important are the Cinchonas (_Cinchona calisaya_, _C. - succirubra_, _C. officinalis_, _C. micrantha_, etc.), whose bark - contains the well-known febrifuge and tonic, Quinine, Cinchonin, - etc.; Quinine is also found in _Exostemma_, _Ladenbergia_, and - _Remijia_. The root “Ipecacuanha” (an emetic) from _Cephaëlis - ipecacuanha_ (Brazils). Caffeine is officinal. The use of the - seeds of the coffee plant (“the beans”) was first known in - Europe in 1583.--There are only a few which contain _aromatic_ - properties, principally among the Stellatæ (coumarin in - _Asperula odorata_, the Woodruff), in which group _colouring - materials_ are also found. The root and root-stalks of _Rubia - tinctorum_, the Madder (S. Eur., Orient., Fig. 587), were - formerly largely used for dyeing, but are now superseded by - the analine colours. Red dyes are also obtained from the roots - of species of _Asperula_ and _Galium_. Gambier is a splendid - colouring material, obtained from _Uncaria gambir_ (S.E. Asia), - which is used in dyeing and tanning.--The order does not furnish - many ornamental flowers. - -Order 2. =Caprifoliaceæ.= This order agrees with the Rubiaceæ in having -opposite leaves and an epigynous flower, most frequently 5-merous -with the ordinary tetracyclic diagram, but in some species it is -zygomorphic; the corolla has imbricate æstivation, _carpels 3–5, most -frequently 3_ (not 2, which is the most usual number in the Rubiaceæ). -The fruit is generally a _berry_ or a _drupe_, but the most important, -and in any case most easily recognisable feature, is the _absence of -stipules_; in exceptional cases, where they are present, they are not -interpetiolar, and are most frequently small.--~The majority of plants -belonging to this order are shrubs or trees. Compound leaves sometimes -occur. Stipules only appear in a few species of _Lonicera_, _Sambucus_ -and _Viburnum_; in the common Elder (_Sambucus nigra_) they are in -some instances glandular and small, but in other cases larger and more -leaf-like (upon long, well-developed shoots); in the Dwarf Elder (_S. -ebulus_) they have the normal leaf-like form; in _Viburnum opulus_ they -are present as narrow lobes at the base of the petiole; in others they -are completely absent. The leaves are frequently penninerved, rarely -palminerved. The calyx, as in the Stellatæ and Aggregatæ, is often very -insignificant.~ - -=1.= LONICEREÆ, HONEYSUCKLE GROUP. This has _campanulate or tubular -corollas_ which are often zygomorphic; in connection with the length of -the corolla the _style is long, filamentous_, and most frequently has a -large, capitate stigma. There are _several ovules_ in the loculi of the -ovary, and the fruit is most frequently a _berry_. - - [Illustration: FIG. 591.--_Lonicera._] - -_Lonicera_ (Honeysuckle). Shrubs, sometimes twiners. The corolla in -some species is considerably bilabiate (Fig. 591), with 4 lobes in -the upper lip, and 1 in the under lip, but in others more regular, -tubular, or campanulate. The flowers are either borne in capitate -inflorescences, which are compound and formed of closely compressed -3-flowered dichasia (sect. _Caprifolium_), or in dichasia with 2 -flowers (the terminal flower is wanting). The ovaries and fruits -coalesce in some (sect. _Xylosteum_). ~The opposite leaves in some -species unite with each other and form a broad collar encircling the -stem (Fig. 591). Above the primary bud 1–2 accessory buds are often -found in the leaf-axils.--_Diervilla_ (_Weigelia_); with a 2-locular, -2-valved capsule.--_Symphoricarpus_ (Snowberry) has an almost regular, -funnel-shaped corolla; a peculiar feature is found in the ovary which -has 4 loculi, the 2 median having many ovules in 2 rows, all of which -are aborted; the 2 lateral ones, on the other hand, each have only 1 -ovule which is developed. Different forms of leaves are frequently -found on the same branch; they are entire or lobed.~ - -=2.= SAMBUCEÆ, ELDER GROUP (Fig. 592). This has a _rotate_, _regular -corolla_, extrorse anthers, a very short and thick (or almost absent) -_style_, with tripartite stigmas, and only 1 pendulous ovule in each of -the 3 (-5) loculi of the ovary. The fruit is a “_drupe_” with 1–3 (-5) -stones. The inflorescence is made up of _cymes grouped in an umbel-like -arrangement_. - -_Sambucus_ (Elder, Fig. 592) has _imparipinnate_ leaves and a “drupe” -with 3 (-5) _stones_. Between the calyx and the style a disc remains -on the apex of the fruit. _S. nigra_ with black fruit; _S. racemosa_ -with red fruit; _S. ebulus_ is a perennial herb; the others are -woody.--_Viburnum_ (Guelder-rose) has _simple_ leaves (penninerved -or palminerved, entire, dentate or lobed), and a “drupe” with only 1 -_stone_, which is compressed, cartilaginous, and parchment-like; 2 of -the loculi of the ovary are aborted. ~(In _V. opulus_ the marginal -flowers of the inflorescence are barren, and in that case their -corollas are generally specially large; the cultivated _Viburnum_ has -only barren flowers, with large corollas.)~ - - [Illustration: FIG. 592.--_Sambucus nigra_: _cor_ corolla; _s_ - calyx.] - -=3.= LINNÆEÆ. _Linnæa borealis_ (the only species) is an extreme form -of the order; it has a 2-flowered dichasium, funnel-shaped, slightly -bilabiate corollas (2/3); 4 didynamous stamens. Two of the 3 loculi of -the ovary have several ovules which are not developed, while the third -has only 1 ovule, which developes into a seed. The fruit is a nut, -which is enveloped by the two large bracteoles, which are covered by -sticky, glandular hairs, and serve as a means of distribution. It is a -small undershrub. - - [_Adoxa_, which was formerly classed in this order, appears, - according to recent investigations, to be more properly placed - among the Saxifraginæ.] - - In cases where the flowers are small, as in _Sambucus_ and - _Viburnum opulus_, they are rendered conspicuous by being - arranged in closely-packed inflorescences; they are massed - together and form large surfaces, and in the last named are - still more conspicuous on account of the barren, but large - ray-flowers, which are of service in this respect. Honey is - secreted in the nectaries at the base of the styles. In the - genera with rotate flowers, as _Viburnum_ and other Sambuceæ, - the honey lies so exposed and in such a thin layer, that only - flies and insects with short probosces can procure it; bees, - however, visit these flowers for the sake of the pollen. There - is hardly any nectar in the Elder; self-pollination frequently - takes place. The flowers of the Caprifoliaceæ, which, with their - long corolla-tube are adapted for evening-and night-flying - insects with long probosces, open in the evening, and at that - time give off their strongest scent. - - DISTRIBUTION. 230 species; especially outside the Tropics in the - Northern Hemisphere. In this country they are found especially - in hedges and as under-shrubs.--OFFICINAL: the flowers and - fresh fruits of the Elder (_S. nigra_), the fruits (“berries”) - being also used in the household. ORNAMENTAL SHRUBS: species of - _Lonicera_, _Symphoricarpus_, _Diervilla_, which are chiefly - from N. Am., _Abelia_ and _Viburnum_. - - - Family 34. =Dipsacales.= - -The leaves are _opposite and without stipules_. The flower (Figs. 593, -595, 598, 599, 600) is _epigynous_, _zygomorphic_ or _asymmetrical_, -5-merous with S5, P5, stamens typically 5, but by suppression _never -more than 4_, sometimes less, carpels 3–2. The calyx is more or -less insignificant, and almost suppressed in the extreme forms. The -ovary has 3–1 loculi, but _only one loculus_ has an ovule, which is -_pendulous_ with the micropyle _turned upwards_ (Fig. 594). Fruit a -nut. Embryo straight, with the radicle _pointing upwards_ (Fig. 597), -without or with endosperm. - -The inflorescences are distinct dichasia in Valerianaceæ, but in -Dipsacaceæ and Calyceraceæ they are crowded together into capitula. - - This family is closely allied to the Rubiales through the - Valerianaceæ, which have almost the same structure as many - of the Caprifoliaceæ. It attains the highest development in - the Dipsacaceæ, which are composite plants, but differs from - Compositæ in the position of the ovule, etc. - -Order 1. =Valerianaceæ.= Herbaceous plants or under-shrubs with -opposite leaves, often pinnate; stipules absent. The flowers are -borne in _dichasia_ and in _scorpioid cymose inflorescences_ and are -_entirely without any plane of symmetry_ (Fig. 593). The calyx and -corolla are 5-merous, but the calyx is frequently very insignificant -and ultimately a pappus, as in Compositæ; the corolla is frequently -saccate or produced into a spur at the base. Most frequently, only 3 -(4–1) of the 5 stamens are developed; these are free. Carpels =3=, -which form an inferior _ovary_, often with 3 _loculi_, but only _1 of -the loculi_ contains =1= _pendulous, anatropous ovule_ (Figs. 593, 594 -_A_), the other loculi are empty and shrink up more or less completely. -(Compare Fig. 593 _A_, _B_). Style 1, stigma tripartite. Endosperm -absent; embryo straight, with the radicle directed _upwards_. - - The inflorescences are dichasia, or unipared scorpioid cymes - with the branches developed in the axil of the second bracteole. - Both the bracteoles are generally present and frequently form - 4 very regular, longitudinal rows on the branches of the - inflorescence.--5 stamens do not occur (except perhaps in - _Patrinia_). The suppression of stamens and carpels takes place - most readily on the anterior side of the flower and that turned - towards the first bracteole (_a_) (Fig. 593), whose branch is - suppressed in the dichasium; after this the posterior median - stamen is next suppressed. - - By the vegetative characters as well as by the inflorescence - and the flower, the order is allied to the Caprifoliaceæ and - especially to the Sambuceæ. - - [Illustration: FIG. 593.--_A_ Diagram of _Valeriana officinalis_. - _B_ Diagram of _Centranthus_.] - -In the least modified (oldest) forms, _Patrinia_ and _Nardostachys_, -there is an almost regular flower, a 5-merous calyx, 4 stamens, and -3 loculi in the ovary, 2 of which however are barren. The stamens in -_Valerianella_ are reduced to 3, in _Fedia_ to 2 (posterior), and -the calyx is less distinctly 5-dentate; the 2 empty loculi in the -ovary are still visible. _Fedia_ has a small spur at the base of the -corolla. _Valeriana_ has a very reduced, hair-like calyx (pappus), an -unsymmetrical, salver-shaped corolla with a _sac-like_, nectariferous -spur at the base, 3 stamens and only 1 loculus in the ovary (Figs. 594, -593). _Centranthus_ (Fig. 593) is still further reduced. The corolla -has a spur and only 1 stamen; ~unipared scorpioid cymes with 4 rows -of bracteoles. In the last two genera there is a peculiar wall in the -corolla-tube, which divides it longitudinally into two compartments -(indicated by a dotted line in Fig. 593), one of which encloses the -style. This wall is low in _Valeriana_, but in _Centranthus_ it reaches -as far as the throat.--The rays of the _pappus_ are pinnately branched -and rolled up before the ripening of the fruit. 12–20 in number (Fig. -594 _A_, _B_).~ - - _Val. officinalis_ and others are protandrous: in the first - period the stamens project from the centre of the flower (Fig. - 595 _a_), the stigmas in the second (_b_) when the stamens have - become bent backwards. (_V. dioica_ is diœcious with large ♂-and - small ♀-flowers).--275 species; especially from the temperate - and colder parts of the northern hemisphere of the Old World, - Western North America and the Andes.--_Bitter_ properties are - characteristic, such for instance as the volatile acid and - volatile oil of _Valeriana_; these occur especially in the - rhizomes. OFFICINAL; the rhizomes of _V. officinalis_.--The true - Indian “Nardus,” an important medicine and perfume in India, - is extracted from _Nardostachys_ (Himalaya). A variety of - _Valerianella olitoria_ is sometimes used as salad. - - [Illustration: FIG. 594.--_Valeriana_: _A_ ovary (longitudinal - section); _B_ ripe fruit.] - - [Illustration: FIG. 595.--_Valeriana_: _a_ flower in the ♂ stage; - _b_ in the ♀.] - - [Illustration: FIG. 596.--_Centranthus ruber._ Flower, its - lowermost portion (the ovary and spur) in longitudinal section. - (Mag.)] - - [Illustration: FIG. 597.--_Scabiosa atropurpurea._ Fruit in - longitudinal section. Inside the “epicalyx” may be seen the fruit - drawn out into a beak, with straight embryo and radicle directed - upwards.] - -Order 2. =Dipsacaceæ= (=Teasels=). Herbs with _opposite_ leaves without -stipules. The flowers are situated in compact capitula each with an -involucre. A characteristic feature of the order is that _each flower_ -of the capitulum has a _gamophyllous_ “_epicalyx_” (Figs. 597, 599, -600), which envelopes the inferior ovary. The flowers (Figs. 599, 600) -are ☿, 5-merous (S5, P5, stamens typically 5, G=2=), but the calyx -often expands at the edge into a membrane with 5, or an indefinite -number of bristles or teeth (pappus, Figs. 597, 600), and the -_zygomorphic, funnel-shaped corolla_ is sometimes 5-lobed and bilabiate -(2/3), but most frequently 4-partite (Fig. 599), the two lobes of the -upper lip coalescing into one lobe, as in certain Labiatæ, _Veronica_ -and _Plantago_; the æstivation is _imbricate_. - - [Illustration: FIGS. 598–600.--_Dipsacus fullonum._ - - FIG. 598.--Inflorescence (the flowers in a zone below the apex - commence to flower first). - - FIG. 599.--Flower (4/1). - - FIG. 600.--The same in longitudinal section.] - -_The stamens are never more than 4_, the posterior one _remaining -undeveloped_; they _usually have free anthers_ which generally project -considerably (Fig. 599). The ovary is unilocular with 1 _pendulous_ -ovule and bears 1 _undivided style_; fruit a nut with 1 _seed, -containing endosperm_ and with the radicle turned _upwards_ (Fig. 597). - - The flowers do not always open in centripetal order, a fact - which may be observed especially in the Dipsacaceæ, in which a - zone of flowers round the centre of the capitulum opens first, - and the flowering then proceeds both upwards and downwards - (Fig. 598). This has probably some connection with the fact - that the capitulum has arisen from the coalescence of several - dichasial inflorescences. In species of _Scabiosa_ the flowers - open simultaneously at the circumference, or in a zone at the - centre.--The morphological explanation of the “_epicalyx_” - is not quite certain; in all probability it is formed from - two united bracteoles, for an “epicalyx” is distinctly formed - in this way in one of the Valerianaceæ, _Phyllactis_.--The - _ray-flowers_ are larger and more irregular, labiate or - ligulate, than the disc-flowers, yet not in so high a degree as - in the Compositæ. - -=A.= A scarious bract to each flower. _Scabiosa_ has a 5-lobed -corolla; the “epicalyx” has a dry, scarious, often finally large -collar, and the true calyx is formed of long bristles (generally 5) -(Fig. 597). _Succisa pratensis_ (Devil’s-bit) has a 4-lobed corolla, -the collar of the “epicalyx” is herbaceous; the calyx as in the -preceding.--_Pterocephalus._--_Dipsacus_ (Teasel); large, spiny and -stiff-haired herbs with capitula, or short, thick spikes on which -both the involucral-leaves and bracts project considerably, and are -stiff and spinose (Fig. 598). The “epicalyx” has short teeth, or is -almost entire. ~The leaves of the stem unite together in pairs, so -that shallow cups are formed round the stems in which rain-water may -collect.--_Cephalaria._--_Morina_: the flowers are falsely verticillate -as in the Labiatæ; the calyx has 2 laterally-placed, entire, or -emarginate lobes; 2 stamens, or 2 large and 2 small ones.~ - -=B.= Bristles, but _no_ true bract to each flower. _Knautia_; the -corolla is 4-partite, the calyx cup-like, with many bristles or teeth -on the edge. - - POLLINATION is in many species effected by insects. The - honey is secreted by a ring round the base of the style. The - flowers in our native species are considerably protandrous. - Gynodiœcious flowers also occur.--150 species; especially in - the Mediterranean and the Orient; the order is not represented - in the South Sea Islands, Australia and America.--The heads of - the true Teasel (_Dips. fullonum_) are used for carding wool, on - account of the elastic bracts, which are hooked at the point. - The order has bitter properties; tanin, etc.; but no species are - used in medicine or the household.--_Scabiosa atropurpurea_, - etc., are used as ornamental plants. - - Order 3. =Calyceraceæ.= This order resembles the Compositæ in - the valvate æstivation of the corolla and the more or less - united stamens, and the Dipsacaceæ in the undivided style, - pendulous ovule and endosperm. The calyx is frequently composed - of 5 distinct scales. An “epicalyx” is wanting.--20 species; - America. - - - Family 35. =Campanulinæ.= - -The flower is _epigynous_, perfect, with 5 sepals, 5 petals, and 5 -stamens in regular alternation, and =3= (2–5) carpels. The sepals -in all cases are _distinct_, but narrow and pointed, so that the -æstivation is open. The corolla is gamopetalous with (as in the -Compositæ) _valvate_, or slightly infolded-valvate æstivation. The -stamens are nearly always _situated on the torus_ without being united -to the corolla (Figs. 601, 604). The anthers adhere or unite and form -a tube with introrse anthers from which the pollen is swept out by the -projecting, brush-like hairs on the style (as in the Compositæ). The -ovary is =3=-(2–5) locular, _many ovules_ in each loculus. The fruit is -generally a _many-seeded_ capsule (or berry). Embryo in the centre of -a fleshy _endosperm_.--The majority are herbs with scattered leaves, -without stipules. The presence of _latex_ and _inulin_, together with -the tubular formation of the anthers, the pollination, etc., indicate -a relationship with the Compositæ. - - The _Cucurbitaceæ_ are by some authorities placed in this family - as being most closely related to the Campanulaceæ. Although the - corolla is most frequently gamopetalous, and other similarities - to the Campanulaceæ are present, yet on account of the structure - of the ovule, and for other reasons, the Cucurbitaceæ are - here placed in the Choripetalæ. The Campanulinæ without doubt - proceed upwards to the Compositæ, with which, in addition to - the occurrence of inulin and laticiferous vessels (Cichorieæ), - there are many corresponding features both in the structural - and biological relations (epigyny, valvate æstivation of the - corolla, tendency of the anthers to adhere or unite, protandry - with a stylar-brush, etc.) The inflorescence of _Jasione_ is - almost identical with that of the Compositæ. - -Order 1. =Campanulaceæ= (=Campanulas=). The flowers are _regular_ and -in some only semi-epigynous, 5-merous, except in the gynœceum which is -3-merous (the unpaired, median carpel being generally posterior), more -rarely 2–5-merous, and has a corresponding number of stigmas and loculi -in the ovary; the placentation is axile with a large number of ovules. -The median sepal is posterior. The stamens frequently have broad, free -bases (Fig. 601 _H_) which cover the nectariferous upper surface of -the ovary; the anthers only fit loosely together, and become separated -as soon, as the pollen is shed (Fig. 601 _G_), 1 long style, which -is studded by sweeping-hairs (stylar-brush), which ultimately become -invaginated; the stigmas do not unfold until the stamens have shed -the pollen (Fig. 601 _E_, _G_). Fruit a capsule.--Herbs, more rarely -under-shrubs or shrubs, with latex and scattered, undivided leaves -without stipules. The inflorescence is most frequently a raceme or -spike _with_ terminal flower. - -=A.= Capsule opening at the side by pores and small valves: _Campanula_ -(Canterbury-bell); the corolla is bell-shaped, rarely almost rotate; -capsule obconical. ~The pores of the capsule are found near the top of -the fruit when it is erect, and near the base when it is pendulous, so -that the seeds are not liberated unless the capsule is forcibly shaken, -and they are thus ejected to a considerable distance.~--_Phyteuma_ -(Rampion) has free petals, which for a long time adhere at the -apex and form a tube round the stamens (Fig. 601); inflorescence -compact, spike-like or capitate, in the latter case resembling -that of the Compositæ, and frequently with an involucre similar to -the one possessed by this order. ~_Specularia_ (rotate corolla, -prismatic capsule), _Michauxia_ (flower 8-merous).--_Symphyandra_ has -syngenesious anthers.~ - -=B.= Capsule with valves at the apex, loculicidal dehiscence: -_Jasione_; the petals are almost free. The anthers are united at the -base (syngenesious). The flowers are situated in capitate umbels with -involucres.--_Wahlenbergia_; _Platycodon_. - - [Illustration: FIG. 601.--_Phyteuma spicatum._ Flowers and parts - of flowers in various stages of development.] - -=C.= Berry: _Canarina_; flower, 6-merous; leaves opposite. - -Protandry is general (Fig. 601). 510 species; principally in temperate -countries. Several genera furnish ornamental plants, but are of -little use for other purposes. The roots of some _Campanula_-and -_Phyteuma_-species are large and may serve as pot-herbs (_C. -rapunculus_, _P. spicatum_). - -Order 2. =Cyphiaceæ.= In this order the corolla is zygomorphic and the -stamens free, hence it is intermediate between orders 1 and 3.--About -24 species; Africa. - -Order 3. =Lobeliaceæ= (=Lobelias=). This order may briefly be described -as Campanulaceæ with _zygomorphic_ flowers and anthers _united into -a tube_, in most cases slightly bent; generally 2 carpels and an -_inverted_ position of the flower, _i.e._ the median sepal is turned -anteriorly (Fig. 602) (a position which is found to occur within the -Campanulaceæ). A twisting of the peduncle takes place even before -flowering (as in the Orchids) so that the ordinary position of the -5-merous Dicotyledons appears to be restored. The zygomorphy of the -flower is especially present in the corolla, which has a _bipartite_ -under-lip and a _tripartite_ upper-lip, and is, in _Lobelia_, -anteriorly (apparently posteriorly) deeply cleft (Fig. 602). There -is 1 style, but the stigma is capitate and bilobed and surrounded -at its base by a _whorl of hairs_, which assists in pollination -(as a stylar-brush) in the same manner as the sweeping-hairs in the -Campanulaceæ and Compositæ. There is _no terminal flower_ in the -spicate, or racemose inflorescences.--_Lobelia_ has a capsule, several -others have berries. ~_Isotoma_ (regular flower); _Heterotoma_ has a -spur; _Siphocampylos_; _Lysipoma_ (pyxidium); _Clintonia_ (1–locular -fruit). _Metzleria_ (all the petals are free).~ - - [Illustration: FIG. 602.--Diagram of _Lobelia fulgens_.] - - [Illustration: FIGS. 603, 604.--_Lobelia syphilitica._ - - FIG. 603. Flower (2/1). - - FIG. 604.--Longitudinal section of the same.] - - Entomophilous and protandrous. About 500 species, especially - in the Tropics; in this country, _L. dortmanna_ (margin of - lakes).--Several are cultivated in gardens and conservatories as - ornamental plants (_Lobelia bicolor_, _erinus_, _fulgens_, etc., - _Siphocampylos_, _Centropogon_). The latex of several species - of _Tupa_ is poisonous; caoutchouc is also obtained from them. - OFFICINAL: “herba _Lobeliæ_” (the alkaloid lobeline) from the - poisonous _L. inflata_ (N. Am.). - - Order 4. =Goodeniaceæ.= Chiefly Australian (200 species), - closely related to Orders 3 and 5, but without latex. The style - is provided with a “collecting-cup” which receives the pollen - before the flower opens; it has a small, hairy aperture through - which the pollen is forced out by the stigmas, and through - which they emerge when the pollen is shed; it is sensitive and - exhibits movements when touched.--Herbs, under-shrubs, less - frequently shrubs. _Goodenia_, _Leschenaultia_, _Scævola_. - - Order 5. =Stylidiaceæ= (or =Candolleaceæ=); 100 species, - the majority Australian; zygomorpbic flowers, but with the - ordinary position. The anterior petal is very small. The chief - characteristic feature is the presence of only 2 stamens (with - extrorse anthers) which are united with the style and form a - _stylar-column_; this is bent like a knee and sensitive at - the bend to such a degree that when touched it jerks violently - across the flower to the opposite side and then loses its - sensitiveness.--Herbs, less frequently under-shrubs. _Stylidium_ - (_Candollea_). - - - Family 36. =Aggregatæ.= - -The flowers, which are borne in “capitula” (Figs. 605, 610), are -_epigynous_ (Fig. 605 _C_, _D_), _5-merous_ in the calyx, corolla and -andrœcium, the corolla is _valvate_ in æstivation, with =2= carpels -(S5, P5, A5, G2). The anthers are united into a tube (syngenesious) -(except _Ambrosieæ_) which surrounds the bifid style. There is never -more than =1= _loculus_ in the ovary, with =1= _erect_, anatropous -ovule. The fruit is a 1–seeded nut (cypsela), with thin pericarp, the -calyx generally persists as a tuft of hairs (_pappus_) (Fig. 606) -on the summit of the fruit. Embryo _without endosperm_; the radicle -_directed downwards_. - -Only 1 Order: Compositæ. - -With respect to the inflorescence and the development of the individual -flowers, there is a very close resemblance to the Dipsacaceæ, which -stand on the same plane of progression as the Compositæ. But while -the latter are allied to Campanulinæ as the last stage in the -process of evolution, the Dipsacaceæ form the final stage of the -Rubiales-Dipsacales. - -Order =Compositæ=. (For the principal characteristics compare those -of the family.) The Compositæ are chiefly herbs, but trees and shrubs -also occur in tropical countries. The leaves may be scattered or -opposite, but have no stipules. The outer leaves of the _involucre_ -as a rule are barren, especially when numerous and imbricate, while -the innermost ones support the ray-flowers of the capitulum; in a -few instances all are fertile (_e.g._ _Tragopogon_, _Tagetes_). The -CAPITULA are many-flowered, with the exception, _e.g._ of _Echinops_, -which has 1-flowered capitula (see page 570). The capitula are again -arranged in inflorescences, most frequently corymbose with centrifugal -order of development. The _form of the receptacle_ is an important -character for the division of the genera (flat, convex, conical), and -also the _presence of scales_; these may be one scale (bract) for -each flower (Fig. 610 _br_), or a large number of bristles, which -do not each correspond to a leaf, or the receptacle may be entirely -without covering (_naked_). The flowers open in acropetal order in each -capitulum. All the flowers in a capitulum may be of the same _sex_, and -their form and colour are in that case the same, or the sexes may be -different, in which case the form and colour are also most frequently -different: the ray-flowers have projecting labiate or ligulate -corollas, while the disc-flowers have tubular corollas. As a rule in -the latter case the ♀ flowers are at the circumference, and the ☿ in -the centre, less frequently ♀-flowers at the edge and ♂-flowers in the -centre. The ray-flowers in some genera are neuter (_e.g._ _Centaurea_). -Some are diœcious. - - [Illustration: FIG. 605.--_Calendula arvensis_: _A_ capitulum; - _B_ capitulum in longitudinal section; _C_ ♀-flower; _D_ - ☿-flower; _E_ the stamens; _F_ capitulum with ripe fruits; _G_ - ripe fruit.] - -There is no trace of an epicalyx (in contrast to the Dipsacaceæ, which -they generally so resemble). The formation of the CALYX is very varied. -The calyx always consists of a very small cushion-like structure, -most frequently developed later than the corolla; the 5 corners, -which correspond to the 5 sepals, in a few instances are raised as 5 -large, flat, membranous bodies, _e.g._ in species of _Xeranthemum_, -_Catananche_, _Sphenogyne_, etc.; in other instances each of these -bears a shorter or longer bristle on its apex, followed by others in -rather uncertain numbers and with but slight indications of order, on -the edge and on the outer side of the calyx between the 5 points; in -other instances, again, the calyx is covered with bristles and hairs -without any indication of order or definite number (Fig. 606 _a_, _b_); -finally instances occur in which the edge is raised as a membranous -collar, irregularly toothed and notched, or divided into small -scales. There are naturally differences in the means of distribution -corresponding to the differences in structure of the calyx. The fruits -_a_ and _b_ represented in Fig. 606 are distributed by the wind, those -like _c_, on the other hand, by attaching themselves to animals and -human beings. The rays of the pappus are termed _rough_ when special -cells project a little beyond the surface, but if these grow out, and -are hair-like, the pappus is said to be _feathery_. In some genera the -pappus is raised on a long stalk, which is developed from the upper -part of the fruit, and termed a _beak_ (Fig. 606 _a_). The pappus does -not attain its full development till the ripening of the fruit, _i.e._ -until it is about to be of use. - - [Illustration: FIG. 606.--_a_ Fruit of _Taraxacum_; _b_ of - _Senecio_; _c_ of _Bidens_.] - -The COROLLA has various forms: (_a_) _tubular_ (Fig. 605 _D_), with -a shorter or longer tube, not always of the same bore throughout and -especially slightly widened at the top to form a bell-shaped opening, -with 5 _regular_ teeth: (_b_) _labiate_ after 2/3, _i.e._ with 2 petals -in the upper and 3 in the under lip: (_c_) _ligulate_, _i.e._ the -corolla is split for a considerable distance on the posterior side (as -in the Labiate genus _Teucrium_) and prolonged into a long, strap-like -portion (Fig. 609 _A_), which projects upwards. A distinction must, -however, be drawn between the true and false ligulate corolla. In the -first case the corolla has 5 teeth at the apex (Fig. 609 _A_) and -is made up of all the petals of the corolla united together; this is -the usual condition in the _Ligulate-flowered_. In the latter case -(Fig. 605 _C_) the tongue has only 3 teeth (or is more irregularly -2–3-dentate), and is only formed of 3 petals; the corolla is then truly -bilabiate, the tongue is the large under lip, and the upper lip is very -slightly developed, or even at an early stage quite suppressed. This -false “ligulate” corolla is found among the _ray-flowers_; sometimes -the upper lip is seen quite plainly, _e.g._ in _Tagetes_, especially in -the double capitula. ~The VENATION of the corolla is peculiar; there -are always commisural veins which branch dichotomously at the angles -between the teeth of the corolla, and send a branch into the edge of -the two nearest teeth. The midrib is frequently absent, but may be -present, and then it has sometimes no connection with the other veins -of the corolla.~ - - [Illustration: FIG. 607.--_Centaurea cyanus_: _A_ the anther-tube - (_st_) with the crescentic curved filament before irritation; - _g_ the style; _k_ the base of the corolla; _B_ the same after - irritation, the anthers are drawn further down.] - -The STAMENS are attached to the corolla, and have free filaments -(_Silybum_ has united filaments), but the anthers, which at first are -free, adhere together and form a tube (Fig. 605 _E_: only _Ambrosieæ_ -have free anthers). The _connective_ is generally prolonged, and -protrudes above the anthers as a thin, brown membrane of various forms -(Fig. 605 _E_); appendages of various forms may also be found at the -base of the anthers. The anthers open introrsely, and the pollen must -be carried out at the top of the tube by upward growth of the style, -and by means of the “stylar-brush” (Figs. 607, 608, 609); the filaments -are sometimes sensitive (_e.g._ in the Corn-flower, Fig. 607), and -shorten on being touched, so that the anther-tube is pulled downwards, -and the pollen swept out at the top (Figs. 607, 608 _A_, _B_). - - [Illustration: FIG. 608.--_Cirsium arvense_: _A_ the upper - portion of a flower, the pollen (_e_) is being ejected; _B_ part - of the upper portion of the style with stylar-brush (_b_, _c_) - and the stigmatic papillæ (_d_).] - - [Illustration: FIG. 609.--_Leontodon autumnale_: _A_ ligulate - flower; _B_ extremity of the style with stylar-brush (_a_), - stigma (_b_) and pollen-grains (_c_). _C_ _Centaurea cyanus_.] - - [Illustration: FIG. 610.--_Achillea millefolium._] - -The STYLE divides at the apex into two branches (Figs. 609, 610), -both of which generally bear on the inner surface two lines of -stigmatic papillæ (Fig. 610 _B_, _C_) and being in shape, etc., -very varied, are therefore employed as systematic characters.--~The -most important types are: =A.= The style is uniformly cylindrical; -its branches are semi-cylindrical, long, and with long hairs, and -finally bend backwards; the stylar branches bear slightly projecting -stigmatic papillæ on the inner side. This form is characteristic -of the _Cichorieæ_ (Fig. 609 _A_ _B_). =B.= The style is uniformly -cylindrical; the branches are long, cylindrical or club-like, short, -not rolled back, with fine hairs externally; the stigmatic lines do -not reach beyond the centre, and do not meet together. Characteristic -of _Eupatorium_, _Petasites_, _Tussilago_. =C.= The style is thickened -beneath the stigmatic branches in the form of a knob, or very hairy -(Fig. 609 _C_); the stigmatic lines reach as far as the apex of the -branches and then converge; sometimes the stigmatic branches are -united as far as the apex. Characteristic of the _Cynareæ_. =D.= The -stylar branches are lanceolate, or linear, pointed; externally flat -and thickly covered with hairs in the upper portion; the stigmatic -lines cease where the hairs commence externally. Characteristic of -_Aster_, _Bellis_, _Inula_, _Dahlia_, etc. =E.= The stylar branches are -linear, with long, brush-like hairs at the apex, where they are either -abruptly cut off or prolonged into a very hairy, conical appendage; -the stigmatic lines are broad, _reach as far_ as the brush-like hairs, -and do not meet together (Fig. 610). Characteristic of _Senecio_, -_Helianthus_, _Xanthium_, _Gnaphalium_, _Artemisia_, _Anthemis_, and -others related to these.~ - -A _ring-like nectary_ is found round the base of the style. - -The thin-walled _cypsela_ (Fig. 606), with seeds fitting closely -to the pericarp, has many different forms (smooth, ribbed, spined, -etc.); its point of attachment generally lies at the lowest end but -sometimes it is drawn obliquely up the side (_Centaurea_, etc.). -The calyx, persistent on the apex of the fruit, has been described -above. Some genera have two or three different forms of fruits in -each capitulum.--The embryo is straight, with the radicle _turned -downwards_, and _without endosperm_, but is rich in oil. - -The variously flowered capitula, whose normal tubular disc-flowers have -been changed to ligulate flowers, may be termed “double flowers.” - - The relationship of the Compositæ to the Campanulinæ has been - described above (page 561). The alliance with the Dipsacaceæ - is more apparent than real. Similar capitate inflorescences - also occur as the final stage in other lines of descent, as in - _Eryngium_ among the _Umbelliferæ_. - -=1. Cynareæ, Thistle Group.= Flowers all ☿, regular, with _tubular_ -corollas. The receptacle is covered with numerous _bristles_, which -surround the flowers without any definite order, or the edges of the -grooves in which these are placed have a well-marked fringe. The -involucral leaves are numerous, imbricate, and are either prolonged -into a _thorn_ or terminate with a _membranous edge_. The style has -been described on page 568 (Fig. 609 _C_). Nearly all have a hairy or -feathery pappus. The filaments are sensitive. - -_Carduus_ (Thistle); capitula ovoid; involucral leaves compact, -imbricate, with thorny points; the pappus-rays are _hair-like_ -and united at the base by a ring (_i.e._ the calyx), and fall off -together.--_Cirsium_ (Fig. 608) has a _feathery_ pappus, in other -respects it is like _Carduus_. ~_C. arvense_ reproduces and passes -the winter by means of suckers.~--_Cynara_ (Artichoke) has a feathery -pappus and large, _solitary_ capitulum, with broad involucral leaves; -these have a fleshy base like the receptacle (edible).--~_Silylum_ -has united filaments. _S. marianum_ (Milk-thistle), has leaves with -numerous _white spots_. _Onopordon_ (Cotton-thistle). _Cnicus_ (_C. -benedictus_) has a large, many-spined thorn on the involucral leaves; -pappus trimorphic.~--_Lappa_ (Burdock) is easily recognized by the -_hooked involucral leaves_, which assist in the distribution of the -fruit; in this respect it differs from the other inflorescences, -and also in the fact that the pappus is short, and quickly falls -off, without serving as a means of distribution.--~_Carlina_; the -external involucral leaves are _leafy_, _thorny_, with branched -or unbranched spines standing straight out or bent backwards; the -_internal ones are dry_, and prolonged as _dry_, _coloured_, radiating -_scales_. The well-developed bristles on the receptacle and edge of -the calyx are _deeply cleft and lobed_.~--_Centaurea_ (Knap-weed, -Fig. 607). The ray-flowers are neuter, and generally larger than the -disc-flowers; the involucral leaves are regularly imbricate, but are -frequently provided at the apex with a dry, chaffy, often lobed, -fringed appendage. The attachment of the fruit is lateral. _Serratula_ -(Saw-wort).--~_Carthamus_, the outer and inner involucral leaves -differ very much.~--_Echinops_ (Globe-thistle) is characterised by -having “compound capitula,” _i.e._ there is only one flower in each -capitulum, but many such capitula are collected into a spherical head, -which at the base may also have a few involucral leaves. The individual -capitula have narrow, linear involucral leaves. ~(There are altogether -about 150 species of Compositæ with 1-flowered capitula, all from warm -countries.)~--_Xeranthemum_, _Staehelina_, _Jurinea_, _Saussurea_, etc. - - =2. Mutisieæ, Labiate-flowered Group.= Tropical (S. American) - forms whose zygomorphic flowers have a bilabiate corolla (2/3). - The involucre is nearly the same as in the Thistles. - -=3. Cichorieæ, Chicory Group= (or LIGULIFLORÆ). The flowers are all -☿ and have a _ligulate, 5-dentate_ corolla. The stylar branches are -thin and prolonged (Fig. 609 _B_). _Laticiferous vessels_ occur -in the majority (in this feature they resemble the Lobeliaceæ and -Campanulaceæ). - -=A.= The pappus is _wanting_, or it is _scale-like_, but not long and -hairy.--_Cichorium_ (Chicory); capitula with _blue flowers_, borne -singly or a few together in the leaf-axil; there are two whorls of -involucral leaves, an outer one of short and radiating, an inner of -more numerous, longer and erect leaves; pappus, scale-like.--_Lapsana_ -(Nipplewort). The few involucral leaves are nearly of the same size, -and persist forming a sort of capsule round the fruits, which are -entirely without a pappus. There are only a few flowers in the small -capitula.--_Arnoseris_ (Swine’s-succory), _Catananche_, etc. - -=B.= The pappus is long and _hairy_ (not branched), generally fine -and snowy-white. There are _no scales_ on the receptacle. The two -genera first considered have _beaked_ fruits.--_Taraxacum_ (Dandelion) -(Fig. 606 _a_); the capitula are many-flowered, and borne singly -on the top of a leafless, hollow stalk.--_Lactuca_ (Lettuce) has -many small, few-flowered capitula borne in panicles.--_Crepis_ -(Hawksbeard).--_Hieracium_ (Hawk-weed) has many imbricate involucral -leaves, and a stiff, brittle, brownish pappus.--_Sonchus_ -(Sow-thistle); the capitula, when a little old, have a broad base, and -are abstricted above in the form of a jug; involucral leaves imbricate; -the fruit is compressed, without a beak, ridged. The soft, white pappus -falls off collectively. - -=C.= The pappus is _feathery_ and branched; no scales on the -receptacle.--_Tragopogon_ (Goat’s-beard) generally has 8 involucral -leaves in one whorl. The fruit has a long beak; the rays of the pappus -are interwoven in the form of an umbrella.--_Scorzonera_ has fruits -like the preceding, but almost without any beak; involucral leaves -many, imbricate.--_Leontodon_ (Hawkbit) has a slightly feathery pappus, -rays not interwoven; beak absent.--_Picris._ - -=D.= Long, chaff-like, deciduous scales on the receptacle; pappus -_feathery_.--_Hypochœris_ (Cat’s-ear). - -=4. Eupatorieæ, Hemp-agrimony Group.= All the flowers are most -frequently ☿; corollas tubular and regular; the involucral leaves are -not stiff and spiny; the receptacle is not covered with stiff bristles. -The stylar branches are long, club-like, or gradually tapering. There -is no swelling below the stigma. - -_Eupatorium_ (Hemp-agrimony); all the flowers are ☿.--_Petasites_ -(Butterbur); ray-flowers ♀, disc-flowers ☿ or ♂; sometimes diœcious. -Capitula in racemes or panicles. The leaves develop after the -flowering.--_Tussilago_ (_T. farfara_, Colt’s-foot) has a solitary -capitulum borne on a scaly, scape-like stem; the ray-flowers are ♀ -with _ligulate_ corollas, disc-flowers ♂. The leaves unfold after the -flowering. _Ageratum_, _Mikania_, _Vernonia_. - -=5. Astereæ, Aster Group= (or RADIATÆ, Ray-flowered). The flowers are -of two forms and different sexes; the ray-flowers are ♀ (sometimes -neuter), most frequently with irregular, _falsely ligulate_, radiating -corollas; the disc-flowers are ☿, regular, with tubular corollas (Fig. -610). Sometimes only tubular flowers are present, as _e.g._ in _Senecio -vulgaris_ (Groundsel), and the exterior of the capitulum is then as in -the Eupatorieæ. The stylar branches are straight, more or less flat and -short (Fig. 610). - -=A.= ANTHEMIDEÆ. Involucral leaves imbricate, generally membranous at -the edge; _pappus wanting_, or at most a _membranous margin_ to the -calyx, but without hairs. - -[+]. _Chaff-like bracts_ on the receptacle are found in _Anthemis_ -(Chamomile), _Anacyclus_ (_A. officinarum_), _Achillea_ (Milfoil, Fig. -610), _Santolina_, etc. - -[++]. A _naked_ receptacle is found in the following: _Bellis_ -(Daisy) has solitary capitula on leafless stalks with white -ray-flowers.--_Matricaria_ (Wild Chamomile) has a conical receptacle. -~(_M. chamomilla_ has a very high, hollow receptacle; _M. -inodora_ has large, odourless capitula, and the receptacle is not -hollow.)~--_Chrysanthemum_ (Ox-eye) most frequently large, solitary -capitula; flat receptacle.--_Pyrethrum_; pappus scanty.--With these are -classed _Tanacetum_ (Tansy) and _Artemisia_ (Wormwood) with tubular -corollas only. - -=B.= HELIANTHEÆ. Most frequently a bract to each flower is found on -the receptacle. The pappus is never exactly hairy, but consists of -scales, spines, etc., and the fruits are most frequently compressed -(Fig. 606 _c_).--_Helianthus_ (Sun-flower); _H. tuberosus_ (Jerusalem -Artichoke) has tuberous underground stems. _Dahlia_ has tuberous roots -(Am.). _Bidens_ (Bur-marigold, Fig. 606 _c_); the fruits are compressed -with 2 (or more) spines provided with reflexed barbs.--_Calliopsis_; -_Rudbeckia_; _Zinnia_; _Tagetes_ has united involucral leaves, -and yellow, transparent oil-glands. _Spilanthes_, _Galinsoga_, -_Melampodium_, _Silphium_ (Compass-plant), _Helenium_, _Gaillardia_. - -=C.= CALENDULEÆ have 1–2 rows of involucral leaves, a naked receptacle, -and large, crescent-shaped, irregularly warted fruits, of different -forms in the same capitulum; pappus absent (Fig. 605).--_Calendula_ -(Marigold); ray-flowers ♀, disc-flowers ♂. - -=D.= SENECIONEÆ, have a fine, _hairy_, white pappus; no bracts, -otherwise as in Anthemideæ. The involucral leaves are most frequently -in 1–2 rows.--_Senecio_ (Groundsel) has two whorls of involucral -leaves, which most frequently have black tips, the external being much -shorter than the internal ones (_S. vulgaris_ has all flowers ☿ and -alike).--_Cacalia_, _Doronicum_, _Cineraria_, _Ligularia_, _Arnica_ -(_A. montana_; large, long-stalked capitula; leaves opposite, forming a -kind of rosette). - -=E.= ASTEREÆ have a bristle-like, unbranched pappus, often -of a dingy brown; receptacle naked; involucral leaves -numerous, imbricate.--_Solidago_ (Golden-rod); capitula small, -yellow-flowered, borne in panicles. _Aster_; disc-flowers most -frequently yellow, ray-flowers violet; _Callistephus_; _Erigeron_ -(Flea-bane)--_Inula_.--All the corollas are tubular in: _Gnaphalium_ -(Cud-weed); involucral leaves dry, rattling, often coloured; the -foliage-leaves and stem often white with woolly hairs; ray-flowers -♀, with narrow, tubular corolla; disc-flowers ☿ (few). _Antennaria_ -(Cat’s-foot; diœcious), _Filago_, _Helichrysum_, _Ammobium_, -_Rhodanthe_ and others. _Leontopodium_ (_L. alpinum_, “Edelweiss”). - - =F.= AMBROSIEÆ, a very reduced type of Compositæ, differing from - the others in having _free anthers_; the capitula are generally - unisexual, monœcious, the ♂ borne in a terminal inflorescence, - the ♀ in the leaf-axils. In other respects they are most closely - related to _Heliantheæ_.--_Xanthium._ In the ♂-capitula there - are many flowers without calyx, but with tubular corolla and - free involucral leaves. In the ♀-capitula there are only 2 - flowers, which are entirely destitute of both calyx and corolla; - involucral leaves 2-spined, united to form an ovoid, bilocular - envelope, each compartment containing one flower. The envelope - of involucral leaves unites with the fruits, enclosing them at - maturity with a hard covering from which numerous hook-like - spines project, assisting very greatly in the distribution of - the fruit. The whole structure thus finally becomes a 1- or - 2-seeded _false_ nut.--_Ambrosia_, the ♀ capitulum 1-flowered. - - POLLINATION. The flowers are somewhat insignificant, but become - very conspicuous owing to a number being crowded together in - one inflorescence. The corollas of the ray-flowers, being - often very large (_Astereæ_; _Centaurea_), frequently render - the capitula still more conspicuous. The capitula display - many biological phenomena similar to those often shown by the - individual flowers in other orders, e.g. by periodically opening - and closing, in which the involucral leaves resemble the calyx - in their action. (The name “Compositæ” originates from the term - “flos compositus,” composite flower). An abundance of honey is - formed, which to some extent fills up the corolla-tube, and - since insects may visit a number of flowers in the course of a - short period they are very frequently visited, especially by - butterflies and bees. The pollination has been described on page - 567. Protandry is universal. In the bud the tips of the styles, - covered by the sweeping-hairs, lie closely enveloped by the - anther-tube; in the next stage the style grows through the tube - and sweeps out the pollen as it proceeds; ultimately the stylar - branches expand and the stigma is then prepared to receive the - pollen. In many, the sensitiveness of the filaments assists in - sweeping out the pollen at the exact moment of the insect visit. - Regular self-pollination is found _e.g._ in _Senecio vulgaris_; - wind-pollination _e.g._ in _Artemisia_ and the plants related to - it. - - This extremely natural and well-defined order is the largest - (and no doubt one of the youngest?); it embraces 10–12,000 - known species (in 770 genera), or about one-tenth of all - Flowering-plants. They are distributed over the whole globe, but - are most numerous in temperate countries; the majority prefer - open spaces; a smaller number are forest-forms. They abound - especially in open districts in America. - - Among the substances frequently found may be mentioned: INULIN - (especially in the subterranean parts), BITTER materials, - Tannin, volatile oils, fatty oils in the fruits. MEDICINAL:[40] - “Herba” of _Artemisia absinthium_ (Wormwood) and _maritima_[+] - (Sea-wormwood), _Achillea millefolium_; the _leaves_ of _Cnicus - benedictus_ and _Tussilago farfara_; the unopened _capitula_ - of _Artemisia maritima_, var. _stechmanniana_; the _capitula_ - of _Tanacetum_, _Matricaria chamomilla_[+] (wild Chamomile), - _Anthemis nobilis_[+] (common Chamomile); the separate flowers - of _Arnica_; the _roots_ of _Arnica montana_[+], _Taraxacum - officinale_[+], _Anacyclus officinarum_[+], _Lappa major_, - _minor_, _nemorosa_ and _tomentosa_, _Inula helenium_ and - _Artemisia vulgaris_; the latex of _Lactuca virosa_[+]. The - following are cultivated for food:--_Lactuca sativa_ (Lettuce), - _Cichorium endivia_ (from E. Asia, for salads), _Cynara - scolymus_ (Artichoke, Mediterranean), _Scorzonera hispanica_ - (S. Eur.), _Helianthus tuberosus_ (Jerusalem Artichoke, from N. - Am., introduced into Europe 1616), _Cichorium intybus_ (roots - as “chicory,”) _Tragopogon porrifolium_ (Salsafy), _Artemisia - dracunculus_. OIL is extracted from the following (the seeds): - _Helianthus annuus_ (Peru), _Madia sativa_ (Chili), _Guizotia - oleifera_ (Abyssinia). DYES from: _Carthamus tinctorius_ - (Safflower, used in the preparation of rouge; Egypt), _Serratula - tinctoria_. INSECT-POWDER from: _Pyrethrum cinerariifolium_ - (Dalmatia) and _roseum_ (Persia, Caucasus). The following are - cultivated in houses and gardens for the sake of their scented - leaves:--_Tanacetum balsamita_ (Balsam), _Artemisia abrotanum_ - (Southernwood) and _A. argentea_. A great many of the genera - enumerated are cultivated in dwelling-houses for the sake of - the flowers; _e.g._ _Pericallis cruenta_ (generally termed - “Cineraria”). _Asteriscus pygmæus_ is supposed to be the genuine - “Rose of Jericho”; the involucral leaves envelop the fruits - after their ripening and keep them enclosed for 8–10 months - until rain occurs. - - - - - APPENDIX ON THE CLASSIFICATION OF PLANTS. - - BY M. C. POTTER. - - -The earliest systems of classification were derived from the properties -and uses of plants; and it was not until some two centuries ago -that any scientific grouping of plants was attempted. Aristotle and -Theophrastus had adopted the groups of Trees, Shrubs and Herbs as the -chief divisions of the Vegetable Kingdom, a system which persisted -and was employed by Tournefort and Ray as late as the end of the 17th -century. The arrangement by which these three divisions were separated -into smaller divisions was often founded upon a single character, such -as the formation of the corolla, the form of fruit, that of the calyx -and corolla, etc. All these systems of classification which brought -into close proximity plants distinguished by some one character alone, -could only be considered as _artificial_, since plants related to one -another would not necessarily be included in the same group. As the -knowledge of the morphology, physiology, and reproduction of plants -increased, such systems were recognised as unscientific, and it became -the aim of botanists to establish a _natural_ system, founded upon -mutual relationships, which would associate together _only_ those -plants which are truly allied. - -The following are some of the chief systems of classification which -will show the gradual development of the natural system, and may be of -service to students making use of this text-book.[41] - - -System of JOHN RAY (1703). - - I. Herbæ. - A. IMPERFECTÆ (Flowerless). - B. PERFECTÆ (Flowering). - _Dicotyledones_. - _Monocotyledones._ - II. Arbores. - A. _Monocotyledones._ - B. _Dicotyledones._ - -Ray was the first botanist who recognised the importance of the one -or two seed-leaves of the embryo, and initiated the division of the -Flowering-plants into Monocotyledons and Dicotyledons. - - -System of LINNÆUS (1733). - -In his well known artificial system Linnæus divided the Vegetable -Kingdom into twenty-four classes, based upon the number, relative -position and union of the stamens with regard to each other, and also -to the gynœceum. - - Class I. MONANDRIA. Flowers with 1 stamen. - „ II. DIANDRIA. „ „ 2 stamens. - „ III. TRIANDRIA. „ „ 3 „ - „ IV. TETRANDRIA. „ „ 4 „ - „ V. PENTANDRIA. „ „ 5 „ - „ VI. HEXANDRIA. „ „ 6 „ - „ VII. HEPTANDRIA. „ „ 7 „ - „ VIII. OCTANDRIA. „ „ 8 „ - „ IX. ENNEANDRIA. „ „ 9 „ - „ X. DECANDRIA. „ „ 10 „ - „ XI. DODECANDRIA. „ „ 11 to 19 stamens. - „ XII. ICOSANDRIA. „ „ 20 or more stamens inserted - on the calyx. - „ XIII. POLYANDRIA. „ „ 20 or more stamens inserted - on the receptacle. - „ XIV. DIDYNAMIA. Stamens didynamous. - „ XV. TETRADYNAMIA. „ tetradynamous. - „ XVI. MONADELPHIA. Filaments united into 1 bundle. - „ XVII. DIADELPHIA. „ „ „ 2 bundles. - „ XVIII. POLYADELPHIA. „ „ „ several bundles. - „ XIX. SYNGENESIA. Anthers united together. - „ XX. GYNANDRIA. Stamens and pistil united. - „ XXI. MONŒCIA. Flowers diclinous, ♂ and ♀ on the same - plant. - „ XXII. DIŒCIA. „ „ ♂ and ♀ on different - plants. - „ XXIII. POLYGAMIA. ♂-, ♀-, and ☿-flowers on the same plant. - „ XXIV. CRYPTOGAMIA. Flowerless plants (Ferns, Mosses, Algæ, - Fungi). - - These classes were further divided into orders, according to the - number of styles, as Monogynia, flowers with 1 style; Digynia, - with 2 styles, etc. Thus a Dock (_Rumex_), having 6 stamens and - 3 styles, would be placed in Class VI., HEXANDRIA, and Order - III., Trigynia. - - Class XIV. was divided into two orders. Order I., Gymnospermia, - with seeds apparently naked, comprising the Labiatæ; and - Order II., Angiospermia, with the seeds enclosed in a capsule - (_Bartsia_, _Rhinanthus_). - - Class XV. was divided into two orders: Order I., Siliculosa, - fruit a silicula (_Capsella_); and Order II., Siliquosa, fruit a - siliqua (_Brassica_). - - Class XIX. was divided into Order I., Æqualis, all the flowers - perfect (_Sonchus_); Order II., Superflua, flowers in the centre - perfect, those at the circumference with pistils only (seemingly - superfluous), _e.g._ _Aster_; Order III., Frustranea, flowers in - the centre perfect, those at the circumference neuter, _e.g._ - _Centaurea_. - - “Fragments” of a natural system have also come down to us from - Linnæus, who himself always recognised the imperfection of his - artificial system. - - -System of ANTOINE LAURENT DE JUSSIEU (1789). - - Class - =Acotyledones.= Plants without cotyledons: Fungi, Ferns, - Mosses, Algæ, Naiades I. - - =Monoctyledones.= Plants with _one_ cotyledon:-- - 1. Stamens hypogynous II. - 2. „ perigynous III. - 3. „ epigynous IV. - - =Dicotyledones.= Plants with _two_ cotyledons:-- - - { Stamens epigynous V. - 1. APETALÆ { „ perigynous VI. - { „ hypogynous VII. - - { Corolla hypogynous VIII. - 2. MONOPETALAE { „ perigynous IX. - { „ epigynous, {anthers connate X. - { „ free XI. - - { Stamens epigynous XII. - 3. POLYPETALÆ { „ hypogynous XIII. - { „ perigynous XIV. - - 4. DICLINES IRREGULARES, male and female flowers on different - plants, corolla generally absent. - - -System of A. P. DE CANDOLLE (1819). - - I. =Vasculares.= Plants with vascular bundles. - 1. EXOGENÆ. Vascular bundles arranged in a ring. - A. _Diplochlamydeæ._ Calyx and corolla present. - _a._ Thalamifloræ. Corolla polypetalous and - hypogynous. - _b._ Calycifloræ. Corolla perigynous or epigynous; - stamens inserted on the calyx. - _c._ Corollifloræ. Corolla gamopetalous; stamens - inserted on the corolla. - B. _Monochlamydeæ._ Perianth simple. - 2. ENDOGENÆ. Vascular bundles scattered, the youngest in - the centre. - A. _Phanerogamæ._ Flowers present. - B. _Cryptogamæ._ Flowers absent. - II. =Cellulares.= Vascular bundles absent. - 1. FOLIACEÆ. Leaves present. - 2. APHYLLÆ. Leafless. - -ROBERT BROWN published in 1827 his discovery of the gymnospermy of the -ovules of the Coniferæ and Cycadeæ, and showed that the Gymnosperms, -which had previously been classed with the Dicotyledons, must be -regarded as an independent group. - - -System of STEPHEN ENDLICHER (1836–40). - - I. =Thallophyta.= No differentiation into stem and root. - 1. PROTOPHYTA. Class I., Algæ; Class II., Lichenes. - 2. HYSTEROPHYTA. Class III., Fungi. - II. =Cormophyta.= Differentiated into stem and root. - 1. ACROBRYA. Stem growing at the point. - _Anophyta_ (Hepaticæ, Musci). - _Protophyta_ (Filices, etc.). - _Hysterophyta_ (Balanophoreæ, etc.). - 2. AMPHIBRYA. Stem growing at the circumference - (Monocotyledons). - 3. ACRAMPHIBRYA. Stem growing both at the point and - circumference. - _Gymnosperma_ (Coniferae). - _Apetala._ Perianth single or absent. - _Gamopetala._ Petals gamopetalous. - _Dialypetala._ Petals polypetalous. - - -System of A. BRONGNIART (1843). - - I. =Cryptogamæ.= Plants without flowers. - 1. AMPHIGENÆ. Not differentiated into stem or leaf (Algæ, - Fungi, Lichenes). - 2. ACROGENÆ. Plants with stem and leaf (Muscineæ, Filicinæ). - II. =Phanerogamæ.= Plants with flowers. - 3. MONOCOTYLEDONES. - _a._ Albuminosæ. Seeds with endosperm. - _b._ Exalbuminosæ. Seeds without endosperm. - 4. DICOTYLEDONES. - _a._ Angiosepermæ. - α. Gamopetalæ. - β. Dialypetalæ. - _b._ Gymnospermæ. - - -System of JOHN LINDLEY (_Vegetable Kingdom_, 1845). - - Asexual, or Flowerless Plants. - - Stem and leaves undistinguishable I. =Thallogens.= - Stem and leaves distinguishable II. =Acrogens.= - - Sexual, or Flowering Plants. - - Fructification springing from a thallus III. =Rhizogens.= - Fructification springing from a stem. - Wood of stem youngest in the centre; cotyledon - single. Leaves parallel-veined, permanent; wood - of stem always confused IV. =Endogens.= - - Leaves net-veined, deciduous; wood of the stem, - when perennial, arranged in a circle with a - central pith V. =Dictyogens.= - - Wood of stem youngest at the circumference, always - concentric; cotyledons, 2 or more. - Seeds quite naked VI. =Gymnogens.= - Seeds inclosed in seed-vessels VII. =Exogens.= - - -System of ALEXANDER BRAUN (1864). - - I. =Bryophyta.= - 1. THALLODEA (Algæ, Fungi, Lichenes). - 2. THALLOPHYLLODEA (Charas, Mosses). - II. =Cormophyta.= - 1. PHYLLOPTERIDES (Ferns, Equisetums). - 2. MASCHALOPTERIDES (Lycopods). - 3. HYDROPTERIDES (Water-ferns). - III. =Anthophyta.= - GYMNOSPERMÆ. - 1. _Frondosæ_ (Cycadeæ). - 2. _Acerosæ_ (Coniferæ). - ANGIOSPERMÆ. - 1. _Monocotyledones._ - 2. _Dicotyledones._ - Apetalæ. - Sympetalæ. - Eleutheropetalæ. - - -W. HOFMEISTER published from 1849 to 1851 his researches upon the -embryology of the Phanerogams, and upon the embryology and life-history -of the Vascular Cryptogams, and established the phylogenetic connection -existing between the Mosses, Vascular Cryptogams and Phanerogams. - - - System of HOOKER and BENTHAM (_Genera plantarum_, 1862–1883). - - Dicotyledones. - - I. Polypetalæ. - -Series I. =Thalamifloræ.= Calyx most often free from the ovary. Petals -uniseriate or often 2–∞-seriate. Stamens ∞ or definite, inserted on the -receptacle, often small, or raised, or stipitate. Ovary most frequently -free. - -Cohort I. RANALES. Stamens ∞, or if definite the perianth is -3–∞-seriate. Carpels apocarpous, or immersed in the receptacle. -Endosperm usually abundant, fleshy. - - Order 1. Ranunculaceæ. - „ 2. Dilleniaceæ. - „ 3. Calycanthaceæ. - „ 4. Magnoliaceæ. - „ 5. Anonaceæ. - „ 6. Menispermaceæ. - „ 7. Berberideæ. - „ 8. Nymphæaceæ. - -Cohort II. PARIETALES. Stamens ∞ or definite. Ovary unilocular, -or divided into loculi by spurious dissepiments, with parietal -placentation. Endosperm absent or fleshy. - - Order 9. Sarraceniaceæ. - „ 10. Papaveraceæ. - „ 11. Cruciferæ. - „ 12. Capparideæ. - „ 13. Resedaceæ. - „ 14. Cistineæ. - „ 15. Violarieæ. - „ 16. Canellaceæ. - „ 17. Bixineæ. - -Cohort III. POLYGALINÆ. Stamens definite. Ovary usually perfectly or -imperfectly bilocular. Micropyle often superior. Fruit very often -compressed laterally. Endosperm very often abundant and fleshy. - - Order 18. Pittosporeæ. - „ 19. Tremandreæ. - „ 20. Polygaleæ. - „ 20_a._ Vochysiaceæ. - -Cohort IV. CARYOPHYLLINEÆ. Stamens definite, or rarely ∞. Ovary -unilocular, or imperfectly septate. Placenta central, more rarely -parietal. Micropyle inferior. Embryo curved, rarely straight. Endosperm -farinaceous. - - Order 21. Frankeniaceæ. - „ 22. Caryophylleæ. - „ 23. Portulaceæ. - „ 24. Tamariscineæ. - -Cohort V. GUTTIFERALES. Sepals inbricate. Stamens usually ∞. Ovary -septate, placentæ on the inner angles of the loculi. Endosperm absent -or fleshy. - - Order 25. Elatineæ. - „ 26. Hypericineæ. - „ 27. Guttiferæ. - „ 28. Ternstrœmiaceæ. - „ 29. Dipterocarpeæ. - „ 30. Chlænaceæ. - -Cohort VI. MALVALES. Sepals valvate. Stamens usually ∞ or -monadelphous. Ovary septate, placentæ on the inner angles of the -loculi. Endosperm absent or fleshy. - - Order 31. Malvaceæ. - „ 32. Sterculiaceae. - „ 33. Tiliaceæ. - -Series II. =Discifloræ.= Calyx usually free from the ovary. Petals -uniseriate. Stamens usually definite, inserted within, or upon, or -around the receptacle, which is more often expanded as a disc. Ovary -usually free, or embedded in the disc. - -Cohort VII. GERANIALES. Disc usually as a ring between the stamens, -or adnate to the staminal tube, or reduced to glands alternating with -the petals, more rarely absent. Gynœceum entire, or more often lobed, -or sub-apocarpous. Ovules most often 1–2 in each loculus, _pendulous_, -_raphe ventral_. Leaves various. - - Order 34. Lineæ. - „ 35. Humiriaceæ. - „ 36. Malpighiaceæ. - „ 37. Zygophylleæ. - „ 38. Geraniaceæ. - „ 39. Rutaceæ. - „ 40. Simarubeæ. - „ 41. Ochnaceæ. - „ 42. Burseraceæ. - „ 43. Meliaceæ. - „ 44. Chailletiaceæ. - -Cohort VIII. OLACALES. Disc cupular or annular, free, or bearing -the stamens and petals on its edge. Gynœceum entire. Ovules 1–3 in -the unilocular ovaries, or 1–2 in each loculus, _pendulous_, _raphe -dorsal_. Leaves simple. - - Order 45. Olacineæ. - „ 46. Ilicineæ. - -Cohort IX. CELASTRALES. Disc tumid, adnate to the calyx, or covering -its base. Stamens inserted round the disc or affixed to its margin. -Gynœceum usually entire. Ovules most often two in each loculus, -_erect_, _raphe ventral_. Leaves simple, or rarely compound. - - Order 47. Celastrineæ. - „ 48. Stackhousieæ. - „ 49. Rhamneæ. - „ 50. Ampelideæ. - -Cohort X. SAPINDALES. Disc various. Stamens variously inserted on the -disc. Gynœceum entire, or more often lobed, or sub-apocarpous. Ovules -more often 1–2 in each loculus, _ascending_ with _ventral_ raphe, or -reversed, or _solitary_ and _pendulous from an ascending funicle_, or -rarely ∞ horizontal. Leaves pinnate, or more rarely simple or digitate. - - Order 51. Sapindaceæ. - „ 52. Sabiaceæ. - „ 53. Anacardiaceæ. - -Anomalous orders, or rather genera,-- - - Order 54. Coriarieæ. - „ 55. Moringeæ. - -Series III. =Calycifloræ.= Calyx-tube usually surrounding the ovary, or -adnate to it. Petals uniseriate, inserted on the calyx-tube. Stamens -∞ or definite, inserted on the calyx-tube, or most often on the disc -lining the calyx-tube. Ovary often enclosed by the calyx-tube, or -inferior. - -Cohort XI. ROSALES. Carpels solitary, or free, or united at the base, -more rarely at the apex; styles distinct, or very rarely united into a -column, and easily separated. - - Order 56. Connaraceæ. - „ 57. Leguminosæ. - „ 58. Rosaceæ. - „ 59. Saxifrageæ. - „ 60. Crassulaceæ. - „ 61. Droseraceæ. - „ 62. Hamamelideæ. - „ 63. Bruniaceæ. - „ 64. Halorageæ. - -Cohort XII. MYRTALES. Ovary syncarpous, inferior, or enclosed in the -calyx-tube, usually divided into loculi; style undivided. Ovules 2–∞ in -the loculi. - - Order 65. Rhizophoreæ. - „ 66. Combretaceæ. - „ 67. Myrtaceæ. - „ 68. Melastomaceæ. - „ 69. Lythrarieæ. - „ 70. Onagrarieæ. - -Cohort XIII. PASSIFLORALES. Ovary syncarpous, inferior or superior, -enclosed in the calyx-tube or exserted, unilocular with parietal -placentation, or divided into loculi; styles distinct, one style -divided, or undivided. - - Order 71. Samydaceæ. - „ 72. Loaseæ. - „ 73. Turneraceæ. - „ 74. Passifloreæ. - „ 75. Cucurbitaceæ. - „ 76. Begoniaceæ. - „ 77. Datisceæ. - -Cohort XIV. FICOIDALES. Ovary syncarpous, inferior or superior, divided -into loculi with sub-basilar placentæ, or more rarely unilocular with -parietal placentæ. Styles distinct, or divided at the apex. Embryo -curved or excentric. - - Order 78. Cacteæ. - „ 79. Ficoideæ. - -Cohort XV. UMBRELLALES. Ovary syncarpous, inferior, crowned by the -disc, divided into loculi, or unicarpellate. Styles distinct or divided -at the apex. Ovules solitary and pendulous in the loculi. - - Order 80. Umbelliferæ. - „ 81. Araliaceæ. - „ 82. Cornaceæ. - - - II. GAMOPETALÆ. - -Series I. =Inferæ.= Ovary inferior. Stamens equal to the lobes of the -corolla, rarely fewer. - -Cohort I. RUBIALES. Stamens adnate to the corolla. Ovary 2–∞-locular, -loculi 1–∞-ovuled. - - Order 83. Caprifoliaceæ. - „ 84. Rubiaceæ. - -Cohort II. ASTERALES. Stamens adnate to the corolla. Ovary formed of 2 -carpels, unilocular and 1-ovuled. - - Order 85. Valerianeæ. - „ 86. Dipsaceæ. - „ 87. Calycereæ. - „ 88. Compositæ. - -Cohort III. CAMPANALES. Stamens generally free from the corolla. Ovary -2–6-locular, loculi most often ∞-ovuled. - - Order 89. Stylidieæ. - „ 90. Goodenovieæ. - „ 91. Campanulaceæ. - -Series II. =Heteromeræ.= Ovary most often superior. Stamens free from -the corolla, opposite to, or double the lobes of the corolla, or ∞, or -if epipetalous, equal and alternating with them. Carpels more than 2. - -Cohort IV. ERICALES. Stamens double the lobes of the corolla, or -alternating with them. Ovary 2–∞-locular. Seeds small, frequently -minute. - - Order 92. Vacciniaceæ. - „ 93. Ericaceæ. - „ 94. Monotropeæ. - „ 95. Epacrideæ. - „ 96. Diapensiaceæ. - „ 97. Lennoaceæ. - -Cohort V. PRIMULALES. Stamens equal to and opposite the lobes of the -corolla. Ovary unilocular, with a free central placenta, 1–∞ ovules. - - Order 98. Plumbagineæ - „ 99. Primulaceæ. - „ 100. Myrsineæ. - -Cohort VI. EBENALES. Stamens equal to and opposite the lobes of the -corolla, or double, or ∞. Ovary 2–∞-locular. Seeds few and large. Trees -or shrubs. - - Order 101. Sapotaceæ. - „ 102. Ebenaceæ. - „ 103. Styraceæ. - -Series III. =Bicarpellatæ.= Ovary most often superior. Stamens equal, -or fewer than the lobes of the corolla, and alternating with them. -Carpels 2, rarely 1 or 3. - -Cohort VII. GENTIANALES. Corolla regular. Stamens equal to the lobes of -the corolla, or if fewer, usually alternating with the carpels. Leaves -generally opposite. - - Order 104. Oleaceæ. - „ 105. Salvadoraceæ. - „ 106. Apocynaceæ. - „ 107. Asclepiadeæ. - „ 108. Loganiaceæ. - „ 109. Gentianeæ. - -Cohort VIII. POLEMONIALES. Corolla regular. Stamens equal to the lobes -of the corolla. Leaves generally alternate. - - Order 110. Polemoniaceæ. - „ 111. Hydrophyllaceæ. - „ 112. Boragineæ. - „ 113. Convolvulaceæ. - „ 114. Solanaceæ. - -Cohort IX. PERSONALES. Corolla most often irregular or oblique. -Posterior stamen less than the others, more often reduced to a -staminode, or altogether absent. Ovary ∞-ovuled, or 2-ovuled. - - Order 115. Scrophularineæ. - „ 116. Orobanchaceæ. - „ 117. Lentibularieæ. - „ 118. Columelliaceæ. - „ 119. Gesneraceæ. - „ 120. Bignoniaceæ. - „ 121. Pedalineæ. - „ 122. Acanthaceæ. - -Cohort X. LAMIALES. Corolla most often irregular or oblique. Posterior -stamen less than the others, most frequently reduced to a staminode or -absent. Carpels 1-ovuled or with 2 collateral ovules. Fruit enclosed in -the persistent calyx, indehiscent, and with one seed, or dehiscing into -2 or 4, rarely ∞, 1-seeded nuts. - - Order 123. Myoporineæ. - „ 124. Selagineæ. - „ 125. Verbenaceæ. - „ 126. Labiateæ. - -Anomalous Order 127. Plantagineæ. - - - III. MONOCHLAMYDEÆ. - -Perianth simple, lobes or segments 1–2-seriate and often sepaloid, or -small, or wanting. - -Series I. =Curvembryeæ.= Endosperm frequently farinaceous. Embryo -curved, excentric, lateral or peripheral, rarely straight. Ovules most -frequently 1 in the ovary, or 1 in each loculus. Flowers ☿, in some -genera unisexual or polygamous. Petals very rare. Stamens equal to the -segments of the perianth, rarely fewer or more. - - Order 128. Nyctagineæ. - „ 129. Illecebraceæ. - „ 130. Amarantaceæ. - „ 131. Chenopodiaceæ. - „ 132. Phytolaccaceæ. - „ 133. Batideæ. - „ 134. Polygonaceæ. - -Series II. =Multiovulatæ Aquaticæ.= Aquatic herbs, submerged. Ovary -syncarpous; ovules numerous in each loculus or on each placenta. - - Order 135. Podostemaceæ. - -Series III. =Multiovulatæ Terrestres.= Terrestrial trees or shrubs. -Ovary syncarpous; ovules numerous in each loculus or on each placenta. - - Order 136. Nepenthaceæ. - „ 137. Cytinaceæ. - „ 138. Aristolochiaceæ. - -Series IV. =Micrembryeæ.= Ovary syncarpous, monocarpous, or apocarpous. -Ovules generally solitary in each carpel, rarely 2 or few. Endosperm -copious, fleshy, or rarely farinaceous. Embryo very minute. - - Order 139. Piperaceæ. - „ 140. Chloranthaceæ. - „ 141. Myristiceæ. - „ 142. Monimiaceæ. - -Series V. =Daphnales.= Ovary monocarpous, very rarely syncarpous, -with 2–4 loculi; ovules in the ovary or in each loculus, solitary, or -in pairs. Trees or shrubs, very rarely herbs; flowers generally ☿. -Perianth perfect, sepaloid, 1–2 seriate. Stamens perigynous, equal to -the lobes of the perianth, or double unless fewer. - - Order 143. Laurineæ. - „ 144. Proteaceæ. - „ 145. Thymelæaceæ. - „ 146. Penæaceæ. - „ 147. Elæagnaceæ. - -Series VI. =Achlamydosporeæ.= Ovary unilocular, 1–3 ovules. Ovules most -frequently poorly developed before flowering. Seeds endospermous, but -without testa, either free in the pericarp or attached to its walls. -Perianth generally perfect, sepaloid or petaloid. - - Order 148. Loranthaceæ. - „ 149. Santalaceæ. - „ 150. Balanophoreæ. - -Series VII. =Unisexuales.= Flowers unisexual. Ovary syncarpous or -monocarpous, ovules in the ovary or in each loculus, solitary, or -in pairs. Endosperm copious, fleshy, or scanty, or absent. Trees or -shrubs, rarely herbs. Stipules generally present. Perianth sepaloid, or -minute, or absent. Styles equal in number to the carpels, not rarely -bifid. - - Order 151. Euphorbiaceæ. - „ 152. Balanopseæ. - „ 153. Urticaceæ. - „ 154. Platanaceæ. - „ 155. Leitnerieæ. - „ 156. Juglandeæ. - „ 157. Myricaceæ. - „ 158. Casuarineæ. - „ 159. Cupuliferæ. - -Series VIII. =Ordines Anomali.= Anomalous Orders. - - Order 160. Salicineæ. - „ 161. Lacistemaceæ. - „ 162. Empetraceæ. - „ 163. Ceratophylleæ. - - - GYMNOSPERMEÆ - - Order 164. Gnetaceæ. - „ 165. Coniferæ. - „ 166. Cycadaceæ. - - - MONOCOTYLEDONES. - -Series I. =Microspermæ.= At least the inner series of the perianth -petaloid. Ovary inferior, unilocular, with 3 parietal placentæ, or -rarely 3-locular, with axile placentation. Seeds minute, numerous, -without endosperm. - - Order 167. Hydrocharideæ. - „ 168. Burmanniaceæ. - „ 169. Orchideæ. - -Series II. =Epigynæ.= At least the inner series of the perianth -petaloid. Ovary most often inferior. Endosperm copious. - - Order 170. Scitamineæ. - „ 171. Bromeliaceæ. - „ 172. Hæmodoraceæ. - „ 173. Irideæ. - „ 174. Amaryllideæ. - „ 175. Taccaceæ. - „ 176. Dioscoreaceæ. - -Series III. =Coronarieæ.= At least the inner series of perianth -petaloid. Ovary free, very rarely slightly adnate at the base. -Endosperm copious. - - Order 177. Roxburghiaceæ. - „ 178. Liliaceæ. - „ 179. Pontederiaceæ. - „ 180. Philydraceæ. - „ 181. Xyrideæ. - „ 182. Mayaceæ. - „ 183. Commelinaceæ. - „ 184. Rapateaceæ. - -Series IV. =Calycinæ.= Perianth sepaloid, small, rigid, or herbaceous -(inner series subpetaloid or small). Ovary free. Endosperm copious. - - Order 185. Flagellarieæ. - „ 186. Juncaceæ. - „ 187. Palmæ. - -Series V. =Nudifloræ.= Perianth absent, or reduced to hairs or scales. -Ovary superior, carpel solitary, or if many, syncarpous, 1–∞-ovuled. -Endosperm most frequently present. - - Order 188. Pandaneæ. - „ 189. Cyclanthaceæ. - „ 190. Typhaceæ. - „ 191. Aroideæ. - „ 192. Lemnaceæ. - -Series VI. =Apocarpæ.= Perianth 1–2-seriate, or absent. Carpels -superior, solitary, or if more, apocarpous. Endosperm absent. - - Order 193. Triurideæ. - „ 194. Alismaceæ. - „ 195. Naiadaceæ. - -Series VII. =Glumaceæ.= Flowers solitary, sessile in the axils of -bracts and arranged in capitula or spikelets with bracts. Segments of -perianth small, scale-like, glumaceous or absent. Ovary 1-ovuled, or -divided into 1-ovuled loculi. Endosperm present. - - Order 196. Eriocauleæ. - „ 197. Centrolepideæ. - „ 198. Restiaceæ. - „ 199. Cyperaceæ. - „ 200. Gramineæ. - - -Classification of the Thallophytes proposed by SACHS (_Text-Book of -Botany_, English Edition, 1882). - - THALLOPHYTES. - - _Containing chlorophyll._ | _Not containing chlorophyll._ - - Class I. =Protophyta.= - - Cyanophyceæ. | Schizomycetes. - Palmellaceæ (in part). | Saccharomycetes. - - Class II. =Zygosporeæ.= - Conjugating cells motile. - - Pandorineæ. | Myxomycetes. - (Hydrodictyeæ). | - - Conjugating cells stationary. - - Conjugatæ (including | Zygomycetes. - Diatomaceæ). | - - Class III. =Oosporeæ.= - - Sphæroplea. | - Vaucheria (_Cœloblastæ_). | { Saprolegnieæ. - | { Peronosporeæ. - Volvocineæ. | - Œdogonieæ. | - Fucoideæ. | - - Class IV. Carposporeæ. - - Coleochæteæ. | Ascomycetes (including Lichens). - Florideæ. | Æcidiomycetes (Uredineæ). - Characeæ. | Basidiomycetes. - - -System of A. W. EICHLER (1883). - - A. =Cryptogamæ.= - I. =Thallophyta.= - 1. Class. ALGÆ. - 1 Group. Cyanophyceæ. - 2 „ Diatomeæ. - 3 „ Chlorophyceæ. - 1 Series. Conjugatæ. - 2 „ Zoosporeæ. - 3 „ Characeæ. - 4 Group. Phæophyceæ. - 5 „ Rhodophyceæ. - 2. Class. FUNGI. - 1 Group. Schizomycetes. - 2 „ Eumycetes. - 1 Series. Phycomycetes. - 2 „ Ustilagineæ. - 3 „ Æcidiomycetes. - 4 „ Ascomycetes. - 5 „ Basidiomycetes. - 3 Group. Lichenes. - II. =Bryophyta.= - 1 Group. Hepaticæ. - 2 „ Musci. - III. =Pteridophyta.= - 1 Class. EQUISETINÆ. - 2 „ LYCOPODINÆ. - 3 „ FILICINÆ. - B. =Phanerogamæ.= - 1. Gymnospermæ. - 2. Angiospermæ. - -The subdivisions of the Phanerogamæ have with little variation been -adopted in this book. - -Classification of the THALLOPHYTES, adopted in the 3rd Danish Edition -(1891). [Algæ by Wille; Fungi by Rostrup (_after Zopf_).] - - =I. DIVISION. THALLOPHYTA.= - I. Sub-division. =Algæ.= - 1 Class. CHLOROPHYCEÆ (GREEN ALGÆ). - 1 Family. Conjugatæ. - 2 „ Protococcoideæ. - 3 „ Confervoideæ. - 4 „ Siphoneæ. - 5 „ Gyrophyceæ. - 2 Class. PHÆOPHYCEÆ (BROWN ALGÆ). - 1 Family. Syngeneticæ. - 2 „ Dinoflagellata. - 3 „ Pyritophyceæ (Diatomeæ). - 4 „ Phæosporeæ. - 5 „ Cyclosporeæ. - 6 „ Dictyoteæ. - 3 Class. ACILIATÆ. - A. Sub-class. _Schizophyceæ._ - 1 Family. Myxophyceæ (Blue-Green Algæ). - 2 „ Bacteria. - B. Sub-class. _Rhodophyceæ._ - 1 Family. Bangioideæ. - 2 „ Florideæ. - II. Sub-division. =Myxomycetes.= - III. „ =Fungi.= - A. =Phycomycetes.= - 1 Class. OOMYCETES. - 2 „ ZYGOMYCETES. - B. =Mycomycetes.= - 3 Class. BASIDIOMYCETES. - A. Sub-class. _Protobasidiomycetes._ - B. „ _Autobasidiomycetes._ - 1 Family. Hymenomycetes. - 2 „ Gasteromycetes. - 3 „ Basidiolichenes. - 4 Class. ASCOMYCETES. - 1 Family. Gymnoasci. - 2 „ Perisporieæ. - 3 „ Pyrenomycetes. - 4 „ Discomycetes. - 5 „ Ascolichenes. - - -System of A. ENGLER (_Syllabus der Vorlesungen_, etc., 1892). - - =I. DIVISION. MYXOTHALLOPHYTA.= - Sub-division. =Myxomycetes.= - 1 Class. ACRASIEÆ. - 2 „ PLASMODIOPHORALES. - 3 „ MYXOGASTERES. - 1 Series. Ectosporeæ. - 2 „ Endosporeæ. - - =II. DIVISION. EUTHALLOPHYTA.= - I. Sub-division. =Schizophyta.= - 1 Class. SCHIZOPHYCEÆ. - 2 „ SCHIZOMYCETES. - II. Sub-division. =Dinoflagellata.= - Class. DINOFLAGELLATA. - 1 Series. Adinida. - 2 „ Dinifera. - III. Sub-division. =Bacillariales.= - Class. BACILLARIALES. - IV. Sub-division. =Gamophyceæ.= - 1 Class. CONJUGATÆ. - 2 „ CHLOROPHYCEÆ. - 1 Sub-class. _Protococcales._ - 2 „ _Confervales._ - 3 „ _Siphoneæ._ - 3 Class. CHARALES. - 4 „ PHÆOPHYCEÆ. - 1 Sub-class. _Phæosporeæ._ - 2 „ _Cyclosporeæ._ - 5 Class. DICTYOTALES. - 6 „ RHODOPHYCEÆ. - 1 Sub-class. _Bangiales._ - 2 „ _Florideæ._ - 1 Series. Nemalionales. - 2 „ Gigartinales. - 3 „ Rhodymeniales. - 4 „ Cryptonemiales. - V. Sub-division. =Fungi.= - 1 Class. PHYCOMYCETES. - 1 Series. Zygomycetes. - 2 „ Oomycetes. - 1 Sub-series. Chytridiales. - 2 „ Mycosiphonales. - 2 Class. MESOMYCETES. - 1 Sub-class. _Hemiasci._ - 2 „ _Hemibasidii._ - 3 Class. MYCOMYCETES. - 1 Sub-class. _Ascomycetes._ - 1 Series. Exoasci. - 2 „ Carpoasci. - 1 Sub-series. Gymnoascales. - 2 „ Perisporiales. - 3 „ Pyrenomycetes. - Appended. Pyrenolichenes. - 4 Sub-series. Hysteriales. - 5 „ Discomycetes. - Appended. Discolichenes. - 2 Sub-class. _Basidiomycetes._ - 1 Series. Protobasidiomycetes. - 1 Sub-series. Uredinales. - 2 „ Auriculariales. - 3 „ Tremellinales. - 4 „ Pilacrales. - 2 Series. Autobasidiomycetes. - 1 Sub-series. Dacryomycetes. - 2 „ Hymenomycetes. - Appended. Hymenolichenes. - 3 Sub-series. Phalloideæ. - 4 „ Gasteromycetes. - Appended. Gasterolichenes. - Fungi imperfecti. - - =III. DIVISION. EMBRYOPHYTA ZOIDIOGAMA= (Archegoniatæ). - I. Sub-division. =Bryophyta (Muscinei).= - 1 Class. HEPATICÆ. - 1 Series. Marchantiales. - 2 „ Anthocerotales. - 3 „ Jungermanniales. - 1 Sub-series. Anacrogynæ. - 2 „ Acrogynæ. - 2 Class. MUSCI. - 1 Sub-class. _Sphagnales._ - 2 „ _Andreæales._ - 3 „ _Archidiales._ - 4 „ _Bryales._ - 1 Series. Cleistocarpæ. - 2 „ Stegocarpæ. - 1 Sub-series. Acrocarpæ. - 2 „ Pleurocarpæ. - II. Sub division. =Pteridophyta.= - 1 Class. FILICALES. - 1 Sub-class. _Filices._ - 1 Series. Planithallosæ. - 2 „ Tuberithallosæ. - 2 Sub-class. _Hydropterides._ - 2 Class. EQUISETALES. - 1 Sub-class. _Isosporæ._ - 2 „ _Heterosporæ._ - 3 Class. SPHENOPHYLLALES. - 4 „ LYCOPODICELES. - 1 Sub-class. _Isosporæ._ - 2 „ _Heterosporæ._ - - IV. DIVISION. EMBRYOPHYTA SIPHONOGAMA. - - (Siphonogamæ, Phanerogamæ). - - I. Sub-division. =Gymnospermæ.= - 1 Class. CYCADALES. - 2 „ CORDAITALES. - 3 „ BENNETTITALES. - 4 „ CONIFERÆ. - 5 „ GNETALES. - II. Sub-division. =Angiospermæ.= - 1 Class. CHALAZOGAMÆ. - Series. Verticillatæ. - 2 Class. ACROGAMÆ. - 1 Sub-class. _Monocotyledoneæ._ - 1 Series. Pandanales. - 2 „ Helobiæ. - 3 „ Glumifloræ. - 4 „ Principes. - 5 „ Synanthæ. - 6 „ Spathifloræ. - 7 „ Farinosæ. - 8 „ Liliifloræ. - 9 „ Scitamineæ. - 10 „ Microspermæ. - - 2 Sub-class. _Dicotyledoneæ._ - - 1 Group of Series. Archichlamydeæ. - - 1 Series. Piperales. - 2 „ Juglandales. - 3 „ Salicales. - 4 „ Fagales. - 5 „ Urticales. - 6 „ Proteales. - 7 „ Santalales. - 8 „ Aristolochiales. - 9 „ Polygonales. - 10 „ Centrospermæ. - 11 „ Ranales. - 12 „ Rhœadales. - 13 „ Sarraceniales. - 14 „ Rosales. - 15 „ Geraniales. - 16 „ Sapindales. - 17 „ Rhamnales. - 18 „ Malvales. - 19 „ Parietales. - 20 „ Opuntiales. - 21 „ Thymelæales. - 22 „ Myrtifloræ. - 23 „ Umbellifloræ. - - 2 Group of Series. Sympetalæ. - - 1 Series. Ericales. - 2 „ Primulales. - 3 „ Ebenales. - 4 „ Contortæ. - 5 „ Tubifloræ. - 6 „ Plantaginales. - 7 „ Rubiales. - 8 „ Aggregatæ. - 9 „ Campanulatæ. - - - TABLE OF ABBREVIATIONS. - - S = Sepals. - P = Petals. - Pr = Perianth. - A = Andrœcium. - G = Gynœceum. - - ♂ = Male. - ♀ = Female. - ☿ = Hermaphrodite. - ∞ = Indefinite. - -Names of continents and countries have sometimes been abbreviated, for -example:--Am. = America; As.=Asia; Af. = Africa; Ind. = India, etc. -N., S., E., W., = North, South, East, West; Temp. = Temperate Regions; -Trop. = Tropics. - - - - - INDEX. - - - Abelia, 556. - - Abies, 124, 129, 130, 132, 133, 148, 155, 165, 246, 264, 265, 266. - - Abietaceæ, 255, 263, 272. - - Abrus, 470, 473. - - Abutilon, 427. - - Acacia, 473, 474, 475. - False, 470. - - Acalypha, 434. - - Acanthaceæ, 518, 529, 530. - - Acanthus, 530. - - Acer, 122, 441, 442. - - Aceraceæ, 441. - - Aceranthus, 390. - - Acetabularia, 12, 63. - - Achillea, 568, 572, 574. - - Achimenes, 528. - - Achlya, 107, 108. - - Achnantheæ, 21. - - Achras, 511. - - Acinetæ, 68, 72. - - Aconitum, 379, 383. - - Acorin, 306. - - Acorus, 303, 304, 306. - - Acrasieæ, 6. - - Acrocarpi, 196. - - Acrocomia, 301. - - Acrogynæ, 192. - - Acrospermaceæ, 132. - - Acrostichum, 213. - - Acrotonous, 331. - - Acrotylaceæ, 83. - - Acrotylus, 83. - - Actæa, 379, 380, 382. - - Actinidia, 415. - - Adansonia, 427. - - Adder’s tongue, 211. - - Adenanthera, 475. - - Adiantum, 201, 206, 213. - - Adinida, 17. - - Adlumia, 395. - - Adonis, 379, 383. - - Adoxa, 453, 555. - - Aerobic, 31. - - Æchmea, 319, 320. - - Æcidiospores, 147. - - Æcidium, 147, 148, 150, 155. - - Ægiceras, 513. - - Ægilops, 296. - - Ægopodium, 494. - - Æschynanthus, 528. - - Æsculinæ, 439. - - Æsculus, 440. - - Æthalium, 8. - - Æthusa, 495, 498. - - Affonsea, 466. - - Agapanthus, 312, 314. - - Agar-Agar, 33, 84. - - Agaricaceæ, 166. - - Agaricinei, 171. - - Agathis, 263. - - Agave, 318. - - Agaveæ, 318. - - Ageratum, 571. - - Aggregatæ, 505, 564. - - Agraphis, 312. - - Agrimonia, 459, 460. - - Agrimonieæ, 459. - - Agrimony, 459. - - Agropyrum, 113, 295. - - Agrostemma, 365, 367. - - Agrostideæ, 294. - - Agrostis, 294. - - Ahnfeltia, 83. - - Ailanthus, 439. - - Aira, 294. - - Aizoaceæ, 374. - - Aizoideæ, 374. - - Aizoon, 375. - - Ajuga, 47, 537. - - Ajugeæ, 537. - - Akebia, 390. - - Akinetes, 10. - - Alaria, 71, 72. - - Albugo, 107. - - Albumen, 246. - - Albuminous, 249. - - Albumose, 473. - - Alchemilla, 460. - - Alchornea, 432. - - Alcoholic fermentation, 97. - - Alder, 8, 118, 341. - - Aldrovandia, 408, 409. - - Aleurites, 434. - - Algæ, 1, 4, 8. - - Algal-Fungi, 95, 96. - - Alhagi, 472. - - Alisma, 281, 282. - - Alismaceæ, 278, 281. - - Alismeæ, 281. - - Alkanet, 534. - - Alkanna, 534, 535. - - Alliariinæ, 404. - - Allieæ, 312. - - Allium, 312, 313, 314. - - Alloplectus, 528. - - Allosorus, 213. - - Almeidea, 437. - - Almond, 461, 462. - - Alnus, 8, 117, 118, 341, 342. - - Alocasia. 306. - - Aloë, 274, 312, 313, 314. - - Aloineæ, 312. - - Alonsoa, 525. - - Alopecurus, 290, 294, 296. - - Alpine Violet, 513. - - Alpinia, 326. - - Alsine, 364, 366. - - Alsineæ, 365. - - Alsodeia, 411. - - Alsophila, 214, 215. - - Alstrœmeria, 318. - - Alstrœmerieæ, 318. - - Alternanthera, 369. - - Althæa, 426, 428, 429, 430. - - Althenia, 279. - - Alyssinæ, 404. - - Alyssum, 400. - - Amanita, 167, 171. - - Amarantaceæ, 364, 368. - - Amarant-tree, 468. - - Amarantus, 368, 369. - - Amarylleæ, 317. - - Amaryllidaceæ, 310, 316. - - Amaryllis, 317, 318. - - Amber, 267. - - Ambrosia, 573. - - Ambrosieæ, 564, 567, 573. - - Ambrosinia, 305. - - Amelanchier, 464, 465. - - Amentaceæ, 337. - - Amherstia, 468. - - Ammannia, 483. - - Ammi, 494. - - Ammieæ, 494. - - Ammobium, 573. - - Ammoniac-gum, 498. - - Ammophila, 295. - - Amomis, 488. - - Amorpha, 470. - - Ampelidaceæ, 445. - - Ampelopsis, 445, 447. - - Amphidinium, 16. - - Amphigastria, 181, 188. - - Amphipleureæ, 21. - - Amphisphæriaceæ, 130. - - Amphithecium, 186. - - Amphitropideæ, 21. - - Amphoreæ, 21. - - Amsonia, 544. - - Amygdalaceæ, 461, 466. - - Amygdalin, 462. - - Amygdalus, 461, 462. - - Amyris, 438. - - Anabæna, 25, 219. - - Anacampseros, 373. - - Anacamptis, 332. - - Anacamptodon, 197. - - Anacardiaceæ, 439. - - Anacardium, 439. - - Anacrogynæ, 192. - - Anacyclus, 572, 574. - - Anadyomene, 62. - - Anaerobic, 31. - - Anagallis, 513. - - Anamirta, 390. - - Ananassa, 319, 320. - - Anastatica, 401. - - Anathyllis, 471. - - Anatropous, 242, 243. - - Anchusa, 150, 531, 532, 534, 535. - - Ancylistaceæ, 104. - - Ancylonema, 44. - - Andira, 472, 473. - - Andreæa, 185, 187, 188, 195. - - Andrœcium, 239. - - Androgenesis, 14. - - Andromeda, 161, 508. - - Andromedeæ, 508. - - Andropogon, 289, 293, 296. - - Andropogoneæ, 293, 296. - - Androsace, 512, 513. - - Androspore, 57. - - Aneimia, 215. - - Anelatereæ, 192. - - Anemone, 379, 384. - - Anemoneæ, 384. - - Anemonopsis, 379. - - Anethum, 496, 498. - - Aneura, 191, 192. - - Angelica, 496, 498. - - Angiopteris, 212. - - Angiospermæ, 3, 234, 239, 250, 273. - - Angiosperms, 237, 245, 248. - - Angiosporeæ, 82. - - Angosturæ, Cortex, 437. - - Anguliferæ, 21. - - Anise, 498. - - Anlage, 90. - - Annatto, 412. - - Annularia, 225. - - Annulariæ, 225. - - Annulus, 195, 209. - inferus, 167. - superus, 168. - - Anoda, 428, 429. - - Anodic, 480. - - Anomodon, 197. - - Anona, 388. - - Anonaceæ, 388. - - Antennaria, 124, 573. - - Anthemideæ, 572. - - Anthemis, 569, 572, 574. - - Anther, 237, 238. - Fibrous layer of, 241. - Structure of, 239. - - Anthericeæ, 312. - - Anthericum, 312, 313. - - Antheridium, 13, 100, 198. - - Antherozoid, 13. - - Anthocarp, 374. - - Anthoceros, 25, 186, 187, 188, 189, 191. - - Anthoceroteæ, 191. - - Antholyza, 321. - - Anthostema, 432, 433. - - Anthoxanthum, 295, 296. - - Anthrax bacillus, 31, 39, 40. - - Anthriscus, 493, 495, 498. - - Anthurium, 304. - - Anthyllis, 471. - - Antiaris, 356. - - Antipodal cells, 248. - - Antirrhineæ, 523. - - Antirrhinum, 524, 527. - - Antisepsis, 32. - - Apeiba, 424, 425. - - Apetalæ, 336, 337. - - Aphanizomenon, 25. - - Aphanocapsa, 24. - - Aphanochæte, 54. - - Aphthæ, 180. - - Aphyllanthes, 312. - - Apiocystis, 51. - - Apios, 471. - - Apiosporium, 124. - - Apium, 494, 498. - - Aplanogametangium, 12. - - Aplanogametes, 12. - - Aplanospores, 10. - - Apocynaceæ, 542, 543, 549. - - Apocynum, 514. - - Apogamy, 203. - - Aponogeton, 281. - - Aponogetonaceæ, 281. - - Apospory, 188. - - Apostasia, 329. - - Apostasieæ, 328, 329. - - Apothecium, 118, 132. - - Apple, 127, 130, 464, 465. - - Apricot, 121, 461, 462. - - Aquifoliaceæ, 444. - - Aquilegia, 378, 379, 381, 382. - - Arabis, 402. - - Araceæ, 276, 278, 303. - - Arachis, 469, 472, 473. - - Aralia, 491. - - Araliaceæ, 454, 491, 549. - - Araucaria, 237, 263. - - Araucariaceæ, 257, 263, 272. - - Arbor vitæ, 267. - - Arbuteæ, 508. - - Arbutus, 508. - - Archangelica, 496, 498. - - Archegoniata, 3, 185. - - Archegonium, 3, 184, 198. - Development of, 201. - - Archesporium, 186, 202. - - Archicarp, 120. - - Archidium, 193, 195. - - Arctostaphylos, 161, 508. - - Arcyria, 7, 8. - - Ardisia, 513. - - Areca, 301, 302. - - Areca-palm, 302. - - Arecineæ, 301. - - Arenaria, 366. - - Arenga, 301. - - Argemone, 395. - - Aria, 152. - - Aril, 255, 258. - - Arineæ, 305. - - Arisarum, 305. - - Aristida, 295. - - Aristolochia, 499, 500. - - Aristolochiaceæ, 499. - - Aristolochiales, 499. - - Aristotelia, 425. - - Armeniaca, 461. - - Armeria, 514. - - Armillaria, 117, 169, 170. - - Arnebia, 533. - - Arnica, 572, 574. - - Arnoseris, 571. - - Aronia, 464. - - Arrack, 296, 301. - - Arrow-head, 282. - - Arrow-poison, 544, 546. - - Arrowroot, 327, 434. - - Artabotrys, 388. - - Artemisia, 569, 572, 573, 574. - - Arthonia, 134. - - Arthoniaceæ, 134. - - Arthrosporous, 29. - - Arthrotaxis, 267. - - Artichoke, 570, 574. - Jerusalem, 572, 574. - - Artocarpeæ, 354. - - Artocarpus, 356. - - Arum, 303, 304, 305, 306. - - Arundo, 294, 296. - - Asafœtida, 498. - - Asarum, 499, 500. - - Asclepiadaceæ, 238, 542, 544. - - Asclepias, 545, 546. - - Ascobolaceæ, 135. - - Ascobolus, 136. - - Ascocarps, 88. - - Ascocorticium, 116, 117. - - Ascogone, 120. - - Ascoidea, 108. - - Ascoideaceæ, 108. - - Ascolichenes, 95, 116, 136. - - Ascomycetes, 95, 114, 116. - - Ascophyllum, 73, 75. - - Ascospore, 88. - - Ascus, 88. - - Aseroë, 173. - - Asexual reproductive cells, 10. - - Ash, 127, 546, 547. - - Asimina, 388. - - Asparageæ, 314. - - Asparagus, 314, 316. - - Aspen, 152, 338. - - Aspergillus, 122. - - Asperifoliæ, 532. - - Asperococcus, 70. - - Asperugo, 534. - - Asperula, 552, 553. - - Asphodelus, 312, 313, 314. - - Aspidistra, 314. - - Aspidium, 203, 204, 207, 213, 214. - - Aspidosperma, 344. - - Asplenium, 213, 214. - - Astelia, 316. - - Aster, 569, 571, 573. - - Astereæ, 571, 573. - - Asteriscus, 574. - - Asterocystis, 78. - - Asterophylliteæ, 225. - - Asterophyllites, 225. - - Astragaleæ, 470. - - Astragalus, 114, 470, 473. - - Astrantia, 493. - - Astrocarpus, 407. - - Atherurus, 305. - - Athyrium, 204, 207, 213. - - Atragene, 379, 385. - - Atraphaxis, 360. - - Atriplex, 371, 372. - - Atripliceæ, 371. - - Atropa, 519, 521, 522, 523. - - Atropine, 522. - - Attalea, 297, 301. - - Attar of Roses, 460. - - Aubrietia, 400. - - Aucuba, 491. - - Aulacomnium, 197. - - Aurantieæ, 437. - - Auricula, 156. - - Auricularia, 156. - - Auriculariaceæ, 145, 155. - - Austrian Pine, 267. - - Autobasidia, 144. - - Autobasidiomycetes, 96, 145, 157. - - Autœcious, 148. - - Autoxenous, 118. - - Auxiliary cells, 81. - - Auxospore, 19. - - Avena, 294, 296. - - Aveneæ, 294. - - Avens, 458. - - Averrhoa, 416. - - Avicennia, 535. - - Avignon grain, 448. - - Awlwort, 401. - - Awn, 288, 290. - - Azalea, 508. - - Azolla, 25, 219. - - - “Bablah,” 475. - - Bacillus, 26, 28, 30, 31, 35, 36, 37. - anthracis, 39. - diphtheriæ, lepræ, mallei, tetani, tuberculosis, typhosus, 40. - - Bacteria, 4, 5, 8, 9, 10, 22, 26. - - Bacterium, 26, 28, 30, 35, 39. - - Bactris, 301. - - Bæomyces, 140, 142. - - Balanophora, 504. - - Balanophoraceæ, 504. - - Ballota, 538. - - Balsaminaceæ, 420. - - Balsamodendron, 438. - - Balsam of Copaiba, 468. - of Peru, 473. - - Bamboo, 289, 291, 292, 293. - - Bambusa, 289, 291, 293. - - Bambuseæ, 293, 296. - - Banana, 324, 325. - - Baneberry, 382. - - Bangia, 77, 78. - - Bangioideæ, 77. - - Banksia, 450. - - Baobab, 427. - - Barbacenia, 318. - - Barbarea, 402. - - Barberries, 389. - - Barbula, 196. - - Bark-canker, 169. - - Barley, 113, 292, 296. - - Barosma, 436. - - Barringtonia, 489. - - Bartonia, 476. - - Bartramia, 197. - - Bartsia, 526. - - Basella, 371. - - Baselleæ, 371. - - Basidial-layer, 89. - - Basidiocarp, 89. - - Basidiolichenes, 96, 145, 176. - - Basidiomycetes, 96, 114, 144, 145. - - Basidiospore, 88. - - Basidium, 89, 144, 146. - - Basitonous, 331. - - Bassia, 511. - - Bast, 251, 425, 430. - - Bastardia, 428. - - Batatas, 516, 517. - - Batidaceæ, 372. - - Batis, 372. - - Batrachium, 383. - - Batrachospermum, 80, 83. - - Bauhinia, 467. - - Bayberry-tree, 490. - - “Bay-rum,” 489. - - Beaked parsley, 495. - - Beak-rush, 286. - - Bear-berry, 508. - - Beard lichen, 143. - - Beech, 127, 134, 164, 165, 526. - - Beef-steak fungus, 166. - - Beer-yeast, 177, 178. - - Beet, 369. - - Beet-root, 372. - - Beggiatoa, 26, 28, 37. - - Begonia, 477, 478. - - Begoniaceæ, 475, 477. - - Bellis, 569, 572. - - Benincasa, 481. - - Berberidaceæ, 238, 389. - - Berberis, 149, 389, 390. - - Bergamot, 438. - - Bergia, 413. - - Berteroa, 400. - - Bertholletia, 489. - - Beta, 369, 370, 372. - - Betel, 363. - - Betonica, 538. - - Betony, 538. - - Betula, 342. - - Betulaceæ, 341. - - Biarum, 305. - - Biatorella, 134. - - Bicornes, 336, 451, 505, 506. - - Biddulphieæ, 21. - - Bidens, 566, 572. - - Biebersteinia, 419. - - Bignonia, 529. - - Bignoniaceæ, 518, 529. - - Bilberry, 509. - - Billardiera, 455. - - Billbergia, 320. - - Bindweed, 515, 516. - - Biota, 268. - - Birch, 117, 135, 165, 342. - - Bird-cherry, 461, 462. - - Birdlime, 501, 504. - - Bird’s-foot, 472. - - Bird’s-foot-trefoil, 471. - - Biscutella, 401. - - Bitter-cress, 402. - - Bitter-sweet, 522. - - Bixa, 412. - - Bixaceæ, 412. - - Blackberry, 461. - - Black-boy, 312. - - Black-currant, 153, 455. - - Black-mustard, 401, 405. - - Black-pepper, 363. - - Blackthorn, 462. - - “Bladder” plums, 117. - - Bladder-senna, 470. - - Bladder-wort, 528. - - Blasia, 25, 191, 192. - - Blattiaceæ, 483. - - Blechnum, 209, 214, 254. - - Bletia, 332. - - Blight, 132. - - Blindia, 196. - - Blinks, 373. - - Blitum, 369. - - Blood-red Currant, 455. - - Blue-green Algæ, 5, 22. - - Bocconia, 395. - - Boehmeria, 353. - - Boerhaavia, 374. - - Bog-mosses, 193. - - Bog-myrtle, 351. - - Bog Wortleberry, 509. - - Boisduvalia, 485. - - Boletus, 166. - - Bomarea, 318. - - Bombaceæ, 427. - - Bombax, 427. - - Bonnemaisonia, 83. - - Bonnemaisoniaceæ, 83. - - Borage, 533. - - Borageæ, 532, 533. - - Boraginaceæ, 515, 531, 532, 537. - - Borago, 533, 534. - - Borassinæ, 301. - - Borassus, 301. - - Borderea, 323. - - Boronieæ, 436. - - Borreria, 550. - - Boschia, 190. - - Bossiæa, 472. - - Boswellia, 438. - - Bo-tree, 356. - - Botrychium, 202, 210, 211. - - Botrydiaceæ, 47, 59. - - Botrydium, 59. - - Botrytis, 128, 134, 135. - - Bottle-gourd, 481. - - Bouchea, 535. - - Bougainvillea, 374. - - Boussingaultia, 371. - - Bouvardia, 550. - - Bovista, 174. - - Bowenia, 253, 254. - - Bowiea, 312. - - Box, 434. - - Brachypodium, 294. - - Brachythecium, 197. - - Bracken-fern, 207, 213. - - Bract, 235. - - Bracteole, 235, 275, 334. - - Bradypus, 8, 54, 356. - - Brahea, 300. - - Bramble, 458. - - Branching of Palm, 298. - - Brand-fungi, 95, 108, 109. - - Brand-spores, 91. - - Brasenia, 386. - - Brassica, 399, 400, 401. - - Brassicinæ, 404. - - Brayera, 460. - - Brazil-nuts, 489. - - Bread-fruit, 356. - - Briza, 290, 294, 296. - - Brome, 296. - - Bromeliaceæ, 308, 309, 310, 318. - - Bromus, 287, 289, 290, 293, 296. - - Brookweed, 513. - - Broom, 472. - - Broom-rape, 528. - - Brosimum, 356. - - Broussonetia, 354. - - Browallia, 521. - - Brown Algæ, 1. - - Brownea, 468. - - Brownian movement, 28. - - Brugmansia, 504. - - Brunfelsia, 521. - - Bryaceæ, 197. - - Bryonia, 481. - - Bryophyllum, 451, 452. - - Bryophyta, 1, 234. - - Bryopsidaceæ, 47, 60. - - Bryopsis, 60, 62. - - Bryum, 197. - - Buchu, 436. - - Buck-bean, 543. - - Buckthorn, 448. - - Buckwheat, 361. - - Buettneria, 422. - - Buettneriaceæ, 422. - - Bugle, 537. - - Bulbine, 312. - - Bulbochæte, 55, 56. - - Bulbocodium, 310. - - Bulbophyllum, 332. - - Bulgaria, 134. - - Bulgariaceæ, 134. - - Bullace, 461, 462. - - Bulliarda, 452. - - Bull-rush, 303. - - Bumelia, 511. - - Bunchosia, 442. - - Bunias, 400, 403. - - Bupleurum, 491, 494. - - Burdock, 570. - - Burmanniaceæ, 328. - - Bur-marigold, 572. - - Bur Parsley, 497. - - Bur-reed, 302. - - Burseraceæ, 438. - - Butcher’s broom, 316. - - Butomeæ, 281. - - Butomus, 281, 282. - - Butterbur, 571. - - Butter-tree, 414. - - Butter-wort, 528. - - Butyric-acid-bacíllus, 38. - - Buxaceæ, 434. - - Buxbaumia, 197. - - Buxbaumiaceæ, 197. - - Buxus, 434. - - - Cabbage, 401. - - Cabomba, 386. - - Cabombeæ, 386. - - Cacalia, 572. - - Cactaceæ, 375. - - Cacti, 375. - - Cactifloræ, 375. - - Cæoma, 147, 148, 152. - - Cæsalpinia, 468. - - Cæsalpiniaceæ, 466, 470. - - Caffeine, 441, 553. - - Cajanus, 471. - - Cajeput-oil, 489. - - Cajophora, 476. - - Cakile, 403. - - Calabar-bean, 471, 473. - - Calabash, 529. - - Caladium, 306. - - Calamagrostis, 289, 294. - - Calamintha, 540. - - Calamites, 224. - - Calamus, 298, 301, 303. - - Calamus-oil, 306. - - Calandrinia, 373. - - Calathea, 327. - - Calceolaria, 525, 527. - - Calcocytaceæ, 15. - - Calendula, 565, 572. - - Calenduleæ, 572. - - Caliciaceæ, 134. - - Calicium, 134. - - Calla, 305, 307. - - Calleæ, 305. - - Calliandra, 475. - - Callianthemum, 379. - - Callicarpa, 535. - - Calligonum, 361. - - Calliopsis, 572. - - Callistemon, 489. - - Callistephus, 573. - - Callithamnion, 78, 79, 84. - - Callitrichaceæ, 434. - - Callitriche, 434. - - Callitris, 269. - - Calloria, 134. - - Calluna, 507. - - Calocera, 158, 159. - - Calonyction, 516. - - Calophyllum, 414. - - Calothamnus, 489. - - Calothrix, 25. - - Caltha, 379, 380, 381, 382. - - Calycanthaceæ, 389. - - Calycanthus, 389. - - Calyceraceæ, 556, 560. - - Calypogeia, 192. - - Calypso, 332. - - Calyptospora, 152. - - Calyptra, 186. - - Calystegia, 516. - - Calyx-stamens, 335. - - Camelina, 400, 401. - - Camellia, 414, 415. - - Campanula, 153, 561, 562. - - Campanulaceæ, 561, 563. - - Campanulinæ, 505, 560, 564, 569. - - Camphor, 392. - - Campion, 367. - - Campylopus, 196. - - Campylospermeæ, 493, 497. - - Campylotropous, 242, 243. - - Canada-balsam, 266. - - Cananga, 388. - - Canarina, 562. - - Canary-grass, 295. - - Canavalia, 471. - - Candollea, 413, 564. - - Candolleaceæ, 564. - - Cane, 298, 301. - - “Canker,” 127. - - Canna, 326. - - Cannabaceæ, 356. - - Cannabis, 357, 358. - - Cannaceæ, 277, 326, 327. - - Canterbury-bell, 561. - - Cantharellei, 172. - - Cantharellus, 170, 172. - - Caoutchouc, 434, 544, 546, 563. - - Capers, 405. - - Capillitium, 7, 174. - - Capirona, 549. - - Capnodium, 124. - - Capparidaceæ, 405. - - Capparis, 405, 406. - - Capraria, 525. - - Caprification, 355. - - Caprificus, 355. - - Caprifoliaceæ, 454, 548, 549, 553, 556, 557. - - Caprifolium, 554. - - Capsella, 400, 401, 402. - - Capsellinæ, 404. - - Capsicum, 521, 522. - - Capsosira, 26. - - Capsule, 186. - - Caragana, 470. - - Caraway, 494, 498. - - Cardaminæ, 404. - - Cardamine, 400, 402, 404. - - Cardamom, 326. - - Cardiospermum, 441. - - Carduus, 569. - - Carex, 113, 151, 247, 286, 287. - - Carica, 476. - - Cariceæ, 286. - - Caries dentium, 38. - - Carlina, 570. - - Carludovica, 302. - - Carmichælia, 470. - - Carnation, 367. - - Carnaueba-wax, 301. - - Carob-bean, 466, 468. - - Carpels, 235, 238. - - Carpinus, 117, 344. - - Carpoasci, 95, 115, 116, 118. - - Carpogonium, 77, 81. - - Carpophore, 91, 492. - - Carpospore, 77, 82. - - Carragen, 33, 84. - - Carrot, 496, 497, 498. - - Carthamus, 570, 574. - - Carum, 493, 494, 498. - - Carya, 350. - - Caryophyllaceæ, 336, 364. - - Caryopsis, 288. - - Caryota, 301. - - Cascara, 448. - - Cascarilla, 434, 550. - - Cashew-nut, 439. - - Cassandra, 508. - - Cassava, 434. - - Cassia, 467, 468. - - Cassine, 444. - - Cassiope, 508. - - Cassytha, 392. - - Castanea, 346. - - Castilloa, 356. - - Castor-oil, 431, 434. - - Casuarinaceæ, 339. - - Casuarina, 273, 274. - - Casuarinifloræ, 339. - - Cataba, 414. - - Catabrosa, 294. - - Catalpa, 529. - - Catananche, 566, 571. - - Catasetum, 332, 333. - - Catch-fly, 367. - - Catechu, 475. - - Catha, 444. - - Catharinea, 197. - - Cathartocarpus, 467, 468. - - Catmint, 539. - - Catodic, 480. - - Cat’s-ear, 571. - - Cat’s-foot, 573. - - Cat’s-tail, 294. - - Cattle-beet, 372. - - Cattleya, 332. - - Caucalis, 497. - - Caudicle, 331, 332. - - Caulerpa, 10, 61, 62. - - Caulerpaceæ, 47, 61. - - Cauliflower, 405. - - Cayenne-pepper, 522. - - Ceanothus, 448. - - Cecropia, 356. - - Cedar, 266. - - Cedrat, 438. - - Cedrela, 436. - - Cedrus, 266. - - Celandine, 394. - - Celastraceæ, 444. - - Celastrus, 444. - - Celery, 494, 498. - - Celidium, 134. - - Cell, Vegetative, 228. - - Celosia, 368, 369. - - Celsia, 525. - - Celtideæ, 352. - - Cenangiaceæ, 134. - - Cenangium, 134. - - Cenchrus, 295. - - Centaurea, 565, 567, 568, 569, 570, 573. - - Centaury, 543. - - Centradenia, 484. - - “Central cell,” 185. - - Centranthus, 557, 558. - - Centrolepidaceæ, 308, 309. - - Centrolepis, 309. - - Centrolobium, 472. - - Centropogon, 563. - - Centunculus, 512, 513. - - Cephaëlis, 550, 553. - - Cephalanthera, 328, 331. - - Cephalaria, 560. - - Cephalotaceæ, 454. - - Cephalotaxeæ, 259. - - Cephalotus, 453. - - Ceramiaceæ, 84. - - Ceramium, 78, 80, 84. - - Cerastium, 364, 366. - - Cerasus, 462. - - Ceratiomyxa, 8. - - Ceratium, 16, 17. - - Ceratocapnos, 396. - - Ceratodon, 196. - - Ceratonia, 468. - - Ceratophyllaceæ, 388. - - Ceratophyllum, 388. - - Ceratostomaceæ, 130. - - Ceratozamia, 238, 253, 254. - - Cerbera, 544. - - Cercis, 467, 468. - - Cereus, 375, 377. - - Cerinthe, 533. - - Ceropegia, 546. - - Ceroxylon, 301. - - Cestreæ, 522. - - Cestrum, 522. - - Ceterach, 214. - - Cetraria, 138, 141, 142. - - Chænomeles, 465. - - Chærophyllum, 495, 498. - - Chætangiaceæ, 83. - - Chætoceros, 20. - - Chætocladiaceæ, 100. - - Chætocladium, 100. - - Chætomiaceæ, 129. - - Chætomium, 129. - - Chætomorpha, 58. - - Chætopeltis, 54. - - Chætophora, 54. - - Chætophoraceæ, 47, 54. - - Chætopteris, 70. - - Chalaza, 242. - - Chalazogames, 273. - - Chalazogams, 273. - - Chamæcyparis, 268, 269. - - Chamædorea, 298, 301. - - Chamædoris, 62. - - Chamælaucieæ, 489. - - Chamælaucium, 489. - - Chamænerium, 484. - - Chamaerops, 298, 300, 301, 302. - - Chamæsiphon, 22, 24, 25. - - Chamæsiphonaceæ, 24, 25. - - Chamomile, 572, 574. - - Chantransia, 83. - - Chara, 65, 66, 67. - - Characeæ, 1, 4, 10, 14, 64. - - Characium, 47, 51. - - Chareæ, 67. - - Charlock, 404. - - Cheilanthes, 213. - - Cheiranthus, 399, 400, 402. - - Cheirostemon, 427. - - Chelidonium, 394, 395. - - Chelone, 525. - - Chenopodiaceæ, 364, 369. - - Chenopodieæ, 369. - - Chenopodina, 371, 372. - - Chenopodium, 369, 372. - - Cherry, 117, 156, 461, 462. - - Cherry-laurel, 462. - - Chervil, 495, 498. - - Chervil-root, 498. - - Chick-pea, 470. - - Chickweed, 366. - - Chicory, 570, 574. - - Chilies, 522. - - Chimaphila, 505. - - Chimonanthus, 389. - - China-grass, 353. - - Chinese galls, 439. - - Chiococca, 550. - - Chionanthus, 547. - - Chionodoxa, 312. - - Chive, 312. - - Chlamydomonas, 48. - - Chlamydomoneæ, 14. - - Chlamydomucor, 97, 98. - - Chlamydospore, 90. - - Chlora, 47, 543. - - Chlorangium, 51. - - Chloranthaceæ, 363. - - Chloranthus, 363. - - Chlorideæ, 295. - - Chloris, 295. - - Chlorochytrium, 47, 51. - - Chlorococcum, 51. - - Chlorocystis, 51. - - Chlorophyceæ, 1, 14, 46. - - Chlorophytum, 312. - - Chlorosphæra, 51. - - Chlorosphæraceæ, 47, 51. - - Chlorosplenium, 135. - - Chlorotylium, 54. - - Choanephora, 100. - - Choanephoraceæ, 100. - - Chocho, 481. - - Choiromyces, 124. - - Choisya, 436. - - Chondrus, 79, 83, 84. - - Chorda, 72. - - Chordaria, 71. - - Chordariaceæ, 71. - - Choripetalæ, 336, 337, 505, 561. - - Chorisia, 427. - - Choristocarpaceæ, 70. - - Choristocarpus, 70. - - Chromaceæ, 15. - - Chromulina, 15. - - Chroococcaceæ, 24. - - Chroococcus, 24, 176. - - Chrysalis Fungus, 127. - - Chrysanthemum, 572. - - Chrysarobin, 473. - - Chrysobalanaceæ, 462, 466. - - Chrysobalanus, 462. - - Chrysomonadinaceæ, 15, 17. - - Chrysomyxa, 147, 148, 153, 155. - - Chrysophyllum, 511. - - Chrysopyxaceæ, 15. - - Chrysopyxis, 15. - - Chrysosplenium, 452, 454. - - Chylocladia, 83. - - Chysis, 333. - - Chytridiales, 95, 102. - - Chytridium, 103. - - Cibotium, 214, 215. - - Cicely, 495. - - Cicendia, 543. - - Cicer, 470. - - Cichorieæ, 561, 568, 570. - - Cichorium, 570, 574. - - Cicinnobolus, 120. - - Cicuta, 494, 498. - - Cilioflagellata, 17. - - Cimaruoli, 355. - - Cimicifuga, 383. - - Cinchona, 548, 549, 550, 553. - - Cinchoneæ, 550. - - Cinchonin, 553. - - Cinclidotus, 197. - - Cineraria, 572, 574. - - Cinnamon, 392. - - Cinnamomum, 391, 392. - - Cinquefoil, 458. - - Cipura, 321. - - Circaea, 485, 486. - - Circinate, 208. - - Cirsium, 151, 568, 569. - - Cissampelos, 390. - - Cissus, 445, 504. - - Cistaceæ, 412. - - Cistifloræ, 406, 451. - - Cistus, 412, 503. - - Citharexylon, 535. - - Citriobatus, 455. - - Citron, 438. - - Citronella oil, 296. - - Citrullus, 479, 480, 481. - - Citrus, 437, 438. - - Cladium, 286. - - Cladochytrium, 103. - - Cladonia, 139, 140, 141, 142, 143. - - Cladophora, 11, 58. - - Cladophoraceæ, 47, 58. - - Cladosporium, 124. - - Cladothrix, 27, 33, 34, 35. - - Clamp-connections, 86. - - Clarkia, 485. - - Clastidium, 25. - - Clatbrus, 173. - - Clavaria, 159, 161. - - Clavariaceæ, 161. - - Claviceps, 125, 126, 127. - - Clavija, 513. - - Claytonia, 373. - - Cleavers, 552. - - Cleistocarpeæ, 195. - - Clematideæ, 385. - - Clematis, 378, 379, 380, 385. - - Cleome, 406. - - Clerodendron, 535. - - Clethra, 509. - - Climacium, 197. - - Clinopodium, 540. - - Clintonia, 563. - - Clitocybe, 171. - - Clitoria, 471. - - Clivia, 317, 318. - - Closterium, 43, 44. - - Clostridium, 31. - - Cloudberry, 461. - - Clover, 135, 471. - - Cloves, 489. - - Club-mosses, 2, 205, 226. - - Club-rush, 285. - - Clusia, 414. - - Clusiaceæ, 414. - - Cluster-cups, 150. - - Clypeosphæriaceæ, 130. - - Cnicus, 570, 574. - - Cnidium, 495. - - Cobæa, 515. - - Coca, 442. - - Cocaine, 442. - - Cocci, 26. - - Coccochromaticæ, 21. - - Coccoloba, 360. - - Cocconeideæ, 21. - - Cocconeis, 21. - - Cocconema, 20. - - Cocculus, 390. - - Coccus, 356. - - Cochineal, 377. - - Cochineal-insect, 377. - - Cochlearia, 398, 400. - - Cochleariinæ, 404. - - Cock’s-comb, 369. - - Cock’s-foot, 294, 296. - - Cocoa-beans, 423. - - Cocoa-butter, 423. - - Cocoa-plum, 462. - - Cocoa-tree, 422. - - Cocoanut, 298, 300, 302. - - Cocoanut, Double, 301. - - Cocoanut-palm, 301. - - Cocoineæ, 300. - - Cocos, 298, 301, 302. - - Codiaceæ, 61. - - Codiolum, 59. - - Codium, 62. - - Cœlastrum, 52. - - Cœlebogyne, 432. - - Cœloglossum, 332. - - Cœlospermeæ, 493, 497. - - Cœlosphærium, 24. - - Cœnobia, 47, 51. - - Cœnogonium, 142. - - Coffea, 550. - - Coffeeæ, 550. - - Coffee, 555. - - Coffee-plant, 550, 553. - - Coix, 293. - - Cola, 422, 423. - - Colchicaceæ, 309, 310. - - Colchiceæ, 310. - - Colchicin, 311. - - Colchicum, 310, 311. - - Coleochætaceæ, 47, 57. - - Coleochæte, 57, 58. - - Coleonema, 436. - - Coleorhiza, 293. - - Coleosporium, 147, 148, 152, 154. - - Coleus, 540, 541. - - Collema, 138, 142. - - Colletia, 448. - - Collinsia, 525. - - Collomia, 515. - - Collybia, 171. - - Colocasia, 303, 305, 306. - - Colocynth, 481. - - Colts-foot, 571. - - Columba-root, 390. - - Columbine, 382. - - Columella, 187, 189, 193. - - Columnea, 528. - - Columniferæ, 421. - - Colus, 173. - - Colutea, 470, 473. - - Comarum, 457, 458. - - Combretaceæ, 487. - - Comfrey, 533. - - Comma-bacillus, 40. - - Commelina, 308. - - Commelinaceæ, 308. - - Commersonia, 422. - - Commiphora, 438. - - Compass-plant, 572. - - Compositæ, 556, 560, 561, 563, 564. - - Comptonia, 350. - - Condurango-bark, 546. - - Cone, 235. - - Cone-scales, 256. - - Conferva, 54. - - Confervoideæ, 47, 53. - - Conidia, 87, 90. - Liberation and distribution of, 91. - - Conidial-layers, 88. - - Conidiocarp, 89, 147. - - Conidio-fructification, 87. - - Conidiophore, 87, 88. - - Coniferæ, 3, 237, 238, 252, 255. - Female flower of, 255, 257. - Pollination, 258. - - Coniocybe, 134. - - Conium, 494, 498. - - Conjugatæ, 1, 12, 14, 41, 88. - - Conjugation, 11. - - Connaraceæ, 435. - - Conocarpus, 487. - - Conomitrium, 196. - - Contortæ, 505, 541, 549. - - Convallaria, 314, 316. - - Convallariaceæ, 309, 314. - - Convallarieæ, 314. - - Convolvulaceæ, 5, 515, 522, 532. - - Convolvuleæ, 516. - - Convolvulus, 114, 516, 517. - - Co-operating cells, 248. - - Copaifera, 467, 468. - - Copal-balsam, 468. - - Copernicia, 300, 301. - - Copper-beech, 157. - - Coprinarius, 171. - - Coprinei, 172. - - Coprinus, 172. - - Coptis, 379, 382. - - Cora, 176. - - Corallina, 79, 84. - - Corallinaceæ, 84. - - Coralliorrhiza, 332. - - Corallorhiza, 5, 332. - - Coral-root, 332. - - Corchorus, 424, 425. - - Cordaitaceæ, 271. - - Cordiaceæ, 47–61, 531, 532. - - Cordyceps, 125, 127, 128. - - Cordyline, 316. - - “Core,” 463. - - Coriander, 497, 498. - - Coriandrum, 493, 497, 498. - - Cork-elm, 352. - - Cork-oak, 348. - - Cormophyta, 1. - - Cormophytes, 234. - - Cornaceæ, 490, 549. - - Cornel, 490. - - Corn-cockle, 367. - - Corn-flower, 567. - - Corn-poppy, 395. - - Cornus, 490, 491. - - Corona, 317, 476. - - Coronilla, 472, 473. - - Correa, 436. - - Corrigiola, 365, 367. - - Corsinia, 190. - - Corsiniaceæ, 190. - - Cortex angosturæ, 437. - - Corticium, 144, 161. - - Cortinarius, 171. - - Cortusa, 512. - - Corydalis, 334, 395, 396, 397. - - Corylaceæ, 341, 343. - - Corylus, 122, 343, 344, 348. - - Corypha, 298, 300. - - Coscinodisceæ, 21. - - Coscinodiscus, 20. - - Coscinodon, 197. - - Cosmanthus, 515. - - Cosmarium, 42, 43, 44. - - Costus, 326. - - Cotoneaster, 463, 465. - - “Cotton” 427, 429, 430. - - Cotton-grass, 286. - - Cotton-thistle, 570. - - Cotyledon, 451. - - Cotyledons, 247. - - Couch, 295. - - Coumarin, 296, 473, 553. - - Cover-scale, 255, 256. - - Cow-bane, 494, 498. - - Cowberry, 509. - - Cow-parsnip, 496. - - Cow-tree, 356. - - Cow-wheat, 526. - - “Crab’s-eyes,” 470. - - Crambe, 400, 403. - - Craniolaria, 529. - - Crassula, 452. - - Crassulaceæ, 451. - - Cratægeæ, 465. - - Cratægus, 152, 465. - - Craterellus, 162, 172. - - Craterocolla, 156. - - Crenothrix, 30, 37. - - Creosote, 438. - - Crepis, 571. - - Crescentia, 529. - - Crinum, 318. - - Crocus, 320, 321. - - Cronartium, 146, 147, 153, 155, 156. - - Crotalaria, 472, 473. - - Croton, 431, 434. - - Crowberry, 434. - - Crown-imperial, 314. - - Crozophora, 434. - - Crucianella, 552. - - Crucibulum, 176. - - Cruciferæ, 398. - - Crucifers, 398. - - Crucigenia, 51. - - Cruoria, 84. - - Cryptogams, 3, 234. - Vascular, 2, 198. - - Cryptoglena, 15. - - Cryptogramme, 213. - - Cryptomeria, 267. - - Cryptonemia, 84. - - Cryptonemiales, 82, 84. - - Ctenanthe, 327. - - Ctenium, 295. - - Ctenomyces, 119. - - Cubeb, 363. - - Cucubalus, 367. - - Cucullus, 545. - - Cucumber, 481. - - Cucumis, 121, 480, 481. - - Cucurbita, 478, 479, 480, 481. - - Cucurbitaceæ, 475, 478, 561. - - Cucurbitariaceæ, 130. - - Cud-weed, 573. - - Cuminum, 497, 498. - - Cunninghamia, 263. - - Cunoniaceæ, 454. - - Cuphea, 482, 483. - - Cupressaceæ, 257, 262, 267, 272. - - Cupressus, 241, 245, 268, 269. - - Cupule, 343. - - Cupuliferæ, 341, 345. - - Curare, 546. - - Curculigo, 318. - - Curcuma, 326. - - Curly-mint, 541. - - Currants, 447, 454. - - Curvembryæ, 363. - - Cuscuta, 5, 515, 517. - - Cuscuteæ, 516. - - “Cushion,” 206. - - Cusparia, 437. - - Cusparieæ, 437. - - Cutleria, 68, 72. - - Cutleriaceæ, 11, 72. - - Cyanophyceæ, 22. - - Cyanophyll, 22. - - Cyanotis, 308. - - Cyathea, 214, 215. - - Cyatheaceæ, 210, 215. - - Cyathium, 432. - - Cyathus, 176. - - Cycadaceæ, 252. - - Cycadeæ, 3, 236, 252, 254. - - Cycas, 25, 231, 236, 238, 251, 252, 253, 254. - - Cyclamen, 334, 512, 513. - - Cyclanthaceæ, 302. - - Cyclanthera, 481. - - Cyclolobeæ, 371. - - Cyclosporeæ, 68, 73. - - Cydonia, 463, 464. - - Cylindrocapsa, 14, 55. - - Cylindrocapsaceæ, 47, 54. - - Cylindrocystis, 44. - - Cylindrospermum, 22, 25. - - Cymbella, 20, 21. - - Cymbelleæ, 20, 21. - - Cymodocea, 281. - - Cymopolia, 63. - - Cynanchum, 546. - - Cynara, 570, 574. - - Cynareæ, 569. - - Cynips, 355. - - Cynodon, 295. - - Cynodontium, 196. - - Cynoglossum, 533, 535. - - Cynomorium, 503, 504. - - Cynosurus, 294, 296. - - Cypella, 321. - - Cyperaceæ, 277, 283, 284, 291. - - Cyperus, 286, 287, 290. - - Cyphella, 162. - - Cyphiaceæ, 562. - - Cypress, 267, 268. - - Cypripedileæ, 329, 330. - - Cypripedilum, 330. - - Cypripedium, 330. - - Cypsela, 564. - - Cyrtandreæ, 528. - - Cystocarp, 14, 58, 82. - - Cystoclonium, 83. - - Cystopteris, 214. - - Cystopus, 107. - - Cytinus, 503, 504. - - Cytisus, 472, 473. - - - Dacrydium, 255, 260, 261. - - Dacryomitra, 158, 159. - - Dacryomyces, 134, 158, 159. - - Dacryomycetaceæ, 159. - - Dacryomycetes, 96, 145, 159. - - Dactylis, 287, 294, 296. - - Dactylococcus, 51. - - Dædalea, 166, 171. - - Dahlia, 569, 572. - - Daisy, 572. - - Dalbergia, 472. - - Dalbergieæ, 472. - - Dalechampia, 434. - - Damasonium, 282. - - Dammara, 263. - - Danæa, 212. - - Dandelion, 571. - - Daphne, 449, 450. - - Darlingtonia, 409. - - Darwinia, 489. - - Dasycladaceæ, 63. - - Dasycladus, 63. - - Dasyscypha, 135. - - Date-palm, 298, 299, 301, 302. - - Date-plum, 511. - - Datisca, 477. - - Datiscaceæ, 477. - - Datura, 519, 520, 522. - - Dauceæ, 496. - - Daucus, 134, 492, 496. - - Davallia, 214. - - Davilla, 413. - - Deadly nightshade, 521. - - Dead-nettle, 538. - - Delesseria, 79, 80, 83. - - Delesseriaceæ, 83. - - Delphinieæ, 383. - - Delphinium, 379, 383. - - Dendrobium, 332. - - Derbesia, 10, 60. - - Derbesiaceæ, 47, 60. - - Dermatea, 116, 134. - - Dermateaceæ, 134. - - Dermateales, 134. - - Dermatophyton, 54. - - Dermocarpa, 25. - - Desmanthus, 475. - - Desmarestia, 71. - - Desmarestiaceæ, 71. - - Desmidiaceæ, 10, 18, 21, 42, 44, 48. - - Desmidium, 44. - - Desmodium, 466, 472. - - Deutzia, 455. - - Devil’s-bit, 560. - - Dianthus, 364, 367. - - Diapensiaceæ, 509. - - Diatoma, 19. - - Diatomaceæ, 10, 12, 14, 19, 20, 21. - - Diatomeæ, 1, 18. - - Diatomin, 18. - - Diatoms, 1. - - Diatrypaceæ, 130. - - Diatrype, 130. - - Dicentra, 395, 396, 397. - - Dichaenaceæ, 132. - - Dichelyma, 197. - - Dichondreæ, 516. - - Dichorisandra, 308. - - Dichospermum, 371. - - Dicksonia, 207, 215. - - Diclinous, 236. - - Dicliptera, 530. - - Dicotyledones, 3, 334. - - Dicranella, 196. - - Dicranum, 196. - - Dictamnus, 436. - - Dictyochaceæ, 15. - - Dictyonema, 176. - - Dictyosiphon, 71. - - Dictyosiphonaceæ, 71. - - Dictyosphærium, 51. - - Dictyostelium, 8. - - Dictyota, 76. - - Dictyotaceæ, 76. - - Dictyotales, 1, 14, 76. - - Dicypellium, 392. - - Didiscus, 493. - - Didymium, 8. - - Dieffenbachia, 306. - - Dielytra, 395. - - Diervilla, 554, 556. - - Digitalis, 524, 525, 527. - - Digraphis, 295, 296. - - Dill, 496. - - Dillenia, 413. - - Dilleniaceæ, 413. - - Dimorphanthus, 491. - - Dimorphochlamys, 481. - - Dinifera, 17. - - Dinobryinaceæ, 15. - - Dinobryon, 15. - - Dinoflagellata, 1, 14, 16, 17, 18, 21. - - Dinophysis, 17. - - Diodia, 550. - - Diœcious, 236. - - Dionæa, 408. - - Dioon, 254. - - Dioscorea, 322, 323. - - Dioscoreaceæ, 276, 309, 310, 322. - - Diosma, 436. - - Diosmeæ, 436. - - Diospyrinæ, 505, 510. - - Diospyros, 511. - - Diphtheria, 40. - - Diphyscium, 197. - - Diplarrhena, 321. - - Diplecolobeæ, 400. - - Diplococcus, 39. - - Diploderma, 78. - - Diplostemonous, 335, 336. - - Diplusodon, 483. - - Dipsacaceæ, 549, 556, 558, 559, 560, 569. - - Dipsacales, 505, 556, 564. - - Dipsacus, 559, 560. - - Dipterocarpaceæ, 415. - - Dipterocarpus, 415. - - Dipteryx, 472, 473. - - Discelium, 197. - - Discolichenes, 142. - - Discomycetes, 95, 116, 132. - - Discosporangium, 70. - - Disease, 32. - - Disinfection, 32. - - Dispora, 36. - - Distichium, 196. - - Doassansia, 110. - - Docidium, 44. - - Dock, 359. - - Dodder, 5, 516, 517. - - Dodecatheon, 513. - - Dog’s-tail, 294, 296. - - Dogwood, 499. - - Dolichos, 471. - - Dondia, 493. - - Dorema, 496, 498. - - Doronicum, 240, 572. - - Dorstenia, 131, 354. - - Dothideaceæ, 131. - - Double Cocoanut, 301. - - Doum-palm, 298, 301. - - Draba, 400. - - Dracæna, 274, 316. - - Dracæneæ, 316. - - Dracocephalum, 539. - - Dracunculus, 303, 305. - - Dragon’s blood, 301, 316. - - Dragon-tree, 316. - - Draparnaldia, 54. - - Drimys, 389. - - Drosera, 408. - - Droseraceæ, 407. - - Drosophyllum, 408. - - Dryas, 458. - - Dryobalanops, 415. - - Dry-rot, 165, 166. - - Dry yeast, 179. - - Duboisia, 522. - - Duckweed, 307. - - Dudresnaya, 84. - - Dumontia, 84. - - Dumontiaceæ, 84. - - Durio, 427. - - Durra, 296. - - Dwarf-elder, 553. - - Dwarf-male, 57. - - Dwarf-palm, 300. - - Dyer’s Weed, 407, 472. - - - Earth-nut, 472. - - Earth-star, 174. - - Earth-tongue, 136. - - Eating-chestnut, 346. - - Ebenaceæ, 511. - - Ebony, 511. - - Ecballium, 478, 480, 481. - - Eccremocarpus, 529. - - Echeveria, 451. - - Echinocactus, 375, 376, 377. - - Echinodorus, 281. - - Echinops, 564, 570. - - Echinopsis, 376, 377. - - Echinospermum, 533. - - Echites, 544. - - Echium, 531, 532, 533, 534, 535. - - Ectocarpaceæ, 70. - - Ectocarpus, 69, 70. - - Edelweiss, 573. - - Edwardsia, 469. - - Egg-cell, 13. - - Egg-fertilisation, 13. - - Egg-plant, 522. - - Ehretia, 533. - - Eichhornia, 316. - - Elachista, 71. - - Elachistaceæ, 71. - - Elæagnaceæ, 449. - - Elæagnus, 450. - - Elæis, 301, 302. - - Elæocarpus, 425. - - Elaphomyces, 124. - - Elaphrium, 438. - - Elatereæ, 192. - - Elaters, 189. - - Elatinaceæ, 413. - - Elatine, 413. - - Elder, 156, 553, 555, 556. - - Elemi, 438. - - Elettaria, 326. - - Eleusine, 295. - - Elisma, 281, 282. - - Elm, 124, 165, 351. - - Elodea, 282. - - Elymus, 113, 296. - - Elyna, 286, 287. - - Embryo, 246, 247, 248. - - Embryo-sac, 241, 247. - - Emericella, 176. - - Emex, 360. - - Empetraceæ, 434. - - Empetrum, 434. - - Empleurum, 436. - - Empusa, 101, 102. - - Enantioblastæ, 277, 308. - - Encephalartos, 254. - - Enchanter’s Nightshade, 485. - - Encoeliaceæ, 70. - - Endocarpon, 142. - - Endomyces, 116, 117. - - Endophyllum, 147, 151. - - Endophytic parasites, 85. - - Endosperm, 233, 246, 248, 249. - - Endospermous, 249. - - Endosphæra, 47, 51. - - Endospore, 89, 187. - - Endosporous, 29. - - Endothecium, 186. - - Endozoic Fungi, 85. - - Enhalus, 283. - - Entada, 473, 474. - - Enteromorpha, 53. - - Entoderma, 54. - - Entomophthora, 102. - - Entomophthoraceæ, 102. - - Entomophthorales, 95, 102. - - Entyloma, 109, 111, 113. - - Enzyme, 32. - - Epacridaceæ, 509. - - Epacris, 509. - - Ephebe, 139, 142. - - Ephedra, 271. - - Ephemerum, 195. - - Epibasal, 186. - - Epichloë, 125, 127. - - Epiclemmydia, 54. - - Epidendreæ, 332. - - Epidendron, 332. - - Epigynum, 544. - - Epilobium, 484, 485. - - Epimedium, 390. - - Epipactis, 331, 333. - - Epipetalous, 336. - - Epiphyllum, 375, 377. - - Epiphytic parasites, 85. - - Epipogon, 331. - - Epipyxis, 15. - - Episepalous, 335. - - Epithemia, 20, 21. - - Epizoic Fungi, 85. - - Equisetaceæ, 202, 204, 221, 234, 235, 236, 240. - - Equisetinæ, 2, 204, 221, 225. - - Equisetum, 200, 206, 221, 222, 224. - - Eragrostis, 294. - - Eranthemum, 530. - - Eranthis, 379, 382. - - Ergot, 125, 127. - - Eria, 332. - - Erica, 507, 508. - - Ericaceæ, 238, 505, 507. - - Ericeæ, 507. - - Erigeron, 573. - - Erinus, 525. - - Eriobotrya, 465. - - Eriocaulaceæ, 308, 309. - - Eriocaulon, 309. - - Eriodendron, 427. - - Eriophorum, 285, 286. - - Erodium, 419. - - Eruca, 402. - - Ervum, 470, 473. - - Eryngium, 493, 569. - - Erysiminæ, 404. - - Erysimum, 402. - - Erysiphaceæ, 119. - - Erysiphe, 119, 120, 121. - - Erythræa, 542, 543. - - Erythrina, 471. - - Erythronium, 312. - - Erythrotrichia, 78. - - Erythroxylaceæ, 442. - - Erythroxylon, 442. - - Escalloniaceæ, 454. - - Escalloniæ, 451. - - Eschalot, 312. - - Eschsholzia, 393, 395. - - Esparto grass, 296. - - Euactæa, 379. - - Euaspergillus, 122. - - Euastrum, 44. - - Eucalyptus, 489. - - Eucalypta, 197. - - Eucharidium, 485. - - Eucharis, 317, 318. - - Euchlæna, 293. - - Eucomis, 312. - - Eudorina, 48, 50. - - Eugeissonia, 301. - - Eugenia, 488, 489. - - Euglena, 103. - - Eunotieæ, 21. - - Euonymus, 152, 444. - - Eupatorieæ, 571, 572. - - Eupatorium, 569, 571. - - Euphacidiaceæ, 133. - - Euphorbia, 148, 151, 430, 432, 433. - - Euphorbiaceæ, 430. - - Euphorbium, 434. - - Euphoria, 441. - - Euphrasia, 526. - - Eupodisceæ, 21. - - Eurhynchium, 197. - - Eurotium, 121, 122. - - Euryale, 386, 387, 388. - - Eusporangiatæ, 202, 210, 239. - - Euterpe, 301. - - Euthora, 83. - - Eutoca, 515. - - Evening Primrose, 484. - - Evernia, 143. - - Evodia, 436. - - Evolvulus, 516. - - Exalbuminous, 249. - - Exidia, 156. - - Exoasci, 95, 115, 116. - - Exobasidium, 160, 161. - - Exochorda, 457. - - Exospore, 87, 187. - - Exostemma, 553. - - Exuviella, 16, 17, 18, 21. - - Eye-bright, 526. - - “Eye-spot,” 10. - - - Faba, 468, 470, 473. - - Fabiana, 521. - - Fabroniaceæ, 197. - - “Fæchel,” 284. - - Facultative parasites, 84. - - Fagonia, 438. - - Fagus, 122, 347, 348. - - “Fairy-rings,” 86, 136, 163, 168. - - Falcaria, 494. - - “Fan,” 284. - - Fan-palm, 298. - - Farinosæ, 308. - - Fatsia, 491. - - Feather-grass, 294. - - Feather palm, 298. - - Fedia, 557. - - Fegatella, 191. - - Fennel, 492, 495, 498. - - “Ferment of wine,” 178. - - Fermentation, 32. - Alcoholic, 97. - - Ferns, 2. - Stem of, 202, 204, 205. - True, 204, 205. - Water, 205. - Various, 208. - - Ferraria, 321. - - Ferula, 496, 498. - - Fescue, 293, 296. - - Festuca, 293, 296. - - Festuceæ, 293. - - Fevillea, 478, 481. - - Ficaria, 334, 383. - - Ficus, 351, 354, 355, 356. - - Field-horsetail, 224. - - Field-madder, 552. - - Field-thistle, 151. - - Fig-wort, 524. - - Filago, 573. - - Filament, 238. - - Filbert, 345. - - Filices, 204, 205. - Systematic division of, 210. - - Filicinæ, 2, 204, 205, 234, 236, 239. - - Fiori di fico, 355. - - Fiorin, 294. - - Fir, 124, 153, 155, 165, 170, 263, 264, 265. - - Fir-cones, 163. - - Firneedle-rust, 152. - - Fissidens, 196. - - Fissidentaceæ, 196. - - Fission-Algæ, 1, 14, 22, 29. - - Fission-Fungi, 26, 29. - - Fission-plants, 10. - - Fistulina, 166. - - Flag, 320. - - Flagellata, 48. - - Flagellatæ, 15. - - Flax, 417. - - Flea-bane, 573. - - “Fleur de vin,” 179. - - Floral-leaves, 235. - - Florideæ, 9, 10, 77, 78. - - Flower, 235. - Monocotyledonous, 276. - - Flowering-plants, 3, 249. - - Flowering-rush, 281. - - Flowers-of-tan, 7. - - Fly-mould, 101. - - Fly-mushroom, 167, 171. - - Fly-trap, 408. - - Fœniculum, 495, 498. - - Foliage-leaves, 235. - - Fontinalaceæ, 197. - - Fontinalis, 197. - - Fool’s-parsley, 495, 498. - - Foot, 186. - - Fore-leaf, 275, 334. - - Forget-me-not, 334. - - Forskohlea, 353. - - Forsythia, 546, 547. - - Fossil Gymnosperms, 271. - - Fothergilla, 455. - - Fourcroya, 318. - - Fovea, 231. - - Foxglove, 525. - - Fox-tail, 294, 298, 369. - - Fragaria, 458, 461. - - Fragilarieæ, 21. - - Franciscea, 521. - - Francoaceæ, 454. - - Frangulinæ, 443, 449, 451, 490. - - Frankeniaceæ, 411. - - Frankincense, 438. - - Fraxinus, 122, 130, 546, 547. - - French-bean, 473. - - French Rose, 460. - - Freycinetia, 302. - - Fritillaria, 312, 313, 314. - - Frog-bit, 282. - - “Fruit,” 91. - - Fruit, 249. - - Fruit-bearers, 91. - - Fruit-bodies, 91. - - “Fruit-forms,” 91. - - Frullania, 191, 192. - - Frustule, 18. - - Frustulia, 20. - - Fucaceæ, 75. - - Fuchsia, 484, 485. - - Fucoideæ, 9. - - Fucus, 13, 73, 74, 75. - - Fuligo, 6, 8. - - Fumago, 124. - - Fumaria, 396, 397. - - Fumariaceæ, 395. - - Fumitory, 395. - - Funaria, 182, 188, 197. - - Funariaceæ, 197. - - Funckia, 312, 313, 314. - - Fundaments, 90. - - Fungi, 1, 4, 5, 8, 84. - - Fungi-galls, 85. - - Fungi Imperfecti, 96. - - Fungus chirurgorum, 164. - laricis, 164. - - Funicle, 241. - - Furcellaria, 79, 84. - - Furze, 472. - - Fusicladium, 130. - - - Gagea, 312. - - Gaillardia, 572. - - Galactodendron, 356. - - Galangal, 326. - - Galanthus, 317, 318. - - Galaxaura, 83. - - Galaxia, 321. - - Galbanum, 498. - - Galega, 470. - - Galeobdolon, 538. - - Galeopsis, 538, 540. - - Galinsoga, 572. - - Galipea, 437. - - Galium, 552, 553. - - Galphimia, 442. - - Gambier, 553. - - Gamboge, 414. - - Gambo-hemp, 430. - - Gametangium, 12. - - Gamete, 11. - - Gametophore, 183. - - Gametophyte, 181. - - Gamopetalæ, 336. - - Garcinia, 414. - - Garden-cress, 405. - - Gardenia, 550. - - Gardenieæ, 550. - - Garidella, 383. - - Garlic, 312. - - Garrya, 491. - - Gasteria, 312. - - Gasterolichenes, 176. - - Gasteromycetes, 96, 145, 173. - - Gastonia, 491. - - Gaultheria, 508. - - Gaura, 485. - - Geaster, 174. - - Gelidiaceæ, 83. - - Gelidium, 83, 84. - - Genipa, 550. - - Genista, 471, 473. - - Genisteæ, 471. - - Gentian, 542. - - Gentiana, 542, 543. - - Gentianaceæ, 542. - - Gentianeæ, 542. - - Geoglossum, 136. - - Geonoma, 301. - - Georgiaceæ, 197. - - Geraniaceæ, 418. - - Geranium, 419. - - Germ-pores, 93. - - Gesneria, 528. - - Gesneriaceæ, 518, 526, 528. - - Gesnerieæ, 528. - - Geum, 458, 460. - - Gigartina, 83, 84. - - Gigartinaceæ, 83. - - Gigartinales, 82, 83. - - Gilia, 515. - - Gillenia, 457. - - Gills, 166. - - Ginger, 326. - - Ginkgo, 255, 257, 259, 260, 272. - - Gipsy-wort, 539. - - Gladiolus, 321. - - Glandulæ, 329. - - Glasswort, 371. - - Glaucium, 394, 395. - - Glaucocystis, 22, 24. - - Glaux, 513. - - Gleba, 172. - - Glechoma, 539, 541. - - Gleditschia, 468. - - Gleichenia, 215. - - Gleicheniaceæ, 215, 236. - - Glenodinium, 17. - - Globba, 326. - - Globe-thistle, 570. - - Globularia, 541. - - Globulariaceæ, 532, 541. - - Glœocapsa, 24. - - Glœotrichia, 25. - - Gloiopeltis, 84. - - Gloiosiphoniaceæ, 84. - - Gloxinia, 528. - - Glume, 287. - - Glumifloræ, 277, 283. - - Glyceria, 113, 290, 294, 296. - - Glycine, 471. - - Glycyrrhiza, 470, 473. - - Glyptostrobus, 267. - - Gnaphalium, 569, 573. - - Gnetaceæ, 3, 251, 271, 272. - - Gneteæ, 252, 270. - - Gnetum, 271. - - Gnidia, 449. - - Gnomonia, 130. - - Gnomoniaceæ, 130. - - Goat’s-beard, 571. - - Godetia, 485. - - Godlewskia, 25. - - Golden-currant, 455. - - Golden-rod, 573. - - Golden Saxifrage, 452. - - Goldfussia, 530. - - Gold-of-pleasure, 401. - - Gomontia, 58. - - Gomontiaceæ, 47, 58. - - Gomphonema, 19. - - Gomphonemeæ, 20, 21. - - Gomphosphæria, 24. - - Gomphrena, 368, 369. - - Gonatozygon, 44. - - Gongrosira, 54. - - Gonidia, 138. - - Gonimoblast, 82. - - Goniotrichaceæ, 78. - - Goniotrichum, 78. - - Gonium, 48. - - Gonococcus, 39. - - Gonolobus, 546. - - Goodenia, 564. - - Goodeniaceæ, 563. - - Gooseberry, 455. - - Goosefoot, 369. - - Gossypieæ, 427. - - Gossypium, 427, 429, 430. - - Gouania, 448. - - “Gourds,” 481. - - Gout-weed, 494. - - Gracilaria, 83. - - “Grains of Paradise,” 390. - - Gramineæ, 277, 283, 287. - - Grape-disease, 121. - - Graphiola, 110. - - Graphis, 140, 142. - - Grasses, 287. - - Grass-flower, 290, 291. - - Grass-fruit, 292. - - Grass of Parnassus, 453. - - Grass-wrack, 279. - - Grateloupiaceæ, 84. - - Gratiola, 525, 527. - - Green Algæ, 1, 14. - - “Greenheart,” 393. - - Grevillea, 450. - - Griffithsia, 84. - - Grimmia, 197. - - Grimmiaceæ, 197. - - Gronovia, 476. - - Ground Ivy, 539. - - Groundsel, 153, 572. - - Gruinales, 416. - - Guaiacum, 438. - - Guano, 20. - - Guava, 489. - - Guava-rum, 490. - - Guazuma, 422. - - Guelder-rose, 455, 555. - - Guepinia, 159. - - Guinea-corn, 296. - - Guinea Pepper-plant, 521. - - Guizotia, 574. - - Gulf-weed, 75. - - Gum-arabic, 475. - - Gum-benzoin, 511. - - Gum-tragacanth, 473. - - Gum-trees, 490. - - Gunnera, 25, 482, 485, 486. - - Guttapercha, 511. - - Guttiferæ, 414. - - Gymnadenia, 332. - - Gymnoascaceæ, 119. - - Gymnoascales, 95, 116, 118. - - Gymnoascus, 119. - - Gymnodinium, 17. - - Gymnogramme, 214. - - Gymnospermæ, 2, 234, 239, 250, 251. - - Gymnosperms, 244, 246. - Fossil, 271. - - Gymnosporangium, 146, 147, 151, 154. - - Gymnosporeæ, 82. - - Gymnostomum, 196. - - Gymnozyga, 42, 44. - - Gynandræ, 278, 328. - - Gynandropsis, 405, 406. - - Gynerium, 294, 296. - - Gynœceum, 237. - - Gynophore, 367. - - Gynostemium, 329. - - Gysophila, 368. - - - Habenaria, 332. - - Hablitzia, 370. - - Habrothamnus, 522. - - Hacquetia, 493. - - Hæmanthus, 317, 318. - - Hæmatoxylon, 467, 468. - - Hæmodoraceæ, 320. - - Hæmodorum, 320. - - Hagenia, 460. - - Hair-grass, 294. - - Hakea, 450. - - Halesia, 511. - - Halianthus, 366. - - Halidrys, 73, 75. - - Halimeda, 62, 63. - - Halimus, 371. - - Halophila, 283. - - Haloragidaceæ, 482, 485, 486. - - Haloragis, 486. - - Halymenia, 84. - - Hamamelidaceæ, 455. - - Hamamelis, 455. - - Hamelia, 550. - - Hankornia, 544. - - Hapalosiphon, 26. - - Haplomitrium, 192. - - Haplospora, 72. - - Haptera, 4, 10. - - Hard-fern, 214. - - Hare’s-ear, 494. - - Hart’s-tongue, 214. - - “Harzsticken,” 169. - - Haschisch, 358. - - Hassalia, 26. - - Haustoria, 86. - - Hawkbit, 571. - - Hawksbeard, 571. - - Hawthorn, 465. - - Hay-bacillus, 37, 38, 39. - - Hazel, 526. - - Hazel-nut, 343. - - Heal-all, 539. - - Heath, 507. - - Hebenstretia, 541. - - Hechtia, 319. - - Hedera, 491. - - Hedge-mustard, 402. - - Hedge-parsley, 497. - - Hedwigia, 197. - - Hedycarya, 389. - - Hedychium, 326. - - Hedyosmum, 363. - - Hedysareæ, 472. - - Hedysarum, 472, 473. - - Helenium, 572. - - Heleocharis, 285. - - Heliantheæ, 572, 573. - - Helianthemum, 412. - - Helianthus, 569, 572, 574. - - Helichrysum, 573. - - Heliconia, 325. - - Heliconiæ, 325. - - Helicophyllum, 303. - - Helicteres, 422. - - Heliophilinæ, 404. - - Heliotropieæ, 533. - - Heliotropium, 533, 535. - - Hellebore, 382. - - Helleboreæ, 381. - - Helleborus, 379, 380, 382. - - Helminthocladiaceæ, 83. - - Helobieæ, 277, 278. - - Helosciadium, 494. - - Helosis, 504. - - Helotiaceæ, 135. - - Helotium, 135. - - Helvella, 136. - - Helvellaceæ, 136. - - Helvellales, 95, 116, 136. - - Helwingia, 491. - - Hemerocallideæ, 312. - - Hemerocallis, 312, 313, 314. - - Hemiasci, 95, 108. - - Hemibasidii, 95, 108, 109. - - Hemichlamydeous, 257. - - Hemileia, 155. - - Hemlock, 494, 498. - - Hemp, 356, 529. - - Hemp-agrimony, 571. - - Hemp-nettle, 538. - - Henbane, 521. - - Henriquezia, 549. - - Hepaticæ, 2, 188. - - Hepialus, 128. - - Heracleum, 492, 496. - - Herb-Paris, 314. - - Heritiera, 422. - - Hermannia, 422. - - Hermaphrodite, 236. - - Herminium, 332. - - Hermodactylus, 321. - - Hernandia, 392. - - Herniaria, 365, 367. - - Herpestis, 525. - - Herposteiron, 54. - - Herpotrichia, 129. - - Hesperideæ, 404. - - Hesperidinæ, 404. - - Hesperis, 400, 402. - - Heteranthera, 316. - - Heterobasidion, 145, 165. - - Heterocysteæ, 24. - - Heterocysts, 22. - - Heterœcious, 148. - - Heteromerous, 138. - - Heteropteris, 442. - - Heterosphæria, 116, 133. - - Heterosphæriaceæ, 133. - - Heterosporous Vascular Cryptogams, 200. - - Heterotoma, 563. - - Heuchera, 452. - - Hibiscus, 427, 430. - - Hickory, 350. - - Hieracium, 571. - - Hierochloa, 295, 296. - - Higher Fungi, 95, 114. - - Hilum, 243. - - Himanthalia, 75. - - Himantidium, 20. - - Hip, 459, 460. - - Hippocrateaceæ, 444. - - Hippocrepis, 472. - - Hippomane, 434. - - Hippophaë, 450. - - Hippuris, 486. - - “Hochblatt,” 235. - - Hog’s-fennel, 496. - - Holbœllia, 390. - - Holcus, 294, 296. - - Holly, 444. - - Hollyhock, 151, 430. - - Holochlamydeous, 256. - - Holosteum, 366. - - Homalia, 197. - - Homalothecium, 197. - - Homocysteæ, 24. - - Homoiomerous, 138. - - Honckenya, 366. - - Honesty, 400. - - Honey-dew, 126. - - Honey-leaves, 379. - - Honeysuckle, 553, 554. - - Hookeriaceæ, 197. - - Hop, 124, 356, 357. - - Hopea, 415. - - Hordeæ, 295. - - Hordeum, 291, 296. - - Horehound, 538. - - Hormidium, 54. - - Hormogonia, 10, 24. - - Hornbeam, 157, 343, 344. - - Horned Pond-weed, 279. - - Horn-nut, 485. - - Horn-poppy, 395. - - Horn-wort, 388. - - Horse-bean, 470, 473. - - Horse-chestnut, 440. - - Horse-radish, 400, 405. - - Horsetails, 2, 204, 221. - - Hosta, 312. - - Hoteia, 452. - - Hottonia, 512. - - Hound’s-tongue, 533. - - House-leek, 452. - - Houttuynia, 359, 362. - - Hoya, 546. - - Humiriaceæ, 421. - - Humulus, 121, 357, 358. - - Hura, 432. - - Hyacintheæ, 312. - - Hyacinthus, 312, 313, 314. - - Hyalotheca, 42, 44. - - Hydnaceæ, 162. - - Hydnophytum, 550, 553. - - Hydnora, 504. - - Hydnum, 162. - - Hydra, 9. - - Hydrangea, 455. - - Hydrangeaceæ, 455. - - Hydrastin, 385. - - Hydrastis, 381. - - Hydrilla, 283. - - Hydrocharis, 282. - - Hydrocharitaceæ, 278, 282. - - Hydrocleis, 281. - - Hydrocotyle, 491, 493. - - Hydrocotyleæ, 493. - - Hydrodictyaceæ, 47, 51. - - Hydrodictyon, 9, 52. - - Hydrolea, 515. - - Hydrophyllaceæ, 515. - - Hydropterideæ, 205, 215, 239. - - Hydruraceæ, 16. - - Hydrurus, 16. - - Hygrophorei, 172. - - Hygrophorus, 172. - - Hylocomium, 197. - - Hymenæa, 468. - - Hymenium, 88. - - Hymenogaster, 174, 175, 176. - - Hymenogastraceæ, 176. - - Hymenolichenes, 176. - - Hymenomycetes, 96, 145, 159. - - Hymenophore, 159. - - Hymenophyllaceæ, 206, 210, 215. - - Hymenophyllum, 215. - - Hyoscyamine, 522. - - Hyoscyamus, 518, 519, 520, 521, 522, 523. - - Hypecoum, 395, 396. - - Hypericaceæ, 413. - - Hypericum, 413, 414. - - Hypha, 85. - - Hyphæ-like threads, 9. - - Hyphæne, 298, 301. - - Hypholoma, 171. - - Hypnaceæ, 197. - - Hypnum, 47, 196, 197. - - Hypobasal, 186. - - Hypochæris, 571. - - Hypochnus, 161. - - Hypocreaceæ, 125. - - Hypocreales, 125. - - Hypoderma, 132. - - Hypodermaceæ, 132. - - Hypomyces, 125. - - Hyporhodius, 171. - - Hypothecium, 132. - - Hypoxideæ, 317. - - Hypoxis, 318. - - Hypoxylon, 131. - - Hypsophyllary leaves, 235. - - Hyssop, 540, 541. - - Hyssopus, 540, 541. - - Hysteriaceæ, 132. - - Hysteriales, 95, 116, 132. - - Hysterium, 132. - - Hysterophyta, 498. - - - Iberis, 398, 400, 401. - - Icacinaceæ, 439. - - Iceland-lichen, 142. - - Iceland-moss, 143. - - Ice-plant, 375. - - Icica, 438. - - Ignatius-beans, 546. - - Ilex, 444. - - Illecebrum, 367. - - Illicieæ, 389. - - Illicium, 389. - - Impatiens, 421. - - Imperatoria, 496, 498. - - Incense, 438. - - Indian-corn, 293. - - Indian-cress, 420. - - Indigo, 470, 473. - - Indigofera, 470, 473. - - Indusium, 210. - - Inflorescence of Palm, 299. - - Infusoria, 9. - - Inga, 473, 475. - - Integuments, 242. - - Inula, 569, 573, 574. - - Inulin, 574. - - Involucre, 189. - - Involution-forms, 36. - - Ionidium, 410. - - Ipecacuanha, 553. - - Ipomæa, 515, 517. - - Iridaceæ, 277, 310, 320. - - Iris, 276, 291, 320, 321. - - Irish-moss, 84. - - Iron-bacteria, 33. - - Iron-wood, 339, 511. - - Irpex, 163. - - Isactis, 25. - - Isaria, 127, 128. - - Isatis, 403, 404. - - Isnardia, 485. - - Isoëtaceæ, 230. - - Isoëtes, 200, 202, 204, 228, 230, 245. - - Isogamous fertilisation, 11. - - Isolepis, 287. - - Isonandra, 511. - - Isopyrum, 382. - - Isosporous Vascular Cryptogams, 200. - - Isothecium, 197. - - Isotoma, 563. - - Ivy, 491. - - Ixia, 321. - - Ixora, 550. - - - Jacaranda, 529. - - Jack, 356. - - Jacquinia, 513. - - Jalap, 517. - - Jambosa, 488. - - Japanese wax, 439. - - Jasione, 541, 561, 562. - - Jasminaceæ, 541, 542, 547. - - Jasmine, 547. - - Jasminum, 547. - - Jateorhiza, 390. - - Jatropha, 431. - - Jequirty, 470. - - Jerusalem-Artichoke, 572, 574. - - Jonquil, 318. - - Judas’-ear, 156. - - Judas-tree, 468. - - Juglandaceæ, 337, 349. - - Juglandifloræ, 349. - - Juglans, 349, 350. - - Juncaceæ, 277, 283, 284, 291. - - Juncaginaceæ, 278. - - Juncus, 283, 284. - - Jungermannia, 191, 192. - - Jungermannieæ, 191. - - Juniper, 259, 268, 269. - - Juniperus, 151, 152, 241, 268, 269. - - Jurinea, 570. - - Jussiæa, 485. - - Justicia, 530. - - Jute, 425. - - - Kalanchoë, 451. - - Kale, 403, 405. - - Kalmia, 509. - - Kæmpferia, 325, 326. - - Kamala, 434. - - Kaulfussia, 212. - - Kefir-grains, 36. - - Kelp, 76. - - Kerria, 457, 460. - - Kidney-bean, 471, 473. - - Kielmeyera, 415. - - “King Charles and the Oak,” 207. - - Kingia, 312. - - Kino, 473. - - Kitaibelia, 429. - - Knap-weed, 570. - - Knapwell, 367. - - Knautia, 560. - - Knot-grass, 359. - - Knowltonia, 379. - - Kobresia, 287. - - Kochia, 371. - - Koeleria, 294. - - Koelreuteria, 441. - - Koenigia, 361. - - Kohlrabi, 405. - - Krameria, 468. - - Kramerieæ, 468. - - Koso-tree, 460. - - - Labellum, 277, 323, 325. - - Labiatæ, 515, 532, 535, 536. - - Labiate-flowered, 567, 570. - - Laburnum, 472, 473. - - Labyrinth Fungus, 166. - - Lace-tree, 449. - - Lacmus, 142. - - Lactarius, 171. - - Lactoridaceæ, 362. - - Lactoris, 362. - - Lactuca, 571, 574. - - Ladanum, 412. - - Ladenbergia, 550, 553. - - Ladies-mantle, 460. - - Lady-fern, 213. - - Lady’s-finger, 471. - - Lælia, 332. - - Lagenandra, 306. - - Lagenaria, 479, 481. - - Lagenedium, 104. - - Lagerstrœmia, 483. - - Lagetta, 449. - - Lagœcia, 494. - - Laguncularia, 487. - - Lagurus, 296. - - Lamellæ, 166. - - Laminaria, 71. - - Laminariaceæ, 71. - - Lamium, 536, 538, 540, 541. - - Lamprothamnus, 67. - - Landolphia, 544. - - Langsdorffia, 504. - - Lantana, 535. - - Lappa, 570, 574. - - Lapsana, 570. - - Larch, 266, 267. - - Larch-canker, 135. - - Larch-fungus, 164. - - Lardizabalaceæ, 390. - - Larix, 266. - - Larkspur, 383. - - Larrea, 438. - - Laserpitium, 497. - - Lasiandra, 484. - - Latania, 301. - - Lathræa, 525, 526, 528. - - Lathyrus, 470, 473. - - Lattice-rust, 147. - - Laudatea, 176. - - Lauraceæ, 238, 391, 449. - - Laurus, 161, 391, 392, 393. - - Lavandula, 536, 540, 541. - - Lavatera, 428, 430. - - Lavender, 540. - Oil of, 541. - - Lawsonia, 483. - - Leafy-mosses, 183. - - Leathesia, 71. - - Leaven, 179. - - Lecanora, 140, 142. - - Lechenaultia, 564. - - Lecidea, 142. - - Lecythideæ, 489. - - Lecythis, 489. - - Ledum, 153, 509. - - Leea, 445. - - Leek, 312. - - Leersia, 291, 293. - - Leguminosæ, 466. - - Legume, 466. - - Lejolisia, 81. - - Lemanea, 80, 82. - - Lemaneaceæ, 82. - - Lemna, 25, 47, 307. - - Lemnaceæ, 307. - - Lemon, 438. - - Lentil, 470, 473. - - Lentinus, 171. - - Leontice, 390. - - Leontodon, 568, 571. - - Leontopodium, 593. - - Leonurus, 538. - - Lepidiinæ, 404. - - Lepidium, 400, 401. - - Lepidocaryinæ, 301. - - Lepidodendraceæ, 233. - - Lepidozia, 192. - - Lepiota, 171. - - Leptobryum, 197. - - Leptogium, 140, 142. - - Leptomitus, 108. - - Leptopleura, 387. - - Leptopuccinia, 151. - - Leptosiphon, 515. - - Leptospermeæ, 489. - - Leptospermum, 489. - - Leptosporangiatæ, 202, 210, 212, 239. - - Leptothrix, 26, 33, 35, 38. - - Leptotrichum, 196. - - Lepturus, 295. - - Lescuræa, 197. - - Leskea, 197. - - Leskeaceæ, 197. - - Lessonia, 72. - - Lettuce, 571, 574. - - Leucobryaceæ, 196. - - Leucobryum, 192, 196. - - Leucodon, 197. - - Leucojum, 317, 318. - - Leuconostoc, 28, 29, 35. - - Levisticum, 496, 498. - - Liagora, 83. - - Libanotis, 495. - - Libocedrus, 269. - - Lichen, 4, 8. - - Lichen-forming Ascomycetes, 116, 136. - Basidiomycetes, 176. - - Lichenin, 142. - - Lichina, 142. - - Licmophoreæ, 21. - - Lignum Vitæ, 438. - - Ligularia, 572. - - Ligulate-flowered, 567. - - Ligule, 283. - - Ligulifloræ, 570. - - Ligustrum, 547. - - Lilac, 547. - - Lilæa, 279. - - Liliaceæ, 274, 309, 311. - - Lilies, 311, 314. - - Liliifloræ, 278, 309. - - Lilium, 245, 312, 313, 314. - - Lily of the Valley, 314. - - Lime, 165. - - Limnanthaceæ, 421. - - Limnanthemum, 543. - - Limnanthes, 421. - - Limnocharis, 281. - - Limodorum, 331. - - Limonia, 437. - - Limosella, 525. - - Linaceæ, 417. - - Linaria, 523, 525, 527. - - Lindera, 393. - - Ling, 507. - - Linnæa, 555. - - Linnæeæ, 555. - - Linociera, 547. - - Linseed, 418. - - Linum, 417, 418. - - Liparis, 332. - - Lippia, 535. - - Liquidambar, 455. - - Liquorice, 470, 473. - - Liriodendron, 388. - - Listera, 331. - - Litchi, 441. - - Lithoderma, 71. - - Lithodermataceæ, 71. - - Lithophyllum, 84. - - Lithospermum, 533. - - Lithothamnion, 80, 84. - - Littorella, 530, 531. - - Liverworts, 2, 181, 188. - - Livistona, 298, 299, 300, 302. - - Lloydia, 312. - - Loasaceæ, 476. - - Lobelia, 562, 563. - - Lobeliaceæ, 335, 562. - - Lobeline, 563. - - Lochnera, 544. - - Locusts, 468. - - Lodicules, 288, 291. - - Lodoicea, 301. - - Loganiaceæ, 542, 546, 549. - - Logwood, 468. - - Loiseleuria, 509. - - Lolium, 295, 296. - - Lomandra, 312. - - Lomaria, 214. - - Lomentaceæ, 403. - - Lomentaria, 83. - - Lonicera, 553, 554, 556. - - Lonicereæ, 549, 553. - - Long-pepper, 363. - - Loose-strife, 482. - - Lopezia, 484, 485. - - Lophiostomaceæ, 130. - - Lophocolea, 192. - - Lophodermium, 132. - - Lophospermum, 525. - - Loquat, 465. - - Loranthaceæ, 501. - - Loranthoideæ, 501. - - Loranthus, 504. - - Loteæ, 471. - - Lotus, 471. - - Louse-wort, 526. - - Love-in-the-mist, 382. - - Lucerne, 473, 529. - - Lucuma, 511. - - Luehea, 424, 425. - - Luffa, 481. - - Lunaria, 400, 401. - - Lung-Lichen, 143. - - Lung-wort, 533. - - Lunularia, 191. - - Lupin, 472. - - Lupinus, 472. - - Luzula, 283, 284. - - Lychnis, 365, 367. - - Lychnothamnus, 67. - - Lycium, 521. - - Lycogala, 6, 8. - - Lycoperdaceæ, 174. - - Lycoperdon, 174. - - Lycopersicum, 521, 522. - - Lycopodiaceæ, 202, 226. - - Lycopodieæ, 205, 226. - - Lycopodinæ, 2, 205, 226, 228, 234, 235, 236, 240. - - Lycopodium, 200, 226, 227, 228, 233. - - Lycopsis, 534. - - Lycopus, 536, 539. - - Lygeum, 293. - - Lygodium, 215. - - Lyme-grass, 296. - - Lyngbya, 24. - - Lyngbyaceæ, 22, 24. - - Lyonia, 508. - - Lysimachia, 47, 151, 513. - - Lysipoma, 563. - - Lythraceæ, 482. - - Lythrum, 482, 483. - - - Maba, 511. - - Machærium, 472. - - “Mace,” 393. - - Macleya, 395. - - Maclura, 354, 356. - - Macrosporangium, 241, 243. - - Macrospore, 200, 242, 243, 245, 246. - - Macrocystis, 72. - - Macrozamia, 254. - - Madder, 552, 553. - - Madia, 574. - - Madotheca, 192. - - Mad-wort, 534. - - Maesa, 513. - - Magnolia, 389. - - Magnoliaceæ, 388. - - Magnolieæ, 388. - - Mahernia, 422. - - Mahogany, 436. - - Mahonia, 149, 390. - - Maiden-hair, 206, 213. - - Maize, 289, 293, 296. - - Maize-blight, 113. - - Majanthemum, 309, 314. - - Malachium, 366. - - Malachra, 428. - - Malaxis, 332. - - Malcolmiinæ, 404. - - Male-Fern, 214. - - Mallow, 425. - - Malope, 429, 430. - - Malopeæ, 428. - - Malpighiaceæ, 442. - - Malpighia, 422. - - Malt, 296. - - Malus, 152, 463, 464, 465. - - Malva, 426, 428, 429, 430. - - Malvaceæ, 425. - - Malveæ, 428. - - Malvaviscus, 428. - - Mamme, 355. - - Mammea, 414. - - Mammillæ, 377. - - Mammillaria, 375, 377. - - Mammoni, 355. - - Mancinil-tree, 432. - - Mandragora, 522. - - Mandrake, 522. - - Manettia, 550. - - Mangifera, 439. - - Manglesia, 450. - - Mango, 439. - - Mangold, 369, 372. - - Mangosteen, 414. - - Mangrove, 486. - - Manihot, 431, 434. - - Manilla Hemp, 325. - - Maniok, 434. - - “Manna,” 547. - - Manna Ash, 546, 547. - - Manna-grass, 296. - - Manna-lichen, 142. - - Mannit, 72. - - Maple, 442. - - Maranta, 327. - - Marantaceæ, 277, 327. - - Marasmiei, 171. - - Marasmius, 168, 171. - - Marattia, 212. - - Marattiaceæ, 209, 210, 212, 236. - - Marcgraviaceæ, 415. - - Marchantia, 181, 183, 184, 190. - - Marchantiaceæ, 190. - - Marchantieæ, 190. - - Mare’s-tail, 486. - - Marigold, 572. - - Marjoram, 539, 541. - - Marrow, 480. - - Marrubium, 538. - - Marsilia, 216, 217, 219, 220, 245. - - Marsiliaceæ, 210, 218, 239. - - Marsh Cinquefoil, 458. - - Marsh-marigold, 382. - - Martynia, 529. - - Masdevallia, 332. - - Massariaceæ, 130. - - Massulæ, 331. - - “Mast,” 347. - - Mastic, 439. - - Mastigobryum, 192. - - Mastigocoleus, 24. - - Maté, 445. - - Matico, 363. - - Matricaria, 572, 574. - - Matthiola, 400, 402. - - Maurandia, 525. - - Mauritia, 301. - - Maxillaria, 332. - - May, 465. - - Mayacaceæ, 308. - - Maydeæ, 293. - - Meadow-grass, 151, 294, 296. - - Meadow Rue, 385. - - Meadow-sweet, 457. - - Mecca-balsam, 438. - - Meconopsis, 395. - - Medicago, 471, 473. - - Medick, 471, 473. - - Medinilla, 484. - - Medlar, 465. - - Meesea, 197. - - Megacarpæa, 400, 401. - - Melaleuca, 489. - - Melampodium, 572. - - Melampsora, 147, 152, 153. - - Melampsorella, 147. - - Melampyrum, 526. - - Melanconidaceæ, 130. - - Melandrium, 367. - - Melanogaster, 176. - - Melanommaceæ, 30. - - Melanoselinum, 497. - - Melanosinapis, 402. - - Melanospora, 125. - - Melanoxylon, 468. - - Melanthium, 310. - - Melastomaceæ, 483. - - Meliaceæ, 435. - - Melianthaceæ, 440. - - Melianthus, 440. - - Melica, 287, 290, 294. - - Melilotus, 466, 470, 471. - - Melinophyl, 18. - - Melissa, 540, 541. - - Melobesia, 80, 84. - - Melocactus, 375, 377. - - Melochia, 422. - - Melogrammataceæ, 130. - - Melon, 481. - - Melosira, 19. - - Melosireæ, 21. - - Menispermaceæ, 390. - - Menispermum, 390. - - Mentha, 47, 536, 539, 541. - - Menthol, 541. - - Mentzelia, 476. - - Menyantheæ, 542, 543. - - Menyanthes, 240, 543, 550. - - Menziesia, 509. - - Mercurialis, 431, 434. - - Mercury, 431. - - Merendera, 310. - - Mericarp, 492. - - Meridieæ, 21. - - Merismopedium, 10, 24. - - Merismopedium form, 27. - - Mertensia, 533. - - Merulius, 166. - - Mesembrianthemeæ, 375. - - Mesembrianthemum, 375. - - Mesocarpaceæ, 46. - - Mesomycetes, 1, 95, 108. - - Mesotænium, 43, 44. - - Mespilus, 463, 465. - - Metaxenous, 148. - - Metrosideros, 489. - - Metroxylon, 298, 301. - - Metzgeria, 191, 192. - - Metzleria, 563. - - Meum, 495. - - Michauxia, 562. - - Miconia, 484. - - Micrasterias, 44. - - Microcachrys, 255, 260, 261. - - Microchæte, 26. - - Microchloa, 295. - - Micrococcus, 26, 35, 38. - - Microcoleus, 22, 24. - - Microconidia, 89. - - Microcycas, 254. - - Microdictyon, 62. - - Microglena, 15. - - Micropyle, 242. - - Microsphæra, 121. - - Microspira-comma, 40. - - Microspora, 54. - - Microsporangia, 237, 240. - - Microspore, 200, 214. - - Microtea, 372. - - Mignonette, 406. - - Mikania, 571. - - Mildews, 119, 122. - - Milfoil, 572. - - Milium, 294. - - Milk-thistle, 570. - - Milk-vetch, 470. - - Milk-wort, 443. - - Millet, 296. - - Mimosa, 473. - - Mimosaceæ, 466, 473. - - Mimulus, 525, 526, 527. - - Mimusops, 511. - - Mint, 539. - - Mirabilis, 374. - - Mistletoe, 501. - - Mitella, 452. - - Mitromyces, 173. - - Mitrula, 136, 159. - - Mnium, 197. - - Mock Orange-blossom, 455. - - Modiola, 427. - - Moehringia, 366. - - Mohria, 215. - - Molinia, 151, 294. - - Mollinedia, 389. - - Mollisia, 135. - - Mollisiaceæ, 135. - - Mollugo, 375. - - Momordica, 481. - - Monacanthus, 333. - - Monangic, 243. - - Monarda, 540, 541. - - Monardeæ, 540. - - Money-wort, 513. - - Monimia, 389. - - Monimiaceæ, 389. - - Monkshood, 383. - - Monoblepharis, 102, 108. - - Monocotyledones, 3, 273, 274, 276. - - Monocotyledonous flower, 276. - - Monœcious, 236. - - Monostroma, 53. - - Monotropa, 334, 506, 507. - - Monstera, 303, 305, 307. - - Montia, 373. - - Moonwort, 211. - - Moraceæ, 351, 353. - - Moræa, 321. - - Morchella, 136. - - Moreæ, 354. - - Morell, 136. - - Moricandiinæ, 404. - - Morina, 560. - - Morinda, 549. - - Mortierellaceæ, 100. - - Mortierella, 100. - - Morus, 351, 354. - - Moschatel, 453. - - Moss, 182. - - “Moss-flower,” 183. - - Moss-fruit, 186. - - Moss-rose, 460. - - Mosses, 1, 2, 181, 188, 192, 234. - - Mougeotia, 46. - - Moulds, 31, 94, 122. - - Mountain-ash, 465. - - Mountain-meal, 20. - - Mountain-pine, 266. - - Mouse-tail, 383. - - Mucor, 97, 98, 99. - - Mucoraceæ, 96. - - “Mucor-yeast,” 97. - - Mucro, 257. - - Mucuna, 471. - - Mud-wort, 525. - - Muehlenbeckia, 360. - - Mulberry, 353, 356. - - Mullein, 523. - - Murracytaceæ, 15. - - Musa, 324, 325. - - Musaceæ, 277, 323. - - “Muscardine,” 128. - - Muscari, 312, 314. - - Musci, 2. - frondosi, 188, 192. - - Muscineæ, 1, 181. - - Museæ, 325. - - Mushroom, 159, 166, 168. - - Musk-rose, 460. - - Mutisieæ, 570. - - Myanthus, 333. - - Mycelium, 85. - - Mycena, 171. - - Mycoidea, 8, 54. - - Mycoideaceæ, 47, 54. - - Mycomycetes, 1, 95, 114. - - Mycorhiza, 124, 175, 180, 506. - - Mycosiphonales, 95, 104. - - Myosotis, 533, 534, 535. - - Myosurus, 379, 380, 383, 384. - - Myrcia, 488. - - Myrica, 350. - - Myricaceæ, 337, 350. - - Myricaria, 411, 412. - - Myriophyllum, 486. - - Myriotrichia, 71. - - Myriotrichiaceæ, 71. - - Myristica, 392, 393. - - Myristicaceæ, 393. - - Myrmecodia, 550, 553. - - Myroxylon, 473. - - Myrrh, 438. - - Myrrha, 438. - - Myrrhis, 495, 498. - - Myrsinaceæ, 513. - - Myrsine, 513. - - Myrtaceæ, 487. - - Myrteæ, 488. - - Myrtifloræ, 451, 482. - - Myrtle, 487, 488. - - Myrtus, 488, 489. - - Myxamœba, 6. - - Myxogasteres, 5. - - Myxomycetes, 1, 4, 5. - - Myxophyceæ, 22. - - Myzodendron, 500, 501. - - - Naccaria, 83. - - Nægelia, 528. - - Najadaceæ, 278, 281. - - Najas, 281. - - Nandina, 390. - - Narcissus, 316, 317, 318. - - Nardostachys, 557, 558. - - Nardus, 291, 295, 558. - - Narthecium, 310. - - Narthex, 496. - - Nasturtium, 400, 402, 420. - - Navicula, 19. - - Naviculeæ, 20, 21. - - Neck-canal-cells, 184. - - Neckera, 197. - - Neckeraceæ, 197. - - Nectandra, 392, 393. - - Nectria, 116, 125, 127. - - Neea, 374. - - Negundo, 441, 442. - - Nelumbo, 386. - - Nelumboneæ, 386. - - Nemalion, 81. - - Nemalionales, 82. - - Nemastomaceæ, 84. - - Nemesia, 525. - - Nemophila, 515. - - Neomeris, 63. - - Neottia, 5, 331. - - Neottieæ, 331. - - Neovossia, 111. - - Nepenthaceæ, 408, 409. - - Nepenthes, 409. - - Nepeta, 536, 539. - - Nepeteæ, 539. - - Nephelium, 441. - - Nephrolepis, 214. - - Nephroselmis, 15. - - Nerium, 544. - - Nesæa, 483. - - Neslia, 403. - - Nest-fungi, 176. - - Nettle, 351, 352, 353. - - Neuradeæ, 457. - - Neuwiedia, 329. - - Nicandra, 519, 522. - - Nicotiana, 520, 522. - - Nicotine, 522. - - Nidularia, 176. - - Nidulariaceæ, 176. - - Nierembergia, 521. - - Nigella, 379, 380, 382. - - Nightshade, 521. - - Nigritella, 332. - - Nile-lily, 305. - - Nipa, 301. - - Nipplewort, 570. - - Nitella, 65. - - Nitelleæ, 67. - - Nitraria, 438. - - Nitrifying Bacteria, 5. - - Nitzchieæ, 21. - - Noble Pine, 264. - - Noctiluca, 17. - - Nodularia, 25. - - Nolana, 522. - - Nolanaceæ, 518, 522. - - Noli-me-tangere, 421. - - Nonnea, 533. - - Nonsexual reproduction, 10. - - Nostoc, 22, 23, 25, 27, 29, 138, 486. - - Nostocaceæ, 22, 24, 25. - - Nostocopsis, 26. - - Nothofagus, 347, 348, 501. - - Notorhizæ, 400. - - Nucellus, 235, 241, 243, 247. - - Nuculiferæ, 505, 515, 531. - - Nucumentaceæ, 403. - - Nullipora, 84. - - Nuphar, 387. - - Nutmegs, 393. - - Nutritive-tissue, 248. - - Nux vomica, 546. - - Nyctaginiaceæ, 373. - - Nyctalis, 172. - - Nyctanthes, 547. - - Nycterinia, 525, 526. - - Nymphæa, 387, 388. - - Nymphæaceæ, 385. - - Nymphæeæ, 386. - - - Oak, 117, 130, 134, 135, 161, 164, 166, 346, 347, 348. - - Oat, 113, 151, 292, 294, 296. - - Oat-grain, 290. - - Oat-grass, 296. - - Obdiplostemonous, 336. - - Obelidium, 103. - - Obligate parasites, 85. - - Ochna, 439. - - Ochnaceæ, 439. - - Ochroma, 427. - - Ocimum, 541. - - Ocrea, 359. - - Odonthalia, 83. - - Odontites, 526. - - Œdogoniaceæ, 47, 55. - - Œdogonium, 10, 11, 55, 56. - - Œnanthe, 495, 498. - - Œnothera, 484, 485, 486. - - Œnotheraceæ, 484. - - Oidia, 90. - - Oidium, 121, 179. - - Oidium forms, 179. - - Oil-mould, 99. - - Oil-palm, 301. - - Olea, 547. - - Oleaceæ, 541, 542, 546. - - Oleander, 544. - - Oligorus, 166. - - Olive, 547. - - Olive-brown Seaweeds, 68. - - Olive Oil, 547. - - Olpidiaceæ, 103. - - Olpidieæ, 103. - - Olpidium, 103. - - Olyreæ, 296. - - Omphalodes, 533, 534. - - Onagraceæ, 484. - - Oncidium, 332. - - Oncobyrsa, 24. - - Onion, 312. - - Onobrychis, 472, 473. - - Ononis, 471. - - Onopordon, 570. - - Ooblastema-filaments, 82. - - Oocystis, 51. - - Oogamous fertilisation, 13. - - Oogonium, 13. - - Oomycetes, 95, 96, 100. - - Oophyte, 181. - - Oosphere, 13, 248. - - Oospore, 14. - - Operculum, 193. - - Ophiocytium, 51. - - Ophioglossaceæ, 209, 210. - - Ophioglossum, 210, 211, 238. - - Ophiopogon, 320. - - Ophrydeæ, 331. - - Ophrys, 332, 333. - - Opium-poppy, 395. - - Oplismenus, 295. - - Opuntia, 375, 377. - - Orange, 438. - - Orchid, diagram of flower, 329. - - Orchidaceæ, 5, 238, 328. - - Orchideæ, 277. - - Orchids, 151. - - Orchis, 276, 331, 332, 333. - - Oreobolus, 285. - - Oreodoxa, 301. - - Organs of attachment, 4. - - Origanum, 536, 539, 541. - - Ornithogalum, 312, 314. - - Ornithopus, 466, 472. - - Orobanche, 334, 528, 529. - - Orontieæ, 303. - - Orontium, 304. - - Orris-root, 321. - - Orseille, 142. - - Orthoploceæ, 400. - - Orthospermeæ, 493. - - Orthothecium, 197. - - Orthotrichum, 197. - - Orthotropous, 242, 243. - - Oryza, 293. - - Oryzeæ, 293. - - Oscillaria, 10, 23, 24, 26, 37. - - Oscillariaceæ, 24. - - Osiers, 152. - - Osmunda, 209, 215. - - Osmundaceæ, 202, 210, 215. - - Ostioles, 73. - - Ostropa, 133. - - Ostropaceæ, 133. - - Ostrya, 345. - - Osyris, 500. - - Ouratea, 439. - - Ouvirandra, 281. - - Ovary, 3, 239, 250. - - Ovule, 241, 242, 248. - - Ovuliferous scale, 256, 257. - - Oxalidaceæ, 416. - - Oxalis, 416. - - Ox-eye, 572. - - Oxslip, 513. - - Oxybaphus, 374. - - Oxycoccus, 509, 510. - - Oxyria, 360. - - Oyster Mushroom, 171. - - - Padina, 76. - - Pæonia, 379, 381. - - Pæonieæ, 381. - - Pæpalanthus, 309. - - Palaquium, 511. - - Palava, 429. - - Paleæ, 209. - - Pales, 288. - - Palisander-wood, 529. - - Paliurus, 448. - - Palm, 275, 276, 297. - Branching of, 298. - Inflorescence of, 299. - - Palm-oil, 301. - - Palm-wax, 301. - - Palm-wine, 301. - - Palmæ, 297. - - Palmella-stage, 15, 16. - - Palmyra-palm, 301. - - Paludella, 197. - - Pampas-grass, 296. - - Panama hats, 302. - - Panax, 491. - - Pancratium, 317. - - Pandanaceæ, 302. - - Pandanus, 302. - - Pandorina, 45, 48. - - Paniceæ, 295. - - Panicum, 295, 296. - - Pansy, 411. - - Panus, 171. - - Papaveraceæ, 394. - - Papaver, 394, 395. - - Papaw, 476. - - Papayaceæ, 476. - - Paper-mulberry tree, 354, 356. - - Papilionaceæ, 335, 468. - - Pappus, 564, 566. - - Papyrus, 287. - - Paradise apple, 465. - - Paraglobulin, 473. - - Paraphyses, 88. - - Paraguay tea, 445. - - Parasites, 5. - - Parasites, endophytic, 85. - endozoic, 85. - epiphytic, 85. - epizoic, 85. - facultative, 84. - obligate, 85. - pathogenic, 85. - - Parasitic Bacteria, 38. - - Parasol-fungus, 171. - - Pariana, 291. - - Parietaria, 353. - - Paris, 309, 314, 316. - - Paritium, 430. - - Parkia, 475. - - Parmelia, 140, 141, 142, 143. - - Parnassia, 453. - - Paronychia, 365, 367. - - Paronychieæ, 366. - - Parrotia, 455. - - Parsley, 494, 498. - - Parsnip, 492, 496, 498. - - Parthenogenesis, 14. - - Pasanea, 346, 348. - - Paspalum, 295. - - Pasta guaranà, 441. - - Pastinaca, 493, 496. - - Passerina, 449. - - Passiflora, 475, 476. - - Passifloraceæ, 476. - - Passiflorinæ, 475. - - Passion-flower, 476. - - Patellaria, 134. - - Patellariaceæ, 134. - - Patellea, 134. - - Paternoster peas, 470. - - Pathogenic Rod-Bacteria, 39. - - Patrinia, 557. - - Paullinia, 441. - - Paulownia, 527. - - Pavonia, 428. - - Paxillei, 172. - - Payena, 511. - - Paypayroleæ, 411. - - Pea, 470. - - Peach, 117, 121, 461. - - Pear, 130, 464, 465. - - Pedagnuoli, 355. - - Pedaliaceæ, 518, 529. - - Pediastrum, 52. - - Pedicularis, 151, 526. - - Peganum, 438. - - Pelargonium, 418, 419. - - Peliosanthes, 320. - - Pellia, 191, 192. - - Pellitory, 353. - - Peltigera, 143. - - Pelvetia, 73. - - Penicillium, 122, 123. - - Penium, 43, 44. - - Pennisetum, 295. - - Penny-cress, 401. - - Penny-wort, 493. - - Pentacyclicæ, 505, 506. - - Pentadesma, 414. - - Pentapera, 505. - - Pentstemon, 524, 527. - - Peplis, 47, 483. - - Pepper, 361. - - Peppermint, 541. - - Peperomia, 361, 362. - - Pepperwort, 401. - - Pereskia, 375, 376. - - Perianth, 235. - - Perichætium, 192. - - Pericarp, 249. - - Pericallis, 574. - - Peridermium, 147, 148, 153, 154, 155, 156. - - Peridinea, 1, 14, 17. - - Peridinin, 16. - - Peridinium, 17. - - Peridiola, 176. - - Peridium, 88, 89, 147. - - Perigynium, 189. - - Perilla, 541. - - Periphyses, 88. - - Periplasm, 104. - - Periploca, 546. - - Perisperm, 249. - - Perisporiaceæ, 122. - - Perisporiales, 95, 116, 118, 119. - - Peristome, 195. - - Perithecia, 125. - - Periwinkle, 543, 544. - - Perizonium, 20. - - Pernambuco-tree, 468. - - Peronocarpic ascocarps, 125. - - Peronospora, 101, 104, 105, 107. - - Peronosporaceæ, 104. - - Persea, 393. - - Persica, 461. - - Personatæ, 505, 515, 517. - - Pertusaria, 140, 142. - - Petals, 235. - - Petasites, 153, 569, 571. - - Petiveria, 372. - - Petrocelis, 84. - - Petunia, 518, 521. - - Peucedaneæ, 496. - - Peucedanum, 496. - - Peyssonellia, 84. - - Peziza, 115, 135, 159. - - Pezizaceæ, 135. - - Pezizales, 134. - - Phacelia, 515. - - Phacidiales, 133. - - Phacidium, 133. - - Phacotus, 48. - - Phæophyceæ, 1, 14, 68. - - Phæophyl, 68. - - Phæosporeæ, 68. - - Phæothamnion, 54. - - Phagocytes, 41. - - Phajus, 332. - - Phalarideæ, 295. - - Phalaris, 295. - - Phallaceæ, 172. - - Phalloideæ, 96, 145, 172. - - Phallus, 172, 173. - - Phanerogams, 3, 234, 236, 249. - - Pharbitis, 516. - - Pharus, 291, 293. - - Phascum, 195. - - Phaseoleæ, 470. - - Phaseolus, 134, 469, 471, 473. - - Phegopteris, 213, 214. - - Phellodendron, 437. - - Philadephus, 451, 455. - - Phillyrea, 547. - - Philodendron, 303, 305. - - Philonotis, 197. - - Phlebia, 163. - - Phleum, 290, 294, 296. - - Phloëm, 251. - - Phlœospora, 70. - - Phlomis, 538, 541. - - Phlox, 515. - - Phœniceæ, 299. - - Phœnix, 298, 299, 301, 302. - - Pholiota, 171. - - Phormium, 312, 313, 314. - - Phragmidium, 146, 147, 148, 151, 152. - - Phragmites, 113, 131, 291, 294. - - Phragmonema, 22, 25. - - Phrynium, 327. - - Phycocyan, 22, 77. - - Phycoerythrin, 22, 77. - - Phycomyces, 99. - - Phycomycetes, 1, 5, 95, 96. - - Phycophæin, 69. - - Phycopyrrin, 16. - - Phycoxanthin, 69. - - Phylica, 448. - - Phyllachora, 131. - - Phyllactinia, 122. - - Phyllactis, 560. - - Phyllanthus, 431, 432. - - Phyllitis, 70. - - Phyllobium, 47, 51. - - Phyllocactus, 377. - - Phyllocladus, 260. - - Phyllodia, 474. - - Phyllodoce, 509. - - Phylloglossum, 228. - - Phyllophora, 83. - - Phyllosiphon, 8. - - Phyllosiphonaceæ, 47, 61. - - Physalis, 521. - - Physarum, 6, 8. - - Physcia, 139, 143. - - Physcomitrium, 188, 197. - - Physiological varieties, 41. - - Physoderma, 103. - - Physostigma, 471, 473. - - Phytelephantinæ, 301. - - Phytelephas, 299, 301, 302. - - Phyteuma, 562. - - Phytoamœbæ, 10, 61. - - Phytolacca, 372. - - Phytolaccaceæ, 372. - - Phytomyxa, 8. - - Phytophthora, 101, 104, 105, 106. - - Piassava, 297. - - Picea, 124, 129, 132, 155, 165, 265. - - Pichurim, 392. - - Picraena, 438. - - Picris, 571. - - Picrotoxine, 390. - - Pilacraceæ, 157. - - Pilacre, 157. - - Pilea, 353. - - Pilobolus, 99, 100. - - Pilostyles, 504. - - Pilularia, 216, 220. - - Pimelea, 449. - - Pimenta, 489. - - Pimento, 489. - - Pimpernel, 513. - - Pimpinell, 498. - - Pimpinella, 494, 498. - - Pine, 127, 153, 161, 165, 255, 263, 266. - - Pine-apple, 320. - - Pine-shoot Fungus, 152. - - Pinellia, 305. - - Pinguicula, 334, 528. - - Pink, 367. - - Pin-mould, 99. - - Pinnularia, 19. - - Pinus, 129, 132, 153, 155, 165, 264, 265, 266, 267, 272. - - Pinoideæ, 256, 258, 259, 262. - - Pipe-flower, 500. - - Piper, 361, 363. - - Piperaceæ, 361. - - Pipereæ, 361. - - Piptocephalidaceæ, 100. - - Piptocephalis, 100. - - Pircunia, 372. - - Pisonia, 374. - - Pistia, 306. - - Pistacia, 439. - - Pistil, 239. - - Pistillaria, 161. - - Pistillate, 236. - - Pisum, 469, 470, 473. - - Pitcairnia, 320. - - Pitcher-plant, 409. - - Pittosporaceæ, 451, 455. - - Pittosporum, 455. - - Placenta, 237, 241. - - Placochromaticæ, 21. - - Plagiochila, 189, 192. - - Plagiothecium, 197. - - Plagiotropideæ, 21. - - Planera, 351. - - “Plankton,” 15, 17, 20. - - Planogametes, 12. - - Plantago, 335, 530, 531, 536, 559. - - Plantaginaceæ, 518, 530. - - Plantain, 530. - - Plasmodia, 4, 5, 7. - - Plasmodiophora, 8. - - Plasmodiophorales, 6. - - Platanaceæ, 455. - - Platanus, 456. - - Platanthera, 332, 333. - - Plate-cultures, 33. - - Platonia, 414. - - Platycerium, 213. - - Platycodon, 562. - - Platystemon, 395. - - Plectonema, 24. - - Plectranthus, 541. - - Pleospora, 130. - - Pleosporaceæ, 130. - - Pleurandra, 413. - - Pleuridium, 195. - - Pleurocarpi, 197. - - Pleurococcaceæ, 47, 51. - - Pleurococcus, 10, 51, 138. - - Pleurorhizæ. 400. - - Pleurotænium, 44. - - Pleurothallis, 332. - - Pleurotus, 171. - - Plocamium, 83. - - Plum, 117, 164, 461, 462. - - Plumbaginaceæ, 514. - - Plumbago, 514. - - Plumeria, 544. - - Plumule, 247. - - Pneumathodia, 267. - - Poa, 287, 290, 294, 296. - - “Pocket-plum,” 85. - - “Pockets,” 117. - - Pod, 466. - - Pod-pepper, 522. - - Podalyrieæ, 469. - - Podocarpeæ, 260. - - Podocarpus, 251, 255, 261, 272. - - Podophyllum, 390. - - Podosphæra, 120. - - Podospora, 129. - - Podostemaceæ, 451, 456. - - Pogostemon, 541. - - Poinciana, 468. - - Point Caraway, 498. - - Polanisia, 406. - - Polemoniaceæ, 509, 515. - - Polemonium, 515. - - Polianthes, 318. - - Pollinarium, 332. - - Pollinia, 329. - - Pollinodium, 100, 120. - - Pollen-chamber, 251. - - Pollen-grain, 240, 244, 245. - - Pollen-sac, 235, 237, 240. - - Pollen-tube, 244, 249. - - Polycarpicæ, 377. - - Polycystis, 24. - - Polydinida, 16, 17, 18. - - Polyembryony, 247. - - Polygala, 442, 443. - - Polygalaceæ, 442. - - Polygamous, 236. - - Polygonaceæ, 239, 359. - - Polygonatum, 314, 316. - - Polygonifloræ, 358. - - Polygonum, 359, 360, 361. - - Polyides, 84. - - Polykrikos, 17. - - Polypetalæ, 336. - - Polyphagus, 103, 104. - - Polypodiaceæ, 202, 205, 206, 209, 210, 212. - - Polypodium, 207, 213. - - Polyporaceæ, 163. - - Polyporus, 163, 164, 165. - - Polysiphonia, 79, 83. - - Polystachya, 332. - - Polystigma, 125, 127. - - Polytrichaceæ, 197. - - Polytrichum, 197. - - Pomaceæ, 456, 462. - - Pomaderris, 448. - - Pomalo, 438. - - Pomegranate, 488, 489. - - Pomona-fungus, 171. - - Pond-weed, 279. - - Pontederia, 316. - - Pontederiaceæ, 308, 316. - - Poplar, 124, 164, 338. - - Poppies, 394. - - Populus, 152, 338. - - Pore-fungus, 163. - - Porogames, 273. - - Poronia, 131. - - Porphyra, 10, 78. - - Porphyraceæ, 78. - - Portulaca, 373. - - Portulacaceæ, 373. - - Posidonia, 281. - - Potamogeton, 47, 278, 279. - - Potamogetonaceæ, 278, 279. - - Potato-fungus, 104, 107. - - Potato-plant, 521, 522. - - Potentilla, 458, 460. - - Potentilleæ, 458. - - Poterium, 460. - - Pothos, 304. - - Pottia, 196. - - Pottiaceæ, 196. - - Pouzolzia, 353. - - Prasiola, 53. - - Preissia, 191. - - Preslia, 539. - - Primrose, 512. - - Primula, 511, 512, 513. - - Primulaceæ, 239, 512, 514. - - Primulinæ, 505, 511. - - Pringsheimia, 54. - - Prionium, 284. - - Pritchardia, 298. - - Priva, 535. - - Privet, 547. - - Procarpium, 81. - - Proembryo, 64. - - Profichi, 355. - - Promycelium, 94, 146. - - Pronucleus, 245. - - Prorocentrum, 17, 18. - - Protea, 450. - - Proteaceæ, 450. - - Prothallium, 198, 244, 248. - Secondary, 233. - - Protistæ, 5. - - Protium, 438. - - Protobasidia, 144. - - Protobasidiomycetes, 96, 145. - - Protococcaceæ, 47, 48, 51. - - Protococcoideæ, 8, 47. - - Protomyces, 108. - - Protomycetaceæ, 108. - - Protonema, 181. - - Provence oil, 547. - - Prunella, 539. - - Prunus, 117, 118, 127, 130, 152, 461, 462. - - Psalliota, 167, 168, 169, 171. - - Psamma, 295, 296. - - Pseudophacidiaceæ, 133. - - Pseudopodium, 10, 193. - - Pseudotsuga, 264, 265, 266. - - Psidium, 488, 489. - - Psilotaceæ, 228. - - Psilotum, 201, 228. - - Psychotria, 550. - - Ptelea, 437. - - Pteridium, 131, 207, 213, 214. - - Pteridophyta, 2, 198, 234. - - Pterigynandrum, 197. - - Pteris, 199, 203, 213, 214. - - Pterisanthes, 445. - - Pterocarpus, 473. - - Pterocarya, 350. - - Pterocephalus, 560. - - Pterogoniaceæ, 197. - - Pterogyne, 468. - - Pterostegia, 360. - - Pterygophyllum, 197. - - Ptilidium, 192. - - Ptilota, 84. - - Ptychogaster, 166. - - Puccinia, 147, 148, 149, 150. - - Puff-ball, 174. - - Pulmonaria, 533, 534. - - Pulque, 318. - - Pulsatilla, 384. - - Pumpkin, 480, 481. - - Punctaria, 70. - - Punica, 483, 488, 489, 490. - - Puniceæ, 488. - - Puschkinia, 312. - - Putrefaction, 32. - - Puya, 319. - - Pycnidia, 89. - - Pylaiella, 70. - - Pyrenoid, 46. - - Pyrenolichenes, 142. - - Pyrenomycetes, 95, 116, 118, 125. - - Pyrenula, 142. - - Pyrethrum, 572, 574. - - Pyrola, 334, 506, 507. - - Pyrolaceæ, 506. - - Pyrrophyl, 16. - - Pyrus, 152, 463. - - Pythium, 101, 106. - - - Quaking-grass, 294, 296. - - Quassia, 438, 439. - - Quassine, 438. - - Quercifloræ, 337, 340. - - Quercitron-wood, 348. - - Quercus, 341, 346, 347, 348, 504. - - Quillaja, 457, 460. - - Quillajeæ, 457. - - Quill-wort, 230. - - Quince, 464, 465. - - Quinchamalium, 500. - - Quinine, 550, 553. - - - Racomitrium, 197. - - Radiatæ, 571. - - Radicle, 247. - - Radiola, 418. - - Radiolarias, 9. - - Radish, 403, 404, 405. - - Radula, 192. - - Rafflesia, 504. - - Rafflesiaceæ, 499, 504. - - Raisins, 447. - - Rajania, 323. - - Ralfsia, 71. - - Ralfsiaceæ, 71. - - Ramalina, 143. - - Ramenta, 209. - - Ramié, 353. - - Rampion, 562. - - Randia, 550. - - Ranunculaceæ, 278, 378. - - Ranunculeæ, 383. - - Ranunculus, 151, 378, 379, 380, 382, 383, 384. - - Rapateaceæ, 308. - - Rape, 404. - - Raphanus, 400, 403. - - Raphia, 301. - - Raphidium, 51. - - Raphiolepis, 463, 465. - - Raspberry, 459, 460, 461. - - Ravenala, 325. - - Ray-flowers, 567. - - Reboulia, 191. - - Receptacle, 210. - - Red Algæ, 1. - - Red-beet, 372. - - Red-cabbage, 405. - - Red-clover, 466, 517. - - Red-currant, 455. - - Red-pine, 264, 266. - - “Red-rot,” 164, 166. - - Red Sandalwood, 473. - - Red Seaweeds, 4, 77. - - Red Snow, 48. - - Red-strip, 165. - - Red-tree, 468. - - Reed, 151, 294. - - Reed-mace, 303. - - Reindeer Moss, 141. - - Reineckea, 314. - - Remijia, 550, 553. - - Renealmia, 326. - - Replum, 398. - - Reseda, 407. - - Resedaceæ, 406. - - Resin, 266. - - Rest-harrow, 471. - - Restiaceæ, 309. - - Restio, 309. - - Restrepia, 332. - - Retama, 472. - - Reticularia, 8. - - Retinospora, 268. - - Rhamnaceæ, 447, 449. - - Rhamnus, 151, 448. - - Rhaphidophora, 305. - - Rhatany, 468. - - Rheum, 151, 359, 360. - - Rhinanthaceæ, 153. - - Rhinantheæ, 525, 526. - - Rhinanthus, 526. - - Rhingia, 320. - - Rhipidium, 320. - - Rhipsalis, 375, 376, 377. - - Rhizidiaceæ, 103. - - Rhizoboleæ, 415. - - Rhizocarpeæ, 205, 215. - - Rhizoclonium, 58. - - Rhizoids, 4, 10. - - Rhizomorpha, 169, 170. - - Rhizopaceæ, 99. - - Rhizophora, 482, 486, 487, 513. - - Rhizophoraceæ, 482, 486. - - Rhizophyllidaceæ, 84. - - Rhizophyllis, 84. - - Rhizopods, 5. - - Rhizopogon, 175, 176. - - Rhizopus, 99. - - Rhizosolenia, 20. - - Rhodanthe, 573. - - Rhodiola, 451, 452. - - Rhodochiton, 525. - - Rhododendron, 161, 508. - - Rhodomela, 83. - - Rhodomelaceæ, 83. - - Rhodophyceæ, 1, 14, 77. - - Rhodophyll, 77. - - Rhodophyllidaceæ, 83. - - Rhodophyllis, 83. - - Rhodoraceæ, 335, 508. - - Rhodotypus, 457. - - Rhodymenia, 83, 84. - - Rhodymeniaceæ, 83. - - Rhodymeniales, 82, 84. - - Rhœadinæ, 393. - - Rhopographus, 131. - - Rhubarb, 359. - - Rhus, 439. - - Rhynchosia, 471. - - Rhynchospora, 285, 286. - - Rhytisma, 132. - - Ribbon-grass, 296. - - Ribes, 121, 152, 153, 241, 454, 455. - - Ribesiaceæ, 454. - - Rib-grass, 530. - - Riccia, 186, 189, 190. - - Ricciaceæ, 190. - - Rice, 291, 293, 296. - - Richardia, 305. - - Richardsonia, 550. - - Ricinus, 431. - - Riella, 192, 231. - - Ringworm, 180. - - Rivina, 372. - - Rivularia, 10, 25. - - Rivulariaceæ, 22, 24, 25. - - Robinia, 470, 473. - - Roccella, 142. - - Rock-cress, 402. - - Rock-rose, 412. - - Rod-bacteria, 39. - - Roestelia, 147, 148, 151, 152, 153. - - Roman spinach, 372. - - Roots, 4. - - “Ropiness,” 35. - - Rosa, 148, 459, 460. - - Rosaceæ, 451, 457. - - Rose, 121. - - Rose-mallow, 428. - - Rose of Jericho, 401, 574. - - Roseæ, 459. - - Rosellinia, 130. - - Rosemary, 540. - Oil of, 541. - - Rosifloræ, 456, 466. - - Rosmarinus, 536, 540, 541. - - Rostellum, 329, 332. - - Rotang, 298. - - Royal-fern, 209, 215. - - Rubeæ, 458. - - Rubia, 551, 552, 553. - - Rubiaceæ, 542, 546, 548, 549, 553. - - Rubiales, 490, 505, 548, 556, 564. - - Rubus, 458, 460, 461. - - Rudbeckia, 572. - - Ruellia, 530. - - Rulingia, 422. - - Rumex, 151, 359, 360. - - Ruppia, 278, 279. - - Ruscus, 316. - - Rush, 283, 284. - - Russula, 171. - - Russulei, 171. - - Rust of Wheat, 148. - - Rusts, 146. - - “Rust spots,” 130. - - Ruta, 436. - - Rutaceæ, 436. - - Ruteæ, 436. - - Rye, 125, 151. - - Rye-grass, 295, 296. - - Rye-stem blight, 113. - - - Sabal, 300. - - Sabaleæ, 299. - - Saccharomyces, 177, 178. - - Saccharomyces-forms, 176. - - Saccharum, 293. - - Safflower, 574. - - Saffron, 321. - - Sagina, 364, 365, 366. - - Sagittaria, 281, 282. - - Sago, 254. - - Sago-palm, 298. - - Sainfoin, 472, 473. - - “Salep,” 333. - - Salicaceæ, 338. - - Salicin, 339. - - Salicifloræ, 337. - - Salicornia, 369, 371, 503. - - Salicornieæ, 371. - - Salisburia, 259. - - Salix, 122, 337, 338. - - Salpiglossis, 521. - - Salsafy, 574. - - Salsola, 370, 371, 372. - - Salsoleæ, 370. - - Saltpetre formation, 35. - - Saltwort, 370. - - Salvadora, 547. - - Salvadoraceæ, 542, 547. - - Salvia, 536, 540, 541. - - Salvinia, 201, 216, 217, 218, 245. - - Salviniaceæ, 210, 218. - - Sambuceæ, 555, 557. - - Sambucus, 156, 553, 555. - - Samolus, 513. - - Samydaceæ, 476. - - Sandalwood, 473, 500. - - Sandarack resin, 269. - - Sand-box tree, 432. - - Sand-star, 287. - - Sanguinaria, 395. - - Sanguisorba, 460. - - Sanicula, 493. - - Sannicle, 493. - - Sanseviera, 320. - - Santalaceæ, 500. - - Santalum, 500. - - Santolina, 572. - - Sapindaceæ, 440. - - Sapindus, 441. - - Saponaria, 368. - - Saponin, 460. - - Sapotaceæ, 510. - - Saprolegnia, 102, 107, 108. - - Saprolegniaceæ, 107. - - Saprophytes, 5. - - Sapucaia-nuts, 489. - - Saranthe, 327. - - Sarcina, 27, 28, 38. - - Sarcophyte, 504. - - Sargassum, 4, 10, 73, 75. - - Sarothamnus, 472. - - Sarracenia, 409. - - Sarraceniaceæ, 408. - - Sarsaparilla, 316. - - Sassafras, 392. - - Satureia, 540, 541. - - Satureieæ, 539. - - Saurureæ, 362. - - Saururus, 362. - - Saussurea, 570. - - Sauvagesieæ, 411. - - Saw-wort, 570. - - Saxifraga, 161, 452. - - Saxifragaceæ, 451, 452. - - Saxifrage, 452. - - Saxifraginæ, 451, 555. - - Scabiosa, 558, 559, 560. - - Scævola, 564. - - Scale-leaves, 235. - - Scammony, 517. - - Scandiceæ, 495. - - Scandix, 495. - - Scapania, 192. - - Scarlet-runner, 473. - - Scenedesmus, 51. - - Scheuchzeria, 278. - - Schistostega, 196, 197. - - Schistostegaceæ, 197. - - Schizæa, 215. - - Schizæaceæ, 210, 215. - - Schizanthus, 521. - - Schizocarp, 492. - - Schizocarpeæ, 195. - - Schizochlamys, 51. - - Schizomeris, 53. - - Schizomycetes, 26, 33. - - Schizopetaleæ, 404. - - Schizopetalum, 402. - - Schizophyceæ, 8, 10, 23, 26. - - Schizophyllum, 171. - - Schizophyta, 1, 14, 19, 22, 24. - - Schœnocaulon, 310. - - Schœnoxiphium, 287. - - Schœnus, 286. - - Schwendenerian Theory, 139. - - Sciadium, 51. - - Sciadopitys, 267. - - Scilla, 312, 314. - - Scirpeæ, 285. - - Scirpus, 285, 286, 287. - - Scirrhia, 131. - - Scitamineæ, 276, 278, 323, 328. - - Scitonemaceæ, 22, 24, 25, 27. - - Scleranthus, 365, 367. - - Scleria, 286. - - Scleroderma, 175. - - Sclerodermataceæ, 175. - - Sclerotinia, 116, 134, 135. - - Sclerotium, 87, 127. - - Scolopendrium, 213, 214. - - Scoparia, 525. - - Scopolia, 519, 521. - - Scorodosma, 496. - - Scorzonera, 571, 574. - - Scotch Fir, 259, 266. - - Scotinosphæra, 47, 51. - - Screw Pine, 302. - - Scrophularia, 524, 526. - - Scrophulariaceæ, 518, 521, 522, 527. - - Scutellaria, 536, 539. - - Scutellum, 293. - - Scyballium, 504. - - Scytonema, 22, 26, 176. - - Scytonemaceæ, 25. - - Sea-holly, 493. - - Sea-kale, 403, 405. - - Sea-lavender, 514. - - Sea-milkwort, 513. - - Seaweed, 4. - - Sea-wormwood, 574. - - Sebacina, 156. - - Secale, 127, 295, 296. - cornutum, 127. - - Sechium, 481. - - “Sedimentary-yeast,” 178. - - Sedum, 451, 452. - - Seed, 247, 248, 249. - - Seguieria, 372. - - Selaginaceæ, 532, 541. - - Selaginella, 200, 203, 228, 229, 230, 232, 233, 245, 254. - - Selaginellaceæ, 231. - - Selaginelleæ, 205, 228. - - Selago, 541. - - Selenastrum, 51. - - Selenipedilum, 329, 330. - - Seligeria, 196. - - Seligeriaceæ, 196. - - Semele, 316. - - Sempervivum, 151, 451, 452. - - Senebiera, 400, 401. - - Senecio, 566, 569, 572, 573. - - Senecioneæ, 572. - - Senna, 468. - - Sepals, 235. - - Sequoia, 267, 272. - - Serapias, 332. - - Serjania, 441. - - Serratula, 570, 574. - - Serum, 33. - - Service-tree, 465. - - Sesamum, 529. - - Seseli, 495. - - Seselineæ, 495. - - Sesleria, 294. - - Sesuvium, 375. - - Seta, 186. - - Setaria, 295. - - Sexual reproduction, 11. - - Sheep-seaweed, 84. - - Shellac, 356, 434. - - Shepherdia, 450. - - Shepherd’s-needle, 495. - - Shepherd’s-purse, 401. - - Sherardia, 552. - - “Sichel,” 284. - - “Sickle,” 284. - - Sicyos, 481. - - Sida, 428, 430. - - Sideritis, 538. - - Sideroxylon, 511. - - Sigillariaceæ, 233. - - Silaus, 495. - - Sileneæ, 367. - - Silene, 367. - - Siler, 495. - - Siliceous earth, 20. - - Siliculosæ angustiseptæ, 401. - latiseptæ, 400. - - Siliqua, 398. - - Siliquosæ, 402. - - Silk-cotton, 427. - - Silphium, 498, 572. - - Silver-leaf, 450. - - Silybum, 567, 570. - - Simaba, 439. - - Simaruba, 439. - - Simarubaceæ, 438. - - Sinapeæ, 404. - - Sinapis, 400, 402. - - Siphocampylos, 563. - - Siphoneæ, 4, 9, 47, 59. - - Siphonia, 434. - - Siphonocladus, 62. - - Sirosiphoniaceæ, 22, 24, 26. - - Sisal hemp, 318. - - Sisymbriinæ, 404. - - Sisymbrium, 399, 402, 410. - - Sisyrinchium, 321. - - Sium, 494, 498. - - Skimmia, 437. - - Skull-cap, 539. - - Slime-fungi, 1, 4, 5. - - Sloe, 461, 462. - - Sloth, 8, 356. - - Smilaceæ, 316. - - Smilacina, 314. - - Smilax, 315, 316. - - “Smut,” 113, 130. - - Smut-fungi, 114. - - Snake cucumber, 481. - - Snapdragon, 523, 524. - - Snowberry, 554. - - Snowdrop, 317. - - Soapwort, 368. - - Soft-grass, 296. - - Soja, 471. - - Solanaceæ, 514, 518, 520, 522. - - Solanine, 522. - - Solanum, 238, 521, 522. - - Soldanella, 513. - - Solenia, 162. - - Solidago, 573. - - Sollya, 455. - - Solomon’s seal, 314. - - Sonchus, 153, 571. - - Sophora, 469. - - Sophoreæ, 469. - - Sorbus, 152, 465. - - Sordaria, 129. - - Sordariaceæ, 129. - - Soredia, 141. - - Sorghum, 296. - - Sori, 205. - - Sorocea, 356. - - Sorrel, 361. - - Southernwood, 574. - - Sow-thistle, 571. - - Spadicifloræ, 277, 297. - - Spadix, 297. - - Sparassis, 161. - - Sparaxis, 321. - - Sparganium, 302, 303. - - Sparmannia, 425. - - Spartium, 472. - - Spathe, 297. - - Spathicarpa, 306. - - Spathulea, 136. - - Spearmint, 541. - - Specularia, 562. - - Speedwell, 525. - - Spergula, 366. - - Spergularia, 366. - - Spermacoce, 550. - - Spermacoceæ, 550. - - Spermagonia, 116. - - Spermaphyta, 3. - - Spermatangia, 81. - - Spermatia, 13, 76, 77, 141, 146. - - Spermatochnaceæ, 71. - - Spermatochnus, 71. - - Spermatozoid, 13, 183. - - Sperm-nucleus, 245. - - Spermocarp, 58. - - Spermogonia, 89, 141, 146, 147, 149. - - Spermothamnion, 84. - - Sphacelaria, 70. - - Sphacelariaceæ, 70. - - Sphacelia, 125, 126. - - Sphacelotheca, 110. - - Sphæralcea, 430. - - Sphærella, 48, 130. - - Sphærellaceæ, 130. - - Sphæriales, 129. - - Sphærobolaceæ, 173. - - Sphærobolus, 173. - - Sphærocarpus, 191, 192. - - Sphærococcaceæ, 83. - - Sphærophorus, 142. - - Sphæroplea, 13, 14, 58. - - Sphæropleaceæ, 47, 58. - - Sphærotheca, 120, 121. - - Sphærozosma, 44. - - Sphagneæ, 193. - - Sphagnum, 186, 188, 192, 194, 195, 197. - - Sphenogyne, 566. - - Sphenophyllaceæ, 233. - - Sphinctrina, 140. - - Spigelia, 546. - - Spikelet, 285, 287, 289. - - Spikes, 285. - - Spilanthes, 572. - - Spinach, 371. - - Spinacia, 371, 372. - - Spindle-tree, 444. - - Spiræa, 151, 451, 456, 457, 460. - - Spiræeæ, 457. - - Spiranthes, 331. - - Spirilla, 27. - - Spirillum, 30. - - Spirochætæ, 27. - - Spirochæte, 28, 38, 40. - - Spirodela, 307. - - Spirogyra, 44, 45. - - Spirolobeæ, 371, 400. - - Spirotænia, 44. - - Spirulina, 24. - - Splachnaceæ, 197. - - Splachnum, 196, 197. - - Spondias, 439. - - Sponges, 8. - - Sporangia, 239. - - Sporangial-layers, 88. - - Sporangiocarp, 88. - - Sporangio-fructification, 87. - - Sporangiophore, 88. - - Spores, 10. - Liberation and Distribution of, 91. - Germination of, 93. - - Sporidia, 112. - - Sporobolus, 295. - - Sporocarp, 205, 219. - - Sporochnaceæ, 71. - - Sporochnus, 71. - - Sporogonium, 186. - - Sporophylls, 223, 235, 236. - - Sporophyte, 181, 186. - - Spring-spores, 147. - - Spumaria, 8. - - Spurge, 431, 432. - - Spurge-laurel, 449. - - Spurry, 366. - - Squamariacæ, 84. - - “Squills,” 314. - - Squirting cucumber, 480. - - Stachydeæ, 538. - - Stachys, 538, 541. - - Stachytarpheta, 535. - - Staehelina, 570. - - Stag-truffle, 124. - - Stalk, 186. - - Stamen, 235, 236. - - Staminate, 236. - - Stangeria, 253, 254. - - Stanhopea, 332. - - Stanleyinæ, 404. - - Stapelia, 546. - - Staphylea, 440. - - Staphyleaceæ, 440. - - Staphylococcus, 39. - - Star-aniseed, 389. - - Statice, 514. - - Staurastrum, 42, 43, 44. - - Steenhammera, 533. - - Stegocarpeæ, 195. - - Stellaria, 364, 365, 366. - - Stellatæ, 550, 552, 553. - - Stemless Plants, 1. - - Stemonitis, 7, 8. - - Stephanospermum, 272. - - Stephanosphæra, 48. - - Sterculia, 422. - - Sterculiaceæ, 422. - - Stereocaulon, 143. - - Stereum, 162. - - Sterigmata, 144, 146. - - Sterilization, 32. - - Sticta, 134, 137, 143. - - Stictidaceæ, 133. - - Stictidales, 133. - - Stictis, 133. - - Stigeoclonium, 54. - - Stigma, 3, 250. - - Stigmaria, 233. - - Stigonema, 26, 142. - - Stilbaceæ, 532, 541. - - Stilbe, 541. - - Stillingia, 434. - - Stilophora, 71. - - Stilophoraceæ, 71. - - Stinkbrand, 113. - - Stink-horn, 172, 173. - - Stipa, 291, 294, 296. - - Stitchwort, 366. - - St. John’s-wort, 413. - - Stock, 402, 405. - - Stonebrand, 113. - - Stonecrop, 451. - - Stone-wort, 1, 14. - - Stork’s-bill, 419. - - Stratiotes, 282. - - Strawberry, 458. - - Strawberry-tree, 508. - - Strelitzia, 325. - - Streptocarpus, 528. - - Streptochæta, 290. - - Streptococcus, 39. - - Streptopus, 314. - - Striaria, 70. - - Striariaceæ, 70. - - Strickeria, 129, 130. - - Stroma, 88. - - Stromanthe, 327. - - Strophanthus, 544. - - Struthiopteris, 209, 214, 254. - - Struvea, 9, 62. - - Strychnine, 546. - - Strychnos, 546. - - Sturmia, 332. - - Stylar-column, 328. - -brush, 567. - - Style, 250. - - Stylidiaceæ, 564. - - Stylidium, 564. - - Stylochrysalis, 15. - - Stylopod, 492. - - Styphelia, 509. - - Styracaceæ, 511. - - Styrax, 511. - - Styrax-balsam, 455. - - Subhymenial layer, 167. - - Subularia, 393, 399, 400, 401. - - Succisa, 517. - - Sugar-beet, 372. - - Sugar-cane, 289, 293, 296. - - Sugar-root, 498. - - Sulphur-bacteria, 37, 38. - - Sumach, 439. - - Summer-spores, 147. - - Sundew, 407. - - Sun-flower, 572. - - Sunn hemp, 473. - - “Surface yeast,” 178. - - Surirayeæ, 21. - - Suspensor, 233, 246, 247. - - Swamp cypress, 267. - - Swarmspores, 10, 87. - - Swede, 405. - - Sweet Cicely, 498. - - Sweet-flag, 303. - - Sweet-gale, 351. - - Sweet oil, 547. - - Sweet-pea, 470. - - Sweet-potato, 517. - - Sweet-vernal, 295, 296. - - Swertia, 542. - - Swietenia, 436. - - Swine’s-succory, 571. - - Sycamore, 133, 442. - - Symbiosis, 85. - - Sympetalæ, 336, 504. - - Symphoricarpus, 554, 556. - - Symphyandra, 562. - - Symphyllodium, 257. - - Symphytopleura, 387. - - Symphytum, 533, 535. - - Symploca, 24. - - Synalissa, 139. - - Synandrium, 306. - - Synangium, 212. - - Syncarp, 278. - - Syncephalis, 100. - - Synchytrieæ, 103. - - Synchytrium, 103. - - Syncrypta, 15. - - Synedra, 21. - - Synergidæ, 248. - - Syngeneticæ, 1, 14, 15, 17, 48. - - Syngonium, 306. - - Synura, 15. - - Syringa, 455, 546, 547, 550. - - Systegium, 196. - - Systematic division of the Algæ, 14. - of Filices, 210. - of Fungi, 95. - of Monocotyledons, 277. - of Thallophytes, 4. - of Vascular Cryptogams, 204. - - - Tabellaria, 19. - - Tabellarieæ, 21. - - Tabernæmontana, 544. - - Taccarum, 306. - - Tacona, 284. - - Tagetes, 564, 572. - - Takamahaka, 438. - - Talinum, 373. - - Talipot, 298. - - Tallow-tree, 434. - - Tamaricaceæ, 411. - - Tamarind, 466, 468. - - Tamarindus, 467. - - Tamarisk, 411. - - Tamarix, 411, 412. - - Tamus, 323. - - Tanacetum, 572, 574. - - Tanghinia, 544. - - Tannin, 490. - - Tansy, 572. - - Tapetum, 203, 239, 240. - - Taphrina, 116, 117, 118. - - Taphrinaceæ, 116. - - Tapioca, 434. - - Tar, 266. - - Taraxacum, 571, 566, 574. - - Targionia, 191. - - Tassel Pond-weed, 279. - - Taxaceæ, 259, 272. - - Taxeæ, 261. - - Taxodiaceæ, 257, 267, 272. - - Taxodium, 267. - - Taxoideæ, 258, 259. - - Taxus, 237, 238, 255, 257, 259, 261, 262, 272. - - Tea, 415. - - Tea-plant, False, 521. - - Tea-rose, 460. - - Teak-tree, 535. - - Tear-Fungus, 166. - - Teasel, 494, 558, 560. - - Tecoma, 529. - - Tectona, 535. - - Teesdalia, 398, 401. - - Telegraph-plant, 466. - - Teleutospores, 146. - - Tellima, 452. - - Terebinthinæ, 435. - - Terfezia, 124. - - Terminalia, 487. - - Ternstrœmiaceæ, 414. - - Testa, 247, 248. - - Testudinaria, 323. - - Tetmemorus, 44. - - Tetracyclicæ, 505, 514. - - Tetradynamia, 398. - - Tetragonia, 375. - - Tetragonolobus, 471. - - Tetraphis, 195, 196, 197. - - Tetrapoma, 400. - - Tetrapteris, 442. - - Tetraspora, 51. - - Tetrasporaceæ, 47, 48, 51. - - Tetraspores, 10, 76. - - Teucrium, 567. - - Thalassia, 283. - - Thalia, 327. - - Thalictrum, 379, 385. - - Thallophyta, 1, 4. - - Thallus, 1, 4. - - Thamnidiaceæ, 99. - - Thamnidium, 100. - - Thea, 414, 415. - - Thecaphora, 110, 114. - - Thëin, 374. - - Thelebolaceæ, 109. - - Thelebolus, 109, 120. - - Thelephora, 162, 176. - - Thelephoraceæ, 162. - - Thelygonum, 372. - - Thelypodieæ, 404. - - Theobroma, 422, 423. - - Theobromine, 423. - - Theophrasta, 513. - - Thesium, 500. - - Thistle, 569. - - Thladiantha, 481. - - Thlaspi, 400, 401, 402. - - Thomasia, 422. - - Thorn-apple, 520. - - Thottea, 499. - - Thrift, 514. - - Thrinax, 300. - - Thrush, 180. - - Thuidium, 197. - - Thuja, 241, 268. - - Thujopsis, 269. - - Thunbergia, 530. - - Thyme, 539, 541. - - Thymelæa, 449. - - Thymelæaceæ, 449. - - Thymelæinæ, 448. - - Thymus, 537, 539, 541. - - Tiaridium, 533. - - Tibouchina, 484. - - Ticorea, 437. - - Tigridia, 321. - - Tilia, 424, 425. - - Tiliaceæ, 423. - - Tillandsia, 320. - - Tilletia, 111, 112, 113. - - Tilletiaceæ, 110, 113. - - Tilopteridaceæ, 72. - - Tilopteris, 72. - - Timothy-grass, 294, 296. - - Tinnantia, 308. - - Tmesipteris, 228. - - Toad-flax, 525. - - Toad-rush, 284. - - Toadstools, 159, 166. - - Tobacco, 520, 529. - Virginian, 522. - - Toddalieæ, 437. - - Todea, 203. - - Tofieldia, 310. - - Tofieldieæ, 310. - - Tolu, Balsam of, 473. - - Toluifera, 473. - - Tolypella, 67. - - Tolypellopsis, 67. - - Tolyposporium, 110. - - Tolypothrix, 26. - - Tomato, 521. - - Tomentella, 161. - - Tomentellaceæ, 161. - - Tonquin-bean, 466, 472. - - Tooth-wort, 526. - - Tordylium, 496. - - Torenia, 525. - - Torilis, 497. - - Torreya, 262, 272. - - Touchwood, 164. - - Tournefortia, 533. - - Trabeculæ, 231. - - Tracheides, 251. - - Trachylobium, 468. - - Tradescantia, 308. - - Trama, 167, 174. - - Trametes, 164, 165. - - Tragacanth, Gum, 473. - - Tragopogon, 113, 564, 571, 574. - - Trapa, 485, 486. - - Travellers’ Palm, 325. - - Tremandraceæ, 442. - - Tremella, 156, 157, 159. - - Tremellaceæ, 146, 156. - - Trentepohlia, 8, 54. - - Tribulus, 438. - - Trichia, 8. - - Trichocoma, 176. - - Trichodesmium, 22. - - Trichogyne, 58, 81. - - Tricholoma, 168, 171. - - Trichomanes, 206, 215. - - Trichophilus, 8, 54. - - Trichosanthes, 481. - - Trichosphæria, 129, 130. - - Trichosphæriaceæ, 129. - - Trichostomum, 196. - - Tricoccæ, 430. - - Tricyrtis, 310. - - Trientalis, 512, 513. - - Trifolieæ, 471. - - Trifolium, 469, 471, 473. - - Triglochin, 278, 279. - - Trigoniaceæ, 442. - - Trillium, 314. - - Triodia, 294. - - Triphasia, 438. - - Triphragmium, 147, 151. - - Triplaris, 361. - - Triteleia, 312. - - Triticum, 288, 295, 296. - - Tritonia, 321. - - Triumfetta, 424, 425. - - Trollius, 379, 381. - - Tropæolaceæ, 419. - - Tropæolum, 420. - - True Ferns, 204, 205. - - True Laurels, 391. - - True Mosses, 192. - - Truffles, 124. - - Trumpet-tree, 356. - - Trumpet-wood, 529. - - Tryblidiaceæ, 133. - - Tryblidiales, 133. - - Tryblidium, 133. - - Tsuga, 265, 266. - - Tuber, 124. - - Tuberaceæ, 124. - - Tubercles, 8, 466. - - Tubercularia, 127. - - Tuberose, 318. - - Tubifloræ, 505, 514, 532. - - Tuburcinia, 110, 111, 113. - - Tulip, 312. - - Tulipa, 312, 314. - - Tulipeæ, 312. - - Tupa, 563. - - Turkish-millet, 296. - - Turmeric, 326. - - Turneraceæ, 476. - - Turnip, 405. - - Turpentine, 266, 439. - - Turritinæ, 404. - - Tussilago, 151, 569, 571, 574. - - Tydæa, 528. - - Tylostoma, 174. - - Tylostomaceæ, 174. - - Typha, 302, 303. - - Typhaceæ, 302. - - Typhula, 161. - - - Ulex, 472. - - Ullucus, 371, 372. - - Ulmaceæ, 351. - - Ulmeæ, 351. - - Ulmus, 351. - - Ulothricaceæ, 47, 53. - - Ulothrix, 12, 14, 53, 54. - - Ulva, 10, 53. - - Ulvaceæ, 47, 53. - - Umbelliferæ, 491. - - Umbellifloræ, 490. - - Umbilicaria, 143. - - Umbilicus, 451. - - Uncaria, 553. - - Uncinia, 287. - - Uncinula, 122. - - Upas-tree, 356. - - Urare, 546. - - Uredinaceæ, 145, 146. - - Uredo, 148. - - Urena, 428. - - Ureneæ, 428. - - Urginea, 312, 314. - - Urocystis, 113. - - Uroglena, 15. - - Uromyces, 148, 151. - - Urophlyctis, 103. - - Urospora, 58. - - Urtica, 134, 151, 351, 353. - - Urticaceæ, 352. - - Urticifloræ, 351. - - Usnea, 143. - - Ustilaginaceæ, 110, 113. - - Ustilagineæ, 109. - - Ustilago, 111, 113. - - Ustulina, 131. - - Utricularia, 527, 528. - - Utriculariaceæ, 518, 527. - - Utriculus, 287. - - Uvularia, 310. - - - Vaccines, 41. - - Vacciniaceæ, 451, 508, 509. - - Vaccinium, 134, 160, 161, 509, 510. - - Vaginula, 189. - - Vahea, 544. - - Vaillantia, 552. - - Valeriana, 557, 558. - - Valerianaceæ, 549, 556. - - Valerianella, 557, 558. - - Vallisneria, 282, 283. - - Valloons, 348. - - Vallota, 318. - - Valonia, 59, 62. - - Valoniaceæ, 47, 62. - - Valsa, 130. - - Valsaceæ, 130. - - Vanda, 332. - - Vandellia, 525. - - Vandeæ, 332. - - Vanilla, 331, 333. - - Vascular Cryptogams, 2, 198, 240. - Isosporous, 200. - Heterosporous, 200. - - Vateria, 415. - - Vaucheria, 10, 33, 61. - - Vaucheriaceæ, 47, 60. - - Vegetable-ivory, 301, 302. - - Vegetable-silk, 545. - - Velamen, 332. - - Vella, 400. - - Vellinæ, 404. - - Vellosia, 318. - - Vellosieæ, 318. - - Ve11theimia, 312. - - Velum partiale, 167, 168. - universale, 167. - - Venter, 184. - - Ventral-canal-cell, 185. - - Venturia, 130. - - Veratreæ, 310. - - Veratrin, 311. - - Veratrum, 310, 311. - - Verbascum, 523, 525, 527. - - Verbena, 535. - - Verbenaceæ, 532, 535, 537. - - Vernonia, 571. - - Veronica, 335, 523, 525, 526, 527, 530, 536, 559. - - Verpa, 136. - - Verrucaria, 140, 142. - - Vesicaria, 400. - - Vetch, 470. - - Vibriones, 27. - - Viburnum, 455, 553, 555, 556. - - Vicia, 469, 470, 473. - - Vicieæ, 469, 470. - - Victoria, 386, 387. - - Vigna, 471. - - Vinca, 544. - - Vincetoxicum, 155, 546. - - Vine, 121, 444. - - Vinegar-bacterium, 31, 32, 35. - - Viola, 410, 411. - - Violaceæ, 410. - - Violets, 114, 410. - - Violet-stone, 54. - - Viper’s-bugloss, 533. - - Virginian-creeper, 447. - - Viscaria, 364, 367. - - Viscoideæ, 501. - - Viscum, 501, 502, 504. - - Vismia, 414. - - Vitex, 535. - - Vitis, 445, 446, 447. - - Vochysiaceæ, 442. - - Volkmannia, 225. - - Volva, 167. - - Volvaria, 171. - - Volvocaceæ, 14, 47, 48. - - Volvox, 48, 50. - - Vomic nut, 546. - - “Vorblatt,” 275. - - - Wahlenbergia, 562. - - Wallflower, 402, 405. - - Wall-lichen, 143. - - Wall-rue, 213. - - Walnut, 165, 349, 350. - - Water-cress, 402, 405. - - Water-dropwort, 498. - - Water-ferns, 205, 215. - - Water-fungi, 96. - - Water-hyssop, 525. - - Water-lilies, 385. - - Water-melon, 481. - - Water-milfoil, 486. - - Water-net, 52. - - Water-purslane, 483. - - Water-soldier, 282. - - Water-wort, 413. - - Water-violet, 512. - - Wax-flower, 546. - - Weberia, 197. - - Weigelia, 554. - - Weingærtneria, 294. - - Weisia, 196. - - Weisiaceæ, 196. - - Wellingtonia, 267. - - Welwitschia, 270, 271. - - “Wendungszellen,” 67. - - West-Indian arrowroot, 327. - - Weymouth Pine, 266, 267. - - Wheat, 113, 291, 292, 295, 296. - - Wheat-grain, 292. - - Wheat, seedling of, 292. - - White-beam, 465. - - White Bryony, 481. - - White-cabbage, 405. - - White-mustard, 405. - - White Pine, 266. - - White-pepper, 363. - - White-rot, 164, 165. - - White Water-lily, 387. - - Whitlavia, 515. - - Whortleberry, 509. - - Wig-tree, 439. - - Wild Basil, 540. - - Wild Cabbage, 404. - - Willow, 124, 133, 338. - - Willow-herb, 484. - - Winter-aconite, 382. - - Winter-cherry, 521. - - Winter-cress, 402. - - Winter-green, 507. - - Winter-spores, 146. - - Wistaria, 470, 473. - - Witches’-brooms, 85, 117, 155. - - Woad, 403, 405. - - Wolffia, 307. - - Wood, 251. - - Wood-rush, 284. - - Wood-sorrel, 416. - - Woodruff, 552, 553. - - Woodsia, 214. - - Wormwood, 572, 574. - - Woundwort, 538. - - - Xanthellaceæ, 15. - - Xanthidium, 44. - - Xanthium, 569, 573. - - Xanthorhiza, 379, 383. - - Xanthorrhæa, 312. - - Xeranthemum, 566, 570. - - Xerotes, 312. - - Xylaria, 131. - - Xylariaceæ, 131. - - Xylem, 251. - - Xylopia, 388. - - Xylophylla, 431, 432. - - Xylosteum, 554. - - Xyridaceæ, 308. - - - Yam, 323. - - Yeast-formation, 94. - - Yeast-fungi, 31, 36. - - Yellow bird’s-nest, 507. - - Yellow-rattle, 525, 526. - - Yellow Water-lily, 387. - - Yellow-wort, 543. - - Yew, 259, 261, 266. - - Ylang-ylang, 388. - - Yorkshire-fog, 294, 296. - - Yucca, 312, 313, 316. - - - Zamia, 253. - - Zannardinia, 12, 72. - - Zannichellia, 278, 279. - - Zantedeschia, 305, 306. - - Zanthoxyleæ, 436. - - Zanthoxylum, 436. - - Zea, 290, 293. - - Zelkova, 351. - - Zingiber, 326. - - Zingiberaceæ, 277, 323, 325. - - Zinnia, 572. - - Zizania, 293. - - Zizyphus, 448. - - Zoochlorella, 9. - - Zoogametes, 12. - - Zooglœa, 27. - - Zoogonicæ, 68, 70. - - Zoosporangia, 10. - - Zoospores, 10, 87. - - Zooxantella, 9. - - Zostera, 279, 280, 306, 316. - - Zostereæ, 278. - - Zygadenus, 310. - - Zygochytriaceæ, 103. - - Zygomorphy, 277. - - Zygomycetes, 95, 96. - - Zygophyllaceæ, 438. - - Zygophyllum, 438. - - Zygospore, 12. - - Zygote, 12. - - Zygnema, 44, 45. - - Zygnemaceæ, 44. - - - Butler & Tanner, The Selwood Printing Works, Frome, and London. - - -FOOTNOTES: - -[1] See Angiospermæ. - -[2] According to the recent investigations of Winogradsky some -micro-organisms (Nitrifying-bacteria) can build organic from inorganic -matter. Sachs’ hypothesis that the first organisms must necessarily -have contained chlorophyll is therefore untenable. - -[3] Myxogasteres, Engler’s Syllabus, p. 1. - -[4] Acrasieæ and Plasmodiophorales, _ibid._ - -[5] Myxophyceæ, Cyanophyceæ. - -[6] The Bacteria are more usually included under Fungi. It seems -better, however, to place them under the Algæ in a separate class with -the Schizophyceæ. - -[7] See Marshall Ward, “On the Characters or Marks employed for -Classifying the Schizomycetes,” _Annals of Botany_, 1892. - -[8] According to Hansen these are not disease forms, but occur -regularly under certain conditions, _e.g._ temperature. - -[9] Before fertilisation the oosphere divides and cuts off at the base -one or more cells (polar bodies?), termed “wendungszellen.” - -[10] From the Greek μὐκης = Fungus, hence “mycology.” - -[11] This term is adopted as a translation of the German “anlage.” - -[12] Also termed Water-Fungi (Wasserpilzen). - -[13] Antheridium is preferred in this sub-class as keeping a more -uniform term (Kn). - -[14] In the _resupinate_ fruit-bodies a fertile and sterile -surface cannot be distinguished (_cf._ Polyporaceæ and some -_Stereum_-species). - -[15] The two last genera are identical, the Algal part being a -_Scytonema_, that of _Cora_ a _Chroococcus_; while the same Fungus--a -_Thelephora_--takes part in the formation of all three (A. Möller, -Flora, 1893). - -[16] Formerly termed _oophyte_. - -[17] The oospore divides by a wall transverse or oblique to the longer -axis of the archegonium. From the upper (epibasal) cell, the capsule -(and seta) is derived, while the lower (hypobasal) gives rise to the -_foot_. In _Riccia_ the hypobasal half takes part in the -formation of the sporangium. - -[18] In the Polypodiaceæ unisexual prothallia as distinct as those of -_Equisetum_ are of common occurrence. - -[19] The position of the annulus varies in the different orders; -longitudinal in Polypodiaceæ, Hymenophyllaceæ, and Cyatheaceæ; -transverse in Schizæaceæ, Gleicheniaceæ; indistinct or apical in -Osmundaceæ, Ophioglossaceæ, Marattiaceæ, Salviniaceæ, Marsiliaceæ. - -[20] The former genus _Pteris_ is divided into _Pteris_ and -_Pteridium_. - -[21] Floral-leaves (hypsophyllary leaves) are here adopted as an -equivalent of the term “Hochblätter,” to signify leaves on the -floral-shoot other than foliage or sporangia-bearing leaves. The -term _bract_ is applied only to leaves in whose axil a flower -is borne, and _bracteoles_ to leaves borne on the flower-stalk -(_pedicel_). - -[22] It may be here remarked that another explanation is possible, -based on the study of the development (_K_). - -[23] Piperaceæ, Nymphæaceæ. - -[24] “Fore-leaf” is adopted as a translation of “Vorblatt.” - -[25] Regarding these and other abbreviations see the appendix in the -book. - -[26] Syncarp = cluster of fruits belonging to one flower. - -[27] “Fan” and “sickle” are adopted as terms for these inflorescences -from the German “_fæchel_” and “_sichel_.” - -[28] [Although unbranched stems are characteristic of the Palms, yet -branched specimens are recorded from some eleven genera. The branches -are developed from lateral buds, which in many instances only develope -when the terminal bud has been destroyed. A few Palms develope axillary -branches at the base of the stem; these form rhizomes, and give rise to -clusters of aerial stems.] - -[29] The aggregation of the fruits of several distinct flowers into one -mass. - -[30] According to Pfitzer, the column is the prolongation of the floral -axis beyond the insertion of the perianth, and is not formed by the -coalescence of sporophylls (filament and style). - -[31] _Cypripedilum_ = _Cypripedium_. - -[32] _Corallorhiza_ = _Coralliorrhiza_. - -[33] This is Eichler’s view.--According to Drude the perianth is -absent; at the base of the bracts, a nectary or cup-like disc. Prantl -holds the same view. According to Pax the perianth is absent, but there -is a disc cup-like, or reduced to a single toothed scale. - -[34] The fruit of the Walnut is thus a false fruit; and the term drupe -must therefore not be used in the same sense as in the Rosaceæ. - -[35] The pollen-tube in _Ulmus_ does not enter the ovule through -the micropyle. - -[36] According to Prantl, some species of _Trollius_ (_T. -europæus_, and _asiatiacus_) have a perianth, differentiated -into calyx and corolla, which does not pass over into the honey-leaves. -The outer leaves of the perianth have frequently an incised apex, the -intermediate ones sometimes present transitional forms to the inner, -and sometimes there is a distinct boundary between them. - -[37] If we suppose a spiral line drawn through the leaves -_upwards_ on a stem with scattered leaves (in the shortest way), -then the side of the leaf first touched is the catodic, or descending, -and the other the anodic, or ascending side. - -[38] Those marked [+] are officinal, and when no home is stated, the -plant is a native. - -[39] Those which are officinal are indicated by [+]. - -[40] Those marked with a [+] are officinal. - -[41] For further reference see Sachs, _History of Botany_; -Lindley, _Vegetable Kingdom_; Le Maout and Decaisne, _General -System of Botany_, etc. - - -Transcriber’s Notes: - -1. Obvious printers’, punctuation and spelling errors have been -corrected silently. - -2. Where hyphenation is in doubt, it has been retained as in the -original. - -3. Some hyphenated and non-hyphenated versions of the same words have been -retained as in the original. - -4. Superscripts are represented using the caret character, e.g. D^r. or -X^{xx}. Subscripts are shown as _{1}. - -5. Italics are shown as _xxx_. - -6. Smaller font is shown as ~xxx~. - -7. Bold print is shown as =xxx=. - -8. The corrigenda have been corrected. - -*** END OF THE PROJECT GUTENBERG EBOOK A HANDBOOK OF SYSTEMATIC -BOTANY *** - -Updated editions will replace the previous one--the old editions will -be renamed. - -Creating the works from print editions not protected by U.S. copyright -law means that no one owns a United States copyright in these works, -so the Foundation (and you!) can copy and distribute it in the -United States without permission and without paying copyright -royalties. 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