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+*** START OF THE PROJECT GUTENBERG EBOOK 79061 ***
+
+
+
+
+ _GLIMPSES INTO PLANT-LIFE_
+
+
+
+
+ _BY THE SAME AUTHOR._
+
+=WILD NATURE WON BY KINDNESS.= Illustrated. Seventh and Revised
+Edition. Crown 8vo, cloth, 5s.
+
+“We have no space to draw particular attention to the multitude of good
+things to be found in this cheerful and unaffected little book, from
+every page of which there breathes a sincerity which is necessary to
+the enjoyment of such stories as these.”—_Saturday Review._
+
+“The book is one which may be warmly recommended for the simplicity
+with which it is written and the power of observation which it
+displays.”—_Athenæum._
+
+
+=MORE ABOUT WILD NATURE.= With Illustrations by the Author. Third
+Edition. Crown 8vo, cloth, 5s.
+
+“No better book can be given to juvenile naturalists.”—_Graphic._
+
+“When this delightful book, full of observation, of tenderness, and of
+humour, has been read, it becomes a friend, to be visited often and
+cherished much.”—_World._
+
+=INMATES OF MY HOUSE AND GARDEN.= Illustrated by +Theo. Carreras+.
+Crown 8vo, cloth, 3s. 6d.
+
+“This is a charming book, and prettily illustrated.”—_Spectator._
+
+“A charming series of sketches.”—_Times._
+
+ LONDON: T. FISHER UNWIN.
+
+
+
+
+[Illustration: NEPENTHES RAFFLESIANA.]
+
+
+
+
+ GLIMPSES
+ INTO PLANT-LIFE
+
+ _AN EASY GUIDE TO THE STUDY
+ OF BOTANY_
+
+ BY
+ MRS. BRIGHTWEN, F.E.S.
+ _Author of “Wild Nature Won by Kindness,” &c._
+
+ WITH ILLUSTRATIONS BY THE AUTHOR AND
+ THEO. CARRERAS
+
+ London
+ T. FISHER UNWIN
+ PATERNOSTER SQUARE
+ 1897
+
+
+
+
+ [_All rights reserved._]
+
+
+
+
+ To
+ SIR JOSEPH DALTON HOOKER,
+ K.C.S.I., P.P.R.S., D.C.L., LL.D., ETC.,
+ _Formerly Director of the Royal Gardens, Kew_.
+
+
+ +Dear Sir Joseph Hooker+,—
+
+In conversation with you I have often been impressed by your conviction
+of the importance of inducing young people to observe the elementary
+facts of botany, and I have heard you express your admiration of the
+efforts made in this direction, in an earlier generation, by that
+distinguished botanist, Prof. Henslow. You have assured me of your
+sense of the value of independent observations made by young students,
+for themselves, in the simplest and clearest language.
+
+By your own example the studies of beginners have often been led in
+this direction, but in this little book, which I have ventured to
+produce, and of which you have kindly accepted the dedication, I have
+not attempted to compete with even your least ambitious flights.
+
+All I have endeavoured to do is to prepare the minds of young people
+for the study of botany by explaining in the simplest language some of
+the elementary phenomena of plant-life. It is an humble experiment, but
+made, as I believe, on lines which are novel so far as they go, and
+essentially practical.
+
+If, as is too likely to be the case, I have fallen into any technical
+errors, your good nature must not be held responsible for my fault.
+
+ Believe me to be,
+ Yours very sincerely,
+ ELIZA BRIGHTWEN.
+
+_April, 1897._
+
+
+
+
+ ⁂ _The greater portion of this work has
+ appeared in serial form in “The
+ Girl’s Own Paper.”_
+
+
+
+
+PREFACE
+
+
+When I was a young girl I can well remember how much I longed for some
+simple book that would help me to learn, not merely the name of a
+plant and what class and order it belonged to, but something about its
+life-history.
+
+It seemed very wonderful that, if I put seeds into the ground, dry and
+dead as they looked, I might feel sure young plants would presently
+come up; that, if I planted an acorn, a young oak-tree would in due
+time be seen; but how all this came to pass I could not discover. I
+had access to an excellent library, but although I searched there hour
+after hour, and found many a learned book about plants, they might
+as well have been written in Sanskrit for all I could understand of
+their scientific pages. There seemed nothing suited to the mind of
+a thoughtful child, and although, since that long-ago time, endless
+books have been written for young readers and thinkers, delightful
+books, too, which meet the needs of those who desire information and
+instruction, I have not hitherto met with one that makes the careful
+study of plant-life really interesting and practicable for those young
+people who may not have a teacher to help them in their study.
+
+It has been my aim in the little volume I now venture to send forth to
+my young friends, known and unknown, to supply this deficiency. I want
+to enable them to share the joy of spending hours in a garden learning
+to understand the structure of plants. I want to make them able, when
+they see a bud, or a root, or a twig, to know what the history of that
+object is, how it comes to have the shape it takes, how it developed
+into its present condition, and what its next form will be.
+
+The possession of the simple facts which I have tried to make plain to
+every intelligence in the following pages will turn a country walk
+from a useless lounge into a lively object-lesson, delightful, from
+beginning to end, alike to teacher and taught. Nor will I apologise
+for the simple language which I have used, for my design has been,
+while taking advantage of all the latest discoveries of science, to
+use no terms and introduce no ideas which cannot be made intelligible
+to a thoughtful child. In the hope that even so humble an effort as
+this may not be without a use in enlarging and quickening a sense of
+that infinite harmony which runs through every part of the Creator’s
+marvellous plan of nature, I put forth, not without a full sense of its
+inadequacy, this little volume. It has, at any rate, given me an excuse
+for endless hours of pleasure within the precincts of my own woods and
+garden.
+
+I have to acknowledge great indebtedness to Mr. J. W. Odell, F.R.H.S.,
+whose wide knowledge of botanical science has been of essential service
+in ensuring, as far as possible, the accuracy of my statements.
+
+ ELIZA BRIGHTWEN.
+
+
+
+
+ CONTENTS
+
+ CHAPTER I.
+
+ PAGE
+
+ +Adaptation+ 25
+
+ Plant collections—General view of vegetable growth—
+ Lowest forms of plant life—Water buttercup—Vallisneria—
+ Water-lily—Mare’s-tail—Sea-weeds—Cacti—Orchids—Tillandsia—Seed
+ dispersion.
+
+
+ CHAPTER II.
+
+ +Roots+ 47
+
+ Root fibres—Hygroscopic water—Root hairs—The evil
+ of stagnant water—Binding roots—Carex arenaria—Psamma
+ arenaria—Cheddar cliffs—Correlation of roots—Land, water, and
+ air roots—Laurel root in well—Horizontal stems—Poa bulbosa—
+ Earth-nut—Potato—Onion—Air roots—Hoya—Aëroids—Parasitic
+ roots—Yellow rattle—Clover dodder—Flax dodder—Mistletoe—Root-
+ cap—Office of the root—Growing mustard-seed—Strength of roots.
+
+
+ CHAPTER III.
+
+ +Tree Stems+ 73
+
+ Expansion of bark—Shedding bark—Repairing injury—Epidermis—
+ Fibro-vascular bundles.
+
+
+ CHAPTER IV.
+
+ +Leaves+ 97
+
+ A leaf a digestive organ—Petiole and blade venation—
+ Monocotyledons—Dicotyledons—Radical leaves—Phyllotaxis—
+ Epidermis—Stomata—Influence of foliage upon climate—Eucalyptus—
+ Mesophyll—Chlorophyllon—Pallisade tissue—Protoplasm—Absorption
+ of carbon-dioxide—Jewel-weed—Alchemilla—Growing wheat—Vertical
+ leaves of eucalyptus cork layer—Fall of the leaf—Useful
+ products of trees.
+
+
+ CHAPTER V.
+
+ +Buds+ 123
+
+ Buds formed in summer—Hollow stalks of plane-tree—Terminal
+ and axillary buds—Spiral arrangement—Pollard willow—Suckers—
+ Dormant buds—Bulbils on lily stem—Protection from cold—Leaf
+ and flower buds—Folding of embryo leaves and flowers.
+
+
+ CHAPTER VI.
+
+ +Flowers+ 149
+
+ Floral envelopes—Buttercup—Gamopetalous—Polypetalous—
+ Epipetalous—Apocarpous—Woodsorrel—Syncarpous pistil—Geranium-
+ coloured bracts—Composite flowers—Fading flowers—Flower
+ expansion—Flower dissection—Cruciferous plants—Papilionaceous
+ flowers—Honey glands—Entomophilous flowers—Catkins—Monœcious
+ and diœcious flowers—Arum—Protection from insects and moisture.
+
+
+ CHAPTER VII.
+
+ +Pollination+ 175
+
+ Cross pollination in dog’s mercury and hazel—Pin-eyed
+ primrose—Maiden pink—Wind pollination—Araucaria—Pollination
+ by moths—Nottingham catchfly—Attraction of scent—Bartsia—St.
+ John’s wort—Japanese toad-lily—Pollination by humming-birds.
+
+
+ CHAPTER VIII.
+
+ +Fertilisation+ 193
+
+ Pollen grains—Micropyle—Nucellus—Embryo-sac—Experiment with
+ lily pollen—Changes after fertilisation—Growth of embryo—
+ Albumen—Arillus in spindle-tree—Yew and nutmeg—Persistent
+ style of clematis—Ovules—Changes in ovary of oak and datura.
+
+
+ CHAPTER IX.
+
+ +Fruit+ 209
+
+ Wide meaning of the word fruit—Diversity in appearance and
+ character of various fruits—Dehiscent and indehiscent
+ pericarp—Epicarp—Chestnut involucre—Mesocarp and endocarp—
+ Pericarp—Achene—Strawberry an apocarpous fruit—Pineapple—
+ Irritating hairs—Resinous protection of cones—Coiled stem
+ of cyclamen—Seed-pod of ivy-leaved toad-flax hidden in wall
+ crevices.
+
+
+ CHAPTER X.
+
+ +Dispersion of Fruits and Seeds+ 227
+
+ Dispersion by hooks and spines—Martynia—Testa—Di Quaglia—
+ Burdock—Bedstraw—Dispersion by winged seeds or achenes—
+ Sycamore, pinus tribe, birch—Dispersion by silky down or
+ hairs—Dandelion, goat’s-beard, groundsel—Willow-herb—Bird
+ agency—Seas and rivers—Dispersion by elastic force—Pansy—
+ Balsam—Furze—Broom—Squirting cucumber—Dispersion by
+ hygrometric sensitiveness—Barley—Feather-grass—Mexican
+ insect—Dispersion by sticky glands—Linnæa Borealis—Salvia
+ glutinosa—Plumbago—Ground-nut self-buried.
+
+
+ CHAPTER XI.
+
+ +Germination+ 249
+
+ Testa and its various forms—Collomia—Axis, tigellum,
+ hypocotyle—Centre of growth—Double embryo—Three conditions
+ required for germination—Varying time in different plants—
+ Cedar of Lebanon—Railway-bank flora—Broad beans—Cress seed—
+ Tillandsia—Collecting seedling trees—Fern and moss spores—
+ Prothallium—Archegonium—Antheridium germ cells—Capsular fruit
+ of mosses—Protonema.
+
+
+ CHAPTER XII.
+
+ +Physiology of Plants+ 273
+
+ Processes of plant growth—Nutrition—Water and gas as plant
+ food—Water culture—Osmosis—Experiment showing absorption—
+ Nitrates—Insectivorous plants able to absorb nitrogen to some
+ extent—Second experiment on absorption—Preparation of plant
+ food—Water bouquet—Transpiration—Use of Stomates—Respiration—
+ Seeds give off carbon-dioxide—Effect of light, darkness, and
+ heat—Reproduction—Protococcus—Strawberry runner—Asexual and
+ sexual reproduction—Effect of cold upon seeds.
+
+
+ CHAPTER XIII.
+
+ +Insectivorous Plants+ 295
+
+ Special purpose of each plant organ—Various modes by which
+ plants entrap insects—Sundew—Venus fly-trap—Trapping insects
+ by sticky hairs—By viscid glands—By pitchers containing
+ fluid—Sarracenias—Roridula—Utricularia—Nepenthes—Pinguicula.
+
+
+ CHAPTER XIV.
+
+ +Habit of Growth in Plants+ 313
+
+ Tropical forest—Perching orchids not parasites—Mistletoe—
+ Yellow rattle—Saprophytes—Murderer fig-tree—Mutualism—Corn
+ blue-bottle—Clover and bacteria—Symbiosis in white poplar
+ and fungus—Sea anemone and algæ—Bryony tendril—Mycetozoa.
+
+ +Glossary+ 335
+
+
+
+
+LIST OF ILLUSTRATIONS
+
+
+ +NEPENTHES RAFFLESIANA+ _Frontispiece_
+
+ PAGE
+
+ +WATER BUTTERCUP+ 36
+
+ +VALLISNERIA+ 37
+
+ +CATTLEYA WALKERIANA+ (_A Brazilian Orchid_) 41
+
+ +YOUNG SCOTCH FIR GROWING IN HOUSE-LEEK+ 44
+
+ +CREEPING GRASS+ 56
+
+ +POA BULBOSA+ 57
+
+ +LILY BULBILS+ 60
+
+ +CLOVER DODDER+ 64
+
+ +SECTION OF ROOT CAP+ 68
+
+ +TURKEY OAK BARK+ 76
+
+ +SCOTCH FIR BARK+ 77
+
+ +SNAKE-BARK MAPLE+ 78
+
+ +TURKEY OAK STEM+ (_struck by lightning_) 79
+
+ +PLANE TREE BARK+ 80
+
+ +HORSE-CHESTNUT BARK+ 81
+
+ +WHITE POPLAR BARK+ 82
+
+ +SYCAMORE BARK+ 83
+
+ +TREE-FERN BARK+ 84
+
+ +STEM OF YELLOW WATER-LILY+ 87
+
+ +STEM OF WHITE WATER-LILY+ 87
+
+ +GROUP OF BEECH-TREES WITH INTERLACING STEMS
+ AND ROOTS+ 93
+
+ +CONVOLVULUS+ 94
+
+ +NETTED VEINS+ 100
+
+ +MONOCOTYLEDON+ 101
+
+ +DICOTYLEDON+ 102
+
+ +TAMARIND SEEDLING+ 103
+
+ +STOMATA+ 107
+
+ +LEAF SECTION+ 109
+
+ +YOUNG SHOOT OF EUCALYPTUS+ 116
+
+ +MATURE FORM OF EUCALYPTUS LEAVES+ 117
+
+ +OAK IN WINTER+ 127
+
+ +OAK IN SUMMER+ 129
+
+ +HORSE-CHESTNUT+ 135
+
+ +YOUNG BEECH+ 138
+
+ +UNFOLDING ARUM LEAF+ 140
+
+ +UNFOLDING LEAVES OF HART’S-TONGUE FERN+ 140
+
+ +PEAR LEAF+ 140
+
+ +BUDS OF WAYFARING TREE+ 145
+
+ +PRIMROSE+ 153
+
+ +POINSETTIA+ 157
+
+ +WINTER CHERRY+ 160
+
+ +WALLFLOWER+ 162
+
+ +SWEET-PEA+ 165
+
+ +BIRCH FRUIT+ 168
+
+ +WILD ARUM+ 170
+
+ +PRIMROSE+ 179
+
+ +MAIDEN PINK+ 181
+
+ +ARISTOLOCHIA+ 186
+
+ +STAPELIA+ 188
+
+ +HYPERICUM+ 189
+
+ +TOAD-LILY+ 191
+
+ +POLLEN-GRAINS+ 196
+
+ +WHITE-LILY PISTIL. SECTION OF PISTIL+ 197
+
+ +POLLEN TUBE+ 198
+
+ +SECTION OF COCOA-NUT+ 203
+
+ +SPINDLE-TREE+ 204
+
+ +NUTMEG AND MACE+ 205
+
+ +CLEMATIS OR TRAVELLERS’ JOY+ 206
+
+ +SECTION OF PEACH+ 216
+
+ +POPPY CAPSULE+ 217
+
+ +WOODY PEAR+ 218
+
+ +PINE-CONES+ 223
+
+ +SEED-POD OF MARTYNIA+ 230
+
+ +BIRCH SEED+ 232
+
+ +PARACHUTE+ 234
+
+ +DANDELION SEED+ 235
+
+ +GOAT’S-BEARD+ 236
+
+ +COCOS-DE-MER+ 238
+
+ +BROOM AND SWEET-PEA PODS+ 242
+
+ +STIPA PINNATA (FEATHER GRASS)+ 244
+
+ +BIGNONIA SEED+ 252
+
+ +DOUBLE EMBRYO OF ORANGE+ 255
+
+ +BROAD BEANS+ 258
+
+ +GROWING MUSTARD SEEDS+ 261
+
+ +BEECH COTYLEDONS+ 264
+
+ +ACORN+ 266
+
+ +HORSE-CHESTNUT+ 267
+
+ +YOUNG DATE-PALM+ 269
+
+ +TRANSFUSION DIAGRAM+ 278
+
+ +SKELETON LEAF+ 284
+
+ +SUNDEW+ 300
+
+ +VENUS FLY-TRAP+ 304
+
+ +SARRACENIA FLAVA+ 306
+
+ +BLADDERWORT+ 308
+
+ +PITCHER OF NEPENTHES RAFFLESIANA+ 309
+
+ +BUTTERWORT+ 311
+
+ +PERCHING ORCHID+ 317
+
+ +RAFFLESIA ARNOLDII+ 320
+
+ +GIANT COW-PARSNIP+ (_Heracleum Giganteum_) 325
+
+ +CORN BLUE-BOTTLE+ 326
+
+ +BRYONY TENDRIL+ 331
+
+ +TRICHIA THROWING OUT SPORES+ 332
+
+ “To me be Nature’s volume broad display’d,
+ And to peruse its all-instructing page;
+ Or, haply catching inspiration thence
+ Some easy passage raptur’d to translate,
+ My sole delight.”
+
+ +Thomson.+
+
+
+
+
+CHAPTER I
+
+_ADAPTATION_
+
+ “My heart is awed within me, when I think
+ Of the great miracle that still goes on
+ In silence round me—the perpetual work
+ Of Thy creation, finished, yet renewed
+ For ever. Written on Thy works, I read
+ The lesson of Thine own eternity.”
+
+ +Bryant.+
+
+
+
+
+CHAPTER I
+
+ADAPTATION
+
+
+The study of plants appears to me to be one of the most delightful and
+instructive that can be taken up by young people. It has this advantage
+over many other pursuits that it can be carried on almost everywhere,
+for, even if the student’s lot is to live in a town, there are
+generally botanic gardens within reach, and visits paid in the country
+are made the more enjoyable when some special study can be carried on
+in the daily walks.
+
+Then collections of dried leaves and flowers can be formed during the
+summer, and the arrangement and classification of these will provide
+pleasant winter occupation.
+
+I fear that many young people are apt to consider botany a very dry
+study. They are naturally repelled by the long words and many technical
+terms used in describing plants.
+
+It has long been my belief that the study of botany should be
+approached through the garden rather than the schoolroom, beginning
+with a country ramble which should be an object-lesson opening out
+endless paths for future study.
+
+Our Heavenly Father has given us a beautiful world to live in, and,
+when our eyes have once been opened to observe what lies around us,
+nature becomes like an exquisite book of pictures, always revealing to
+us something new and wonderful as we turn over each fresh page.
+
+It is suited to all ages; the baby child begins by gathering daisies
+and buttercups, while older children make wild-flower collections and
+perhaps work in their own little gardens watching the growth of seeds
+and slips.
+
+The beauty of ferns and mosses is sure to lead to some painstaking
+study of those fascinating growths.
+
+Later on the fact that all trees have flowers comes as a surprise to
+the unobservant, and thus, when rightly guided, young people can hardly
+fail to love a pursuit that promises such endless sources of interest.
+
+In the chapters that will follow on the subject of plant life, I do
+not purpose to write for quite young children, as my hope is that
+older readers will explain what is written, and make it interesting to
+the little ones as they walk in gardens and fields, giving as it were
+object-lessons on buds, leaves, and flowers, and training young minds
+to search for themselves into the wonders that lie around them.
+
+How much there is to learn about, even in the simplest things, some of
+the succeeding chapters will endeavour to show, for example:
+
+How young plants grow out of seeds;
+
+How those seeds are dispersed;
+
+How much is folded up in a bud;
+
+How flowers are formed;
+
+How the bark splits off different trees.
+
+Any one of these subjects would need very careful, patient observation
+truly to understand it.
+
+I stand as it were only on the threshold of scientific research, and
+look with wonder at the work of such a student as Darwin, who gave
+twenty long years to observation of the common earth-worm before he
+wrote his deeply interesting book upon it. Again, we see Sir John
+Lubbock giving years of his life to the growing of seeds and their
+seed leaves, in order to learn exactly how plants begin their life,
+and two very thick volumes are required to contain the vast amount of
+information he has thus obtained.
+
+These two examples will suffice to show that the minutest objects in
+nature are worthy of reverent attention, and if these chapters tend to
+awaken young people to a perception of this fact and act as a humble
+guide to new lines of thought, I shall feel that they have not been
+written in vain.
+
+I fear it is impossible to explain the processes nature is carrying on
+in the plant-world without occasionally using scientific words, but,
+when I am obliged to do so I shall try to explain their meaning,[1],
+and when once we rightly understand an exact expression we soon begin
+to use it, because it is more convenient and often saves repeating a
+long sentence.
+
+[1] See glossary at the end of the book.
+
+I would ask my readers to try and obtain from their gardens and fields
+the various objects mentioned at the close of each chapter, and
+compare them with the plates, learning all about them as they read the
+letterpress.
+
+This will, I feel sure, add much interest to the study, for having
+something to collect and examine tends to lighten mental work and
+enables us better to understand descriptive writing.
+
+In this introductory chapter I will simply take a general view of
+vegetable growth and its adaptation to the situation in which it is
+found.
+
+In many respects plants require the same conditions as animals, birds,
+and insects; they must have air, food, moisture and light in order to
+attain healthy growth, and although they differ from animals in being
+usually stationary, their life is carried on in a very similar way. Let
+us take a forest tree as a type.
+
+It is anchored in the soil by its roots which are its feeding organs;
+through them it draws up various kinds of nourishment from the earth
+in which it stands.
+
+The roots by several chemical processes render the elements they have
+taken up from the soil fit for the nourishment of the tree; they send
+it up through the stem and branches into the leaves, and these being
+the breathing organs have essential work to do in receiving from the
+air, and giving out again, certain gases which contribute largely to
+maintain the life and vigour of the tree. Thus it grows year by year,
+producing annually its flowers and seed, which is the end and aim of
+all plant life.
+
+We can trace another analogy with animal life, in the necessity for
+pure sweet air, plants growing in a vitiated or smoke-laden atmosphere
+soon showing unmistakable signs of weakness. The stunted hedges and
+trees on the fringe of London always remind me of the poor, ill-grown
+children of the slums.
+
+Besides the plant life which we see around us in the shape of trees,
+shrubs, and flowers, there are lower and perhaps still more wonderful
+forms of vegetable life affording endless fields of study.
+
+Mosses, lichens, and fungi we are familiar with everywhere in the
+country, but below these again are such growths as the green stain[2]
+which makes the tree trunks in moist places as brilliant in colour
+as the leaves themselves. Looked at through a lens we see the colour
+arises from a growing plant of extremely simple form, little more in
+fact than a succession of cells, each living and increasing “after its
+kind.”
+
+[2] _Protococcus._
+
+Again, if we consider the process of fermentation, we find that when it
+is set up in a cask of wine its action is due to the growth of a minute
+vegetable that feeds upon the alcohol and sugar, and by robbing the
+wine of those two elements turns it into vinegar or acetic acid.
+
+A somewhat similar growth causes the thick jelly-like substance we
+sometimes find in our inkglass when it has been allowed to remain too
+long without renewal; the minute germs floating in the air have found
+the ink suitable to them, and thus their mycelium[3] begins to form at
+the bottom of the glass, to the great discomfort of the writer.
+
+[3] First form of fungoid growth.
+
+The yeast with which our bread is fermented is another of these minute
+plants, and consists of oval cells which multiply with great rapidity
+when placed in a pan of flour, and kept in a warm atmosphere.
+
+By the careful study of these lower forms of vegetable life, Pasteur,
+Koch, Frankland, and others have discovered and classified the germs or
+microbes,[4] as they are called, which give rise to various diseases.
+In books upon the subject, their different shapes are figured as they
+appear when immensely magnified, so that we can see that which will
+give rise to consumption, erysipelas, or cholera, and one reads with
+deep wonderment of all that science has ascertained of late years as
+to the presence in the air of these seeds of disease which are ever
+floating more or less around us. But for the restraining hand of God,
+it appears as if universal sickness and death would be our fate.
+
+[4] Small living atoms.
+
+Leaving these lower forms of growth, we may consider the three
+divisions into which plants are naturally classed as to their duration
+of life.
+
+Annuals are those which grow and flower, and form their seeds in one
+year, within which their life-history is closed.
+
+Biennials produce leaves only in the first year; by their aid they lay
+up stores of nutriment in the form of tuberous roots, on this food they
+can exist through the winter, produce flowers the following summer,
+perfect their seeds, and then die.
+
+To this class we owe such useful plants as the carrot, parsnip,
+beetroot, and many others which afford us such nourishing vegetable
+diet.
+
+Perennial plants live on for an indefinite number of years, flowering
+annually, in some cases dying down to the root in autumn, and producing
+fresh foliage the following year.
+
+Water plants seldom have a fixed root, but remain floating, borne up
+and kept in position by the water, their roots being the means by
+which, in conjunction with the leaves, they derive nourishment from air
+and water. It is well worth while to observe the two forms of leaves
+in the water buttercup. Those on the surface are three-lobed, flat,
+and round, they absorb from the air such gases as the plant requires;
+while the leaves beneath the surface are divided into threads so as
+to offer no obstruction to the flow of water and enable the plant to
+collect needful food from the water. It can vary the form of its leaves
+according to its requirements, since in running streams it may often be
+found with the hair-like leaves only.
+
+[Illustration: WATER BUTTERCUP.]
+
+On the other hand, if its seeds are sown in moist earth, the seedlings
+will grow and develop those flat leaves only which are characteristic
+of land plants. This water buttercup, therefore, gives us a wonderful
+example of adaptation to surrounding influences.
+
+[Illustration: VALLISNERIA.]
+
+Adaptation is remarkably shown in the Vallisneria, a grass-like
+water-plant, found in Southern Europe;[5] it grows in freshwater lakes,
+rooted in the mud, and yet its flowers need to be fertilised in the
+air. In order to effect this, the small male flowers detach themselves
+from their stems, and, rising through the water, float about upon its
+surface. The female flowers are borne on a stalk, spirally twisted, so
+that it can uncoil and allow the flower to reach the top of the water
+whether it be deep or shallow. There the two kinds of flowers meet, the
+seeds are formed and the stem coils up again and brings the capsule
+below the surface, where it gradually matures.
+
+[5] It can generally be met with at naturalists’ shops where aquaria
+are sold.
+
+The water-lily can grow a long or short stem as the depth of the water
+may require to enable its leaves to lie flat upon the surface. I have
+gathered lily flowers in my lake with stems from four to five feet
+long, where the plant happened to be growing in deep water.
+
+In such plants as the mare’s-tail (_Hippuris vulgaris_), we find the
+stem specially adapted to a submerged life. Growing out of mud at
+the bottom of a stream the plant upholds its slender stalks by two
+different methods. Inside the epidermis (or outer skin) a strand of
+rather tough tissue running through the centre gives flexible support,
+whilst the rest of the space is filled up with very large air cells,
+which give such buoyancy to the stems that even if they are three feet
+in length they are kept upright in the water, rising ten or twelve
+inches above the surface. It is a valuable as well as a curious plant,
+as it has the property of absorbing the gases emitted by stagnant
+water, and tends thus to purify the air.
+
+The same power of adaptation is to be found in sea-weeds. Those growing
+on rocky shores having short fronds covered with fructification, while
+out at sea, ribbons of oar-weed may be found many yards in length,
+formed, like the gulf-weed, of tough texture to bear the friction of
+waves and storms.
+
+If we were travelling in a Mexican desert, we should find those
+remarkable plants which can be so well studied in the cactus-house at
+Kew Gardens. Bearing in mind that for many months the plant must do
+without a drop of rain, or in fact without moisture of any kind, it has
+been necessary that the leaf-surface should be reduced to prevent loss
+of moisture by evaporation, and so spines take the place of leaves, and
+the stems are encased in a thick leathery skin, which protects the
+plant from the burning heat of the sun. Very little moisture escapes
+through this thick green epidermis; therefore when rain falls the
+plants receive and store up their liquid food, and live sparingly upon
+it during the long periods of drought, which last for three-quarters
+of the year. Some of these cacti, as we see them at Kew, are tall,
+straight-stemmed plants, others low-growing rounded masses, little
+spiny cushions, almost like vegetable hedgehogs.
+
+In the arid prairies of Texas, advantage is taken of the watery stores
+of the cactus, for when other supplies fail, its fleshy stems are cut
+open, and horses and cows greedily devour the succulent food, which
+answers the purpose of drink, as well as affording nutritious fodder.
+
+Our British spurge-plants have green leaves, a thin epidermis, and all
+the ordinary characters of the plants of a temperate region, but by
+comparing them with the spurges found in Madeira, we see how climate
+causes adaptation to differing conditions. One of these spurges growing
+in my greenhouse has a tall column-like stem, no leaves, and a thick
+leathery skin, which would enable it to bear a hot, dry climate. It
+thus mimics the giant cacti of Mexico.
+
+[Illustration: +CATTLEYA WALKERIANA+ (_a Brazilian Orchid_).]
+
+We may trace another contrast in our common groundsel and the large
+succulent groundsels of the Cape and the Canary Isles, with their thick
+fleshy leaves, the difference in form and texture being simply an
+expression of the wonderful modification due to climate.
+
+The lovely tribe of orchids make the same provision for long periods of
+drought. Many of the species live in countries where the rainy season
+lasts about six months, and is succeeded by as many months of dryness
+and heat.
+
+The air-plants we obtain from these countries have large pseudo-bulbs,
+that is, the stems are enlarged so as to be storehouses of nutriment
+upon which the plant exists, and by means of which it brings out the
+gorgeous flowers which make Brazilian forests such fairylands of
+beauty; every tree-branch being laden with parasitic orchids, their
+lovely blossoms lasting month after month without the aid of rain or
+dew, because Nature has provided each plant with its special store of
+food, and has thus adapted it to the position it is created to adorn.
+
+Another of these perching-plants is _Tillandsia Usneoides_, known in
+Florida as Spanish moss, and often called “old man’s beard.” It hangs
+from the tree-branches in tufts, like grey hair, and grows in such
+profusion that it is collected and used for stuffing cushions. This
+curious plant has no roots, but simply hangs from the branches, and
+lives like the orchids by absorbing water from the moist air in the
+humid forests where it is found.
+
+The absorption by the long, hanging, grey roots of the orchids in one
+case, and by the finely-divided leaves and stems in the other, are both
+instances of the wonderful way in which Nature “adapts” the parts of a
+plant to its requirements.
+
+It often happens that seeds, blown hither and thither by the wind,
+chance to fall upon places which are quite unsuitable to their mode
+of growth; then we have an opportunity of seeing how their power of
+adaptation enables them to triumph over almost insuperable difficulties.
+
+I have observed a tiny plant of groundsel growing out of a chink in
+a wall where there was scarcely any soil from which it could derive
+nourishment, contriving to live on, however, and make the best of its
+hard lot. Its stem, which should have been a foot high, could only
+attain about two inches, and instead of dozens of leaves it had but
+four, and yet it survived and even produced two small flowers, thus
+touchingly displaying its power of adaptation.
+
+[Illustration: YOUNG SCOTCH FIR GROWING IN HOUSE-LEEK.]
+
+Another more remarkable instance which occurs to me was that of a
+seedling Scotch fir, which had rooted itself in a lump of house-leek
+on the top of a garden wall. For eight years the young tree managed to
+live and grow, until it became a symmetrical well-branched fir-tree,
+almost twelve inches high. By a supreme effort it produced a crop of
+miniature cones, and soon after it died from drought and starvation,
+the wonder being that it could have lived so long upon the modicum
+of food the barren wall supplied, besides having to endure at times
+periods of scorching heat as well as drought. The chief interest in
+this example is centred in the fact that as soon as fruit-bearing has
+been attained, then, and not till then, the little tree died, showing
+how persistently under all hindrances and difficulties a plant will
+endeavour to carry out the purpose of its creation.
+
+We have seen in these instances some striking examples of the way in
+which plant-life is adapted to its surroundings. Our examples have
+been such as are easy of attainment, and such as we can verify with
+our own eyes; but even more wonderful are the adaptations hidden away
+in the recesses of the plant, and as we progress in our study these
+arrangements of cells and tissues will be revealed to us. In order
+however to see them, and to understand their true significance, we must
+proceed step by step to study the parts of an ordinary plant; because
+it is only by first mastering all we can of one part of a plant, and
+then comparing that part with other plants, that we can hope to gain
+real knowledge. Accordingly in our next chapter we shall take the root
+as our starting-point, and ascertain its functions and uses, and the
+part it has to play in the economy of the plant.
+
+Specimens to be obtained:—Green stain on treebark (_Protococcus_);
+yeast; annual, biennial, and perennial plants; water buttercup leaves;
+vallisneria; water-lily stems; mare’s-tail plant; cacti; spurge;
+orchids; tillandsia; plants growing in wall crevices.
+
+
+
+
+CHAPTER II
+
+_ROOTS_
+
+ “While thus through all the stages thou hast push’d
+ Of treeship—first a seedling, hid in grass;
+ Then twig; then sapling; and, as century roll’d
+ Slow after century, a giant bulk
+ Of girth enormous, with moss-cushion’d root
+ Upheaved above the soil.”
+
+ +Cowper.+
+
+
+
+
+CHAPTER II
+
+ROOTS
+
+
+Let us begin our study of roots by considering the way in which plants
+obtain their nourishment from the earth, and are kept in an upright
+position by means of their root-fibres. These being out of sight, we
+may easily not be familiar with this part of the economy of plant life,
+but we shall soon see what important duties the roots have to fulfil,
+and how much they vary in character and appearance according to the
+soil, the climate, and the work they are required to do. The greater
+number of annual plants (those which live only one year) have fibrous
+roots, and of these we can find examples almost everywhere. A piece of
+groundsel or tuft of grass will answer our purpose. On pulling it out
+of the ground we see a bunch of whitish threads or fibres springing
+from the crown of the plant (which is the junction between the stem and
+the root), and on these slender fibres are hairs which are really the
+active part of the root, for it is only through these hairs that the
+rootlets are able to absorb the liquid from the soil, the fibres simply
+acting as channels to convey the watery nourishment to the stem and
+leaves.
+
+Common earth consists of small particles of mineral substances such as
+flint, chalk, or iron, and also of such vegetable matter as decayed
+leaves and rotten wood.
+
+The spaces between the particles are more or less filled with air, each
+mineral particle being enveloped with a film of water. However dry
+the soil may appear, this will always be found to be the case. It may
+be tested by weighing in an agate balance some dry soil on a summer’s
+day. There is a very delicate instrument called a hygroscope, which can
+tell us when there is the slightest amount of moisture in the air, and
+a clever German writer, Von Sachs,[6] has termed this film of water,
+which gathers round earth-particles, hygroscopic water. It has been
+ascertained by careful experiment that it is only on this delicate
+watery film that the root-hairs of plants are able to feed. As these
+hairs drain away the hygroscopic film it is always being renewed by the
+free water which comes from rain and dew. The free water of the soil is
+constantly passing from the surface to the subsoil, and by this action
+plant-food, in the form of soluble earth salts, is presented to the
+roots. The passage of the water is of the highest service to the roots,
+since the warm air follows the water through the soil, and helps to
+oxidise the mineral particles; these are thus rendered soluble, and are
+taken up by the fine films of water, and so indirectly the roots are
+fed. If, however, there is no outlet for the water and the soil becomes
+water-logged this beneficial action is retarded, and to land-roots the
+water is hurtful.
+
+[6] Author of “Vegetable Physiology.”
+
+We can now understand why stagnant water in the ground is so injurious
+to plant-life, as it prevents the needful air from coming into contact
+with the roots, and this is the reason why farmers are careful to
+remove the surplus water from their fields by thorough drainage and
+ploughing. Roots adapt themselves very wonderfully to their situation.
+
+This piece of grass, which we are examining, if it grew in sandy soil,
+would have its root-fibres covered with a downy growth to enable them
+the more readily to absorb every particle of moisture in the sand.
+Dr. Bonar speaks of the date-palm as having this same characteristic.
+“These palm roots are peculiarly fitted to obtain every drop of water
+that the sand contains; they consist of long fleshy strings or ropes,
+shooting straight down into the sand, in numbers quite beyond our
+reckoning, and extending over a large circle.”
+
+The tendency of fibrous roots to bind sand together is taken advantage
+of on many of our sea-coasts, where the sand blows inland and renders
+acres of ground sterile and useless. There, if the _Carex arenaria_
+(a kind of sedge) is planted, its roots will spread far and wide,
+interlacing and creeping through the sandy soil, until in time the
+latter becomes solid and no longer drifts inland.
+
+An allied species of grass, _Psamma arenaria_ (or marrem grass) grows
+abundantly at Bournemouth, and wishing to ascertain how far one of its
+underground stems extended, with some amount of patience I disinterred
+about six or seven feet of it in a bank on the sea-shore where it was
+accessible. As it seemed to have no end, I could not ascertain its
+entire length.
+
+Another instance of root growth adapting itself to situations occurs to
+me. In visiting the Cheddar Cliffs in Somersetshire I was struck by the
+beauty of a plant which grew here and there out of the crevices of the
+rocks. Its tufts of vivid green leaves looked so healthy and vigorous I
+could not help wondering how it could obtain moisture enough to produce
+such foliage, placed as it was high up on the dry face of a rock.
+
+Failing to reach its roots in any other way, I climbed up to a spot
+where I could remove some of the horizontal layers of stone. At last I
+lifted a flat piece of rock just above one of those plants, and there I
+saw at a glance the secret of its vigorous growth:
+
+The roots had spread out over the surface of the stone for a distance
+of eight or nine inches in a perfectly flat layer of fine fibrous
+rootlets no thicker than a sheet of paper; these would doubtless suck
+up abundant moisture whenever the rain beat upon the rocks, and there,
+pressed closely between the two layers of stone the plant has its
+water-supply stored up, and is enabled to look fresh and green when
+other vegetation is suffering from drought.
+
+In plant-life there is a marvellous variety in root-structure. Roots
+differ much, not only in form, but in texture and duration of life, so
+that to gain a true knowledge of them we must carefully examine those
+of herbs, shrubs, and trees, and observation will soon teach us the
+fact that there exists a close correlation between the form and texture
+of the root and the size and character of the plant. The external
+shape will depend principally upon whether a tap-root is developed
+or no. Such, for instance, as the carrot and the dock are those of
+the true tap-root character. Of branching roots we may find endless
+modifications amongst ordinary field or garden flowers from the fibrous
+roots of the little groundsel to the large fleshy tubers of the dahlia.
+Between these two types there are others of an intermediate kind, but
+it is possible to recognise amongst common plants the roots belonging
+to one or other of the types I have described. For the purposes of
+study we may broadly group roots into classes according to their method
+of collecting and absorbing food. Thus we find one group growing in
+soil and feeding upon the soluble earth salts and moisture of the soil.
+Another group will be found growing in water, like the water-lily and
+pond weeds. A third group simply hangs down in space from some perching
+plant like the tropical orchid, whilst a fourth and very small group
+consists of parasitic roots, of which a very common example is the
+mistletoe. We will now study each of these groups separately.
+
+I have already spoken of some kinds of fibrous roots, and may add that
+if the root of a land plant is immersed in water, it will after a time
+develop a different kind of fibre, capable of receiving nourishment
+from water instead of earth. I remember seeing an instance of this in
+the case of a laurel bush which grew near a well in our garden. We had
+occasion to examine the water, and found that the laurel had thrown
+down its roots below the surface, where they grew luxuriantly, finely
+subdivided, of a delicate ivory white, owing to the absence of light,
+and more than a yard in length. They had adapted themselves to the duty
+of absorbing water only, but had we replanted them in earth they would
+have withered, from their unfitness to take up the hygroscopic water of
+which I have already spoken. On the other hand, if the seeds of a plant
+formed to live in the water, such, for instance, as the water-lily, are
+sown in ordinary soil, they adapt themselves to the new conditions,
+and are able to live on the hygroscopic water they find around the
+particles of earth.
+
+[Illustration: CREEPING GRASS.]
+
+Some plants send out a horizontal stem (culm) along the ground, with
+a bud and some roots growing out of it at regular intervals. Each of
+these joints (or nodes) takes root and forms a separate plant. What
+are called strawberry runners are stems of this kind, and so are the
+creeping stems of _Potentilla reptans_.
+
+[Illustration: POA BULBOSA.]
+
+I once found a plant of the latter growing on a low wall, and, as I
+imagine, because it desired to reach the ground and root itself there,
+it had thrown down a stem a yard and a half long with eight young
+plants growing upon it at intervals ready to form so many colonies
+when they should reach the ground.
+
+One may frequently find stems of various grasses running along the
+ground, and taking root at each joint. I have one such spray in my
+herbarium, with twelve young plants upon it at regular intervals.
+
+Some plants store up nourishment in their roots, as may be seen in one
+of our common seaside grasses (_Poa bulbosa_); this soon withers after
+flowering, and becoming uprooted, its bulbs, which are like small round
+cheeses strung together, may be seen blowing about in the wind.
+
+With such a provision as this, the parent plant is able to bear
+extremes of cold and drought.
+
+It is well for us that plants have this power of storing up their food
+underground, for to it we owe such useful tubers as the potato and
+Jerusalem artichoke.
+
+One of our native plants, the earth-nut (_Bunium flexuosum_), has a
+single round tuber which is eatable when roasted, and is often dug up
+by children. Long ago, when England was liable to famines, even this
+small tuber was valued as a means of eking out the labourer’s daily
+meal. It is worth while to examine the curious divided tubers of some
+of our common orchises, such as the spotted orchis (_O. maculata_), or
+the meadow orchis (_O. morio_). The tuber which produces the leaves and
+flowers withers away at the end of the summer, but it leaves behind it
+a second tuber in which is stored up the nourishment required to enable
+it to bring forth leaves and flowers in the following spring.
+
+Tubers are in reality underground stems which have thickened into
+rounded balls to contain plant food.
+
+[Illustration: LILY BULBILS.]
+
+If we examine a potato we shall see that it contains true buds in the
+little hollows on its surface; these are called “eyes,” and each of
+them if sown in the ground will produce a new potato plant. If a potato
+is left in a damp cellar, each of these eyes will send out a stem, thus
+proving that the “eye” has the nature of a bud. If we cut the potato in
+half we shall see it is of an even substance mainly composed of starch,
+but if we halve an onion it will be found to consist of rings or
+layers of a thick fleshy nature, which proves it to be a bulb and not
+a tuber. The onion is like a large bud growing underground, instead
+of on a tree branch. We can prove how similar the onion and the bud
+are, by searching on a lily stem for buds or bulbils, which are often
+produced in the axils of the leaves; if we plant such a bud it will
+throw out fibres and become a bulbous-rooted plant. Some of our native
+grasses seem to have a singular power of adapting themselves to their
+position. For instance, the common Timothy grass (_Phleum pratense_),
+which usually lives by means of a fibrous root, can, if needful,
+produce a bulb which enables it to keep living in a very dry place, but
+if removed to a wet soil it returns to a fibrous root. Other grasses
+have been observed to alter their root-growth in the same way, adapting
+themselves to their surroundings.
+
+
++Air Roots.+
+
+These absorb the watery vapour of the air; they cannot adapt themselves
+to live in earth, but under certain conditions they can put forth other
+kinds of roots that are partially adapted for growing in soil.
+
+I may here give some personal observations about a certain _Hoya_ plant
+that came into my possession so long ago as 1855. This muchenduring
+plant lived in a hanging basket for many years, in the dry air of a
+sitting-room. Its leaves were sometimes shrivelled from lack of water,
+and it never had vigour enough to produce flowers. At last, after
+enduring this life for twenty years, it was placed in a stove-house
+where the moist heat suited its requirements. Then it flowered
+charmingly, and even now is showing a further degree of enterprise
+by growing a bunch of fibrous roots at the end of one of its stems. I
+imagine it intends to plant itself into another pot standing near. I
+am watching it with much curiosity, because if it does this, the old
+plant will prove that it has a high degree of intelligence, and that
+although it remained quiescent for so many years, it was only from lack
+of opportunity to do more than quietly endure its privations.
+
+In tropical countries, some plants and trees such as _Monstera_ and
+_Philodendron_ send down slender aerial roots called lianes, many
+hundred feet in length.
+
+In the Aëroid House at Kew, I remember seeing these lianes coming down
+from the roof of the house in search of water and earthy nourishment.
+It seemed like actual intelligence that directed these roots to a tank
+of water twenty-five feet distant from their starting-point above.
+Whilst we are considering this subject, I may mention the curious root
+action of a kind of fig-tree growing in the tropics which is sometimes
+known by the name of the “Murderer.” Its seed often falls, or is
+dropped by birds, amongst the leaves in the head of a palm-tree, there
+it begins to grow and forms root after root, gradually descending the
+stem of the tree and clasping it so tightly that at last the palm is
+strangled and falls to the ground carrying its destroyer with it, where
+it roots and grows into a tree.
+
+
++Parasitic Roots.+
+
+As in human society there are thievish characters who live by preying
+upon their neighbours, so in vegetable society we find quite a number
+of different plants growing at the expense of others, inserting their
+roots into the stems and roots of trees instead of drawing their
+nourishment from the ground. Careful distinction must be drawn between
+such plants as ivy, virginian creeper, clematis, lichens, &c., which
+simply grow and climb on the bark of trees, and the true parasites
+which are nourished by the juices of the trees and plants into which
+their routs penetrate.
+
+[Illustration: CLOVER DODDER.]
+
+Some plants are only partially parasitic, such as the cow-wheat
+(_Melampyrum_) and the yellow rattle (_Rhinanthus_). These represent
+a very deceitful kind of growth. To all appearance the plants are
+getting an honest living, the leaves are perfectly green and capable of
+performing all the duties of leaves, and yet, if we remove a little of
+the soil the plant will be found to be attached to, and growing from
+the roots of some strong kind of grass, and is deriving its nourishment
+from the food collected by those grass roots.
+
+Yellow rattle grows abundantly in undrained marshy fields, where it
+is easy to obtain the plant, so as to examine its mode of growth. We
+may then go on to a clover-field and seek for that true parasite and
+most troublesome enemy to the farmer, the clover-dodder (_Cuscuta
+trifolii_). Its seeds are frequently mixed with the clover, and when
+sown they germinate on the surface, but the little thread-like stem,
+instead of entering the ground, feels about in the air until it reaches
+a young clover-plant. It soon clasps its victim with its fast-growing
+stem; as the clover grows the dodder coils around it and is carried
+away from the ground.
+
+As the wiry stem gains strength, it developes a series of suckers that
+eat into the clover stem and rob it of the food it has collected; it
+lives, flowers, and grows at the other’s expense. The rate of growth
+of the dodder exceeds that of the clover, so that the latter is both
+exhausted and choked by its snake-like enemy.
+
+I once sowed a patch of flax in a garden, and not knowing that it too
+had a parasitic enemy, I was greatly puzzled to find quantities of
+pinkish threads growing out of the flax stems. These threads bore round
+bunches of tiny flowers. All this was very pretty and interesting, but
+it resulted in my patch of flax becoming a mass of interlacing threads
+and dying a miserable death, fairly strangled by the flax dodder.
+Another species of _Cuscuta epilinum_, grows on furze and also on
+heather, it having the twine-like stems by which dodder may readily be
+known.
+
+We are all familiar with the mistletoe, its leathery leaves and its
+white berries.
+
+This plant grows out of the branches of poplar, hawthorn, and apple,
+and very occasionally upon the oak.
+
+In France and Belgium the custom of bordering the fields with single
+rows of Lombardy poplars seems to favour the growth of mistletoe, for
+its large green bunches form quite a feature in the landscape, and
+cannot fail to be observed by the traveller as he journeys in the
+railway train. I have been told that mistletoe is sufficiently abundant
+to be used in Normandy as cattle-food.
+
+If a mistletoe-berry is gently pressed upon a young branch of an
+apple-tree, its own viscid juice will cause it to adhere, and before
+long it germinates and sends its roots into the tissues of the tree; as
+it grows, it fuses with them, and derives all its root nourishment from
+the substances in the branch. Of course the tree is weakened by this
+parasite, the sucking roots of which disturb the flow of the sap; woody
+knots are apt to form, and not unfrequently the branch is killed by the
+intruder which has fastened upon it.
+
+Having touched upon the four principal kinds of roots, we will now take
+a single root-fibre and examine it more closely. It seems scarcely
+possible that such a brittle, feeble thread should be able to penetrate
+into the ground and make its way amongst stones and sharp-edged
+fragments of earth without being bruised or torn. The chief friction
+is borne by the growing-point, and this always has for its protection
+a root-cap; the section of the growing-point of root-fibre given in
+the plate shows the outer skin, called the epidermis, and over that
+is the root-cap shaped like a thimble formed of small cells. As they
+are worn away outside and become dead tissue, owing to friction with
+the soil, the cells are constantly being renewed from within. The root
+is thus enabled to grow and perform its part in maintaining the life
+of the plant. The presence of this root-cap and the absence of leaves
+are the marks by which a true root is known and distinguished from an
+underground stem. With a small lens one can see this extinguisher-like
+cap protecting the extreme point of the root, and it is well to examine
+a variety of specimens, and see how they differ slightly in size and
+shape.
+
+[Illustration: SECTION OF ROOT CAP.]
+
+The one especial office of the root is to absorb liquid nourishment
+from the soil for the benefit of the plant, and, as I have already
+explained, this is done mainly through the hairs which grow upon the
+fibres of the roots. For instance, there is no absorption in old
+tree-roots, such as we sometimes see above the ground, nor in carrots,
+turnips, and parsnips, but thrown out from such bulbous plants are
+the fibres and their hairs which enable them to grow to maturity. We
+may naturally inquire how the solid materials in the soil, which are
+needful to the growth of the stem and leaves, can possibly be taken up
+by these extremely minute hairs.
+
+We may look upon the earth as being a sort of storehouse of
+indigestible, unprepared plant-food which must be altered in its
+character before it will be fit for absorption by the roots. Some
+substances, such as sugar, will readily dissolve in water; others,
+such as starch and sand, are insoluble, but the effect of rain-water
+and atmospheric air passing through the soil, converts this insoluble
+dormant food into soluble active food.
+
+The root-hairs convey this food to the small fibres, and through them
+as channels it passes on to larger ones, until it reaches the stem and
+goes to feed the growing leaves and flowers.
+
+In order to remain in a healthy state, roots must absorb oxygen gas,
+and for this reason gardeners, when they find the soil growing caked
+and hard on the surface, dig and rake the flower-borders in order that
+air may freely permeate the soil and find access to the roots of the
+plants.
+
+Roots appear to be endowed with certain remarkable attributes, about
+which learned books have been written of late, giving the result of
+patient investigation as to their power of movement, the way in which
+they are affected by gravitation, the influence of light, and other
+forces.
+
+The experiments of Darwin and other scientists have revealed very
+singular facts about the movements of plants. The term used to describe
+their motion is one we must learn, as it frequently appears in
+botanical works. Circumnutation we may translate as wavering around,
+and it well describes the curious way in which rootlets, for instance,
+are always moving slowly from one side to the other, describing a kind
+of oval zig-zag track through the earth. The fibres appear to have
+a discriminating power, enabling them to choose convenient crevices
+through which to penetrate hard soil, to avoid stone, and to seek out
+any attractive food which lies in their way.
+
+As soon as roots emerge from the seed they at once turn from the
+light and seek to bury themselves in the earth; the plumule from
+which the leaves will spring has exactly the reverse tendency, and
+invariably seeks the light and grows upwards. This can be proved by
+growing some mustard seeds on a piece of flannel about the size of a
+shilling, floating it on water in a saucer exposed to light from a
+single window; as soon as the leaves appear, they will lean towards the
+light, whilst the roots will point towards the dark part of the room.
+If a germinating seed is even placed with the root uppermost, and the
+plumule pointing downwards, it will very speedily right itself, the
+stem will turn and grow up, and the root will seek the ground.
+
+The amazing strength of growing tree roots can be imagined when we
+watch a tree in full leaf during a high wind. As the terrific force of
+the gale sways the trunk backwards and forwards the roots are subjected
+to an enormous strain. Like great india-rubber cables they give and
+retract, and when the wind subsides we find the trunk as rigid as ever.
+
+If my readers will seek for the specimens enumerated below, and compare
+them with the remarks made in this chapter, they will have such a
+general idea of the functions of roots as will, I trust, enable them
+to enjoy the study of more advanced works upon the subject.
+
+Specimens to be obtained and compared with the descriptions in this
+chapter:—Sedge or marrem grass growing on a sandy sea coast; plants
+growing between layers of stone; tree roots at the edge of a pond;
+strawberry runners; a plant of _Potentilla reptans_; creeping grasses;
+_Poa bulbosa_ roots from the seaside; potato. Earth nuts; lily bulbils;
+Timothy grass; cow-wheat (_Melampyrum_); yellow rattle (_Rhinanthus_);
+clover dodder (_Cuscuta trifolii_); flax dodder (_Cuscuta epilinum_);
+mistletoe. Root fibres of various plants. Mustard seed sown on flannel.
+
+
+
+
+CHAPTER III
+
+_TREE STEMS_
+
+ “If thou art worn and hard beset
+ With sorrows, that thou wouldst forget,
+ If thou wouldst read a lesson, that will keep
+ Thy heart from fainting and thy soul from sleep,
+ Go to the woods and hills! No tears
+ Dim the sweet look that Nature wears.”
+
+ +Longfellow.+
+
+
+
+
+CHAPTER III
+
+TREE STEMS
+
+
+A walk through a wood on a bright day in February will afford us many
+interesting intuitions about the growth of trees.
+
+We are apt to think of winter as a dead season, and long for summer
+days once more, that we may pursue our botanical studies; but as soon
+as February begins there is already a secret work going on within the
+tree-stems, the sap is rising from the roots, and this ascent is easily
+to be traced if we look carefully at the trunks of those trees, such as
+the oak, elm, and others, which have rugged bark. The wood within is
+swelling; fresh layers of material will, a little later on, be added to
+the inner side of the bark as a result of this ascent of the sap.
+
+As the bark is hard and inelastic, it cannot expand in proportion, and
+therefore has to crack and split in yielding to the internal pressure.
+If we look for these fresh cracks, we shall see the clean new bark
+within, which, before long, will harden and become of the same shade of
+grey as the rest of the stem.
+
+[Illustration: TURKEY OAK BARK.]
+
+It is at this season, too, that the plane-tree sheds off its fragments
+of bark in greatest quantity, as one may plainly see in the London
+squares, where this tree grows so remarkably well. Its stem is always
+peeling more or less throughout the year, and possibly that fact may be
+one of the reasons of its flourishing so well in the midst of smoke and
+fog.
+
+[Illustration: SCOTCH FIR BARK.]
+
+Trees shed their bark in many different ways.
+
+A reference to the illustrations will show the concentric rings of the
+horse-chestnut, the square pieces of the sycamore, which are due to
+the cleavage being both vertical and horizontal, the hexagonal shape of
+the divisions of the Scotch fir, the rugged bark of the Turkey oak, the
+sycamore and other species.
+
+[Illustration: SNAKE-BARK MAPLE.]
+
+Where a woodpecker or a nuthatch has bored a hole into the living wood
+of a tree-stem, it is interesting to watch how the injury is repaired.
+New bark begins to form at the edges of the wound, and to this a layer
+is added each year, until at last the hole is filled up, and only a
+scar is left to show where it once existed.
+
+[Illustration: +TURKEY OAK STEM+ (_struck by lightning_).]
+
+I have been able to watch this repairing process going on for twelve
+years in the case of a Turkey oak, which was injured by lightning. I
+was watching the progress of the storm from one of our upper windows,
+and happened to be looking at this particular tree in the park, when
+out of a lurid cloud above it, a streak of forked lightning descended
+upon the tree, and rent off the bark of one side from the top to the
+bottom, carrying away portions of it to a distance of fifty feet or
+more, leaving a white gash which looked pitiful enough for many months.
+Year by year a wave of new bark rolls on, covering the bare place by
+slow degrees, but it is never destined to be quite healed in this case,
+for the inner wood was killed to some extent by the lightning, so it
+has become a home for the boring beetles, who are riddling it with
+holes wherein to lay their eggs.
+
+[Illustration: PLANE-TREE BARK.]
+
+[Illustration: HORSE-CHESTNUT BARK.]
+
+Such a tree becomes a happy hunting ground for the woodpecker, who is
+attracted by the insect diet he finds there. The large holes he makes
+in getting at his prey will let in the rain, so that after a time the
+moist rotten wood forms a suitable place for various fungoid growths,
+and all these agencies work together for the destruction of the wood
+until the tree becomes a hollow stem, and the leafage above is solely
+produced by the sap carried upward by the bark.
+
+[Illustration: WHITE POPLAR BARK.]
+
+[Illustration: SYCAMORE BARK.]
+
+Let us inquire a little more carefully into the formation of a
+tree-stem, and the different parts of which it consists. Some rather
+hard names are given to the four principal parts of a tree trunk but,
+by reference to the plate, and by knowing the meaning of the names,
+I hope they will soon be mastered, and then our future walks in the
+woods will be fuller of interest than ever, when once we understand
+something about the hidden work that is being carried on in those grand
+old trunks around us. A tree may be compared to a large manufactory. As
+we stand outside the building we see the brick walls and the roof, and
+smoke is coming out of the chimneys. We know that a great deal of work
+is being done inside, and carts are leaving its doors laden with the
+products of the machinery within, but how the work is done we cannot
+tell from the outside. We perhaps desire to obtain this knowledge, and
+under the guidance of the manager, we are taken from room to room and
+see the marvellous processes by which raw material is converted into
+exquisite fabrics, or it may be clay is turned into priceless china
+or porcelain. We leave the building full of wonder at the things we
+have seen, and those particular manufactures will ever afterwards be
+invested with a special interest for us, because we have seen with our
+own eyes how they are produced.
+
+[Illustration: TREE-FERN BARK.]
+
+Just in the same way we shall look upon trees in a new light, if we are
+able in some measure to follow the processes nature is carrying on in
+them year by year so as to ensure the foliage, flower, and fruit, which
+minister so much to our pleasure and profit.
+
+The four names we must learn about in order to understand the
+formation of wood are these. First the outer bark, called epidermis,
+from two Greek words _epi_ upon, and _derma_ the skin. _Cortex_, a
+Latin word meaning bark. Fibro-vascular bundles; this long phrase
+refers to certain threads or fibres which exist in stems and give
+them toughness and elasticity. From such fibres in the flax plant we
+obtain linen, and from the hemp fibres ropes are made. _Fibro_ comes
+from the Latin _fibra_, a thread or fibre; and _vasculum_ is Latin
+for a little vessel; we know the word better, perhaps, in another
+sense as _vasculum_, the tin box in which botanists place their plant
+collections.
+
+These thread-like vessels are well called bundles, because they exist
+in little masses in the substance of the stem.
+
+Most young people know what is called King Charles’s Oak in the stem of
+the brake fern, so plainly seen when it is cut across with a penknife.
+The dark markings are the ends of the fibro-vascular bundles which
+happen to resemble an oak tree in form, though some think them more
+like an eagle with outstretched wings, so the fern is named _Pteris
+aquilina_, from _aquila_, an eagle.
+
+The fourth word is pith, the white substance in the centre of the stem,
+which can readily be seen by dividing a piece of elder branch, when the
+middle will be found full of white pith.
+
+When we have these four parts of the stem clearly in our minds it will
+be possible to go on with our study and learn about the spaces between,
+which are filled with different kinds of cells.
+
+The honey-comb formed by bees consists of small cells, little hollow
+spaces in which they store the honey or bee-food. Woody structure
+consists largely of cells of various shapes to contain sap and other
+substances. A beautiful specimen of cell net-work may be obtained
+by placing a thin slice of either white or yellow water-lily stem
+on a piece of glass and, holding it up to the light, a fine sort of
+lace-work will be seen. These are the cells which convey air and water
+through the stem up to the leaves and flowers. Or if we examine a
+flower petal with a magnifying glass we shall find it to be entirely
+composed of minute cells.
+
+[Illustration: STEM OF YELLOW WATER-LILY.]
+
+[Illustration: STEM OF WHITE WATER-LILY.]
+
+In these little spaces are stored very many and very different
+materials, all necessary to the growth of a tree; we shall try and
+learn about them by degrees; at present we must endeavour to obtain a
+clear idea of their structure.
+
+A tree-stem increases in size yearly by the growth of fresh cells
+within the outer bark, and this active increase of tissue is due mainly
+to what is called the cambium layer, which is developed only in the
+spring and summer and does not exist in winter; it forms bast, or
+phloëm, on the outer side next the bark, and on the inner side next the
+pith it creates woody tissue.
+
+Our English lime tree has a layer of fibre beneath the bark which is
+worth examination; it is the same in character, but not so wide or
+strong, as the bast which we import from Russia in mats to protect
+vegetation from frosts. Squirrels are very fond of this soft material;
+they strip it cleverly off the branches of our lime trees to form a
+warm lining for their nests.
+
+It is easily found by cutting the outer bark off any small branch of
+lime within reach, when we can peel off the inner layer of bast, or
+phloëm, as botanists call it.
+
+The phloëm from the lace-bark tree of the West Indies is like the
+finest possible net-work, and is used for many ornamental purposes.
+_Liber_ (Latin for the inner rind of a tree) is another term applied to
+this cell formation.
+
+The study of different forms of woody fibre will be found most
+interesting.
+
+I obtained one of my best specimens of it by placing a very old Swedish
+turnip in water for some months until the soft parts had melted away
+and only the round ball of fibre remained. If any one wishes to follow
+my example I would suggest placing the turnip and its pan of water in
+some outhouse where its perfume will not incommode any one. A maid
+came to me one day with a sad account of a fearful smell which had
+been noticed for some time in a lumber-room at the top of the house,
+and very naturally she thought that the plumber should be called in
+to remedy the evil. I had almost forgotten my interesting skeleton,
+but in due time I traced the odour to its right cause, and the turnip
+was banished to a distant spot, where many washings and some soaking
+in chloride of lime changed it into a really beautiful specimen of
+woody fibre. I possess now only a quarter of it, for botanists have so
+earnestly begged for pieces of it that I have been persuaded to share
+it with them.
+
+I have sometimes picked up on the seashore old cabbage-stems bleached
+to a delicate ivory white, forming really beautiful instances of woody
+fibre. These we can prepare for ourselves, if desired, by soaking the
+stems in water until they can be brushed perfectly clean, and then
+bleached by mixing a little chloride of lime in water and letting them
+soak in it till they are white and free from odour.
+
+In a manufactory there must of necessity be a series of windows on
+the different floors, not only to let in light but for purposes of
+ventilation. Now, the processes of tree-growth are carried on without
+light in the stem, but air is necessary, and it is supplied by means
+of small apertures called lenticels. These are not open holes, but
+are more like gratings which admit a small amount of air through
+loosely-packed cells.
+
+These lenticels are the small brown specks which may be traced in
+great numbers on the young branches of almost any tree. They remain
+open through the spring and summer, admitting the needful air to the
+interior of the bark, but when the tree-growth is over for the season,
+and air is no longer needed, a layer of cork forms within the lenticel
+which entirely shuts it up and keeps out the wintry cold. Thus it
+remains sealed up till, by the growth of the cambium layer in the
+following spring, the corky barrier is split open and air is again
+admitted.
+
+These lenticels are nature’s ventilators, opening and shutting in this
+curious way in order that the manufacture which is going on beneath the
+bark may receive from the outer air the various gases essential to the
+work which is being carried on within.
+
+I have said that many and various things are stored in the stem-cells
+of trees. It would occupy too much space to attempt to make anything
+like a complete list of the liquids and solids which are obtained from
+trees, but I will enumerate a few of those with which we are familiar
+from their usefulness in every-day life.
+
+Turpentine is obtained from various kinds of firs—the Scotch fir,
+larch, and others. Burgundy pitch from the spruce fir. A kind of tar is
+also prepared from Scotch fir and larch. From various kinds of cinchona
+we obtain quinine, so valuable as a remedy for fever. Camphor is a
+product of a Chinese tree. Tannin, by which skins are converted into
+leather, is obtained from the bark of the oak-tree. A kind of sugar is
+made from the sap of the maple, which is largely used in America. Gum
+arabic and a great number of gums used in medicine are produced by
+foreign trees of various kinds. The interior pith of a West Indian palm
+tree produces the sago of commerce.
+
+Stems, like every other part of a plant, are to be seen in endless
+variety when we come to examine them for ourselves. In common garden
+plants such as the calceolaria and petunia, the consistence is soft,
+and such stems are known as herbaceous; these generally die down in
+autumn. Roses and rhododendrons have stems of a harder and more rigid
+character, and seem to be intermediate between the soft herbaceous
+stems and tall tree trunks.
+
+If in some country ramble we resolve to make the trunks and bark of
+trees our study, we shall find much that is interesting and well worthy
+of observation.[7]
+
+[7] For instance, I have noticed some curious examples of trees growing
+together. A Turkey oak and Silver fir in my own grounds are closely
+united at the base. The fir-seed and the acorn must have germinated
+in such close proximity that the stems have almost grown into each
+other. The group of beeches shown in the plate gives another example of
+interlacing stems and roots.
+
+[Illustration: GROUP OF BEECH-TREES WITH INTERLACING STEMS AND ROOTS.]
+
+The Lombardy poplar, with its tall bending stem, the graceful willow
+and the silver birch, contrast strongly with the thick and sturdy
+trunks of the elm and oak. Even these two differ, the wood of the elm
+being short and brittle, whilst that of the oak is hard and flexible.
+Again, we may note the slender drawn-up stems of trees growing thickly
+together in a wood, where light and air are in a measure shut out,
+and compare them with other specimens standing in a park in free air
+and light. There we see trees, growing as nature intended, with grand
+sturdy trunks and welldeveloped branches spreading out on all sides.
+Lastly, in this chapter, we may note the climbing stems; these are
+especially numerous and diversified in their manner of growth. Almost
+every part is modified and adapted to assist the stem to climb. The
+common ivy develops upon the surface of its stem numerous rootlets, and
+by their clasping nature the ivy is enabled to ascend the smoothest
+tree-trunk. The hop and the convolvulus climb by means of their habit
+of twining around some rigid stem or twig. Then the peas and vetches
+send out little clasping tendrils in the place of leaflets, whilst that
+lovely ornament of the hedges—traveller’s joy—climbs by occasionally
+using the leaf stalk for a clasping holdfast. Not less interesting are
+the plants that climb by means of their hooks; the common bramble is
+of this kind; it scrambles over the hedge in a very enterprising and
+aggressive manner, while its spines and hooks effectually prevent it
+from slipping back.
+
+[Illustration: CONVOLVULUS.]
+
+A very highly developed organ of climbing is that to be found upon
+the stems of the small Virginian creeper (_Ampelopsis Veitchii_). On
+the points of its small tendrils we shall discover little globular,
+crimson-coloured pads, which, when pressed against a tree or wall,
+secrete a kind of vegetable glue. This fixes the tendril and enables
+the weak slender stem to climb upwards. In these instances, as well as
+others mentioned earlier in the chapter, we have again evidences of how
+wonderfully plants are adapted to their wants and environment.
+
+Things to observe and collect:—The various ways in which trees shed
+their bark; how trees repair holes in the stem; fibres in flax stem and
+in hemp; specimens easily obtained by sowing linseed and hemp-seed;
+section of brake-fern stem; section of elder stem; thin section
+of white or yellow water-lily stem; flower petal; piece of bast
+matting; West Indian lace-bark; turnip and cabbage stalk prepared as
+specimens of woody fibre; lenticels on various trees; suitable leaves
+for skeletonising—holly, magnolia, tulip-tree, pear, poplar, aspen,
+mahonia, plum and maple; suitable capsules—poppy, stramonium, henbane,
+winter-cherry, campanula, and the calyces of the yellow-rattle.
+
+
+
+
+CHAPTER IV
+
+_LEAVES_
+
+ “These naked shoots
+ Barren as lances, among which the wind
+ Makes wintry music, sighing as it goes,
+ Shall put their graceful foliage on again,
+ And more aspiring, and with ampler spread,
+ Shall boast new charms, and more than they have lost.
+ Then each, in its peculiar honours clad,
+ Shall publish even to the distant eye,
+ Its family and tribe.”
+
+ +Cowper.+
+
+
+
+
+CHAPTER IV
+
+LEAVES
+
+
+We have learned in the previous chapters that the roots are the means
+by which a plant gathers out of the earth the various constituents
+which are needful to maintain its life.
+
+The leaves have also to do their part in collecting from the air such
+gases as are required to effect the processes carried on within the
+substance of the leaf.
+
+The leaf is really the digestive organ of the plant; it feeds,
+breathes, and gives off in the form of vapour any excess of water
+not required for its work. For these purposes sunlight and air are
+necessary.
+
+A leaf consists of a stalk, called a petiole, and the flat green part,
+which we may call the blade.
+
+If we hold a leaf up to the light we see a network of veins, and it is
+by their help the leaf becomes a broad expansion of tissue, so exposed
+that it gets the fullest possible benefit from the sunlight and air.
+This fibrous network gives strength to the leaf, and answers to the
+bones in animal structure.
+
+[Illustration: NETTED VEINS.]
+
+The fibro-vascular bundles, which we see in the stem, go up through
+the petiole, and branch out in a beautiful and regular manner. We may
+observe this arrangement very clearly in a skeleton leaf, the midrib
+forming a backbone to the whole structure, while the smaller veins tend
+off to the edge of the leaf, and then overlap so as to form a system of
+girders supporting the edge, and preventing the wind from tearing the
+delicate tissues into shreds.
+
+The arrangement of leaf network is called venation, and by a glance at
+it we can at once see to which of the great divisions in botany a plant
+belongs. If the fibres are straight and run parallel to each other
+without being netted, then we know the leaf is that of a plant which
+begins its life with only one seed-leaf; such are all the species of
+corn and grass, bulbs, palm-trees, bananas, and others.
+
+The long name applied to this division of plants must be explained, as
+it is a term we cannot do without, and I must own it looks formidable
+until we understand its meaning.
+
+[Illustration: MONOCOTYLEDON.]
+
+The first leaf that comes out of a seed is called a cotyledon, from
+_kotúle_, a cavity, or cup. The Greek for one is _mónos_, so plants
+with one seed-leaf are called monocotyledons.
+
+If we sow a date-stone or a few seeds of Indian corn in moist soil they
+will grow readily, and afford us nice little specimens of a one-seed
+leaf-plant.
+
+If we see that a leaf has netted veins, then we know its seed produced
+two leaves at first,[8] so plants belonging to this great division are
+called dicotyledons.
+
+[8] The Maranta and a few other plants are exceptions to this rule.
+
+[Illustration: DICOTYLEDON.]
+
+In order to watch the growth of two-leaved seedlings, we may select a
+broad bean, or some of the seeds out of tamarind jam; either will grow
+readily in a pot of earth, if it is placed in a sunny window, or near a
+stove, and kept moist.
+
+Orange and lemon pips may sometimes be found sprouting within the
+fruit, and either of these seeds will germinate, and form charming
+little evergreen plants to brighten a town window-ledge.
+
+[Illustration: TAMARIND SEEDLING.]
+
+Now we need not be afraid of those two long words which are used to
+describe one-leaved and two-leaved seedlings, since we know their
+meaning, and it will be interesting when we come across some new plant
+to see to which division it belongs, because knowing that will mean
+knowing a great deal besides.
+
+All our English trees (with the exception of the firs, which have
+many seed-leaves) are dicotyledons; they increase their stems from
+the outside, and are therefore called exogens, and most of our plants
+belong to this division.
+
+The monocotyledons increase from the centre, that is to say, the
+second leaf grows out of the first, and the third leaf and its stem
+grow out of the sheath of the second leaf, and so on; and this is
+the law of their growth, whether they be corn plants or palm-trees.
+These sheathing leaves and the straight veins will always enable us to
+recognise a one-seed leaf-plant at sight.
+
+The development of the stem has a marked influence upon the arrangement
+of the leaves; these, in such plants as the cyclamen, sundew, or
+primrose, are said to be radical; that is, growing from the root.
+Close observation will reveal the cause to be the non-development of
+the internodes, the leaves being crowded upon a very short, suppressed
+stem, and thus we get the beautiful little rosettes we find in the
+daisy and plantain. When the stem is of greater length the leaves
+are ranged at definite intervals, the spaces between the leaves (the
+internodes) varying in length in proportion to the size of the leaf.
+Small leaves are thus much thicker upon the tree than larger ones.
+This will readily be seen if we compare a branch of sycamore with one
+of elm, the former having its large leaves much further apart than the
+latter.
+
+Then, also, the arrangement of leaves upon the stem (_phyllotaxis_)
+varies much. If we take a spray of beech we shall find that its buds
+are placed alternately on either side of the stem, so that the third
+bud is exactly below the first, and the second bud is in a line with
+the fourth, and so on. This is also the plan of the elm, hazel, lime,
+hornbeam, and many other trees. In the alder and whitebeam the buds
+occur in three rows, and in some of the willows in series of eight.
+
+The leaves of the horse-chestnut are borne in pairs on alternate sides
+of the stem, and this plan is common to a number of plants, especially
+those of the type of the dead nettle and speedwell.
+
+Quite a distinct arrangement is that to be found in the woodruff and
+bedstraws, where the leaves are placed in a ring (a whorl) at regular
+intervals on the stem.
+
+The botanical student should carefully observe the differing methods
+of leaf arrangement, since, as branches are developed from buds, the
+varying order in their position must naturally modify the general
+aspect of a tree, and has also much physiological importance. We shall
+find that buds are so placed that each leaf shall receive its full
+share of sunlight and air, for it needs this position in order to
+enable it to carry out the wonderful work of assimilation which it has
+to perform.
+
+The upper surface of a leaf is covered by a thin layer of cells, known
+as the epidermis (or skin); this does not prevent the light from
+falling through, and its outer surface is protected by a thickening,
+known as the cuticle. This is of great use in controlling the escape of
+moisture, otherwise the leaf would soon shrivel up in a hot sun. In a
+young seedling leaf the cuticle is not developed, and it can therefore
+breathe out moisture very rapidly; later on, when the cuticle is
+formed, it controls the escape of moisture, which can then only exude
+through the under surface of the leaf.
+
+We can easily peel off a portion of the skin from the under surface
+of the leaf, and if we place it in a little water between two pieces
+of glass and look at it in a microscope we shall see that it consists
+of an extremely thin layer of cells, with numbers of little openings
+called stomata (from the Greek _stoma_, a mouth), answering somewhat
+to the lenticels to be found in young tree-stems, only those are solely
+for the admission of air, while these little mouths are to let in and
+out not only air, but water, vapour, and oxygen.
+
+These stomata look like little crescent-shaped slits with a curved cell
+on either side, and as they curve more or less, the mouths are opened
+or shut as the plant may require. These little mouths play a very
+important part in the economy of the leaf, and they exist in immense
+quantities on its under surface.
+
+[Illustration: STOMATA.]
+
+It has been calculated that a million stomata exist on a single leaf
+of the lime tree. When the root has taken up more moisture than is
+required, then it is the office of these pores, or stomata, in the
+leaf to give out this extra water in the form of vapour, and we can
+thus see how the action of leaves must influence climate. If forests
+are recklessly cut down, the bare country, with no foliage to throw
+moisture into the air, may become an almost barren desert, and again
+in marshy places, where the air is too damp, a wise reduction in the
+number of trees may alter the climate to a healthy condition.
+
+Remarkable results have been obtained by planting the Australian
+gum-tree, _Eucalyptus globulus_; it thrives well in malarious places,
+and at once produces a marked hygienic change in the air. A Monsieur
+Gimbert relates that “A farm some twenty miles from Algiers was noted
+for its pestilential air, and in the spring of 1867, 13,000 eucalyptus
+trees were planted there, since which time not a single case of fever
+has occurred.
+
+“The gum-tree grows rapidly and absorbs as much as ten times its weight
+of water from the soil, and emits camphoraceous antiseptic vapour from
+its leaves. It is therefore often called the fever-destroying tree.”
+
+Experiments have been made to try and find out how much moisture is
+really given out by leaves. It was found that a sunflower three and
+a half feet high, with a leaf expanse of over five thousand inches,
+exhaled one pint of liquid in the course of the day.
+
+No wonder, therefore, that trees tend to make the air damp.
+
+Each stomate leads into air spaces between the cells, and is thus
+connected with the interior of the leaf.
+
+[Illustration: LEAF SECTION.]
+
+The tissue and cells of a leaf (bifacial)[9] can be understood by
+reference to the accompanying diagram. Between the upper and under
+surfaces of a leaf there is a layer, more or less thick, of soft green
+tissue known as _mesophyll_, and if we hold a leaf to the sunlight we
+shall see the veins traversing this tissue.
+
+[9] That is, a leaf like the beech or sycamore, having an upper and
+under surface; vertical leaves, like the iris, have palisade tissue on
+both sides.
+
+The upper part of the mesophyll consists of elongated cells arranged
+at right angles to the surface, and placed so evenly parallel to each
+other that they have been compared to the pales of a fence, and are
+called palisade tissue. These cells contain a quantity of the green
+substance called _chlorophyllon_ (from _chloros_, green, and _phyllon_,
+a leaf), so named because to this bright green substance we owe all the
+lovely verdure of our woods and gardens.
+
+Below this palisade tissue is another of quite a different form,
+consisting of large spongy cells, and therefore known as spongy tissue.
+
+In its intercellular spaces are stored those secretions which make
+certain herbs, such as thyme, marjoram, and others so fragrant when
+bruised.
+
+The chemical changes which are ever going on in these various layers,
+require a constant supply of the outer air, and this is secured by the
+little openings, called stomata, on the under surface of the leaf,
+which have been already described; these constitute the breathing
+apparatus of the leaf, for they open and shut, and regulate the
+supply of air into little air chambers, from which it passes into the
+structure of the plant.
+
+Before going any further I must try and explain a little about the
+wonderful substance called protoplasm.[10]
+
+[10] Greek: _proto_, “first”; _plasma_, “anything moulded.”
+
+If we have ever watched a potter at work, we know he takes a lump of
+clay and moulds it according to his purpose, into a rough pot, or a
+lovely vase; now protoplasm seems to be just such a foundation material
+from which the Divine Creator causes animal and vegetable forms to
+proceed. _First material_ seems to me to be a term that actually
+expresses the meaning of the word protoplasm.
+
+It lines the cell walls of leaves, it is capable of forming fresh
+cells, it can absorb moisture and other matters, it contracts and
+expands, it has power of movement, as one may readily see when a
+portion of a leaf is placed in a microscope, so as to show the grains
+of bright green chlorophyll circulating in the lining of each little
+cell.
+
+Learned volumes would be needed to explain the nature of protoplasm, so
+I must be content with these simple facts about its nature, and proceed
+to the chemical action going on in leaves.
+
+In ordinary atmosphere there is a very small quantity of a gas called
+carbon-dioxide.[11] The leaves absorb this gas from the air, and
+because there is so little of it, each tree needs to spread out an
+immense amount of foliage, that it may drink in, by its means, all the
+carbon-dioxide that can possibly be obtained.
+
+[11] Carbon meaning charcoal, and dioxide meaning two parts oxygen.
+Sometimes called carbonic-acid gas.
+
+When this gas comes in contact with the chlorophyll in a leaf, one part
+of the oxygen is set free, and returns to the air in a pure condition,
+thus making it more healthy for us to breathe; then the carbon and the
+remaining oxygen combine with water in the leaf cells, and form starch,
+the leaves retain the carbon, to build up their own structure; it
+enters indeed so largely into the composition of vegetable substance,
+that in some cases if we could burn one hundred parts of it, fifty
+parts of the ashes would prove to be carbon or charcoal.
+
+In a rough sort of way we may see for ourselves how much carbon there
+is in woody fibre, by lighting an ordinary wooden match and letting it
+burn itself out; the black portion that remains will be a piece of
+charcoal not very much smaller than the original match.
+
+Of course, in the process of burning, the match has lost the resin, and
+other organic substances which were stored up in the cells of the wood;
+all these have passed into the air, and only the carbon remains. If,
+however, instead of this slow manner of combustion, we had set light to
+a whole box of matches so that it burnt fiercely, the flame would have
+been strong enough to consume the charcoal, and nothing would then be
+left but mineral ashes.
+
+When charcoal burners are at work in a forest, we may see them making a
+stack of wood, which they cover with a thick layer of clay so that the
+wood may burn away very slowly; in this case the charcoal will be left
+in the same way as when we burnt the single match.
+
+As long as the upper side of leaves are soaking in the sunlight, starch
+is being formed, as I have described; but during the night the starch
+thus formed is dissolved, and passing through the leaf fibres finds its
+way into every part of the plant, either to be used in forming new
+tissue, or else to be stored up for future use.
+
+The net-work of veins act as a service of tiny pipes, to convey the
+liquids up and down the petiole (leaf-stalk).
+
+Generally the water given off from the stomata is in the form of
+vapour; but in some plants drops of water exude from the apex or point
+of the leaf through the water pores. In _Saxifraga crustata_, there
+are pores round the edges of the leaves, through which water, highly
+charged with lime and other salts, passes out, and as it evaporates a
+white deposit of lime remains which is quite visible in the form of a
+frosted edging to the leaves.
+
+There is an American plant called the jewel-weed, which shows to
+perfection this power of distilling drops of water. I will quote a
+short description of its appearance at night-fall.
+
+“Upon the approach of twilight, each leaf droops as if wilted, and from
+the notches along the edge, the crystal beads begin to grow until its
+border is hung full with its gems. It is Aladdin’s lantern that you see
+among a bed of these succulent pale green plants, for the spectacle is
+like dreamland.”[12]
+
+[12] “Sharp Eyes,” by Wm. Hamilton Gibson.
+
+A very similar effect may be observed if we visit a plant of
+Lady’s-mantle (_Alchemilla vulgaris_) at early morning after a warm
+dewless night; each leaf will be found beautifully decked with dewdrops
+at equal distances round the edge of the leaves where the pores have
+exuded the moisture with which they are charged.
+
+Nasturtium and fuchsia may also be examined for this purpose and will
+show exudation from their leaf pores.
+
+If a small quantity of wheat is grown in some cocoa fibre, it will
+illustrate this power of giving off water, for when the little blades
+are a few inches high, they will be found each morning tipped with a
+large dewdrop, the result of exudation during the night.
+
+In countries where the sun is intensely hot, if the leaves of trees
+were to be exposed to its full power, they would probably wither, and
+vegetation would perish.
+
+[Illustration: YOUNG SHOOT OF EUCALYPTUS.]
+
+Against this danger some trees are enabled to make special provision,
+by changing the form of their leaves, and their mode of hanging on the
+branch. In Australia, for instance, where the sun is almost vertical,
+the acacias and eucalyptus trees, instead of holding their leaves flat
+or horizontally as trees do in England, so that they may catch every
+ray of sunlight, avoid the heat as much as possible, by holding them
+edgeways to the light.
+
+[Illustration: MATURE FORM OF EUCALYPTUS LEAVES.]
+
+While eucalyptus trees are young, and partially shaded by surrounding
+vegetation, their leaves are flat and oval, and English seedlings
+of this tree usually retain such leaves from five to ten years, our
+climate not being hot enough to require the mature form of leaf which
+hangs vertically, and is of an entirely different form.
+
+Reference to the plates will show a young shoot of _Eucalyptus
+globulus_ and a branch of the older leaves, with their edges only
+exposed to sunlight.
+
+The curved sickle-shaped leaves of the eucalyptus afford very little
+shade to the traveller in Australia for this reason, that only fine
+intercrossing lines of shadow are seen on the ground. To make this
+clear, let my readers take a sheet of notepaper out of doors on a sunny
+day and hold it perfectly flat, so as to expose it to all the sunlight
+it can receive upon its surface, as if it were a growing beech-leaf,
+and it will throw a large shadow on the ground. Then hold it edgeways
+to the sun, and it will form the kind of thin line of shadow that would
+be cast by a mature eucalyptus leaf.
+
+Preparation for the fall of the leaf begins in spring, when a fine
+line or ridge may be traced just below the junction of the leaf with
+the stem. This dark line is in reality a thin layer of cork, which,
+during the summer months, continues to grow inwards to form in due time
+a covering for the bare place on the stem that will be left when the
+leaf falls off; this is called the leaf-scar.
+
+It is interesting to watch this line, growing more and more visible as
+the year goes on.
+
+Another curious fact is, that some of the starch which the leaves have
+been making during the summer, becomes stored up in autumn at the base
+of the leaf-stalk, so as to afford nourishment to the bud which will
+arise out of the axil of the leaf. When a weak solution of iodine is
+applied to it, this starch turns blue, and in this way its presence can
+be ascertained.
+
+The fall of the leaf appears to take place mainly because the starch
+has the effect of softening the cells of the leaf-stalk; as it dries up
+it loses its hold of the twig, and either the wind or a slight frost
+will suffice to bring the leaves down to the ground in showers.
+
+Another reason for their fall is, that their year’s work is done. Like
+good servants, they have been hard at work all through the summer and
+autumn months, taking in stores of nourishment for the benefit of the
+tree, and giving out volumes of oxygen, so helpful for the maintenance
+of human life. They have secured and laid up sufficient nutriment
+for the development of the next year’s buds, and having done this,
+their special office being at an end, they fall beneath the tree to
+become leaf-mould, which, in its turn when fully decayed, will yield
+nourishing elements to be carried by the winter and spring rains to the
+tree roots.
+
+I might add many more useful objects which we owe to trees, and I
+commend it to my young readers as an instructive study to try and make
+out a complete list of the useful products of our English trees. I
+imagine we do not yet know all that might be obtained from them, new
+discoveries continue to reveal their value in the way of medicines;
+for instance, the crystals of the willow (called salicine) are now
+frequently prescribed as a remedy for rheumatism. Euonomine and many
+others might be included amongst the valuable gifts which nature has
+stored in the cells of tree-stems.
+
+Specimens to be obtained:—Leaves with straight veins, such as grass
+or corn, hyacinth, narcissus, or any bulbous plants; leaves with
+netted veins, such as oak, ivy, vine, &c.; monocotyledon seedlings;
+dicotyledon seedlings. Leaf-skin to be examined through a microscope,
+in order to see stomata, chlorophyll, network, and cells. Examine
+waterpores in leaves when exuding moisture. Observe shadows thrown
+by leaves held flat and edgeways to the sun. Compare young and old
+eucalyptus leaves. Observe line of cork below leaf-scars.
+
+Leaves can be made into beautiful skeletons by soaking a good many
+together in a pan of soft water until the upper and under surfaces of
+the leaves are sufficiently decayed to be easily removed by a soft
+brush; the fibre which is left can then be bleached with chloride
+of lime. When mounted with fine wire these skeleton leaves form an
+interesting group to place under a glass shade.
+
+
+
+
+CHAPTER V
+
+_BUDS_
+
+ “Oh! who can speak the joys of spring’s young morn,
+ When wood and pasture open on his view,
+ When tender green buds blush upon the thorn
+ And the first primrose dips its leaves in dew.”
+
+ +Clare.+
+
+
+
+
+CHAPTER V
+
+BUDS
+
+
+How we watch for the buds as tokens of the coming spring! We delight to
+see them daily growing larger, and opening out their leafy treasures to
+the sun.
+
+The re-clothing of the trees has always an element of wonder about it;
+the change is truly a resurrection; a few days of warm sunshine and
+gentle rain, and then the dry, dead-looking branches begin to bud and
+blossom as if by a miracle.
+
+We may, however, trace the secret of this sudden change, if we look
+back to the processes Nature was carrying on during the previous
+summer, and we may learn from her many a useful lesson of foresight and
+preparation.
+
+If during the summer we lift up the branch of any deciduous tree
+and search amongst the leaves, we shall find that the buds for the
+following year are already there, waiting to be developed in due time.
+When the leaves turn dry and sere, they fall off and leave the buds to
+be hardened and matured by the rain, snow, and frost of winter.
+
+Certain species of Turkey oak, young beeches, hornbeams in hedges, and
+other trees, appear to retain their leaves, to some extent, as if to
+protect the buds until the rising sap in spring loosens their hold upon
+the branches, and makes them fall off.
+
+The plane-tree appears to be an exception to most trees in the curious
+protection it affords its young buds. If we search for these in the
+summer or autumn, they are not to be found, for the leaf-stalk is so
+swollen and hollow at the base as to enclose the bud within it; even
+when the leaf falls off, the bud is covered by a tough outer case
+coated with resin, and within are many fur-lined scales. When these are
+removed we see the tiny leaves wrapped in silky coverings, and when the
+warmth of spring enables them to expand, their under surfaces have
+such a thick coat of down that the plane is known in some countries as
+the cotton-tree. From its fruit being in the form of hanging circular
+balls, its name in America is the button-wood. The need of this
+special protection against cold is shown by the fact that if severe
+frost returns after the leaves have expanded, they frequently shrivel
+and perish. Some Japanese maples have the same arrangement of hollow
+leaf-stalks to contain the buds.
+
+[Illustration: OAK IN WINTER.]
+
+When buds are situated at the end of a branch they are called terminal,
+and their office is to increase the length of the branch.
+
+When they grow in the axil of a leaf (that is, where the leaf-stalk
+joins the stem) then they are called axillary, and as they grow out and
+form fresh stems and leaves, the branch broadens on either side.
+
+[Illustration: OAK IN SUMMER.]
+
+Seeing that the branches of a tree thus spring from the buds, it
+follows that the position and development of the buds upon the stem,
+as we tried to show in the last chapter, have much to do with the
+ultimate shape of the tree. The development of the axil buds, as well
+as of the terminal bud, gives rise to a branched tree like the oak;
+these buds, however, are often erratic, and in some trees the terminal
+bud of the shoot is often suppressed and the axil buds grow with extra
+vigour, whilst in other instances the terminal bud grows strongly and
+the axil buds either grow feebly or are altogether suppressed. In the
+bamboos, palms, and sugar-cane we get good examples of this terminal
+bud-growth, the axillary buds being suppressed; the suckers that grow
+from the axils of the lower leaves of the palm are often evidence of
+the presence of axillary buds, although they are, as a rule, dormant.
+We are all more or less familiar with the character of ordinary forest
+trees, the rounded outline of the oak, the slender sprays of the birch,
+the spreading branches of the beech, but perhaps we may not have
+remarked how much these variations of form are due to the position
+of the buds upon the branches. We will suppose that on a winter’s
+day we are looking at the tracery of some elm-branches against the
+sky; the form of each branch shows that the terminal bud in this tree
+usually ceases to grow, and allows the lateral shoots to increase in
+length, and take its place; this produces short, twiggy branches, and
+a stem which makes a tall tree rather than a wide-spreading one. The
+horse-chestnut, again, produces its flowers in the terminal buds; this
+arrests their growth, and side shoots have to grow on instead, thus
+usually giving height rather than breadth to the tree. We may note
+the differing outline of the willow, birch, and many others where the
+terminal buds do not cease to grow, but each year continue to add to
+the breadth as well as the height of the tree.
+
+In pine-trees the buds are produced at the ends of the branches, and
+several shoots proceed from one bud.
+
+The spiral arrangement of leaves is well seen in a young coniferous
+shoot, also in the flower-bud, and especially in the fir-cone itself,
+in which an ever-varying double spiral can be traced.
+
+Loudon remarks, “The perfection of a fir consists in height rather
+than in lateral expansion; buds are produced very sparingly and nearly
+always at the extremities of the shoots. Provision is thus made for the
+upward growth of the tree more than for side expansion.”
+
+When we speak of a coniferous shrub having lost its leader, we mean
+that the terminal bud on the topmost shoot having been broken off, one
+or more of the lower branches must rise up and take its place, and
+thus lateral buds in time become terminal and grow upright instead of
+sideways.
+
+A silver fir, that I have been observing for years past, bears such a
+crop of heavy cones on its slender upper branches that the leader is
+almost invariably broken off by the weight, and the lateral shoots have
+to take its place, to the great detriment of the central stem, which is
+twisted and curved out of shape by the efforts the tree makes to repair
+its terminal shoot.
+
+In other trees, again, the unfolding of all the buds is nearly
+simultaneous, but in the fir tribe the bud which terminates the summit
+of the tree and is destined to form its leading shoot and increase its
+height is developed last; this delay seems a provision of nature for
+the safety of the most important shoot which the tree can produce,
+ensuring its height rather than its breadth, and the production of
+timber by the preservation of its permanent trunk rather than by its
+temporary branches.
+
+If a willow is deprived of the upper part of its stem and so made a
+pollard tree, it develops a bushy head of small stems which spring from
+the other buds thrown out to repair the loss of the central stem. This
+pollarding is often resorted to in order to obtain wood of the right
+kind for basket-making, and young ash trees are thus treated, so that
+slender rods suitable for hop-poles and tool-handles may spring from
+the lopped stem.
+
+When buds are found growing on any other part of a plant except those
+just mentioned, they are called adventitious buds. These may be found
+growing on the edges of the leaves of the marsh tway-blade; they also
+spring out of the flat surface of the fronds of the viviparous fern.
+
+Under favourable conditions every part of a plant will produce buds,
+and, taking advantage of this fact, florists increase their stock of
+succulent plants by putting the leaves on a wet surface, which induces
+them quickly to send out buds and roots. Such plants as begonias,
+gloxinias, hoyas, and sedums are readily increased by this mode of
+propagation. Underground stems will often send out buds, and they
+produce the underwood from the stumps of fallen trees.
+
+We are all familiar with the suckers of trees which spring up in our
+lawns and gravel paths often many yards away from the parent tree;
+these all arise from active buds on underground stems. Gardeners
+are always careful to prune away such growths at the base of their
+wall-fruit-trees, since they rob their valuable peaches, nectarines,
+and apricots of strength and nourishment. These well-named “suckers”
+spring from the common stock upon which the choice fruit-trees were
+grafted, as one may see by gathering a leaf from a sucker and comparing
+it with a peach or nectarine leaf.
+
+On the oak, chestnut, lime, beech, and other trees there are sometimes
+to be found dormant buds in the form of rounded knobs covered with bark
+and increasing in size with the growth of the tree; these, in the event
+of other buds perishing, will start into active growth and do their
+part in preserving the life of the tree.
+
+Such woody balls when found on the oak are worth examination, as when
+divested of their bark they show exquisite structure of woody fibre.
+
+The small bulbils we find in the axils of lily stems, on the
+cuckoo-flower, on _Dentaria bulbifera_, and on some species of Allium,
+are all adventitious buds, which drop off in due time and become young
+plants.
+
+They are in many respects similar to bulbs, and if we cut one in half
+and compare it with a divided hyacinth we shall see that they both
+consist of over-lapping scales. In the onion these scales are fleshy
+and succulent, but in most tree buds they are dry, hard membranes.
+
+The pear and magnolia buds are secured against wintry cold by woolly
+linings to the scales, and in the horse-chestnut they are covered with
+a kind of resin which renders them impervious to moisture.
+
+[Illustration: HORSE-CHESTNUT.]
+
+It requires a careful use of the microscope to trace all that a bud
+contains; I will therefore quote the words of a German naturalist who
+dissected a horse-chestnut bud gathered in winter, and found that it
+contained sixty flowers. It would be interesting to select a terminal
+flower-bud of this tree; by taking it carefully to pieces one might,
+with patience and using a powerful lens (or a microscope if one is
+available), see for ourselves a good deal of what the writer describes:—
+
+“Having removed the outer scales, seventeen in number, cemented
+together by a gummy substance to render the bud waterproof, I
+discovered four leaves surrounding a spike of flowers, so clearly
+visible when magnified that I not only counted the number of flowers,
+but could discern the pollen on the stamens.”
+
+The winter covering of a bud, both the inner and outer scales, are
+only a temporary protection in order to keep out moisture and keep in
+warmth, so that as the sun begins to gain power, the gummy covering of
+the bud melts and yields to the expanding pressure from within, when
+one after another the sticky scales fall off, showing the young leaves
+with their soft woolly surfaces; these leaves rapidly unfold and hang
+droopingly until the midribs gain strength enough to hold them upright.
+
+Evelyn remarked that, “As soon as the leading shoot of the
+horse-chestnut has come out of the bud, it continues to grow so fast as
+to be able to form its whole summer’s shoot, sometimes eighteen inches
+long, in about three weeks. After this it grows but little more in
+length, only thickens, becomes strong and woody, and forms the buds for
+next year’s shoot.”
+
+Buds have always been to me a most interesting subject of study; there
+is much variety of character in them, and to those who observe them
+closely they reveal in the autumn and winter what the tree is purposing
+to do in the following season.
+
+A beech-tree on my lawn bears its nuts only every second or third
+summer, and in the previous autumn I can always tell whether the
+squirrels are likely to be well off for food in the coming year, by
+observing the size and shape of the buds. Those which contain the
+flowers are round and bulky, whilst the leaf-buds are long and slender.
+
+[Illustration: YOUNG BEECH.]
+
+Embryo flowers are disposed in the buds in different ways. The
+woodsorrel is rolled into a spiral, rose-petals are placed one within
+the other, the pink is folded in five divisions, and others are pleated
+and fluted into the smallest possible space. Perhaps of all others
+the bud of the great Oriental poppy is the best example of exquisite
+packing. Early on a summer’s morning you may see its huge green hairy
+bud at the end of a stem several feet in length, and whilst you are
+looking the sepals or calyx leaves suddenly divide and fall off, the
+mass of vivid scarlet petals crumpled into a thousand folds begins to
+open out, and before long the glorious flower, which is often as much
+as seven inches across, holds itself erect in majestic beauty.
+
+Those who possess a tulip-tree will find its opening buds reward
+examination. The leaves are folded in half and bent double, a pair
+of leaf-scales enclosing each of the true leaves. One may unpack the
+entire bud until we come to leaves almost too minute to be discerned.
+
+Young sycamore-trees often have buds of large size and brilliant
+crimson colour; the foldings of their leaves are very intricate, and
+form an interesting contrast to those of the tulip-tree. Hart’s-tongue
+fern, arum, and pear leaves afford three very remarkable modes of
+folding in the bud.
+
+[Illustration: UNFOLDING ARUM LEAF.]
+
+[Illustration: PEAR LEAF.]
+
+[Illustration: UNFOLDING LEAVES OF HART’S-TONGUE FERN.]
+
+Another point of character in buds is of considerable importance to the
+horticulturist, namely, the fact that in some cases the value of the
+flowers produced varies with the position of the buds. For instance,
+the blossoms produced from the crownbud[13] of certain chrysanthemums
+are poor and pale in colour compared with those grown on the side
+shoots; the latter are therefore retained and fostered, so that from
+them flowers of the finest description may be obtained.
+
+[13] The uppermost bud of the central shoot.
+
+In cultivating fruit-trees it is found needful not only to prune away
+redundant branches which bear leaves only, but also where strong
+woody roots are promoting the growth of leaf-buds, they also have to
+be pruned, so that the check thus given to the growth of the tree
+may result in the formation of fibrous roots, which will tend to the
+production of flower-buds and a resulting crop of fruit.
+
+I have often observed that the transplantation of trees leads to their
+throwing out flowers in the succeeding year. This was notably the
+case with an avenue of deodars which had overgrown my carriage drive;
+they received a considerable check in being transplanted, but in the
+following year their branches were covered with male catkins and some
+few cones succeeded.
+
+For this reason the removal of fruit-trees is not unfrequently resorted
+to, as a means of inducing fruit-bearing.
+
+So much vigour is stored up in the bud, that it will bear being
+removed from one tree and inserted in the stem of another, within which
+it will grow and become a part of the living tree. This is one of the
+means by which we have obtained such an infinite variety of roses; the
+buds from choice species being readily made to grow upon strong briar
+stocks, and thus one may also see roses of several different colours
+blossoming on the same stem. Choice varieties of fruit-trees are
+cultivated in the same way by means of buds inserted in the bark.
+
+Having observed how flowers are arranged in the bud, we may go on to
+dissect incipient leaves and learn how they are placed.[14] We shall
+find that the frond of the hart’s-tongue fern is rolled up from the
+tip, the arum gracefully curved lengthwise. Pear leaves are rolled
+from side to side towards the middle, and so is the primrose, but the
+reverse way. Beautiful examples of curled leaves may also be seen in
+the water-lily and banana.
+
+[14] Venation.
+
+In grasses the first leaves are equivalent to budscales, and protect
+those which continue to grow from the centre, each one sheathing out of
+the previous leaf after the manner of monocotyledons.[15]
+
+[15] One seed leaf plants.
+
+The colouring of buds is one of the lovely features of spring. Seen
+against the blue of the sky, the coral red of the lime, sycamore,
+and Japanese maple buds, cannot be passed by without notice. The
+whitebeam has a beauty of its own for its buds are large and white
+with downy coverings, giving promise of the future leaves which are so
+light-coloured underneath, that the effect when they are blown aside by
+the wind is curious and beautiful. The Germans call it _mehl-baum_ or
+meal-tree, from its whitish downy leaves.
+
+The variegated vine, sometimes seen in greenhouses, has exquisite buds
+of pinkish crimson, with bright yellow stipules. By way of contrast,
+I once placed some sprays of it in a glass with twigs of purple hazel
+which are of a deep claret brown; they were not only opposite in
+colour, but curiously different in habit, the vine holding its bud
+erect, and the hazel as persistently drooping. These variations lead me
+again to remark that, to a close observer, buds will be found to differ
+much in character and to be well worthy of close attention.
+
+I will mention some trees whose buds are specially remarkable for
+beauty of form whilst unfolding. The mountain ash has very graceful
+leaves when just emerging from the bud; they show on their upper and
+under surfaces two distinct shades of green.
+
+The unfolding weigelia buds are extremely pretty in shape, the leaves
+being pointed and delicately curled.
+
+I need hardly mention the beech; nothing can be more exquisite than a
+spray of its opening buds with their silky fringed young leaves and
+crimson leaf-scales. I look forward every spring to the joy of watching
+the unfolding of these caskets.
+
+A warm shower or two and some sunny days cause them to expand with a
+rapidity which seems magical, and one almost regrets to find the beauty
+of the buds in their early stages so quickly passing away. The ash
+attracts notice by its jet-black buds, and the wayfaring tree by the
+delicate venation of its young leaves.
+
+I cannot refrain from mentioning another beautiful effect arising from
+young buds in the case of a _Picea nobilis glauca_, which long name
+simply means a sea-green silver-fir, standing on our lawn. In the
+summer its terminal buds are a very pale sea-green, and as they grow
+and are seen against the dark green of the rest of the foliage the
+effect is very curious, as though each branch had become tipped with
+frosted silver.
+
+[Illustration: BUDS OF WAYFARING TREE.]
+
+The soft silky buds of the willow, and especially those of the low
+growing sallow which are gathered as “palm” for church decoration, are
+amongst the welcome signs of early spring. The sallow has its male
+blossoms on one tree, but not far away we shall find the female tree
+bearing the flowers which will eventually produce the seeds. We may
+therefore seek for three kinds of buds, those which produce the flowers
+on each tree, and the others which will clothe the tree with leaves
+when the blossoms are over.
+
+This chapter shows us how much there is to instruct the student of
+nature during the winter as well as the summer months.
+
+I have but indicated a very few out of the many lines of study which
+may be taken up; one could write essay after essay upon the growth of
+a single hedgerow, but all I can hope to do in simple chapters of this
+kind is to throw out hints and indications, and trust that my young
+readers may find their interest sufficiently excited by what they have
+read, to lead them on to fuller, deeper study of each point touched
+upon.
+
+Nature is an inexhaustible storehouse of wonders, and the further we
+explore, the more our eyes are opened to see the vistas that lie before
+us, branching out in various directions.
+
+This special path of botanical study is one that, more or less, can be
+pursued at intervals, as opportunity may offer through life, and as it
+adds much pleasure to leisure hours, I specially commend it to my young
+readers.
+
+Specimens to be obtained and compared with the descriptions in this
+chapter:—Search for buds in summer; plane-tree buds; Japanese maples;
+terminal and axillary buds; observe shape and outline of trees; buds
+of coniferous trees; fir cone; fir-tree that has lost its leading
+shoot; pollard willow, and other trees, buds on marsh tway-blade, and
+viviparous fern; buds on underground stems; suckers from wall-fruit
+trees; dormant buds or knobs on tree-stems; bulbils on lily, dentaria
+and allium; horse-chestnut terminal bud; observe leading shoot of
+horse-chestnut in early summer; flower and leaf buds on beech; various
+flower-buds; Oriental poppy; tulip-tree buds; various leaf-buds
+unfolding; colouring of Japanese maple, lime, and sycamore buds;
+whitebeam; variegated vine; purple hazel; mountain ash; spray of beech
+buds; ash buds; _Picea nobilis glauca_; willow and sallow, male and
+female flower buds and leaf buds; bamboo.
+
+
+
+
+CHAPTER VI
+
+_FLOWERS_
+
+ “Your voiceless lips, O flowers, are living preachers;
+ Each cup a pulpit, every leaf a book
+ Supplying to the fancy numerous teachers
+ From loneliest nook.”
+
+ +Horace Smith.+
+
+
+
+
+CHAPTER VI
+
+FLOWERS
+
+
+Instead of looking at flowers as bright and beautiful objects made to
+be a source of continual delight in our daily lives, though such they
+truly are, we will rather now, for purposes of study, consider them as
+the means by which the plant carries out the purpose of its creation,
+namely, to perfect its seed and thus perpetuate its species.
+
+In the life-history of shrubs, trees, and plants we find this is their
+one aim, and that everything else is subservient to it.
+
+The stamens and pistil being of essential importance in forming the
+seed, we find them placed for safety in the centre of the flower;
+folded round them are the petals or coloured parts of the flower, and
+outside these again are the green sepals, or leaves of the calyx.
+
+These two sets of enfolding leaves are called “floral envelopes,”
+because they fold over and protect the central organs, the stamens and
+the pistil.
+
+We will select a buttercup as a type, and taking it to pieces we will
+try to learn the names and uses of its various parts.
+
+The outside is a greenish-yellow cup which is called the calyx.
+
+The divisions of this little green cup are called sepals, and their
+office is to protect the five bright yellow leaves within, which are
+called petals when we speak of them singly, but, taken all together,
+form the corolla.
+
+In the buttercups the petals are all separate, but if we look at a
+primrose we shall see that the corolla is in one piece, united in a
+tube; so also is the calyx.
+
+The botanical term for a corolla thus formed is _gamopetalous_, a long
+word but easily understood when we know that _gamos_ means united; a
+flower with petals in one instead of many divisions is more easily
+referred to by this word than if we had each time to express it by a
+sentence.
+
+[Illustration: PRIMROSE.]
+
+Gathering a newly-opened flower, we can see at a glance that the sepals
+are placed quite below the central green organs of the flower, and
+that they are in no way influenced by the petals; we also see that
+the petals are entirely separate from the other parts of the flower,
+and we learn, as the result of our examination, that the parts of the
+buttercup are _free_. To express this botanically we prefix the word
+“poly” to the words sepals and petals, and so we get _polysepalous_,
+meaning that the sepals are quite free and distinct, and _polypetalous_
+referring to the same condition of the petals.
+
+Now, having removed the petals and sepals, we can proceed to study the
+other parts of the flower.
+
+First we find a great number of little yellowish stalks tipped with
+tiny pouches; these are the stamens, and in the little pouches
+(anthers) the yellow powder termed pollen is developed. We will
+carefully take away these stamens, and note in so doing that they are
+all distinct and all sprung below the green central part. Like the
+sepals and petals, we find the stamens are free and uninfluenced by the
+other parts. If we again compare this with a primrose-flower we shall
+find a difference; the stamens of the primrose spring from the petals
+and are therefore called _epipetalous_ (_epi_ upon, a petal). Again in
+the sweet-pea or scarlet runner we find the stalks of the stamens are
+all joined together. We now have left upon the flower-stalk the little
+central green parts previously mentioned; there are quite a number
+of them; each one is distinct from its neighbour and is free. These
+bodies are known as carpels, they are large at one end and taper to a
+curved point at the other, the broad end being attached to the stem.
+Collectively these carpels constitute the _pistil_, and because the
+carpels are apart and free it is said to be _apocarpous_.
+
+The flower of the little woodsorrel (_Oxalis acetosella_) will help us
+to understand better the arrangement of the carpels. If we take away
+the sepals, petals and stamens, we shall have only the carpels left,
+and these are five in number. They are in the same position as those
+of the buttercup, but they are not separate, they are joined by their
+inner surfaces. We can plainly see that this is the case, since each
+carpel is distinctly outlined and there are five little tapering ends
+(stigmas). The pistil in this case is said to be _syncarpous_.
+
+Names are given to express some quality, and they often draw our
+attention to interesting facts about the plant’s mode of growth or the
+place where it is found; for instance, the pretty blue nemophila is so
+called from _nemos_, a grove, and _philo_, I love, because it delights
+in shady places.
+
+Geranium is derived from _geranos_, a crane, because the fruit of some
+of the species resemble the beak of that bird.
+
+Some plants are named after famous botanists, as _Linnæa_ after Linnæus.
+
+Others derive their names from their mode of growth, as stone-crop,
+which is called sedum, from _sedo_, I sit, the plant having scarcely
+any stalk, and sitting, as it were, on walls and rocks.
+
+These instances will show that it is well worth while to study names
+and learn their meanings, as they often throw so much light upon the
+history of a plant.
+
+In the flowers of bulbous plants we find that the calyx and petal
+leaves are frequently alike in colour and texture; in that case the
+three sepals and three petals, of which they usually consist, are
+spoken of as a perianth.
+
+In looking at the brilliant colouring of a flower we should hardly
+imagine that the petals have to some extent the nature of leaves, and
+under certain conditions may be changed to the green colour and form of
+ordinary leaves.
+
+In very wet seasons we may sometimes find rose-buds with the sepals of
+the calyx developed into perfect green leaves. The floral envelopes
+therefore possess the nature of true leaves.
+
+[Illustration: POINSETTIA.]
+
+The brilliant scarlet so-called flowers of the poinsettia are really
+coloured bracts, the true flower being the small inconspicuous
+blossom in the centre.
+
+In the chapter on leaves we saw that bracts are those small
+imperfectly-shaped leaves in the axils of which flowers are placed.
+They are usually green, but may be also brilliantly tinted as in the
+mauve-coloured Bougainvillia, the bright violet spikes of the _Salvia
+Hormineum_, and also pure white as in the spathe of the arum.
+
+By special cultivation flowers can be made double, for excess of
+nourishment will cause the plant to multiply its petals. Instead of
+the five pink petals of the wild rose we find one of our garden roses
+bearing as many as eighty or a hundred petals.
+
+Double flowers but rarely produce seeds, because the stamens and pistil
+have been turned into petals, and as there is no need to attract
+insects for fertilising purposes, there is no secretion of honey, and
+therefore we scarcely ever see honey-bees in double flowers; they are
+wise enough to know that their visits to them would be in vain.
+
+In composite flowers such as asters and sunflowers the change, when
+they are double, occurs in several ways.
+
+The centre may become filled with florets similar to those in the
+outside ring, or the florets in the middle may become larger or of a
+different colour.
+
+These various changes may be readily observed in the cultivated
+chrysanthemums, in which every form and variety of flowering can be
+traced.
+
+When the pollen has reached the pistil the flower begins to fade,
+because its end has been attained; nature, however, has such variety
+in even the smallest of her operations that the passing away of a
+flower is accomplished in different ways. In the primrose the corolla
+withers and drops to the ground. The flower of the spiderwort, one
+of our common garden plants, becomes pulpy as it fades, in this way
+resembling the pineapple plant, the flower of which eventually becomes
+the luscious succulent fruit.
+
+The poppy is proverbial for its fleeting petals, which scarcely last
+more than a few hours, a passing wind soon scattering them far and wide.
+
+ “Pleasures are like poppies spread,
+ You seize the flower, its bloom is shed!
+ Or like the snow-fall in the river,
+ A moment white—then melts for ever.” (+Burns.+)
+
+Some flowers, as the hydrangea, have persistent petals, which simply
+lose their brilliant tints and become tough and brown.
+
+[Illustration: WINTER CHERRY.]
+
+The calyx of the physalis or winter cherry continues to grow after the
+flowers are fertilised until the round balloon-like bag is formed in
+which the fruit is enclosed.
+
+We will now examine the parts of a flower separately, beginning with
+the calyx.
+
+In the buttercup the calyx consists of one whorl or ring of five sepals.
+
+In the strawberry there are two whorls of sepals, and in the cotton
+plant there are three whorls forming its green calyx.
+
+There are also variations in the mode of flower expansion.
+
+As a poppy-bud opens it detaches its calyx from the stem, and the
+sepals fall off (the calyx is therefore called caducous, a term which
+means ready to drop off).
+
+Many flowers retain the calyx until the petals wither and it falls off
+with them. It is then called a deciduous calyx.
+
+Others again have a permanent calyx, so that when, as in the primrose,
+the corolla withers and drops off, the sepals close over the
+seed-vessel and protect it until the seeds are matured; this would be
+called botanically a persistent calyx.
+
+The best way to learn the names of the different parts of a flower is
+to pull it carefully to pieces and arrange the separate organs on a
+thin card. They can be tacked on to the card with a stitch or two of
+fine thread, and when the lesson is over, if the card is placed between
+sheets of blotting-paper under a weight, the flower dissections will
+dry and be useful for reference later on.
+
+Each separate part of the flower should have its name neatly written
+beneath it, so that when a good many different flowers have been thus
+dissected they may be compared and the variations in form and position
+duly noted.
+
+[Illustration: WALLFLOWER.]
+
+A wallflower will be a good subject for our dissection.
+
+At the back of the petals we first take off the calyx, which consists
+of four divisions called sepals. We then pull off the four yellow
+petals, and as they are placed in the form of a cross it shows
+that this plant is a crucifer, or cross-bearer, one of a very large
+natural order, _Cruciferæ_,[16] none of which are poisonous and very
+many are useful food-plants, such as cabbage, turnip, watercress, and
+cauliflower. Now there remain six stamens—four long and two shorter
+ones; these last rise outside of and alternate with two nectaries or
+honey-glands.
+
+[16] All cross-shaped flowers do not, however, belong to this order.
+
+The stems of the stamens are called filaments, from _filum_, a thread;
+and the upper part, containing yellow powder, is called the anther, the
+proper name for the powder itself being pollen.
+
+In the centre of the flower is the pistil, the lower part of which is
+the ovary, the part of a flower which contains the ovules, and is so
+named from _ovum_, an egg.
+
+The stem part of the pistil is called the style and the top of it is
+the stigma.
+
+Such simple words as I have given must be learned, else we cannot
+understand botanical descriptions, and if this page is studied whilst
+we have the flowers in our hands it will not be difficult to identify
+each separate organ; when these are once arranged on a card with the
+name of each part written beneath it, we shall have attained some very
+useful information ready for future study.
+
+In the buttercup flower all the five petals are the same size and
+shape; therefore, like hundreds of other evenly-formed blossoms, it
+would be described as “regular”; but if we take a sweet-pea, balsam, or
+monkshood-flower and examine its separate petals, we shall find they
+vary very much in form, and they are known as “irregular” flowers.
+
+The sweet-pea is a type of a large order of plants producing what
+are called butterfly-shaped flowers, and _papilio_ being Latin for
+a butterfly, they are therefore called papilionaceous flowers. If
+we learn clearly about the various parts of such a flower we shall
+henceforth be able to recognise it at a glance.
+
+In the sweet-pea we find a broad petal at the back of the flower which
+is called the standard, beneath it are the two side petals called
+wings, and within them is the keel, so named because it is shaped like
+the bottom of a ship. Within the keel lie the stamens and pistil—the
+most important parts of the flower, and to protect them from injury the
+standard is so formed as to catch the wind like a sail and turn the
+blossom round so that this broad petal shelters the keel from rain.
+
+[Illustration: SWEET-PEA.]
+
+In our next ramble out of doors it will be well to try and gather all
+the specimens we can find of this order of plants. If it be in summer
+or autumn we shall soon collect a handful of these butterfly-shaped
+flowers.
+
+On a common we shall find broom, furze, restharrow, vetches, tares,
+trefoil, clover, saintfoin, and other plants. In the garden and
+greenhouse we shall see many more species belonging to this class.
+
+Having shown the difference between a regular and irregular flower, we
+will now proceed to notice how irregularity is caused.
+
+If we pull off one of the buttercup petals and look at the base of it,
+we shall see a small pouch which contains honey; it is called a nectary
+or honey gland, and the position of this gland has much to do with the
+shape of the flower.
+
+As each petal of the buttercup has a nectary at its base it follows
+that, all the petals being the same size and shape, the flower is
+perfectly regular—like a small golden cup. Now in other flowers we
+shall find the nectary very large and confined to one petal or sepal
+only, and this results in the flower having an irregular shape. Gather
+a violet, examine and compare the petals; four of them will be found
+to be nearly alike, but the lower petal is much larger because it has
+grown into a tube (called a spur) to secrete honey, and I need hardly
+say that the honey is intended to attract the bees so that the flower
+may be enabled to produce fertile seed. The enlargement of the lower
+petal gives the flower an irregular shape, and the same thing happens
+in the monkshood and many other flowers, where both the petals and
+sepals are thrown out of shape to form nectaries. In the orchid family
+this influence may be traced to a wonderful degree. The contrivances
+for insuring the fertilisation of their flowers are so many and various
+that books of the greatest interest have been written on that subject
+alone.
+
+In the flowers we have hitherto noticed, both stamens and pistils are
+found, the petals are coloured, honey-glands exist, and some specimens
+also possess a powerful scent.
+
+Such flowers are obviously very attractive to insects, and on that
+account they are called by modern botanists, entomophilous, which long
+word means that they are beloved by insects.
+
+In sharp contrast to these gay and conspicuous flowers we may observe
+the very simple catkins of the birch, _Betula alba_. If we examine a
+twig of this tree in spring, we shall find two very distinct kinds of
+flowers (or catkins, as tree-blossoms ought properly to be called),
+one a stiff green spike standing upright, and the other longer and of
+yellowish colour, always to be found hanging down.
+
+The former consists of a number of scales arranged on a central stem,
+and in the axil of each scale is the little pistil, with its pointed
+and divided stigmas. This catkin, later on, becomes the fruit of the
+tree, and sheds out with every passing breeze its little winged fruits,
+which are carried far and wide and often sow themselves in rocky
+crevices, and appear able to grow and flourish with only a modicum of
+soil.
+
+[Illustration:
+
+ _Natural Size._ _Magnified._
+
+BIRCH FRUIT.]
+
+The pendulous catkin is very soft and loose, and on the inner surface
+of its scales we find the stamens, which in due time will shed from
+their anthers the fertilising pollen. Here then we see flowers which
+are not so attractive to insects, flowers in which the stamens and
+pistils are separated and developed in different catkins, and such
+flowers are termed monœcious, from _monos_, single, and _oikos_, a
+house.
+
+The most interesting feature of these tree-blossoms is their
+fertilisation by the wind; the slightest puff of air liberates little
+clouds of pollen from the loose swinging anthers; these pollen grains
+become entangled in the upright catkins bearing the pistils, and the
+future seed thus becomes fruitful. There are many trees and plants
+which are thus fertilised by the agency of the wind, and they are
+termed by botanists _anemophilous_, from the Greek words _anemos_,
+wind, and _philos_, beloved by.
+
+In the common bryony of the hedges, we get another example of a green
+inconspicuous flower. Gather a few sprays of this in early summer,
+taking care to keep the specimens of each plant separate. Take up one
+specimen and you will find each flower has a small green calyx, a
+minute corolla, and five little stamens; not one pistil can we find on
+the spray.
+
+The flowers on the next spray look very similar, but in them there are
+no stamens, the centre of each flower being occupied by a small pistil,
+and thus we learn that there are two distinct sexes in the bryony
+plant, the one bearing only staminate flowers, and the other producing
+those bearing only pistils. Such plants are termed diœcious, from _di_,
+two, and _oikos_, a house.
+
+[Illustration: WILD ARUM.]
+
+One of the earliest spring flowers is the arum of the hedges, known
+to village children as “lords and ladies.” Accustomed as we are to
+bright-hued flowers if in our gardens and fields, it is somewhat
+difficult to recognise that the pale-green sheath of the arum is a
+flower at all. It consists of a beautifully-folded spathe or bract,
+curving over at the top, and if we remove that we find a central stalk
+bearing a number of little naked flowers, arranged in the order shown
+in the plate.
+
+First, below the club-like apex, a few hairs tending downwards,
+then the anthers containing pollen, and below these the pistils with
+protruding stigmas. The whole stalk is termed a spadix.
+
+The outer green spathe forms a kind of prison, into which flies are
+enticed by the somewhat fetid odour which is exhaled by the flower. The
+flies easily creep in past the circle of hairs, which, as they point
+downwards, do not prevent their entrance, but, once in, these hairs are
+like a _chevaux-de-frise_, and hinder the escape of the insects. The
+flies in all probability carry upon their wings pollen from some other
+arum flower, and in their efforts to escape they brush off this pollen
+upon the stigmas, which thus become fertilised. When this has taken
+place the stigmas throw out a sweet juice upon which the insects feed;
+the anthers now shed out their pollen, with which the flies become
+covered; the hairs meanwhile have withered, and thus the flies, having
+done their appointed work in fertilising the flower, are free to crawl
+out and perform the same office for some neighbouring plant.
+
+We have not space to do more than allude to certain plants, whose
+flowers never open and are self-fertilised. The common violet, for
+instance produces, in addition to its well-known fragrant flowers,
+certain inconspicuous blossoms, hidden under the leaves and close to
+the root, very seldom noticed by any but botanists, and known to them
+as cleistogamic flowers; these are fertile, and always produce seed.
+Other such plants are the woodsorrel and sundews.
+
+It is interesting to observe the various ways in which flowers are
+protected from browsing animals, snails, and caterpillars by thorns,
+spines, prickles, and spiny bracts. The teasel secretes water in the
+bracts around its stem, which prevents ants from ascending to the
+flowers, and in many plants we may see quantities of small insects
+caught by a sticky gum exuded from the leaves and twigs.
+
+Many delicate plants entirely alter the position of their flowers in
+order to protect them from rain. On a sunny day the wood-anemone holds
+its little snowy cup so as to receive the full sunlight, but on a damp
+day every blossom is closed and held downwards. We may observe this in
+the poppy, the blue-anemone, and nearly all composite flowers.
+
+These are merely hints scattered over a wide field of study, which
+some readers may like to follow out.
+
+Objects to collect and examine:—Buttercup flowers, seed-vessel of
+wild-geranium, stonecrop growing on walls, flowers of bulbous plants,
+flowers of poinsettia, bougainvillia, salvia hormineum, arum. Examine
+various chrysanthemum flowers, sunflowers, asters and woodsorrel.
+Difference between hydrangea and poppy flowers, winter cherry
+(physalis); prepare flower dissections. Examine various cruciferous
+flowers and pea-shaped flowers, regular and irregular flowers, birch
+catkins, wild arum flowers, cleistogamous flowers, protection of
+flowers, position of flowers.
+
+
+
+
+CHAPTER VII
+
+_POLLINATION_
+
+ “When summer shines,
+ The bee transports the fertilising meal
+ From flower to flower, and even the breathing air
+ Wafts the rich prize to its appointed use.”
+
+ +Cowper.+
+
+
+
+
+CHAPTER VII
+
+POLLINATION
+
+
+We now come to the consideration of the real function of the flower
+of a plant. In whatever form it is developed, whether as a gay and
+fragrant blossom, in a dull foul-smelling structure like the arum, or
+as a green inconspicuous little floret like the grass, its main office
+is to reproduce itself by the formation of seed. We will first glance
+at some of the wonderful agencies that actively help in this work.
+
+There are at least three distinct processes necessary for the complete
+formation of a perfect seed, and we must, I fear, persuade ourselves
+to learn some of the long words by which botanists speak of these
+processes. They are known as pollination, fertilisation, and the
+growth of the ovule. There is so much to be said about the first
+subject, that I must leave the two latter for a succeeding chapter.
+
+Before seed can be formed it is necessary that the powder contained
+in the anthers, which is called pollen, should be transferred from
+those anthers to the stigma or upper part of the pistil, and this
+transference is called pollination. If we examine a tulip or, better
+still, a buttercup, we find the anthers and stigmas so near together
+that the transfer of the dust-like pollen to the sticky-looking
+stigmas can easily take place. This would be called an instance of
+self-pollination, but although cases of this kind do occur in nature,
+they are not at all common. As a rule, in order to ensure what is
+called cross-pollination, the transfer of the pollen of one flower to
+the stigma of another, many wonderful and interesting arrangements
+exist even in some of our commonest flowers.
+
+Cross-pollination must be the case in such plants as dog’s mercury,
+because we find in a colony of these plants—so frequently seen by the
+roadside—that some plants have flowers with stamens only, and others
+containing only pistils. Again, in the hazel we may see how impossible
+it is for self-pollination to take place, as, if we examine the
+pistils, we find that they consist of scales bearing stamens and pollen
+only, whilst somewhere close by, on the same stem, hangs the pretty
+little red flower which possesses the pistil and forked stigma. If seed
+is to be formed in either of these flowers and in many others similarly
+arranged, then the pollen of one flower must be transferred to the
+stigma of the other.
+
+[Illustration: PRIMROSE.]
+
+There are interesting facts to be learned about the common primrose.
+When we examine a little bunch of these flowers we find quite half of
+them are what children call pin-eyed, meaning that the stigma, which
+is at the end of a long pistil, is like the head of a pin in the throat
+of the primrose.
+
+Looking at the sketch, we see at once that self-pollination is hindered
+by the fact that the anthers in this flower being at the bottom of the
+tube, the pollen they contain must be transferred by some direct agency
+before it can come in contact with any stigma. Now let us examine the
+other flowers in our primrose nosegay; we find the stamens in these are
+placed in the mouth of the tube, and the pistil is quite short and low
+down in position. At first sight it appears as if the pollen would fall
+directly upon the pistil, since the stamens are above that organ, but
+this is not exactly what happens; the pollen of this particular form of
+flower is shed before the stigma is mature, so that when it has reached
+maturity the pollen is all gone.
+
+The arrangement of nature is as follows. An insect attracted by the
+sweet-smelling bank of primroses will visit the flowers, thrusting
+its proboscis down a pin-eyed flower until in so doing its head has
+been dusted with the pollen of the stamens; then withdrawing from that
+flower the insect visits another near by, possibly one with a short
+pistil; the pollen on its head is now rubbed off and falls upon the
+stigma below and pollinates it, for that is the term used when this act
+takes place.
+
+[Illustration: MAIDEN PINK.]
+
+The pretty maiden-pink will help us still more clearly to understand
+how cross-pollination is promoted in flowers containing both stamens
+and pistils. Select a flower that has just opened, the petals of which
+are spreading and fringed, whilst from the centre of the flower a
+cluster of stamens projects with the pollen mature and easily shaken
+out of the anther lobes; the pistil is concealed in the long tube, and
+in this stage there is no sign of stigma. In a short time, however, if
+we examine the flower again, we shall find the stamens have shrivelled
+up, and in their place a forked stigma appears, as shown in the sketch.
+Here again it is obvious that the fact of the stamens ripening first
+and expending their energy before the pistil is ripe must mean, that
+in order to secure seed the pollen from some younger flower must
+be transferred, probably also by insect agency. It will give fresh
+interest to our garden rambles if we remember that the bees and flies
+we see hovering over the flowers are not only collecting honey or
+feasting upon it, but are also performing a very important office for
+the benefit of the plants they are visiting.
+
+We may now proceed to notice the various agencies for the conveyance of
+pollen between flowers.
+
+These agencies are water, wind, insects and birds.
+
+In an earlier chapter I gave an account of the _Vallisneria spiralis_,
+which will serve as a type of a water-pollinated flower.
+
+Those pollinated by wind are, as I have said in a previous chapter,
+called anemophilous (_anemos_, wind, and _philos_, loving). They are
+usually of small size and inconspicuous character, with very little or
+no scent, and devoid of colour; these are characteristics that are not
+always associated in the same species; thus in the hazel, which is a
+wind-pollinated flower, we find a bright yellow catkin (so well known
+to children as lambs’ tails) and a small but bright red pistil.
+
+Let us notice, however, how wonderfully these plants are adapted
+for this method of pollination; the stamens are usually hanging,
+and the pollen, produced in great quantities, is easily set free by
+the slightest breath of wind. The stigma of the hazel, of different
+grasses and of sedges are both forked and plumed, so that pollen grains
+floating in the air are readily intercepted.
+
+The firs and pines are excellent examples of wind-pollinated trees. I
+remember once possessing a ripe male cone of the _Araucaria imbricata_,
+and ascertaining that it contained as much as a wine-glassful of
+pollen. Speaking about this fact to the gardener at the Pinetum
+at Dropmore, I was shown how this fertilising dust from the great
+Araucaria (which was planted there in 1830) was carried by the wind
+for an amazing distance to a female tree on the other side of the
+garden, pollinating its cones so that they produced fertile seeds.
+In some of the Canadian pine forests, the trees shed forth such
+quantities of pollen in the flowering season that the ground becomes
+perfectly yellow. The early settlers, being unable to account for the
+strange phenomenon in any other way, ascribed it to showers of sulphur
+descending from the clouds. Even in our own country the foliage and
+undergrowth in the neighbourhood of fir woods is often thickly coated
+with the yellow dust falling from the male catkins of the trees; the
+structure of the pollen grains is such that they float very buoyantly,
+each grain being provided with two air bladders. I may mention in
+passing that this apparently wasted pollen affords a rich feast to
+endless species of bees and flies, and is in many cases stored up by
+them as food for their young grubs. The various adaptations for wind
+pollination will perhaps be better understood if we glance at the
+attractions which flowers offer to birds and insects.
+
+Colour serves to render flowers attractive to insects, and to make them
+conspicuous; the bracts, petals, and sepals of flowers are usually of
+some light or dark colour quite distinct from the green tone of the
+foliage.
+
+It has been ascertained also that plants which are pollinated by
+night-flying moths generally have white or light-yellow flowers so as
+to be easily seen in twilight.
+
+One of the most interesting of these night-pollinated flowers is
+_Silene nutans_, the Nottingham catchfly. In the daytime the five
+narrow petals are curled up and look dead and withered, but as night
+comes on they change their position, and the flower has the expanded
+shape of an alpine pink. In this open condition it is visited by the
+moths which, flying from one flower to another, transfer the pollen,
+and thus accomplish at night what more frequently occurs in the
+sunlight; at daybreak the petals roll up once more, and one would again
+suppose the flower to be dead; but no, it will continue to open at
+nightfall until some moth finally succeeds in pollinating its blossom.
+A small species of moth[17] visits this catchfly in order to deposit
+its eggs; these, by means of a very long ovipositor, it places in the
+ovary, and in that somewhat inflated cavity they produce microscopic
+caterpillars which find shelter and nutriment in the strange nest.
+When the caterpillars arrive at maturity they escape by biting a hole
+in the wall of the capsule, and creeping out, they seek for a suitable
+place in which to turn to chrysalides.
+
+[Illustration: ARISTOLOCHIA.]
+
+[17] _Dianthræcia albimacula._
+
+Scentless flowers usually have some equivalent form of attraction, such
+as honey, brilliant colour pollen in abundance, or the grouping of a
+number of small florets, in order to secure a conspicuous effect as in
+the ox-eye daisy, or hedge parsley.
+
+Strong and varied odours are great helps to ensure pollination by
+insects. The bee-tribe and moths and butterflies are specially
+attracted by the sweet scents of roses, violets, carnations, and
+sweet-peas, and the powerful odour emitted by such flowers as the
+evening primrose, tobacco, and night-flowering rocket as evening comes
+on tends to guide the nocturnal moths to these and similar flowers. An
+odour may, of course, be pleasant to an insect which to us would be
+simply intolerable. The arum of the hedges, and those curious plants,
+the aristolochias and stapelias, all emit scents of the most fœtid
+description, as we think, but flies, on the contrary, are attracted by
+thousands, and hold apparently joyous revels in the blossoms which
+they are pollinating by their frequent visits.
+
+[Illustration: STAPELIA.]
+
+A little care and patience in watching the visits of insects to
+different flowers will soon be rewarded by a perception of the tastes
+and likings of insect life, and we shall gradually learn to expect to
+see certain insects on the flowers they specially frequent.
+
+[Illustration: HYPERICUM.]
+
+I would call attention to the interesting fact that if one agency
+fails to effect pollination, another is adopted in order to attain the
+desired end. Thus, when the flowers of the common bartsia first open,
+they are visited by insects; but, in the later stages of flowering,
+the pollen is blown out by the wind, and the neighbouring stigmas thus
+become pollinated. We see in the arrangement of the flower of the St.
+John’s wort (_Hypericum_) a perfect type of this provision against any
+possible failure of pollination. The stigma is surrounded by groups of
+stamens of unequal length; those in the centre nearest to the stigma
+are as long as the style itself, whilst those on the outside are short,
+and these shed their pollen first, whilst those in close contact with
+the stigma shed their contents last. Thus we find that if insects fail
+to effect cross-pollination by means of the short and early opened
+stamens, it is secured by means of the longer stamens whose anthers are
+in close contact with the stigma. Again, when we stand under a sycamore
+tree, we may see that the green tassel-like flowers are having their
+pollen dispersed both by wind and bees.
+
+We cannot draw hard-and-fast lines in nature, for although a special
+end may be kept in view, the various means and adaptations by which
+it is attained are a continual source of admiration and wonder to the
+reverent student of nature.
+
+We have already seen that there are all kinds of devices by which the
+pollen of one flower may be made sure to reach the stigma of another;
+but, if by any means this crossing fails, if the weather is such that
+insects are scarce, or other conditions cause failure, then, in the
+case of many flowers, most curious contrivances are provided to secure
+seed by self-pollination. Truly this is one of the most beautiful of
+God’s wonders in floral construction. One of the gems of my own flower
+garden is a lovely little Japanese toad-lily (_Tricyrtis hirta_). In
+this flower there are three styles which stand well above the stamens;
+the points of the styles are bent over as in the plate, and the
+stigmatic surface grows mature before the anthers shed their pollen;
+if, however, no insect visits the flowers, pollination is effected in
+the following way. The styles bend down and place their forked points
+in direct contact with the open anther-lobes (as shown in drawing),
+the style assuming almost the form of a semicircle. This is done very
+deliberately, for it is often fully a week before the act is complete.
+
+[Illustration: TOAD-LILY.
+
+_Stigma and Stamen._]
+
+Pollination is effected in tropical countries not only by insects of
+many kinds, but by the lovely tribes of humming-birds which abound in
+those regions. Their slender, curved beaks are specially adapted to
+penetrate the honey-laden flowers with long-tubed blossoms, which could
+only be pollinated by some such agency.
+
+Those who are within reach of the Natural History Museum at South
+Kensington may there see a gallery filled with exquisite specimens of
+humming-birds, arranged in cases, and some of the birds are shown as
+they appear in life, hovering over tropical flowers, drawing honey
+from their hanging blossoms, and performing the useful office of
+transferring the pollen from one flower to another, thus ensuring the
+fertilisation of the seed.
+
+I might go on multiplying examples of the various methods by which seed
+is rendered fertile, but perhaps enough has been said to show what
+hidden force exists in flowers to enable them to attain the end for
+which they mainly exist, namely, the perpetuation of their species by
+means of seed.
+
+Specimens to be obtained and compared with the descriptions in this
+chapter:—Buttercup flower, dog’s mercury, hazel catkins, primrose
+flowers, male blossoms of pine trees in June, Nottingham catchfly,
+ox-eye daisy, bartsia, St. John’s wort flowers, and Japanese toad-lily.
+
+
+
+
+CHAPTER VIII
+
+_FERTILISATION_
+
+ “The men
+ Whom Nature’s works can charm, with God Himself
+ Hold converse.”
+
+ +Akenside.+
+
+
+
+
+CHAPTER VIII
+
+FERTILISATION
+
+
+Having now considered some of the many wonderful arrangements by which
+the pollen of plants is dispersed, we will endeavour by tracing the
+course of the pollen-grains after they reach the stigma, to learn what
+is meant by the term “fertilisation of the ovules.” These are the
+minute specks contained in the ovary which are to become seeds, and by
+means of which the plant will eventually reproduce itself.
+
+To the naked eye the yellow pollen we see on the anthers of flowers
+appears as small grains; but, when magnified, these grains are seen to
+be singularly beautiful, each little sphere having on its surface a
+chequered network and delicately sculptured patterns.
+
+The forms, too, are as varied as the ornamentation.
+
+Some plants have triangular grains, some oval-shaped and others
+many-sided.
+
+[Illustration: POLLEN-GRAINS.
+
+ 1 _Morina._
+ 2 _Cobea._
+ 3 _Convolvulus._
+ 4 _Dianthus._
+ 5 _Pinus._
+ 6 _Albucca._
+ 7 _Buphthalmum._
+]
+
+I have given a few examples, and would specially call attention to the
+pollen-grains of the Pinus tribe (fir-trees), to which I alluded in the
+last chapter. These are remarkably buoyant, owing to the two little
+bladders with which they are furnished.
+
+[Illustration: WHITE-LILY PISTIL.]
+
+[Illustration: SECTION OF PISTIL.]
+
+Now we are going to watch this yellow dust performing its appointed
+office in the central organ of a flower. In order to do so we will take
+a white garden lily, and remove the petals, sepals, and stamens,
+leaving only the pistil, which, as shown in the drawing, consists of
+three parts, the club-like stigma, a very long style, and its base the
+ovary, which contains three cavities. In these last we see a number
+of small, colourless spore-like bodies termed ovules (from _ovum_, an
+egg), each consisting of an outer coat, and a mass of cells in the
+centre called the _nucellus_.
+
+[Illustration: POLLEN TUBE.]
+
+An opening exists at one end of each ovule called the micropyle
+(meaning a little gate or entrance), and this opening leads down
+into the middle of the nucellus, where lies what we may call the
+life-principle, but what is known in botany as the embryo-sac.
+
+We need the aid of a microscope to enable us to see how the pollen
+exerts its influence upon the ovules.
+
+If we place a drop of very weak sugar and water upon a slip of grass,
+and sprinkle over it some pollen grains of the common white lily, then
+allowing the slide to remain for a few hours in a dark place, it will
+be fit for our purpose.
+
+When placed in the microscope we shall observe that many of the
+grains will have thrown out long thread-like tubes, and this is just
+what happens when pollen falls upon the viscid stigma of the lily.
+Referring to the section of a lily pistil we see that a pollen grain
+has rested on the stigma, and, excited into growth by the sweetish
+fluid which holds it there, it sends down a slender tube through the
+centre of the pistil, which is lined with a very delicate loose tissue
+of cells filled with starch, oils and food-materials. The pollen-tube
+is stimulated and fed by this nourishment stored up in the conducting
+tissue, and on it goes until, passing through the micropyle, it enters
+the embryo-sac of one of the ovules, adheres to it, and renders it
+fertile.
+
+Only one grain is shown in the drawing for the sake of clearness, but
+of course each ovule is sought out and fertilised by a pollen-tube.
+With infinite variation this process takes place in every flower,
+so that even the commonest weed affords evidence of the marvellous
+provisions made by an All-Wise Creator for the preservation of species.
+
+The time occupied by the passage of the pollen-tube varies
+considerably. In the fir tribe it takes nearly twelve months, in the
+hazel-nut and orchis it requires several weeks, whilst in many other
+plants the whole process is completed in a few hours.
+
+One of the first results of fertilisation is a rapid withering of
+the style and flower; the great end of the flowering period has been
+attained, and so without further expense of energy the bright petals
+die away.
+
+At the same time other external changes take place, which are obvious
+to every observer of nature. The lower end of the pistil, known as the
+ovary, begins its second growth, and in a short time swells into a
+large structure, the shape of which varies much in different species
+of plants. Finally, the ovary changes colour and develops other
+characteristics quite different from its former conditions. These
+characters have reference to the distribution of its seeds, and in
+our chapter on fruits we shall learn something about the interesting
+botanical significance of the various hard and soft fruits, and see how
+they all arise from fertilisation.
+
+Take, for example, the flower of an apple immediately after
+fertilisation is effected. The petals fall off, the styles shrivel up
+and the ovary rapidly enlarges; the tube of the calyx becomes fleshy,
+and finally the well-formed apple is produced. The change, however,
+does not end here; in this stage of development the little apple
+is bitter and is charged with a vegetable acid. As the fruit grows
+on, however, this acid changes into sweet juice varying in flavour
+according to the species of apple.
+
+Now let us examine the interior of the ovary and see what changes have
+arisen as a consequence of fertilisation.
+
+The egg cell which has received the pollen grain becomes filled with an
+embryo, whilst the thin delicate coat of the ovule develops into strong
+seed-coats.
+
+The embryo is the first germ of the young plant that is to be. It is
+a tiny speck indeed in its beginning, but deeply interesting to us
+when we realise that, because it possesses life, it will grow on and
+on, and result, according to its species, either in a plant but a few
+inches in height, or in a grand forest-tree which may give shelter to
+man and animals for hundreds of years.
+
+The naked eye can scarcely trace any indications of form in the embryo,
+but when dissected and examined with a lens it is seen to consist of a
+tiny plant, root, stem and leaves (cotyledons).
+
+The size of the embryo in comparison with the other part of the seed is
+a point which should be observed.
+
+As the embryo develops it absorbs the special nutrient or reserve
+tissue that exists in all ovules; a bean embryo, for example, rapidly
+absorbs all the nucellus of the ovule, so that at length the seed-coat
+contains nothing but the embryo, the two cotyledons of which are thick
+and filled with stores of food for the first growth of the seed.
+
+I would advise students to plant a few broad beans in a little damp
+cocoa fibre, and carefully watch their growth. It is advisable to
+dissect these beans successively at different stages, so as to watch
+the development of the radicle (root) and plumule (young leaf-bud).
+Place the seed in what position we may, the radicle will always find
+its way down into the earth, while the plumule obeys its vegetable
+instinct, and rises into the air. The embryo of the castor-oil bean
+and that of the cocoa-nut do not, however, use up all the nutritive
+matter in the ovule as the broad bean does, so that when the seed is
+ripe we find inside it, not only the embryo, but also a quantity of
+cheesy matter known as _albumen_, and seeds of this kind are hence
+called _albuminous_, whilst peas, beans and hazel-nuts are classed as
+_ex-albuminous_ (without albumen).
+
+[Illustration: SECTION OF COCOA-NUT.]
+
+An interesting development consequent upon fertilisation is a growth
+which occurs in some plants from the base of the ovule. The pretty red
+coverings of the seeds of the spindle-tree, and the bright berry-like
+structure on the seeds of the yew-tree are examples of this growth,
+which is known botanically as an aril (from _arillus_, a wrapper). In
+the willows this aril is a very lovely covering of silky hairs, these
+serve to float the seeds on the atmosphere at every puff of wind.
+
+[Illustration: SPINDLE-TREE.]
+
+The pretty lace-like covering on the nutmeg is another example of an
+aril, better known to us in the form of the fragrant spice called mace.
+
+The style, which in most plants dies as soon as the ovules are
+fertilised, is in other cases persistent, as in the hedge-climber
+called travellers’ joy. The white, feathery-looking seeds owe their
+special character to the persisting styles, which, after fertilisation,
+grow into the bunches of fluffy seeds, which hang in profusion on
+hedges in the country.
+
+[Illustration: NUTMEG AND MACE.]
+
+[Illustration: CLEMATIS OR TRAVELLERS’ JOY.]
+
+I will conclude this chapter with a reference to a change of quite a
+different character. Not unfrequently, fertilisation results in the
+suppression of certain chambers in the ovary, and in the consequent
+failure of the development of the ovules.
+
+A cross-section of a young oak ovary shows a three-chambered structure,
+each cavity containing two ovules, so that the ovary in this stage
+contains six ovules in three chambers. Soon after the act of
+fertilisation, one of the fertilised ovules takes the lead in growth,
+starves the other five ovules, and, as it grows, pushes the partitions
+of the other chambers aside, and gradually fills up the whole interior,
+converting it into a one-celled structure. This change happens also in
+the birch; its two-chambered ovary becomes one; and in the lime, though
+at first it has a many-chambered ovary, yet in the ripened fruit there
+is rarely more than one to be found.
+
+In a few plants, changes of quite an opposite character take place.
+In the ovary of the datura,[18] for instance, we find two cells;
+after fertilisation, two false or spurious partitions are developed,
+dividing the original two-celled structure into four parts, and as a
+consequence we get a four-chambered fruit. The same change takes place
+in some of the pea family.
+
+[18] Thorn-apple.
+
+Specimens to be observed:—Examine pollen grains, with lens or
+microscope, dissect white lily, flower-pollen on glass slide. Observe
+changes in growing apple, plant broad beans, castor-oil seeds, and
+maize; examine spindle-tree berries (_euonymus_), yew-tree berries,
+willow seeds, nutmeg, and mace; travellers’ joy (clematis), section of
+oak ovary in the pistillate flower. Examine birch catkins and lime-tree
+flowers. Datura seed-vessel.
+
+
+
+
+CHAPTER IX
+
+_FRUIT_
+
+ “Here, as I steal along the sunny wall,
+ Where Autumn basks, with fruit empurpled deep,
+ My pleasing theme continual prompts my thought;
+ Presents the downy peach; the shining plum;
+ The ruddy, fragrant nectarine; and dark,
+ Beneath his ample leaf, the luscious fig.
+ The vine, too, here her curling tendrils shoots,
+ Hangs out her clusters, glowing to the south,
+ And scarcely wishes for a warmer sky.”
+
+ +James Thomson.+
+
+
+
+
+CHAPTER IX
+
+FRUIT
+
+
+If we are shown a collection of delicious apples, pears, grapes,
+peaches and cherries, we form a very appreciative opinion of the use
+and function of fruit, but that opinion is somewhat modified when we
+are shown a basket of poppy-heads, acorns, the light downy seeds of the
+thistle, the small dry carpels of the buttercup or the winged fruits
+of the maple. We usually connect the term fruit with some luscious
+product of the vinery or kitchen-garden, and we may include as such
+the brightly-coloured berries of the hawthorn and wild rose, which are
+so conspicuous on trees and hedges in autumn; but if we examine the
+subject botanically we shall have to widen our ordinary conception of
+the term.
+
+There is probably no part of a plant so difficult to understand as
+its fruit, and this difficulty is due to those many changes which I
+described in my last chapter. A very general definition of fruit is
+that it consists of the ripened ovary, and this will be found to be
+correct in a great number of cases, but this term is not exactly wide
+enough to express the general formation of all fruit. In some cases
+it is composed of the ripened ovary with the parts of the stalk or
+the original flower, enlarged or incorporated in the structure of the
+fruit, but in other specimens we find the ovary, although present, very
+little enlarged, and playing but a minor part in the ultimate character
+of the mature fruit.
+
+No fact seems so emphatic to the observant botanist as that which
+upsets his artificial rules and classifications of plants and the parts
+of plants. We say, for instance, that fruit is the ripened ovary, and
+yet directly we leave our books and go out to study botany in the
+fields and woods, we find a large group of fruits perfectly innocent of
+any such structure. The firs and pines have no organ of this kind, and
+yet their fruits are most important and extremely interesting. Scarcely
+any part of a plant varies so much in different species as the fruit
+does. Although leaves may be found of every size and shape, they still
+have some general similarity of form, but we hasten to observe what
+an immense contrast there is between the huge _Musa_ fruit (banana)
+and that of the oak (acorn), although the former is, compared to the
+latter, but a poor weakly plant.
+
+Again, let us note the difference between the cocoa-nut palm fruit, a
+nut, which with its outer husk is almost as large as a peck measure,
+and that of the St. John’s wort or any other of our native wild flowers.
+
+These differences in size have their counterparts in other directions.
+We generally think of fruits as being soft, luscious, and pleasant to
+the taste. Many fruits of delightful colour and texture are, however,
+bitter as gall, and possess highly noxious qualities. I well remember
+gathering a plateful of rich purple berries from a plant I discovered
+in one of my childish rambles and carrying them home as a great prize;
+I was not a little disappointed when I learned that they were the
+poisonous fruits of the deadly nightshade; their deceitful resemblance
+to plums, as well as the berries of the woody nightshade to red
+currants, make these two of our most dangerous native plants.
+
+As offering very distinct contrasts to the above, we may note the dry
+membranous fruits of many of our forest-trees, the hard nuts of the
+hazel and walnut and the leathery husk of the chestnut. Again, the
+shape of fruits is wonderfully diversified. We have round and oval
+apples, plums, and gooseberries; the linear seed-pods of the cabbage,
+cauliflower, wallflower, peas and beans, and other plants in endless
+varieties of forms.
+
+There are contrasts again in the smooth surface of some fruits and the
+hairy coats of others where the roughness is due to hooks, prickles
+and other contrivances. How different, too, is the airy pappus of the
+dandelion to those heavy fruits which drop like stones and are to be
+found lying exactly beneath the branches where they have ripened.
+
+These differences in external form are multiplied when we examine fruit
+more minutely. We shall then find a useful dividing line in the manner
+in which fruits allow their seeds to escape. In one large division the
+fruit when perfectly ripe splits open and allows the seed to fall out;
+such fruits are termed dehiscent (from _dehisco_, I gape). In the other
+division the fruit remains closed, and the substance of it must decay
+before the seeds can escape and grow; these are classed as indehiscent
+(I gape not). Before referring to a few examples of each division we
+will endeavour to distinguish clearly the various parts of a fruit and
+learn their proper botanical names.
+
+We must be careful not to confound the seed and the coats of the ovary;
+the latter is termed the pericarp (_peri_, around, _karpos_, a fruit).
+In some fruits this pericarp is developed into distinct coats, or
+layers. In a peach, for instance, the outer coat is rough and hairy,
+this is called the epicarp (1) (_epi_, upon, _karpos_, a fruit); the
+middle coat is the succulent delicious fruit, and is known as the
+mesocarp (2) (_mesos_, middle, _karpos_, fruit), whilst the inner coat
+is the hard stone, or endocarp (3) (_endon_, within, _karpos_, fruit),
+and inside it lies the kernel, or true seed. As a type of a dehiscent
+fruit we may select a pea-pod; here we get no division of the coats
+into distinct parts, the pericarp is dry and tough, and when perfectly
+ripe it bursts open, and allows the seeds to escape.
+
+[Illustration: SECTION OF PEACH.]
+
+It would be very interesting to make a collection of various
+seed-vessels, and note the immense variety of ways in which the seeds
+find their way out of the dry capsules. A poppy-head, campanula and
+antirrhinum sprays, henbane, columbine, stramonium, and many other
+plants afford good examples.
+
+[Illustration: POPPY CAPSULE.]
+
+The woody pear is the hard fruit of a New Holland plant which splits
+open to release the seeds. The horse-chestnut is a conspicuous instance
+of a dehiscing fruit, the rough prickly part is the pericarp, and
+when the fruit is mature this splits open and allows the two large
+chestnuts (seeds) to escape. In the sweet-chestnut we get an altogether
+different structure. If we pick up one of its spiny burrs, we hold in
+our hand what is called in botany an involucre (from _involucrum_,
+a cover), that is, a number of bracts which have grown together and
+formed an outer case to the fruit. The acorn-cup is an involucre, and
+we may find other good examples in composite flowers and those of the
+umbelliferæ. The small green whorl in which a daisy-flower is set is,
+therefore, not a calyx, but an involucre consisting of minute bracts
+grown together. The true fruit of the sweet-chestnut is enclosed in a
+mass of spiny bracts, and thus differs entirely from the pericarp of
+the horse-chestnut; if we wish to speak of it correctly we must call
+it either a cupule or involucre. We will now select a few examples of
+fruits that are indehiscent.
+
+[Illustration: WOODY PEAR.]
+
+On the outside of an orange we find the yellow coat of the pericarp,
+next to it is the white mesocarp, and inside is the juicy endocarp,[19]
+in which the seeds are embedded. When an orange falls to the ground
+these different coats simply decay, and the seeds are aided in their
+efforts to grow by the succulent flesh of the fruit, which affords them
+moisture and nutriment. The hazel-nut is a fruit of another texture
+altogether. The hard shell is the pericarp, and the one or two seeds
+within it must remain enclosed there until the shell decays and the
+kernels can germinate and become new plants.
+
+[19] Strictly speaking, the endocarp of the orange is a thin membrane,
+and the pulp grows from it and fills up the ovary cavities.
+
+In the currant, gooseberry, and date we find examples of indehiscent
+fruits with a sweet fleshy pericarp. In the date there is only one seed
+in each fruit, and a curious thin endocarp can be observed enveloping
+the solitary seed. Many allied species, as well as the date, possess
+this sweet pericarp, which must decay in order to liberate the seeds,
+and in the case of succulent fruits the process is frequently assisted
+by the fruit-eating birds.
+
+It may be well to draw attention to the very simple kind of fruit
+possessed by the buttercup and other similar plants. It is a dry
+membranous pericarp, and inside one seed exists free from the pericarp;
+this remains closed, like other forms of the indehiscent types, and
+technically this fruit is known as an achene (from _achanes_, not
+gaping), and it is well named, as it remains closed until decay enables
+the growing radicle to break through the pericarp and enter the ground.
+The curious after-development of the strawberry fruit is worth a little
+careful study.
+
+This flower is known as apocarpous (_apo_, apart, _karpos_, fruit),
+consisting of a number of distinct ovaries each with one ovule; these
+ovaries when ripe are exactly like the achenes of the buttercup, but
+they are developed upon a receptacle which, when fertilisation has
+taken place, begins to dilate and swell, with the result that the
+little achenes are gradually scattered over the surface of a large
+fleshy receptacle which, as it nears its time of perfection, becomes
+of a most tempting crimson colour. The little seed-like dots we notice
+on the strawberry are distinct and perfect fruits embedded in a sweet
+succulent floral receptacle. Thus we find that the strawberry, speaking
+botanically, is not a berry, but a collection of achenes, the term
+“berry” being usually restricted to such fruits as the currant and
+gooseberry. For this reason the strawberry and the common fig are
+sometimes termed spurious fruits, for in these the soft pulpy flesh is
+really the receptacle and the little round so-called seeds are the true
+fruit.
+
+There is a very different formation in the pineapple, since this fruit
+is the development of an entire spike of flowers; these in their early
+stage are crowded together on the flower stalk, but as time goes on
+they coalesce and fuse, with their ovaries, bracts, and receptacles,
+into a succulent mass, the various parts of which can be well defined
+if we cut a section through a pineapple before it is quite ripe.
+
+This chapter may fittingly conclude with a brief reference to the
+ultimate purpose of these varied forms and textures of fruit, for
+that they each have their special work, and that there is a meaning
+for every form, is a truism we may accept without doubt. The fruit is
+in reality the storehouse for the seeds, the latter being the vital
+part of the plant. If we review the life-history of a plant, first
+its producing flowers, then the special and intricate processes of
+pollination and fertilisation, and subsequently the growth of that
+wonderful little part, the ovule, into a seed, and further if we
+reflect that the whole strength of the plant has been concentrated on
+producing that seed, we shall then comprehend the true significance of
+fruit.
+
+The seed is first stored up in the recesses of the ovary; clearly
+then the ovary, which subsequently becomes the fruit (pericarp), is
+intended to protect the seeds, and it is interesting to note some of
+the various ways in which this protection is afforded. Take first the
+soft and sweet fruits so plentiful in the autumn; this edible sweet
+flesh is not developed until the seeds are quite ripe. All through the
+period of growth and ripening the pericarp is hard or stringy or it
+may be also sour or acid. This is especially true of hedgerow fruit,
+such as crab-apples, sloes, and wild pears, texture and juice alike
+affording complete protection.
+
+Again, such fruit as the walnut and chestnut are protected by their
+rough covering and hard shells, and many others have their outer coats
+covered with prickles and spines for the same reason. The most extreme
+case is perhaps that of _Mucuna pruriens_, a leguminous climber found
+in the tropics; this has downy pods not unlike those of a sweet-pea,
+and these pods are covered with brownish hairs which, if incautiously
+touched, enter the pores of the skin and cause a most intolerable
+irritation; a truly formidable protection this to the seed.
+
+Let me now point out how the seed is protected in some of the pine
+family (firs), where there is no pericarp. During the growth and
+development of the pine seeds, the woody cone is rich in resin, and
+should an enterprising nuthatch try to peck out the seeds, he finds his
+beak covered with the resin and his effort baffled.
+
+[Illustration: PINE-CONES.]
+
+Protection is also afforded to the seed by the movements of fruit
+after fertilisation, and of this the cyclamen flower affords a good
+illustration. As soon as fertilisation has taken place the flower stalk
+coils up like a watch-spring, and the seed-pod is thus placed safely
+beneath the leaves to ripen.
+
+In crevices of old walls we may often find that charming little
+wilding, the ivy-leaved toad-flax; it has a highly intelligent method
+of protecting its seeds. When the flower is fertilised its stalk bends
+its point round to the wall, and places the tiny ovary in a cranny
+of the brickwork to mature and ripen its seeds. These are but two
+instances, out of hundreds, of plants whose fruits are protected by
+what we call instinctive movements.
+
+It is of essential importance to young seedlings that they should have
+sufficient soil, light, and air, to ensure their healthy growth. To
+begin life directly under the leaves of the parent plant is to court
+failure and starvation, and so we find in the fruit that wonderful
+provisions are made to ensure the dispersion of the seed when it
+leaves the parent plant, and so endless are the contrivances for the
+dispersion of fruits and seeds, that it will be needful to devote the
+next chapter entirely to that subject.
+
+Objects to collect and examine:—Compare various fruits, fir-cone,
+banana, acorn, seeds, and berries, &c. Examine a peach and pea-pod.
+Collect seed-vessels, horse-chestnut, sweet-chestnut, daisy-flower,
+orange, hazel-nut, date-fruit, strawberry, pineapple.
+
+Observe seed coverings, pine-cones, cyclamen stems after flowering,
+seed capsules of ivy-leaved toad-flax in wall crevices.
+
+
+
+
+CHAPTER X
+
+_DISPERSION OF FRUITS AND SEEDS_
+
+ “Who gave the thistle’s feather’d seed its plumes,
+ That wing-like waft it on each gentle breeze
+ To sterile yet to it congenial soils,
+ Investing them with purple beauty, rife
+ With fragrant treasures for the wild bees’ store?”
+
+ +T. L. Meritt.+
+
+
+
+
+CHAPTER X
+
+DISPERSION OF FRUITS AND SEEDS
+
+
+I purpose in this chapter to explain some of the many remarkable ways
+in which plants are enabled to scatter their fruits and seeds. The
+chief agencies which assist in carrying out this purpose are wind,
+animals, birds, running water, and moisture in the atmosphere. We
+shall find that many seeds are furnished with certain outgrowths and
+peculiarities which are specially adapted to the action of these
+agencies, with the result that such seeds are distributed far and wide.
+We will first examine some of those fruits which are scattered by
+animals; this end is generally attained by means of hooks and curved
+spines on the outside of the fruit.
+
+Perhaps one of the most remarkable instances of this class is the
+seed-pod (or capsule) of the Martynias. During the visit of the Prince
+of Wales to India, a panther killed in one of the shooting excursions
+was found to have quantities of long-hooked seeds attached to his skin:
+these must have been brushed from a plant of _Martynia proboscidea_,
+which has sharp curved horns three or four inches long.
+
+[Illustration: SEED-POD OF MARTYNIA.]
+
+Another species called by the Italians _Testa di Quaglia_, or quail’s
+head, sows itself in a similar manner by clinging to moving objects.
+
+Many common hedgerow plants have their fruits armed with quite
+formidable hooks, so that creeping or flying creatures may be made
+unwittingly the means of distributing the fruits. The burdock is a
+most persistent plant in this respect, each of its numerous fruits
+being covered with long hooks which successfully retain their hold
+of our clothing if we happen to brush past the plant when covered
+with its troublesome burrs. Other examples are the rough seeds of
+the forget-me-not, agrimony, enchanter’s nightshade—a great pest in
+gardens—and all the bedstraw tribe.
+
+These plants, we may observe, are low-growing and herbaceous, quite
+distinct in the matter of position from the tall trees and shrubs which
+depend upon the wind to scatter their seeds.
+
+We are all familiar with the winged fruits of the sycamore; they are to
+be seen in early autumn. The clusters are first of a pale green, and
+then the seeds[20] often attain a flush of pale crimson which adds
+much to the picturesque beauty of the tree. The equinoctial gales
+separate the seeds from their stalks, and away they go far and wide,
+borne up by the delicate membrane attached to the seed which catches
+the wind, and is carried by it to a great distance from the parent
+tree. In the same way the winged keys of the ash, being very light,
+are borne by the autumn gales to strange habitats, so that the tree
+may often be found growing on church towers, in ruins, and on crags
+inaccessible to man.
+
+[20] In botany the fruit of the sycamore, maple, ash, &c., is called a
+_samara_, and is properly speaking a winged _achene_.
+
+[Illustration:
+
+ _Natural Size._ _Magnified._
+
+BIRCH SEED.]
+
+The pinus tribe of trees have seeds with wings slightly twisted so
+that, if we hold up a dry fir-cone, the seeds descend from it with a
+whirling motion like small shuttlecocks.
+
+The winds which blow strongly in mountainous places carry these seeds
+before them, and are thus ever renewing the pine-forests by sowing
+the products of their cones on bare tracts of land. The lightest of
+all tree seeds is that of the birch; it is gifted with two wings or
+membranes, so that it floats in the air before the lightest breeze,
+and this may account for the wide distribution of the tree which has
+been found growing from Mount Etna to Iceland and Greenland. I may give
+an instance of a common which, twenty years ago, was covered only by
+furze, broom, and brake-fern; about fourteen years since, a shower of
+birch seed must have been strewn over the ground, and now it has become
+a wood, shutting out the distant views and quite altering the character
+of the landscape.
+
+The wind again is the agency for the dispersion of the seeds of such
+plants as the common groundsel; here it may not be uninteresting to
+note the beautiful provision made in regard to the buoyancy of the
+seeds. These winged structures which the wind so lightly blows into the
+air must attain a certain altitude from which they can be successfully
+launched, and therefore we find that a large class of low-growing
+plants have their seeds furnished with accessories in the form of light
+silky down or hairs.
+
+[Illustration: PARACHUTE.]
+
+[Illustration: DANDELION SEED.]
+
+Most of the plants known as _compositæ_ have their seeds thus
+feathered, and amongst them are those plagues of the farmer, the
+thistle, dandelion, goat’s-beard and others. The dandelion may serve
+as our example, and I would advise my readers to watch carefully the
+variations of position in the flowering stems. Whilst the flower is
+still fully expanded the stalk remains in an upright position so that
+it is conspicuous and likely to attract the notice of insect visitors.
+After the florets are fertilised it gradually lowers itself until it
+lies on the ground under the leaves for a period of ten or twelve
+days. During this time the seed-vessel matures and ripens, then the
+stalk rises to the erect position once more, and the beautiful downy
+globe expands into a soft fluffy ball of seeds hanging so loosely
+that the first breeze carries them away, and their descent into the
+ground is curiously provided for. Persons have sometimes alighted on
+the earth from a balloon by means of a parachute, a machine which
+closely resembles an open umbrella with a car at the lower end. Now
+the dandelion seed descends in a similar manner, touching the ground
+first with its lower end, the weight of the seed enabling it to drop
+into some hole in the soil, and the spiny projections at the upper
+end preventing the feathery part of the seed from dragging it out
+again. The common goat’s-beard is perhaps the most beautiful English
+example of fruit with a downy pappus. A single flower will produce a
+sphere as large as a cricketball, and each seed is furnished with a
+starlike crown of branched feathers which the wind can bear away to a
+considerable distance.
+
+[Illustration: GOAT’S BEARD.]
+
+The handsome willow-herb, which adds so much colour and beauty to our
+river banks, bears its seed in long, narrow pods, and these, when ripe,
+split up into five segments which, curling back as they open, leave the
+downy seeds free to be carried off by the passing breeze.
+
+Bird agency in seed dispersion is a most interesting subject, and
+one can but admire the wonderful way in which the services of winged
+creatures are made available.
+
+Succulent berries and sticky fruits are highly attractive to many kinds
+of birds, and whilst they revel upon the sweet, soft flesh of the
+berry, the seeds which they swallow with it are enabled to resist the
+action of digestion by a hard covering which protects the kernel until
+the shell shall decay and allow the seed to germinate. In this way I
+find my garden in early spring quite thickly strewn with the seeds of
+the Irish ivy, always a favourite food of the common wood-pigeon which
+is so frequently to be heard cooing in my woods.
+
+The seeds of aquatic plants often cling to the feathers of birds that
+visit pieces of inland water, and are widely distributed by them in
+their flight from one lake to another.
+
+[Illustration: COCOS-DE-MER.]
+
+Darwin has shown by careful experiment that the mud clinging to the
+feet of various birds almost always contains seeds. A wounded partridge
+had a ball of earth weighing six and a half ounces adhering to its
+legs. From this earth Darwin reared no less than eighty-two separate
+plants of five distinct species. Seas and rivers also do their part in
+dispersing seeds. The huge nuts of the _Cocos-de-mer_ palm, which grows
+only upon the Seychelles Islands, are often thrown upon very distant
+shores. This nut is said to take ten years to come to perfection; it
+is exceedingly hard, and sometimes weighs as much as forty pounds.
+The common cocoa-nut is often found growing on the shores of coral
+and other islands in the Pacific Ocean, and owes its position there
+to the buoyant nature of the nut, which floats uninjured in the sea
+until it finds a resting-place and a home on some atoll or island. In
+this way the cocoa-palm has spread to such an extent that it is now
+perhaps the only palm common to the western and eastern hemispheres.
+West Indian seeds and fruits have even been thrown upon the Norwegian
+coasts, and, but for the unsuitability of the climate, there is little
+doubt that tropical trees and plants might sometimes be found growing
+even so far north. It is obvious that the seeds of all vegetation on
+the banks of rivers, small running streams and lakes, must be liable
+to very wide distribution. Darwin made many interesting experiments as
+to the length of time seeds could retain their vitality when floating
+in fresh or salt water. Ripe hazel nuts germinated after being ninety
+days in water. An asparagus plant with mature berries, when dried,
+floated for eighty-five days, and the seeds afterwards grew vigorously.
+Out of ninety-four plants experimented upon, eighteen floated for
+more than a month and some for three months, their germinating power
+not being destroyed. In quite a large number of species the plants
+themselves possess the means necessary to distribute the seed. It is
+true the distance traversed by each seed may not be great, but it is
+sufficient to give the seed a new field of growth. This power varies in
+different species. It is perhaps best defined as elastic force, and in
+the majority of cases the seed is actually thrown away from the parent
+plant by the expenditure of this force. The seed-pod is generally in
+a state of tension, due to the gradual drying up of the tissues. Then
+a puff of wind, a slight blow, or even a change in the atmospheric
+condition of the air, gives the final impetus, causing the pod to
+burst with such force that seeds are thrown out in all directions. The
+fibro-vascular cords are often found crossing the pod in an oblique
+direction, or even in a spiral manner, so that finally, as they
+shorten through dryness, they act upon the walls of the legume and we
+see the result in such dried pods as those of the sweet pea, broom, and
+laburnum.
+
+[Illustration: BROOM AND SWEET-PEA PODS.]
+
+The pansy has a three-valved seed-pod, and as it dries the edges of
+the valves press upon the polished, hard-shelled seeds and they are
+squirted out with a jerk to a distance of several feet. I was once
+greatly puzzled by a strange, crackling sound in my room, and after
+a few minutes’ search I discovered it was caused by a fusillade of
+pansy seeds striking against the sides of a small box in which I had
+placed the capsules to ripen. It is worthy of notice that the capsule
+hangs down to protect the seed-valves from rain; but when the seeds
+are matured the capsule rises to an upright position so that they
+may be projected far and wide. A conspicuous example of the elastic
+force of which I have spoken is seen in the British balsam, _Impatiens
+Noli-me-tangere_ (touch-me-not). When its seeds are mature, the valves
+of the capsule curl up in a spiral form with such force as to project
+both themselves and the seeds through the air many feet from the plant
+dropping the seeds by the way. On a hot summer’s day one may hear the
+dispersion of seeds! The furze and broom pods, the sweet peas, and
+especially fir tree cones, make quite a loud report as they split and
+scatter their contents. The tension causing these explosions is in some
+cases brought about by the fluids inside the fruit. This is the case
+with the squirting cucumber, which, when fully ripe, is so distended
+with fluids that the slightest touch or movement is sufficient to
+cause it to break away from its stalk, and then the whole contents are
+ejected with great force, so that the seed is thrown some distance. The
+extent of dispersion is very limited in those plants that are dependent
+upon the varying moisture of the air. Such plants are usually furnished
+with special awn-like[21] appendages; these are hygroscopic[22] in
+their nature, and the difference in the amount of moisture in the air
+lengthens and contracts these apparently moving organs. When the seeds
+fall from an ear of barley they lie thickly strewn around the bottom
+of the stem, and, were they to take root there, they must inevitably
+choke each other; but each awn is thickly set with bristles, and as the
+morning sun shortens and the evening dew lengthens the hair-like awn,
+the prickles only allow the awn to move in one direction, and the seed
+which is attached to it is slowly but surely drawn many inches away.
+What is popularly called the dancing oat is another curious example
+of this hygrometric property. If a dry seed (or oat) is placed for a
+moment in water, and then laid on a smooth table, it will be seen to
+wave its long horns as if they were the antennæ of an insect, and to
+turn over and over until it has progressed some inches from the point
+where it was first placed. In _Avena elator_ (the tall oat grass) and
+_Stipa pinnata_ the awns are bent sharply just as they emerge from the
+flowers, the part below the bend being like a corkscrew and highly
+sensitive to moisture, relaxing and contracting according to the amount
+of moisture in the air, with the result that the seed travels along the
+ground. By the help of the long awn it can pass over small obstacles,
+such as stones or clods, the movement resembling that of a lever.
+
+[Illustration: STIPA PINNATA (FEATHER GRASS).]
+
+[21] The beard of corn.
+
+[22] Sensitive to moisture.
+
+I must here guard my readers against those movements that are caused
+by some insect larva. The so-called jumping bean imported from Mexico
+is now so well known that it may be taken as a type of these curious
+movements due, not to the seed itself, but to the efforts of an
+imprisoned insect, the grub of a small moth which passes its larval
+stage inside the hard-shelled seed of a kind of euphorbia.
+
+In conclusion, we may glance at a small group of plants that develop
+sticky glands for the purposes of dispersion.
+
+That charming Alpine plant _Linnæa borealis_ has a pair of bracts
+closely adherent to the fruit and these bracts are covered with
+stalked glands of a sticky nature, so that when an animal, bird, or
+even a passing moth brushes against the little fruits they stick to
+the intruder and are thus borne away. Now it may perhaps occur to the
+thoughtful reader that the Linnæa seed-vessel, being part of a growing
+plant, would not readily break off with a slight touch, but it is
+another instance of that consummate skill and arrangement that is so
+apparent to the close observer. In the stalk of the little fruit there
+is a special separating layer[23] (analogous to that of the falling
+leaf which we noted in a previous chapter), and at this point the
+fruit readily separates if the slightest pressure is brought to bear
+upon it. This example is typical of what takes place in such plants as
+_Salvia glutinosa_ and _Plumbago capensis_ and _Rosea_. As a contrast
+to these various modes of dispersion I may mention those seed-vessels
+which are actually buried by the plants themselves, such as the
+ground-nut, ivy-leaved toad-flax, and others. We must bear in mind that
+these plants usually have aerial flowers in addition to those matured
+underground, and that these aerial flowers produce fruits which are
+subject to dispersion. We may therefore conclude that the underground
+seeds are to ensure the continuance of the plant when the ordinary
+methods have perhaps partially failed. My readers may each autumn find
+an endless source of wonder and interest in the thousands of differing
+fruits and seed-vessels which may be obtained in any hedgerow and
+field; and by careful observation they may yet learn many new facts and
+be ever adding to their store of knowledge by gathering and comparing
+the fruits and their dispersion, as shown in the types sketched in this
+chapter.
+
+[23] Called botanically an “absciss layer.”
+
+Objects to collect and examine:—Fruits and seed-vessels of martynia,
+burdock, forget-me-not, agrimony, enchanter’s nightshade, bedstraw,
+samara of sycamore, ash-keys, pinus seeds, birch seeds, dandelion and
+goat’s-beard seeds, pods of sweet-pea, broom, laburnum, and pansy.
+Seed-vessels of balsam, wild oat, feather-grass, _Linnæa borealis_,
+salvia, plumbago, ground-nut, and ivy-leaved toad-flax.
+
+
+
+
+CHAPTER XI
+
+_GERMINATION_
+
+ “O Source unseen of life and light,
+ Thy secrecy of silent might
+ If we in bondage know,
+ Our hearts, like seeds beneath the ground,
+ By silent force of life unbound,
+ Move upward from below.”
+
+ +T. T. Lynch+
+
+
+
+
+CHAPTER XI
+
+GERMINATION
+
+
+Having considered the processes which lead up to the formation of seed,
+we may now investigate the life-history of a seed and its various forms.
+
+Like fruits, seeds differ much in their outward shape. In size alone
+we find a great contrast between the dust-like seeds of the orchids
+and the huge seeds of the cocoa-nut-palm, while between those two
+extremes we may note every gradation of size. In other respects, also,
+the seed offers no less variety of form and covering than the fruit,
+such variations having relation to the particular mode of dispersion
+and germination. The outer skin or coat of a seed, called the _testa_,
+offers a very interesting field of study, and such seeds as the poppy
+and _silene_ with beautiful network, the _bignonia_ and _pinus_ with
+membraneous wings, the cotton-plant seed with long hairs, and the
+_collomia_ with hairs that are resolved into mucilage when wetted, are
+all worth special study. When a small portion of _collomia_ seed is
+moistened and placed in a microscope one may see the rapid change being
+effected; that which had been a hard dry atom suddenly throws out coils
+of gum, like watch springs, and a novice is led to ask, “Is the thing
+alive?” so full of motion does the object appear.
+
+[Illustration: BIGNONIA SEED.]
+
+We may regard a seed under various aspects. As a special means of
+continuing the life of a plant, one of its modes of reproduction, as
+a special means of tiding a plant over a season that would be fatal
+to its life in its ordinary condition of leafage, in the seed we have
+the germ of the future plant, a reproduction of its parent. This germ
+or embryo is lethargic or hibernating like many animals which exist
+throughout the winter in a dormant condition, yet still continue to be
+living vital bodies waiting for some special influence to come into
+play, and ready to resume all the activity of a growing organism.
+The construction of a seed is simple; inside the coat or _testa_ we
+find the embryo with or without a special supply of albumen; if the
+seed is ex-albuminous, then we may expect to meet with thick, fleshy
+seed-leaves especially stored with this substance. The embryo contains
+all the essential parts of the plant, the root, stem, and leaves; the
+root in the seed state is called the radicle, and is that part of the
+embryo which usually points towards the micropyle; this radicle forms
+one end of the first shoot which comes out of a seed, the other end
+terminating in the stem or plumule. This first shoot is known by three
+names—axis, _tigellum_, or hypocotyle. The _tigellum_ in many plants
+gives rise to a special structure; thus in the cyclamen it forms the
+tuber, and the greater part of the “roots” of radishes and turnips is
+due to it. In other instances it is a mere collar forming a slightly
+thickened surface between the base of the cotyledon and the radicle.
+The _tigellum_ is in reality a centre of growth, as may easily be shown
+by cutting off an inch of the upper part of a well-grown carrot and
+placing the slice in a saucer of water; before long a crown of young
+leaves will spring up and will continue to grow and flourish as long
+as the plant food contained in the slice is sufficient to maintain the
+leafage. In botanical language we have thus been growing carrot leaves
+from this _tigellum_.
+
+The embryo varies very much in the relative position of its parts.
+Thus the embryo of the reed-mace is straight in the _tigellum_ of the
+embedding albumen. In contrast to this is the curved embryo of the
+deadly nightshade and the spiral embryo of the hop.
+
+[Illustration: DOUBLE EMBRYO OF ORANGE.]
+
+The seeds of the orange often contain two embryos, which is rather
+a rare occurrence in the vegetable world. Before we can trace the
+future of these parts we must attain a clear idea of the change the
+seed undergoes when it germinates. In the whole of our studies our
+attention has been drawn to no process so deeply interesting and yet
+so mysterious as that of the breaking into life of the seed. There
+are three conditions that promote the process of germination: warmth,
+moisture, and air. When these three conditions are present and the
+seed is healthy, growth begins, and its first stage is the absorption
+by the seed of moisture; this, combined with warmth and the oxygen of
+the air, sets up a change in the contents of the seed. We have already
+seen that seeds are of a dry and starchy nature, and in this condition
+they are insoluble and unfit to be active plant food. The change that
+ensues results in this starchy matter being converted into sugar which
+is soluble; then the parts of the embryo begin to unfold, first the
+radicle and finally the plumule are developed. In this early stage
+these parts live entirely upon the contents of the seed, just as a
+young chick is developed and nourished upon the albumen of the egg.
+
+The temperature requisite for germination varies according to the
+species; those of us who possess gardens know to our cost at what a
+low temperature such plants as chickweed, bittercress, groundsel,
+and some of the speedwells grow; as long as the thermometer is above
+freezing-point these troublesome weeds will make their appearance in
+our flower borders. Sach’s experiments on germination tend to show that
+wheat and barley begin to grow below five degrees centigrade, whilst
+French beans and maize germinate at nine degrees centigrade.
+
+Some plants start into growth very quickly. Garden cress, vegetable
+marrows, and some grasses appear above ground a few days after they
+are sown, whilst other seeds, enclosed in a hard, woody seed-case,
+will require twelve months to germinate. This was the case with a
+seed taken out of a cedar cone brought from Mount Lebanon; I vainly
+watched for the young plant, and when a year had passed by the pot
+was thrown aside on a rubbish heap. Shortly after I was passing by and
+observed a fir-cotyledon growing on the heap, and this proved to be the
+long-desired young cedar-plant.
+
+Seeds have the power to retain their vitality for years, especially
+those of the _Leguminosæ_, but I believe the stories of Egyptian mummy
+wheat germinating are scarcely to be believed. A good object-lesson
+upon this subject is furnished by a newly-made railway cutting; here
+we may always find growing upon the freshly-turned soil quite a crop
+of plants which have sprung from seeds that in the course of years
+have become embedded in the earth, it may be at so great a depth as
+to preclude the admission of air or prevent one of the necessary
+conditions of germination. When, however, the underlayer of soil is
+brought to the surface and exposed to light, air, and moisture, the
+seeds are able to grow.
+
+[Illustration: BROAD BEANS.]
+
+To this we owe the richness of our railway-bank flora, and many a
+rare plant may be discovered there which cannot be found elsewhere in
+the neighbourhood. We will now in imagination conduct a few simple
+experiments that we may learn something of the behaviour of seeds
+during their early stages of growth. Each seed that we thus study may
+be regarded by us as a type of many others. First, then, we will sow,
+in a few pots, about a dozen broad beans; before doing so we may notice
+on the seed the black stripe or ridge known as the _hilum_; this is the
+scar showing where the seed was attached to the pod, and at one end of
+it is the micropyle (_small gate_). If we remove the skin of the seed
+we shall observe the two fleshy cotyledons or seed leaves, a tiny point
+which is the rudimentary root, and, lying close to the inner face of
+the cotyledon, the slightly curved plumule. After the beans had been
+sown a few days and carefully watered, we may take up two or three for
+examination. At first we may only see the radicle just emerging from
+the little hole at the end of the _hilum_, but if we wait, say, eight
+or nine days, we shall get a further development.
+
+Before digging up our seed we will see if any others are peeping
+through the soil. Yes, here is one, just an arched kind of shoot, no
+leaves, only the bow of the arch pushing up the particles of the soil,
+so that the point of the shoot is clearly still below the ground.
+Now, taking up a seed we notice that the radicle has penetrated some
+way down into the soil, and with a pocket lens we are able to see a
+little higher than the tip of the root quite a crop of delicate little
+root-hairs. The cotyledons are still enclosed in the tough skin, but
+the upward growth of the _tigellum_ is acting on them like a lever,
+and we can now plainly see that it is this _tigellum_ that, by its
+upward growth, is penetrating the soil, and in so doing is drawing
+the cotyledons from the seed coat. All this time the delicate plumule
+is kept out of danger by the arched shape of the _tigellum_ and the
+folding of the cotyledons. Leaving our seeds for a day or two longer
+we find a further change. The plumule has been carried up beyond the
+soil-level and has begun to expand into leafage. It is interesting
+to note how the curved _tigellum_, pushing through the soil first,
+effectually guards the plumule from injury arising from contact
+with rough particles of earth; the cotyledons remain just below the
+soil-level and we see that the _tigellum_ is thickening and forming
+a distinct connecting branch between the new shoots and the fleshy
+seed leaves; these latter are full of plant food, and the plumule is
+supplied from this storehouse of nutriment until the first leaves are
+formed and are able to decompose carbon-dioxide for the nourishment
+of the plantlet. The seed-leaves in this case do not perform this
+function, but act simply as storehouses.
+
+Our next seed example will be the familiar mustard plant. These we may
+sow in two lots, the first we only need to sprinkle upon some fine soil
+and the second may be sown in a shallow drill and covered with fine
+earth.
+
+[Illustration: GROWING MUSTARD SEEDS.]
+
+The first sowing will quickly germinate, and the movement of the
+radicle which pushes out of the micropyle may be understood by
+reference to the appended diagram. In it we see the white thread-like
+radicle emerging from the seed coat; it turns very quickly towards
+the ground and pushes directly into the soil. Here I must direct my
+readers’ attention to one of those minute arrangements which, though
+apparently insignificant enough if we fail to study the context, is
+really an evidence of the infinite perfection, care, and wisdom of the
+Creator in even such a tiny detail as the springing up of a mustard
+seed. As the seed lies upon the ground, the lengthening radicle, while
+it penetrates the ground, has a tendency to force the seed into the
+air (as shown in the illustration), and were it allowed to do so the
+seedling would soon shrivel up and die. This catastrophe is, however,
+averted by the development upon the radicle of quite a crop of fine
+white root-hairs; these adhere closely to the minute particles of the
+soil, and are thus enabled to counteract the force exerted by the tip
+of the radicle; the latter pushes through the ground without uplifting
+the seed. This action can be watched and the growth of the root-hairs
+observed by means of a pocket lens and by the exercise of that virtue,
+most necessary for all young naturalists—patience.
+
+Returning to the seeds that were sown under the soil, we find they
+have germinated; the radicle is pushing downwards, and just above the
+soil-level we may see the short curved _tigellum_. This very quickly
+straightens itself, and then we observe that the cotyledons have been
+drawn out of the seed-coats and are displayed as two green leaves,
+which in a few days will be an inch or two above the ground, owing
+to the growth of the _tigellum_. Here we get quite a departure from
+the bean seed, whose cotyledons were _hypogean_ (under the earth),
+those of the mustard being _epigean_ (upon the earth). There is also
+another point of difference; the mustard cotyledons are green, they
+contain chlorophyll corpuscles, have stomates, and so can perform
+all the functions of the normal green leaf; thus they help at once
+to feed the young plantlet by decomposing the carbon-dioxide of the
+air and forming starch, whilst in contrast to this we learnt that the
+seed-leaves of the bean were storehouses only. We are now sufficiently
+acquainted with the functions of the seed to be able to appreciate the
+variations of the _testa_, or seed-coat. In numerous instances the
+spines, prickles, hairs, and other growths on the surface have, in
+addition to their use in dispersing the seed, an essential purpose in
+holding the seed in its rightful position. We will take cress as our
+next example, since it may be regarded as a type of all smooth seeds.
+Cress seed remains intact until water comes in contact with it; then it
+becomes slimy by the liberation of a mucilaginous cement from the outer
+coat layer; this is, of course, highly adhesive, and thus the seeds are
+fixed firmly into the soil.
+
+Another example is that of the little epiphyte (mentioned in our first
+chapter), _Tillandsia usneoides_, or old man’s beard. When the seeds
+leave the capsule they are furnished with silky hairs, which enable
+the tiny little structures to float through the air; they soon come in
+contact with the bark of trees, and then the little hairs cling to
+the rough surface. In this position the seeds germinate, and are held
+firmly in their place by the tightly-clasping silken strands.
+
+[Illustration: BEECH COTYLEDONS.]
+
+Hardly any pursuit is more delightful than the collecting and drying
+of seedling trees; a ramble through the woods in early summer will
+reveal many specimens under or near the outskirts of the foliage.
+Under the beeches we shall soon light upon the nuts of last year
+coming up through the moist, rotting soil, in the form of two broad,
+green seed-leaves. As they often retain the dry, three-cornered
+seed-husk upon them, we can easily see that they are young beeches;
+otherwise, the cotyledon leaves being so unlike the perfect form, it
+might be rather difficult to distinguish the species. These seedlings
+have germinated somewhat like the bean seed, the radicle has grown
+downward, and the curved _tigellum_, pushing upwards, has drawn the
+cotyledons out of the seed-coat. We may notice with surprise through
+how small an aperture the cotyledons have been pushed, and still they
+are uninjured, a fact that is due to their being folded up like a fan
+in the seed-husk. As soon as the _tigellum_ reaches light and air it
+straightens out, and the flat seed leaves, which are at first of the
+palest green, soon deepen in colour, and are working away preparing
+food for the growth of the young plumule which springs up from between
+the cotyledons, crowned with two perfect young beech-leaves. This
+is all the baby-tree can do the first year. We can distinguish the
+second-year seedlings by their woody stem, brown leaf-scales, and
+silken-fringed young beech-leaves.
+
+[Illustration: ACORN.]
+
+We shall not find cotyledons on the young oak, horse-chestnut, or
+sweet-chestnut seedlings, because these remain normally below the
+ground (hypogean), forming a storehouse of nutriment for the young
+tree. It is interesting to watch the growth of an acorn when placed in
+damp moss in a saucer. After a few weeks the acorn will have absorbed
+water, and the leathery seed-coat will burst at the pointed end;
+through this rent the radicle will protrude, fibres will be found
+growing upon the root, the _tigellum_ is thick, and just where the
+stalks of the cotyledons are joined to it the plumule emerges as from
+a sheath. The plumule is in no hurry to develop leaves; its first
+growth is provided for by the rich supply of food within the acorn.
+If, however, we look carefully at its little stem, we shall observe
+upon its surface a few scattered scales, each with a rudimentary bud in
+its axil. When the shoot has attained a height of three or four inches
+it develops its first green leaf, and by the end of its first summer
+about six will have been formed. A collection of these seedling trees,
+carefully dried[24] and neatly arranged in a blank book, with the
+English and Latin names to each, a note of the age of the seedling, the
+spot where it was obtained, and the date, will in time form a pleasant
+memento of forest rambles, and, probably, may lead to further studies
+of a similar kind.
+
+[Illustration: HORSE-CHESTNUT.]
+
+[24] They merely need to be placed between sheets of blotting paper,
+which should be dried daily and kept in a press or under a weight for a
+few days until the specimens are fit to be placed in a book.
+
+To make the collection complete there should be some seedlings of the
+other great division of plants, namely, the plants with one seed-leaf
+(monocotyledons). A few date-stones will supply these specimens; they
+should be sown in moist earth and placed either in a greenhouse or on a
+sunny window-ledge, where their growth can be watched.
+
+Their germination is quite different from that of the other seeds we
+have described, and if a number of seeds are sown the different stages
+can be seen as in the accompanying figure.
+
+One long cotyledon is pushed out from the seed, the free end is like
+a sheath. The part nearest the seed forms a structure resembling a
+rolled-up stalk; from the former roots are developed, whilst from
+the rolled-up stalk or sheath grows the next formed leaf, and each
+successive leaf is sheathed like its predecessor. This arrangement can
+be well seen in young growing grasses which can be taken to pieces and
+examined. I shall conclude this chapter with a brief reference to the
+spores or so-called seeds of ferns and mosses.
+
+[Illustration: YOUNG DATE-PALM.]
+
+These are essentially different from the seeds that have formed
+our study in the earlier part of this chapter, they do not contain
+an embryo. Let us first notice fern-spores, which we shall find in
+abundance at the back of maiden-hair and other fern fronds; they are
+contained in little brown patches known as spore cases (_sporangium_,
+from _spora_, a spore, and _aggeion_, a vessel). If we collect some
+of these and sow them on some very fine damp earth, keeping it at the
+same time shaded and warm, the spores will soon germinate. We shall
+not find a radicle this time as the result of growth, but in its
+stead a flat expansion of green tissue (prothallium, Gr. _protos_,
+first, _thallos_, a branch) growing upon the earth like an exceedingly
+delicate leaf. From the underside of this green film a few very fine
+root-like hairs (rhizoids, Gr. _rhiza_, a root) are developed; very
+soon with a microscope we shall be able to discern upon the surface of
+this structure a few little projections. In one of these is developed
+a flask-shaped mass of cells (archegonium, Gr. _archegonos_, first
+of a race), in the other (antheridium, diminutive of Gr. _anthera_,
+an anther) some minute bodies (antherozoides, Gr. _anthera_ and
+_zooid_, a minute life) with tails; these escape from the covering and
+wriggle about very much like tiny animalcules until finally they come
+into contact with the flask-shaped opening before mentioned. These
+tailed structures are something like pollen grains in their function,
+only they differ from pollen grains, which are passive, by being
+endowed with the power of motion; the result of their fusion with the
+flask-like body is to fertilise the germ cell (oospore, Gr. _oon_,
+an egg) in that structure, and from the germ cell so fertilised is
+developed an embryo from which at once springs the young fern plant.
+The first leaf grows from the upper part of the embryo and from the
+lower part is developed the “foot,” a little connecting-link between
+the green prothallus and the baby fern which serves to nurse the little
+plant until two or more leaves have been produced; the roots also grow
+from the same part of the embryo. I imagine that fern spores could
+be grown and watched through all their various stages even by those
+of my readers who dwell in towns, as a bell glass would maintain the
+requisite dampness and shelter the young ferns from smoky air.
+
+Lastly I will describe an even simpler form of spore development.
+At any season of the year we may find the capsule fruit of mosses
+(Calyptra, Gr. _Kaluptra_, a veil), a very common one being the hair
+moss (Polytrichum, Gr. _Polutrichos_, having much hair), borne upon
+long wiry stalks. Inside the capsule we shall find a large quantity
+of small greenish bodies; these are the spores, which of course fall
+out when the spore-case is blown by the wind, and being light are
+easily carried away and at length find a resting-place in some damp
+nook or shady bank. In such a place they find the conditions necessary
+for their germination, which is not unlike the same process in other
+seeds and spores we have studied. The result is very simple. A fine,
+silky, thread-like body (protonema, Gr. _protos_, first, and _nema_,
+a thread) is developed; when this has attained a fair size, a little
+moss plant begins to grow upon its surface exactly as we see a bud grow
+upon a tree-branch, and it is upon this moss plant that the organs of
+reproduction are produced. We have now come to the end of our study of
+seeds.
+
+An endless source of interest to the student of nature is opened up to
+view by carefully observing the beginning of all vegetable life, and
+the seed or spore of the commonest weed or fern will teach us lessons
+that should ever make us mindful of the wonderful mystery of life and
+its genesis.
+
+Objects to collect and examine:—Poppy, silene, and collomia seeds.
+Examine _tigellum_ of cyclamen, radish, and carrot. Sow broad beans,
+mustard, and cress seed. Collect seedling trees. Sow date-stones.
+Examine fern and moss spores.
+
+
+
+
+CHAPTER XII
+
+_THE PHYSIOLOGY OF PLANTS_
+
+ “Lo! on each seed, within its tender rind,
+ Life’s golden threads in endless circles wind;
+ Maze within maze the lucid webs are roll’d,
+ And, as they burst, the living flames unfold.”
+
+ +Erasmus Darwin+, _The Botanic Garden_.
+
+
+
+
+CHAPTER XII
+
+THE PHYSIOLOGY OF PLANTS
+
+
+In this chapter I will endeavour to present to my readers a concise
+view of the nature and method of the various processes that go on
+continually in the growing plant.
+
+These processes were incidentally referred to in our examination of the
+character of the various organs of the plant. Thus, in dealing with the
+root, we spoke of its physiology so far as concerned the absorption of
+water by its root-hairs. In the leaf, we touched upon the correlation
+between the shape and arrangement of the leaf tissues and the part
+the leaf plays in the economy of the plant. The physiology of the
+reproductive organs, again, we briefly explained in connection with
+their natural history.
+
+In order to arrange our studies systematically, we may divide the
+physiology or function of plants into groups, and, taking each group
+separately study their effect on the plant.
+
+We may then divide the functions of plants into
+
+ Nutrition,
+ Assimilation, and
+ Reproduction.
+
+The first teaches us how a plant feeds and what it feeds upon; the
+second, how the food is prepared by the plant so as to enable it to
+use this food for growth and to store some of it away for future use.
+The third group deals with the various means adopted by plants for
+multiplying and increasing the species.
+
+Plants, like animals, must _feed_ and _breathe_ in order to live; the
+food of plants, however, differs from that of animals in being more
+simple and elementary.
+
+Plant food is of two kinds, water and gas. Water is an actual necessity
+to the plant, both as a direct food and as a medium to convey inorganic
+food. If we burn some wood to a white ash and then analyse it, six
+inorganic elements will always be found—potassium, magnesium, calcium,
+iron, phosphorus, and sulphur. These substances have been proved by
+experimental water-culture[25] to be indispensable to plant-life;
+others are found in larger or smaller quantities, but they are not,
+judging by experimental tests, essential to plant life. These inorganic
+elements do not enter the plant as such, but in the form of salts
+dissolved in water; the phosphorus and sulphur as phosphates and
+sulphates. Exactly how these salts and other elements are absorbed will
+be best learnt from a simple experiment.
+
+[25] Testing the effect of plant food by water-culture is carried out
+in the following manner. Six large jars are filled with distilled
+water. In No. 1 all the six elements above mentioned are placed in
+small quantities, so as to form a weak solution. In No. 2 only five of
+them are added to the water, and in each succeeding jar one element
+is left out. A seedling plant which has been germinated on damp sand
+is suspended in each jar in such a manner that the leaves are in the
+air and the roots in the water without the seed touching the liquid.
+The growth of the young plants is carefully observed, and the result
+is found to be that No. 1 will grow and flourish, finding all its
+needful food in the water, whilst the rest of the seedlings will show
+plainly by their feeble and starved condition that, the food elements
+being absent, they cannot build up their stems and leaves, and must
+eventually perish.
+
+We must first provide a large glass jar three parts full of clear
+water. Then a lamp chimney, to the bottom of which a piece of membrane
+(which any butcher will supply) has been affixed, should be partly
+filled with water coloured by sulphate of copper, and then suspended in
+the glass jar. Through a cork fitted to the top of the lamp chimney a
+long tube should be inserted. The fluid in the lamp-glass will be seen
+to rise in the tube shortly after the experiment is made, and the clean
+water in the large jar will become slightly coloured.
+
+[Illustration: TRANSFUSION DIAGRAM.]
+
+This experiment teaches us that liquids have the power of passing
+through a membrane; this power is known as diffusion, or _osmosis_.
+Further, we notice that the clear fluid passes into the coloured water
+more rapidly than the heavy coloured water passes out.
+
+Now the fine _root hairs_ of a growing plant are _membranes_, having
+the same property as the membrane we placed on the lamp shade; inside
+the root hairs there exists heavy dense cell sap, outside are the films
+of hygroscopic water containing (dissolved) inorganic salts, and this
+water passes in through the membrane of the root, whilst a very little
+of the cell sap passes out into the soil, the quantity passing in being
+greatly in excess of that which escapes.
+
+When once the crude water of the soil is inside, it is soon passed
+along to the stem and leaves by the pressure of more water coming in,
+and by what is called _capillary power_, this power we may easily see
+if we dip a fine tube into water, when at once the water will rise up
+some distance into the tube. I have pointed out that plant food is
+gaseous as well as aqueous.
+
+Oxygen is absorbed by the root very freely from the soil, and,
+therefore, farmers and gardeners frequently plough and stir the soil
+of fields and gardens so that the roots may obtain a supply of this
+needful gas.
+
+Let us now endeavour to see how the gaseous food is taken into the
+plant. In order to do so we must remember that the gases necessary
+for plant food form part of the air we breathe; this air is made up of
+two-thirds nitrogen, one-third oxygen, with a small and varying, but
+always present, quantity of carbon-dioxide, and of these the latter is
+the most essential to the life of plants.
+
+We have learnt in our study of the leaf how it, by the aid of the green
+chlorophyll granules, and under the influence of sunlight, absorbs
+this carbon-dioxide and effects certain changes in it. One of the most
+essential elements in the growth of plants is _nitrogen_; this we
+have just seen constitutes two-thirds of the air we breathe, but the
+plant is unable to make use of it in this free form; that is to say,
+although the leaf can freely absorb carbon-dioxide it cannot absorb
+nitrogen; it has to be taken in by the roots of ordinary plants in the
+form of nitrates, that is, in conjunction with some other element.
+There is, however, an important exception to this rule; for what are
+called the insectivorous plants have the power to absorb nitrogen under
+certain conditions. These will be explained in the succeeding chapter.
+We can now summarise the processes of nutrition. The roots absorb
+water containing earthy salts as well as oxygen gas. The leaves absorb
+gaseous food in the form of carbon-dioxide, and I may add sometimes
+water vapour. There are two simple experiments that my readers can
+make which will prove these statements, and will give them a greater
+interest in the somewhat dry details of vegetable physiology. Our first
+experiment to show the absorptive power of roots is taken from Sir
+Joseph Hooker’s Primer on Botany.
+
+“Take up three plants of the buttercup carefully by the roots; leave
+one (No. 1) on the table; place another (No. 2) with its roots in
+water; hang the third (No. 3) upside down over a tumbler of water with
+a few of the leaves in the water, but the root exposed. In due time No.
+1 will have faded; No. 2 will be quite fresh; No. 3 will have the parts
+not in the water faded. No. 1 shows that water contained in the plant
+has evaporated from its surface; No. 2 that the water has been absorbed
+by the root and conveyed to the leaves; No. 3 that the immersed leaves
+have not supplied the other portions of the plant with water.”
+
+The second function, assimilation, depends upon several processes
+that together go to make up the work of digestion and preparing plant
+food. These processes are transpiration, respiration, and evolution
+of oxygen; the latter process is associated with the feeding of the
+leaf—that is, the absorption of carbon-dioxide. This compound gas
+is under the influence of sunlight, and by the agency of the green
+colouring granules, decomposed into carbon-monoxide and oxygen; the
+latter is eliminated, whilst the carbon and a part of the oxygen is
+retained, and with the absorbed water is converted into material that
+the plant can use for the purpose of increasing its structure.
+
+By a very simple experiment we can prove the escape of oxygen from the
+foliage of plants. A few sprays of such leaves as laurustinus, bay,
+arbor vitæ, and maiden-hair fern should be tied firmly to a piece of
+stone. We should have ready a soup-plate, a glass shade, and a tub
+full of fresh spring water (one large enough to allow the shade to be
+held upright under the water). When all is ready, place the bunch of
+leaves and stone in the glass shade held horizontally, and gradually
+sink it under the water till the shade is quite full; place the
+soup-plate at the open end where the shade is, and slowly raise the
+glass until it is upright, and then it can be lifted out and placed on
+a table in a window where the sun or bright light can reach it. The
+bubbles of oxygen will soon begin to form along all the edges of the
+leaves and the jewelled effect of the bouquet will be very curious and
+beautiful. It is hardly needful to say the stone is simply required to
+keep the group in an upright position. By the following day there will
+be a large bubble of oxygen collected in the upper part of the shade,
+eliminated from the leaves by the aid of chlorophyll and sunlight.
+
+These changes resulting in assimilation are always in correlation with
+the process known as _transpiration_. The root is continually taking in
+fluids charged with inorganic salts; these are by the water conveyed
+to the leaves by means of the network of veins, which we know by the
+term fibro-vascular bundles. These, as we may see in skeleton leaves,
+traverse the entire substance of the leaves where the salts are used up
+in the constructive work of the plant. The water is not all wanted;
+part of it passes off in the form of vapour. Transpiration, then, is
+the passing off of this water.
+
+[Illustration: SKELETON LEAF.]
+
+We can easily see this process going on if we place a few tropæolum
+leaves in a cool tumbler, and then expose the tumbler to sunlight.
+In a short time the sides of the glass will show a film of moisture
+due to the transpiration of the leaves. This process takes place more
+freely in a warm temperature than in cool conditions; consequently, in
+hot weather there is rapid transpiration, and as the water is parted
+with more cell sap passes into the leaves and stems, and so the plant
+is kept cool. We can now see the great use of the little pores known
+as _Stomates_; these are found mainly on the under surface, and it is
+principally through these pores that the leaf transpires.
+
+We must now carefully note the fact that all growing parts of the
+plant take up oxygen and give off carbon-dioxide. This power which is
+common to all life is known as _respiration_. It is a process that
+cannot be observed in daylight in green plants because this respiration
+is feeble, and also because the opposite power of assimilation is
+so strong that the action of breathing is obscured. In the absence
+of sunlight, however, it can be observed, as also it may be traced
+in connection with parts of the plant other than the green leaves.
+Seeds, for example, during their earlier growth (germination) give off
+carbon-dioxide freely by respiration. This we can prove for ourselves
+by taking a large glass jar holding about two or three quarts; fill
+this about half full of beans that have been well soaked in water so
+as to swell them and induce them to commence germination. Close the
+jar with a tight fitting cork; after six or seven hours the presence
+of carbon-dioxide may be easily seen. Have ready a small phial of
+clear lime water, and with a piece of twine let this down into the jar
+without spilling its contents; allow it to remain there some minutes,
+keeping at the same time the top closed with a handkerchief. We shall
+see that the clear lime water will after a short time become cloudy
+or milky; this is due to the carbon-dioxide, liberated by the seeds,
+forming chalk with the calcium of the lime water, the chalk being
+insoluble and easily seen. Now take out the phial and let it stand,
+well covered, when the chalk in the form of a fine precipitate will
+be seen at the bottom of the phial. If desired, a second experiment
+can be made with the same jar by lowering into it a lighted taper; we
+shall find it will go out owing to the presence of the carbon-dioxide;
+as this gas does not support combustion our lighted taper is quickly
+extinguished.
+
+We can see from these experiments that respiration goes on in the
+growing plant and that this process is independent of chlorophyll. It
+is an essential part of the life of all plants, and my readers who may
+perhaps wonder why it is that two such opposite processes as I have
+described are both carried on in the plant must remember that in the
+main the feeding process which depends on sunlight and the presence
+of chlorophyll is carried on in the _daytime_, whilst respiration is
+practically counteracted in the daytime by the vigorous intake of
+carbon-dioxide. At night when the rays of light cease and no longer
+enable the plant to feed, the respiration is evident. Briefly, we
+learn that _in light_ the plant gains in weight, whilst _in darkness_
+(by respiration) it loses. The green plant can only construct growing
+material out of simple substances in light, having no power to do so in
+the dark.
+
+Heat is just as needful to plant-life; it must be above freezing point,
+and a somewhat high temperature is necessary to set in motion all those
+chemical processes that I have briefly described.
+
+At a low temperature the work of assimilation and other processes
+are arrested; on the other hand, a rise in temperature increases the
+activity of these processes.
+
+We now come to the third function called reproduction. We have seen
+in connection with the food of plants how they convert inorganic
+material into organic. This one fact is significant of the great office
+of plant-life in nature; animal-life could not exist without its
+help. Plant-life may be said to prepare the food of animal-life, and
+retain that balance of gases in the atmosphere necessary to healthy
+respiration. How important then it is that all kinds of herbs, trees
+and plants should multiply and be fruitful, life of any sort is of
+limited duration, and subject to all the vicissitudes of accident,
+constitution, and climate, and so we find that plants have been endowed
+with wonderful powers of reproduction in order that the earth may be
+constantly clothed with vegetation, necessary for the life of man and
+all animal nature.
+
+By reproduction I want my readers to clearly understand the power
+possessed by the individual plant to multiply its kind or species; and
+this power is carried into effect in a variety of ways in different
+species. These various methods of reproduction then will occupy the
+concluding pages of this chapter. The protoplasm (or life principle)
+of any individual plant is endowed with the power of giving rise to an
+entirely new individual. This is accomplished in one of two ways. In
+the first by cells forming a part of the plant, but yet not specially
+modified for the purpose of reproduction. This mode of increase
+is known as vegetative reproduction. We will illustrate it by two
+examples widely apart. Many lowly plants like protococcus (the bright
+green substance which so beautifully colours tree trunks in moist
+situations) and yeast, are formed of one cell only, and when such cells
+attain their full size they simply divide into two or more cells which
+grow, and finally attain maturity when the process is repeated.
+
+The other example is that known as the strawberry “runner,” this, as we
+know, is only an elongated stem bearing at the end a bunch of leaves,
+and from the base of the leaves a few roots, the whole being a new
+plant which may be removed from the parent and grown in some other
+place.
+
+These, then, are examples of vegetative reproduction, and my readers
+can discover for themselves many other instances in the garden.
+
+The plan of propagation by “cuttings” is simply the gardener’s
+practical application of vegetative reproduction.
+
+The second mode of increase is by special reproductive cells, which are
+set free by the parent plants and become new individuals. The second
+mode is common to all plant-life, and in it two distinct processes can
+be observed. We often see on a decayed pear or apple a patch of brown
+mould (mucor). If we examine it with a lens we see a little forest of
+tiny erect stalks, and upon the apex of each is a round ball containing
+reproductive cells, each of these, which are called spores (the
+spore-case being called the sporangium), contains protoplasm, which is
+endowed with the power of giving rise to a new individual mould.
+
+This process is typical of what is common to ferns, and many other
+cryptogamic plants, and is called _asexual reproduction_.
+
+The second form is that in which two such spore-like organs as we have
+noticed in the mould, fuse together and form a spore capable of giving
+rise to a new plant.
+
+This is known as _sexual reproduction_, and is dependent upon the fact
+that the protoplasm of either of the two organs is incapable of giving
+rise to a new individual plant, and that they must come in contact and
+fuse organically before a new plant can be formed. This process of
+fusion I have in an earlier chapter described as fertilisation. The
+pollen grain, the fertilising agent, is one of the reproductive cells,
+and the other, the ovule, is the cell that has to be fertilised. After
+this there is the subsequent development of the ovule into the seed,
+and in this seed we may recognise a plant in embryo endowed with powers
+not possessed by its parent, that enables it to resist extremes of heat
+and cold which would result in many cases in death to the parent plant.
+By way of experiment some seeds have been subjected to 40 degrees of
+cold, and yet have not lost their germinating power, whilst, on the
+other hand, it is known that seeds of some plants growing in sandy
+deserts lie baking in the sun for many months in a temperature of over
+70 degrees, and yet begin to grow as soon as moisture reaches them.[26]
+
+[26] From “Nat. Hist. of Plants,” p. 554: “It has been proved
+experimentally that seeds which have been deprived by calcium chloride
+of as much water as possible are not killed even at the boiling point
+of water.” Careful experiment has shown that there are three stages of
+activity in the life and work of a plant—(1) A _minimum or zero_, at
+which the processes are just possible; (2) a _medium stage_ or _optimum
+point_ where the activity is the greatest; and (3) a _maximum stage of
+heat_ where _growth is arrested_. So that we learn that plant-life can
+suffer from too high a temperature as well as that which is too low.
+
+Things to be observed or collected:—Experiments to be made in order to
+show diffusion, transpiration, and respiration, collection of oxygen
+from water bouquet. Carbon-dioxide from germinating beans. Observe—
+
+ Blue mould on fruit.
+ Strawberry runner.
+ Rooted cuttings.
+ Stamens and pistil of any flowering plant.
+
+
+
+
+CHAPTER XIII
+
+_INSECTIVOROUS PLANTS_
+
+ “Beyond, the moorland has its wealth
+ Of pink and purple, blue and gold;
+ Heather and gorse, whose breath gives health,
+ And ling, a hive of bees that hold:—
+ And when there’s moisture in the brake,
+ The clammy sundew’s glistening glands
+ ’Mid carmine foliage boldly make
+ Slaves of invading insect bands.”
+
+
+
+
+CHAPTER XIII
+
+INSECTIVOROUS PLANTS
+
+
+The statement in our previous chapter that the leaf has no power to
+absorb nitrogen, has to be received with a certain exceptions. These
+exceptions are discovered in a large group of plants, having little
+or no botanical relationship, and widely separated as regards their
+geographical distribution and habit of growth. The term insectivorous
+(insect-eating) has been applied to these by eminent botanists who have
+studied their habits and mode of growth. We may, as a preliminary to
+our study, summarise the main features of these interesting plants,
+because I wish my readers to see in them an extension and elaboration
+of the various processes we have tried to investigate in plant-life,
+and not a mere description of a few vegetable wonders. Rather would I
+point out that in studying these deviations from the ordinary type, as
+elsewhere, the young botanist should try to arrive at some explanation
+of these peculiarities, bearing always in mind that every part of the
+plant is created for some special purpose. This train of thought, if
+brought to bear upon our botanical study will prevent our regarding the
+contrivances of these insectivorous plants as mere freaks of nature,
+which appears to me to be a low and unworthy view to take of such
+delicate and wonderful structures.
+
+Occasionally, it is true, we meet with monstrosities, in the formation
+of which we fail to see any hidden purpose; but even here by careful
+observation we shall probably be able to perceive that it is the result
+of some injury or the accompaniment of disease from which plant-life is
+no more free than animal-life is.
+
+Let us now trace the features that are common to the plants which form
+the subject of this chapter.
+
+Perhaps their most interesting function is that of catching and
+retaining insects. This is accomplished in various ways, by viscid
+fluids which imprison small flies, as in the leaves of the sundew and
+other plants; by movements in the leaves, as in the Venus fly-trap; by
+a combination of both, as in the butterwort; or by special pitfalls
+and traps, as in the pitcher plants, sarracenias, bladderwort, and
+cephalotus. Having caught their prey, these plants dissolve it by
+means of an acid secretion; the dissolved animal-life is then absorbed
+and appropriated for the purposes of vegetable growth. Not all these
+processes are carried on by insect-eating plants. In some, for example,
+the secretion of dissolving acid is not very apparent, in others the
+absorbing glands are not fully developed; but, briefly, the above
+features are those possessed by this singular class of plants, and
+there is every reason to believe that powers of this kind are more
+widely spread than is usually supposed.
+
+We will now notice a few types in detail.
+
+The sundew (_Drosera rotundifolia_) is the pretty and poetic name of a
+plant which may often be found on boggy moors. It is barely an inch in
+height, a mere rosette of leaves shaped like a battledore, radiating
+from a very short root stock, and bearing, in early summer, a central
+flower-stalk from four to six inches high, furnished with a few tiny
+white flowers. The whole plant lies close to the ground, and is often
+embedded in bogmoss, and, were it not for the bright colour of the
+leaves[27] and their sparkling dewy effect, it would be a difficult
+plant to find. With the naked eye we can see that the leaves are
+covered with hairs, and a lens will show still more plainly that these
+hairs have each a club-like end bearing a gummy fluid, in appearance
+not unlike glycerine. These globules of fluid sparkle in the sun; hence
+the name of sundew and the botanical name of _drosera_, from the Greek
+“_aroseros_,” or dewy.
+
+[27] On sunny heaths they are often of a rich crimson tint.
+
+[Illustration: SUNDEW.]
+
+Leaves with glandular hairs are not rare amongst our wild plants, and
+if this was the only character that the sundew possessed it would not
+be specially noticeable. It is, however, the unusual structure and
+behaviour of these hairs that claims our notice. The term tentacle is a
+not inappropriate one to apply to these “hairs.” A leaf of sundew, with
+all its tentacles standing out at different angles from the surface
+of the leaf, and each point armed with a drop of viscid fluid, is an
+effective arrangement for catching insects. The bright glistening
+drops are a fatal attraction to flies, gnats, and other small insects.
+When they alight upon the points of the tentacles they soon find that
+they are held prisoners. In their efforts to get free they entangle
+themselves more and more on the slimy points of the treacherous hairs.
+If we watch the tentacles after a fly has been caught, it will soon
+be seen that the hairs are bending over and closely pressing down the
+wretched captive. This folding over occupies four or five hours from
+the time the capture is made. The glands also begin to give out an
+increased amount of gummy secretion, and this flow kills the insect
+by stopping up its breathing pores, so that literally it dies of
+suffocation. The fluid not only increases in quantity, but becomes
+acid, and its effect is to dissolve the insect and render it soluble;
+the dissolved parts are then absorbed by the glands and digested. This
+interesting process can be watched quite easily by carefully taking up
+a few plants of sundew with some of the bog-soil and moss in which they
+were growing and placing them in a glass dish, where they will continue
+for months in perfect health if kept very wet and covered with a bell
+glass.
+
+I once lighted on some magnificent sundew growing on boggy land near
+Woolmer Forest. Whilst taking up some roots of it I was persistently
+attacked by a stinging fly, and, my hands being occupied, I could
+not well defend myself. Happily the sundew acted a friendly part! I
+was carrying a tuft of it in my hand when, looking down, I saw my
+tormenting fly was securely caught upon its leaves. Somehow one always
+feels compassion for the unfortunate, and I confess I tried to rescue
+the captive, but the creature’s wings and legs were already so glued
+together by the viscid dew that it was impossible to release it, and I
+realised more than ever how effective the sundew is as a fly-trap.
+
+In transplanting specimens of drosera great care should be taken that
+the leaves are untouched, else, being sticky, they will cling together
+and lose their delicate beauty. Every few days the plants may be fed,
+and happily they are quite willing to accept very minute pieces of raw
+beef, so that flies need not be sacrificed in the cause of science. The
+little “beafeater” must not be fed a second time until the hairs have
+uncurled and the leaf has fully expanded, showing that the last meal
+has been digested. I have kept a large pan of sundew in great beauty
+for about four months in summer, and when the glass was taken off and
+bright sunshine lit up the jewelled leaves the effect was lovely, and a
+magnifying glass showed the structure of the leaves and the prismatic
+colouring of the dew-tipped hairs.
+
+[Illustration: VENUS FLY-TRAP.]
+
+The Venus fly-trap is an exotic member of the insectivorous family. Its
+leaves are remarkably like an ordinary spring rat-trap. A glance at the
+drawing will show its formation. On the two lobes of the leaf are a
+row of stiff bristles occupying the precise position of the teeth of a
+rat-trap. The inner surface of the leaves is of a reddish colour, due
+to its being thickly covered with minute red glands; on each lobe there
+are three stiff hairs. If a fly alighted on the leaf and walked across
+its surface, it would touch one of these hairs, and no matter how light
+the touch might be, the hairs are so sensitive they would convey the
+signal to the hinge of the lobes, and they would instantly rise up and
+clasp the fly, eventually crushing it to death. Then would follow, as
+in the case of the sundew, the emission of acrid secretion and the
+absorption and digestion of the insect.
+
+Insect-destroying plants are numerous in the vegetable world. They may
+be roughly divided into three groups, although there is no strict line
+of demarcation between them. First, those like the red lychnis and
+others, which, by means of sticky hairs, catch and kill small insects,
+an operation that, so far as we know, results in no special good to
+the plant. Then there are those, like the sundew, which catch, kill,
+and digest the insect for food; whilst the third group consists of
+plants which catch and kill insects, but have no digestive process.
+Decomposition of the captured insects takes place, but the absorption
+which goes on is simply that of the liquid products of decomposition,
+the latter process resulting from the insects being immersed in
+fluid. To this latter group belong the pitcher plants (_Nepenthes_)
+and sarracenias. These last are North American plants of peculiar
+structure and appearance. The leaf is folded and modified into a
+tunnel-shaped tube differing in form in the various species. In all
+there is a kind of cap or lid to the tube, so that rain is kept out. In
+one or two species the lid is so arranged that the mouth is exposed.
+In the bottom of these tubes there is usually a quantity of somewhat
+slimy fluid. The inner face of the lid and surface just inside the rim
+of the tube is smooth, usually of a bright shining colour and covered
+with minute honey-secreting glands, a most attractive lure for insects.
+Below this honeyed surface the character of the sides of the tube
+changes completely; for, down to the fluid, it is covered with stiff
+hairs all pointing downwards. Now we see how the trap is set. The honey
+just inside the tube is attractive, and the insect feeding finds it
+very easy to descend the tube; the smooth surface offers no foothold,
+and the downward pointed hairs prevent it from returning, until at last
+the insect becomes engulfed in the pool of water at the bottom of the
+tube. In this fluid insects generally accumulate, decompose, and become
+liquid manure.
+
+[Illustration: SARRACENIA FLAVA.]
+
+In Georgia and North Florida these sarracenias are found in the swamps
+in large quantities attaining one to two feet in height, their great
+tubes half-filled with insects showing their value in tending to
+reduce the swarms of flies which abound in such localities. We can
+see from these characteristics of the sarracenia a link between the
+insect-eating plants which have a true digestive process and ordinary
+plants that obtain their food in part direct from the soil. The
+sarracenia is simply making an attempt to collect nitrogenous food
+by the aid of its form and sweet secretions; thus it lures on flies
+and other insects to their doom, which to the plant means an increased
+supply of liquid manure for its nourishment.
+
+[Illustration: BLADDERWORT.]
+
+Between the two types of insectivorous plants and ordinary plants there
+are endless varieties. The largest known species of “fly-catcher” is
+the _Roridula dentata_ of South Africa, which attains a height of six
+feet, with leaves similar to the sundew in character. So efficient are
+these leaves in catching flies that the Boers hang up branches in their
+rooms as fly-traps.
+
+The smallest insect-eating plant is probably the bladderwort
+(_Utricularia vulgaris_), a rootless water plant with minute bladders
+on small thread-like leaves. The bladders only open inwards, so that
+when an insect pushes against the opening or valve it easily enters,
+and cannot get out again. The bladder contains water, but the insect
+quickly consumes the oxygen in it, and consequently dies, and when
+decayed its substance is absorbed by glands on the inner surface of the
+bladder.
+
+[Illustration:
+
+PITCHER OF NEPENTHES RAFFLESIANA.
+]
+
+Perhaps the most attractive of the group of plants we are considering
+is the pitcher plant or Nepenthes. It grows commonly in Borneo and
+Ceylon. The pitcher is a direct development of the midrib of the
+leaf. It varies in size from the little thimble-like pitcher of
+_Nepenthes gracilis_ to the large jug-like receptacles of _Nepenthes
+Rafflesiana_[28] and others, each capable of holding nearly a pint of
+fluid. The pitchers are furnished with a lid overhanging the mouth of
+the receptacle, this is kept open by a thick rim. This rim and the
+under-surface of the lid both secrete a sweet fluid which is attractive
+to insects, and from the rim and opening of the mouth a smooth surface
+directs the ill-fated flies to the sweet sticky fluid always found at
+the bottom of the pitcher, out of which they rarely come alive.
+
+[28] See Frontispiece.
+
+Another of our native plants exhibiting these insectivorous habits is
+the butterwort (_Pinguicula_). Like the sundew it is a mere rosette of
+radical leaves, having upturned margins and a very succulent pellucid
+appearance. These leaves are covered with glands which exude a viscid
+kind of fluid like that on the tentacles of the sundew. This natural
+birdlime catches and holds small flies, midges, and other tiny flying
+creatures, as well as crawling insects. The presence of these insects
+on the leaf appears to stimulate it to further secretion which must,
+of course, lessen the chances of the insect’s escape, and as a further
+barrier to prevent its creeping away, the edges of the leaf begin
+slowly to curve inwards, so that the caught insect is imprisoned in the
+folds of the leaf. The acid secretion which now exudes from the glands
+soon dissolves all the nitrogenous and soft parts of the insect, which
+are taken up by the absorptive glands of the leaf. There are many other
+plants, of which I have not space to make mention, although they are
+full of interest, as owing to their curious structure, it is probable
+that insectivorous habits might also be ascribed to them. The field
+of study is a wide one, and throws much light upon the physiology of
+plants as well as the relationship between the plant and animal world.
+I would suggest to my young readers, as a practical means of knowing
+more of this subject, to try and grow for themselves the sundew,
+pinguicula, and sarracenia.
+
+[Illustration: BUTTERWORT.]
+
+The two first can be found, as I have already said, on boggy moors in
+England, and the latter plant can be obtained from any florist. All can
+be successfully grown in a greenhouse or garden frame, and studying
+their growth and habits in this way will teach the young botanist far
+more agreeably than learning only from books.
+
+At Kew there is always a fine collection of these insectivorous plants
+to be seen in vigorous growth, whilst at the South Kensington Natural
+History Museum (Botanical Department) there are some highly interesting
+cases illustrating the life history of these remarkable plants.
+
+
+
+
+CHAPTER XIV
+
+_HABIT OF GROWTH IN PLANTS_
+
+ “Some clothe the soil that feeds them, far diffused
+ And lowly creeping, modest and yet fair,
+ Like virtue, thriving most where little seen;
+ Some, more aspiring, catch the neighbour shrub
+ With clasping tendrils, and invest his branch,
+ Else unadorn’d, with many a gay festoon
+ And fragrant chaplet, recompensing well
+ The strength they borrow with the grace they lend.”
+
+ +Cowper.+
+
+
+
+
+CHAPTER XIV
+
+HABIT OF GROWTH IN PLANTS
+
+
+My readers have possibly noticed that in the previous chapters my aim
+has been to describe the various organs of a plant, and that I have
+tried to show not merely the botanical meaning of the many differences
+in the organs of allied species, but to point out also how these
+structures are adapted to help the plant to multiply itself. The object
+of this final chapter is to take a more general view of plant-life,
+and to give some idea of the different habits of plants; how in their
+struggle to grow and reproduce themselves they form such habits as tend
+to assist them in this effort, and also how entirely, in some cases,
+they differ from our ordinary conception of plant-growth.
+
+We have already seen how beautifully plants are adapted to the life
+they have to lead, how they are specially fitted to grow in some
+particular place and climate, and now I will ask my readers to study
+with me certain of the varying habits of plant-life. A typical plant of
+an ordinary kind grows, of course, in the earth, produces root, stem,
+and leaves, and finally flowers, which are the origin of fruits and
+seed; by the latter the plant is again produced, and by this circular
+action the continuity of that particular plant is maintained.
+
+Let us now, in imagination, peep into a tropical forest. On its
+outskirts we shall see the prototypes of our typical plant; but inside
+there are also others of quite a different aspect, and the first to
+attract our attention would probably be the curious orchids perched
+upon the tree-branches. Their mode of growth differs greatly from that
+of a normal plant, for they are merely attached to the branches by
+means of clasping rootlets, which do not in any way extract sap from
+the tree to which they are clinging.
+
+The moisture they need is collected by the leaves and hanging rootlets
+from the humid atmosphere of the forest. These plants that have
+acquired a perching habit sometimes grow to an immense size, and where
+they do so vegetable _débris_ accumulates about their lower leaves and
+roots to such an extent that it serves to supply them with needful food.
+
+[Illustration: PERCHING ORCHID.]
+
+This habit of growth is not confined to the lovely orchids; mosses,
+lichens, ferns, and many other plants have acquired a similar mode of
+growth, and the various ways by which they attach themselves to the
+bearer plants would form an interesting subject of investigation. It
+is a not uncommon error to regard these perching plants as parasites,
+but this term is properly used for plants which actually feed upon the
+branches of the trees where they grow, and of course seriously injure
+the trees by so doing. The orchids, on the other hand, do not in any
+way injure the branch upon which they rest. Robert Louis Stevenson in
+one of his later poems has, with a poet’s license, which in this case
+is contrary to fact, described the perching orchid thus—
+
+ “For in the groins of branches, lo!
+ The cancers of the orchid grow.”
+
+This inaccurate observation is, however, more than atoned for by
+the wonderful impression Stevenson has given us of the character of
+woodland strife, the ceaseless struggle for light and air which goes on
+in tropical forests.
+
+In studying the parasites as a group of plants associated by the
+same habit of growth, we are led to the conclusion that there is some
+difference after all in the morality of plants! Here, for example, we
+are confronted with a group of plants that differ entirely from those
+we have hitherto examined. The mistletoe, which is the commonest type,
+is certainly lower in the social plant-scale than the perching orchid,
+the latter with its leaves and rootlets being enabled to earn its own
+living, while the mistletoe sends its roots down into the soft sap of
+the branch upon which it is growing and—there is no other name for
+it—steals its means of living and growing from the substance of the
+poor tree upon which it preys. It is true it does, in a half-hearted
+kind of way, assimilate a little gaseous food for itself, but the
+sickly metallic hue of its leaves is evidence that even in this respect
+it is shirking its proper duties of nutrition.
+
+[Illustration: RAFFLESIA ARNOLDII.]
+
+If we desire to study the curious habits of parasitic plants, the two
+examples referred to in a previous chapter, the clover-dodder and
+the yellow rattle, will afford good examples, the latter plant being
+easily obtainable in fields where the pasture is poor and scanty. Very
+curious are the modifications and contrivances developed by plants
+which have acquired this habit of parasitism, especially amongst such
+weird tropical species as _Rafflesia_, a huge parasite growing on the
+_Cissus_ in Sumatra. When the leaves and flowers of the cissus have
+withered, then here and there a huge knob protrudes from the stem or
+root, and this grows in time to an immense stemless flower, measuring
+more than three feet across, its cup frequently containing as much as
+twelve pints of liquid, and the weight of the whole flower being said
+to be about fifteen pounds.
+
+Differing a little in habit from the parasites are the _saprophyte_
+plants, which live on decaying vegetation. The little brown leafless
+orchid called the bird’s-nest orchis is of this character, as well
+as the equally curious coral-root orchis. These plants, as well as
+many other parasites, are destitute of chlorophyll, and are therefore
+dependent on organic material for food; this they obtain either as we
+have seen from living plants or from decaying organic matter. In their
+efforts to obtain a needful supply of light and air, some plants assume
+climbing habits, using as supports other trees and plants, to the very
+obvious disadvantage of the latter. We can well understand how, in a
+tropical forest, the weak-climbing plants strive to pass out of the
+shaded recesses and force their way to the tops of the slower growing
+trees, in order to obtain the share of light, moisture, and air which
+are essential to their existence. Very vividly has the late Mr. Louis
+Stevenson described such a scene in a tropical forest—
+
+ “The hooked liana in his gin
+ Noosed his reluctant neighbours in;
+ There the green murderer throve and spread,
+ Upon his smothering victims fed,
+ And wantoned on his climbing coil.
+ Contending roots fought for the soil
+ Like frighted demons; with despair
+ Competing branches pushed for air.”
+
+ * * * * *
+
+ “So hushed the woodland warfare goes
+ Unceasing; and the silent foes
+ Grapple and smother, strain and clasp
+ Without a cry, without a gasp.”
+
+I may explain that the “murderer” alluded to is a species of fig-tree
+which, in its early youth climbs up the trunks of other trees, and
+by means of its clasping roots so constricts their stems that they
+ultimately perish.
+
+In pleasing contrast to this phase of vegetable growth is the habit
+which indicates to us something of mutual help and co-operation. In
+the _Compositæ_ we find many instances of a habit of growth that bears
+distinctly upon this “help-one-another” mode of life. A common daisy
+will serve as a type-flower of this kind. The little head is a colony
+of flowers, but so close is the association of its individual florets
+that it is usual to regard it as one flower rather than a distinct
+inflorescence composed of numerous separate and distinct flowers.
+
+In order to understand the mutualism displayed by this little flower,
+we must remember that it is an insect-fertilised blossom, and,
+therefore, insects must be attracted to it. If we carefully dissect a
+flower-head we shall find first a ring of strap-shaped flowers on the
+outside, constituting the ray florets—these are imperfect;[29] but
+placed side by side on the outer edge they become conspicuous; then we
+find in the centre of the flower-head a number of tiny yellow flowers,
+each one containing stamens and pistils. What wee things they are, and
+if they were developed singly how inconspicuous they would be! When,
+however, they are grouped side by side in the centre, and further, when
+the outer florets are of a different colour and shape, what a beautiful
+and symmetrical whole they make! Truly this is another rendering of
+the maxim, Union is strength. From a different point of view the
+arrangement is equally interesting. The white and pink tipped florets
+of the ray are not capable of bearing seed, and yet we see how they
+help those florets that are perfect by their attractive appearance;
+then at night or on a cold rainy day these same ray florets bend over
+and completely cover up the florets in the centre which are busy
+producing seed. My readers will find a rich field of investigation open
+before them in studying the flowers of the daisy family, and finding
+out for themselves how the florets are grouped together, and to what
+extent this principle of co-operation can be traced.[30]
+
+[29] Barren.
+
+[30] A single flower of the Heracleum giganteum would not be specially
+noticeable, but when hundreds of them are grouped together in a huge
+umbelliferous head they form a most striking object, as may be seen in
+the plate. I have often watched the swarms of flies, beetles, and bees
+visiting these attractive blossoms on sunny days, and the great umbels
+of seed in autumn showed how effectually the insects had carried out
+their work of fertilisation.
+
+[Illustration: +GIANT COW-PARSNIP+ (_Heracleum Giganteum_).]
+
+Students will find the corn blue-bottle especially interesting; the
+large outer florets contain no organs of reproduction, but still they
+are brightly coloured and highly attractive to bees; the inner florets
+with their protruding stigmas and anthers, are much smaller; they are
+the seed-bearers, and cannot fail to receive pollination when the
+bee alights on the flower-head, allured by the showy outer florets,
+which apparently exist solely that they may draw insects to visit the
+unattractive flowers of the disc.
+
+[Illustration: CORN BLUE-BOTTLE.]
+
+The direct influence of the separate parts of a plant upon one
+another, and the very distinct habit of associating together that
+they may attain some end such as the visits of insects, leads us to
+consider two other aspects of plant-life, both of which are so full
+of interest that no botanical work can now be considered complete
+without some reference to the matter. If we carefully dig up a clover
+plant or a broad bean and examine the little rootlets we shall observe
+some small knobs or swellings upon them. These swellings are only
+found here and there on some of the roots, so that their presence is
+not a normal condition. Placing one of these knobs under a powerful
+microscope, we shall find it to be not ordinary root tissue but a
+substance teeming with countless numbers of rod-like or rounded atoms
+which botanists who have investigated the subject tell us are bacteria,
+_i.e._, inconceivably small one-celled plants which are often the
+cause of terrible diseases. But some of these mysterious organisms,
+on the other hand, are capable of beneficial results. It has of late
+been clearly proved that leguminous plants having these colonies of
+bacteria on their roots possess the power of assimilating the free
+nitrogen that forms such a large proportion of atmospheric air. When
+therefore a farmer sows his wheat in a field previously occupied by
+clover he finds the clover roots left in the soil contribute the best
+possible supply of nitrogen to the wheat crop. This seems a remarkable
+fact, since vegetable physiologists have hitherto insisted upon the
+fact that plant-life is unable to make use of the free nitrogen of the
+air. The other instance of strange habit is that of a symbiosis,[31]
+which exists between certain trees on the one hand and the threads of
+spawn of some fungi on the other. If the roots of the white poplar are
+examined minutely, quite a mantle of whitish threads will be found
+covering the growing point. It is said by that eminent botanist,
+Professor Kerner, and by others that, as the roots are developed from
+the young seedling-tree, they are enclosed in the meshes of the fungus,
+and that this particular fungus is always a close associate of the
+roots as they grow in all directions. This fact we can see when we
+dig up the roots, but the most striking part of the story is this,
+that between this fungus root and the roots of the tree there is an
+organic connection, a division of labour which results in the tree
+receiving from the thread-like filaments of the fungus (_hyphæ_) both
+moisture and certain food stuffs from the ground, whilst the fungus
+gets in return such organic food as the tree has produced by means of
+its green leaves. Such cases as these present to us a manner of growth
+that is akin to social habit, and, strange as the union may appear, the
+circumstance is by no means uncommon in the vegetable kingdom. Stranger
+still perhaps is the union that is sometimes to be found between plants
+and some member of the animal world, of which union I shall give an
+example. On one of the larger species of sea-anemones (_Anthea cereus_)
+are small yellowish spots, which at one time were supposed to form
+part of the animal itself. But now the spots turn out to be vegetable
+cells, which can be isolated and induced to continue growing after
+the death of the anemone. The yellow spots are small algæ, and are
+furnished with chlorophyll. We must not regard the algæ as parasites
+on the sea-anemone, because they split up the carbon-dioxide under the
+influence of sunlight, and by so doing supply the anemone with oxygen
+for respiration, whilst the starch formed in the protoplasm of the algæ
+passes by diffusion into the anatomy of the animal. The transaction
+does not end here; the algæ in all probability receives nitrogenous
+substances in return, so that there is a mutual interchange.
+
+[31] A word meaning two plants living together and deriving mutual
+benefit.
+
+These are but one or two of the many wonderful phases of vegetable
+life, and I hope by thus briefly sketching a few of them my readers
+will be stimulated into a greater desire to explore God’s marvellous
+works in nature. There is an endless succession of such wonders to be
+investigated, but in order to find them we need a careful spirit of
+observation, passing nothing by without trying to learn something of
+its life history. Every hedgerow is full of delightful problems which
+will reward the interested student. A single field has been found to
+contain as many as fifty different species of plants, and every month
+of the year will present a new aspect of life. In the early spring we
+have the germinating seed and the tiny growing moss. A little later the
+opening buds with their wealth of interesting points to study, then the
+unfolding of the leaves and the gradual development of the flower.
+Here and there a climbing plant will engage our attention, its mode of
+climbing, its modification of part or parts to enable it successfully
+to overcome difficulties, its acceptance of help by the way—as in the
+case of a bryony tendril I once came across which cleverly attached
+itself to a minute hole in a laurel leaf—these and many other items
+will interest us in our walks if we keep our eyes open.
+
+[Illustration: BRYONY TENDRIL.]
+
+Then, as summer slowly passes away and autumn approaches, the fruits
+will engage our attention; their forms and shapes and modes of
+dispersion will afford ample subjects for study.
+
+[Illustration: TRICHIA THROWING OUT SPORES.]
+
+Winter, too, still brings its store of pleasure for the young botanist.
+Nature is not dead—she only sleeps. Nay, unless there is hard frost and
+deep snow the field for observation is just as wide and the harvest
+as plentiful as at any other season. Look on the old apple-trees and
+see what a host of tiny plantlets there is there to glean. Here are
+pale-green bearded moss and lichens, there a branch, perhaps, lies
+on the ground dead and decaying, under whose mouldering bark, if we
+have keen eyes, we may discover tiny tufts of the _Mycetozoa_, whose
+capsules, under the microscope (and in some cases even with the naked
+eye) are seen to give off clouds of spores, actually thrown out by the
+active movements of fine waving threads, a sight never to be forgotten
+when it has been watched under favourable circumstances. Winter is
+also rich in its harvest of mushroom-like fungi; these will well repay
+a little study. We shall be led to note their form, colour, mode, and
+habit of growth, how they affect certain trees and soils, and the
+important difference of some kinds being eatable and others virulently
+poisonous; the mere book student can know very little of the keen
+pleasure enjoyed by those who thus think about what they see, and are
+ever adding to their stock of knowledge by personal observation. I may
+close with some true and beautiful thoughts by one[32] who is herself a
+reverent student of the book of nature.
+
+[32] Miss Blanche Atkinson, member of the Barmouth Branch of the
+Selborne Society.
+
+“No pleasure is more sure and none less costly than that of watching
+day by day the signs of the coming spring; than the delight of seeing
+unexpectedly the first primrose, and of finding that the anemones
+and hyacinths are pushing their way to the sunshine. Year by year the
+miracle of springtime, when the green leaves are shaken forth from the
+hard bud is more miraculous. Summer after summer the lilies are fairer,
+the wild roses more exquisite, and on through the seasons the varying
+pleasures succeed one another. These things never pall; and if the time
+should come when we can no longer go out to the hills and woods to
+welcome the spring and revel in the bounty of summer we know that the
+past is not lost. The fair remembrance of the flowers of the field is
+safe in our hearts, and will ‘flash upon that inward eye which is the
+bliss of solitude.’”
+
+
+
+
+_GLOSSARY OF SCIENTIFIC WORDS USED IN THIS VOLUME_
+
+
+
+
+GLOSSARY.
+
+
+A clear definition of scientific terms involves an exact knowledge
+of several languages, and when translated into technical phraseology
+these definitions often appear to me to be as difficult to a simple
+comprehension as the original words they purport to explain.
+
+I have endeavoured therefore, in this glossary, to put scientific terms
+into plain words as clearly as was consistent with the facts, and not
+by any means to attempt a really exhaustive scientific definition.
+
+
+A
+
+_Absciss_—A term applied to a layer of separating cells.
+
+_Absorption_—Taking in food by diffusion.
+
+_Accessory_—Anything additional.
+
+_Acetic_—Applied to an acid, sour.
+
+_Achene_—A small dry indehiscent fruit with a leathery coat.
+
+_Adaptation_—As applied to plant-life meaning the structure of the
+plant becoming most fitted to its environment.
+
+_Adventitious_—Not developed in regular order.
+
+_Aerial_—Inhabiting or existing in the air.
+
+_Æstivation_—The arrangement of the parts of the flower in the bud.
+
+_Albumen_—Reserve material contained in the seed, analogous to the
+white of an egg.
+
+_Alchemilla_—A genus of rosaceous plants with small green flowers.
+
+_Allium_—The onion genus.
+
+_Altitude_—Height.
+
+_Ampelopsis_—A genus of climbing plants allied to the vine whose leaves
+are brilliantly coloured in autumn.
+
+_Anemophilous_—Pollinated by the wind.
+
+_Animalcule_—Microscopic insect life.
+
+_Annual_—A plant whose duration of life is one season: _Ex._ mignonette.
+
+_Anthea_—A genus of sea-anemones.
+
+_Anther_—The dilated end of the stamen in which the pollen grains are
+developed.
+
+_Antheridium_—The case containing the antherozoids in cryptogamic
+plants.
+
+_Antherozoides_—The male cell, or active member in fertilisation of
+cryptogams.
+
+_Antirrhinum_—The snap-dragon genus.
+
+_Antiseptic_—Counteracting decay or putrefaction.
+
+_Apocarpous_—Applied to the pistil when the carpels are distinct or
+when the pistil consists of one carpel.
+
+_Appendages_—Something hanging or appended, extra.
+
+_Aquatic_—Relating to water.
+
+_Araucaria_—The generic name of the monkey-puzzle tree.
+
+_Archegonium_—The flask-shaped organ containing the female cell in the
+cryptogams.
+
+_Arid_—Dry and waterless.
+
+_Arillus_—An out-growth from the funicle (or seed-coat).
+
+_Aristolochia_—A genus of climbing plants with curious “prison” flowers
+which attract and retain insects.
+
+_Arum_—A genus of poisonous plants with an inflorescence consisting of
+spadix and spathe.
+
+_Asexual_—Not sexual.
+
+_Asparagus_—A genus of edible vegetables and climbing plants.
+
+_Assimilation_—The conversion of crude food into protoplasm.
+
+_Aster_—The generic name of the Michaelmas daisies.
+
+_Avena_—The generic name of the oat.
+
+_Awn_—The beard of barley and other corn.
+
+_Axillary_—Growing in the axil of the leaf.
+
+
+B
+
+_Bacteria_—Minute one-celled living atoms, the cause of most contagious
+diseases.
+
+_Bamboo_—A giant grass.
+
+_Banana_—The fruit of the genus Musa.
+
+_Bark_—The rough external part of a stem.
+
+_Barm_—Same as yeast.
+
+_Bast_—The fibrous tissue between the bark and the wood of a
+dicotyledonous stem.
+
+_Begonia_—A genus of plants with bright flowers and oblique or
+one-sided leaves.
+
+_Betula_—Generic name of the birch-tree.
+
+_Biennial_—A plant whose duration of life is two seasons: _Ex._
+Beetroot.
+
+_Bifacial_—With upper and lower sides structurally different: _Ex._
+laurel leaf.
+
+_Bignonia_—A genus of flowering climbing plants.
+
+_Blade_—The broad part of the leaf.
+
+_Bougainvillia_—A genus of climbing tropical plants with bright pink
+bracts and small yellowish flowers.
+
+_Bulb_—A dormant bud surrounded with fleshy scales.
+
+_Bulbils_—Small bulbs.
+
+_Bunium_—A genus of tuberous Umbelliferæ, earthnut.
+
+_Buoyant_—Light, able to float in air or water.
+
+_Button-wood_—A term applied in America to the plane tree.
+
+
+C
+
+_Cacti_—A family of succulent plants usually devoid of leaves.
+
+_Caducous_—Quickly dropping off.
+
+_Calceolaria_—A genus of herbaceous garden plants with pouched flowers.
+
+_Calcium_—An element present in all calcareous rocks.
+
+_Calyptra_—The hood of a moss-fruit.
+
+_Calyx_—The outer whorl of the flower or floral envelope, cup-shaped.
+
+_Cambium-layer_—A layer of active growing tissue.
+
+_Campanula_—A genus of Alpine and herbaceous plants with bell-shaped
+flowers.
+
+_Camphor_—A drug obtained by dry distillation of the leaves and stems
+of Camphora officinarum.
+
+_Capillary_—Fine and minute, hair-like.
+
+_Carbon-dioxide_—Symbol CO₂. A gas existing in small quantities in
+the air, otherwise called carbonic-acid gas.
+
+_Carbon-monoxide_—A poisonous gas whose molecule is composed of one
+atom of carbon and one atom of oxygen.
+
+_Carex_—A genus of sedge-like plants.
+
+_Carpel_—A pistillate leaf, one of the component parts of the pistil.
+
+_Caterpillar_—The form of an insect after it is hatched, first stage.
+
+_Catkin_—A spike of staminate or pistillate flowers usually pendulous.
+
+_Checkered_—Outlined into a square-like pattern.
+
+_Chevaux de frise_—An obstacle consisting of iron spikes set in a
+framework of iron.
+
+_Chlorophyll_—The green colouring matter of leaves and stems.
+
+_Cholera_—A contagious disease.
+
+_Chrysalis_—_pl._ Chrysalides. The form assumed by some insects before
+they reach the winged state.
+
+_Chrysanthemum_—A genus of showy flowering plants belonging to the
+Compositæ.
+
+_Cinchona_—A genus of trees yielding quinine.
+
+_Circumnutation_—The rotating motion made by the growing point of the
+stem and leaf.
+
+_Cissus_—A genus of vine-like plants often with brilliant coloured
+leaves.
+
+_Climatic_—Influenced by a climate.
+
+_Coalesce_—To fuse, cohering of parts not usually joined.
+
+_Cocos-de-mer_—The large double cocoa-nut tree of the Seychelles Isles.
+
+_Collomia_—A genus of plants whose seeds are remarkable for the spiral
+fibres which expand elastically when wetted.
+
+_Compositæ_—A group of plants having an inflorescence of florets
+arranged upon a common receptacle or head.
+
+_Concentric_—A number of rings having a common centre.
+
+_Cone_—The hard woody fruits of the fir-tree.
+
+_Coniferous_—Fir-like, or cone-like; belonging to the cone-bearing
+family.
+
+_Continuity_—Unbroken succession.
+
+_Corolla_—The second whorl of the floral envelope usually brightly
+coloured.
+
+_Corpuscles_—Grains or granular.
+
+_Correlation_—_i.e._, connection, interdependence.
+
+_Cortex_—The bark or outer covering of stems.
+
+_Cotyledon_—A seed leaf.
+
+_Cruciferæ_—A group of plants having their petals arranged crosswise,
+with six stamens two of which are longer than the others.
+
+_Cryptogamic_—Relating to flowerless plants.
+
+_Culm_—The straw-like stems of the grasses.
+
+_Cuscuta_—The dodder genus, parasitic upon flax and clovers, &c.
+
+_Cuticle_—The exterior and thickened part of the epidermis.
+
+_Cyclamen_—Dwarf primulaceous plants with shortened stems (corms).
+
+
+D
+
+_Dahlia_—A genus of tuberous-rooted plants.
+
+_Darlingtonia_—A genus of Californian plants related to the side-saddle
+plants.
+
+_Datura_—The generic name of the thorn-apple.
+
+_Débris_—Remains, rubbish.
+
+_Deciduous_—Applied to plants, the leaves of which fall off in autumn.
+
+_Dehiscent_—Splitting open when ripe.
+
+_Deodar_—A tree allied to the cedar of Lebanon.
+
+_Dentaria_—A cruciferous plant bearing bulbils in the axils of the
+leaves.
+
+_Diagrammatic_—Drawn to illustrate a statement.
+
+_Dicotyledon_—A plant whose embryo has two primary seed-leaves.
+
+_Diffusion_—The intermingling of fluids (gases or liquids).
+
+_Diœcious_—When the pistillate flowers and staminate flowers are borne
+upon separate plants of the same species.
+
+_Dispersion_—Scattering.
+
+_Drosera_—The generic name of the sundews.
+
+
+E
+
+_Elastic_—Springy.
+
+_Embryo_—The future plant contained in the substance of the seed.
+
+_Embryo-sac_—The cavity in the substance of the nucellus, containing
+the egg-cell, which after fertilisation becomes the embryo.
+
+_Endocarp_—The inside layer of the pericarp.
+
+_Entomophilous_—Pollinated by insects.
+
+_Epicarp_—The outside layer of the pericarp.
+
+_Epidermis_—A layer of generally flattened cells forming the skin of
+the plant.
+
+_Epigean_—Developed like the cotyledons of mustard, above ground.
+
+_Epipetalous_—Growing upon the petals.
+
+_Erysipelas_—A disease of the blood causing a red eruption.
+
+_Eucalyptus_—The generic name of the Australian blue gum tree.
+
+_Euonomin_—A dry extract made from the root-bark of Euonymus
+altro-purpureus, a North American shrub.
+
+_Euonymus_—A genus of shrubs and hedgerow trees.
+
+_Euphorbia_—The spurge genus.
+
+_Exogen_—Growing by addition to outside of wood and inside of bark,
+synonymous with dicotyledon.
+
+
+F
+
+_Fermentation_—Changes that take place in wort when barm or yeast is
+added, or when fluids are exposed to the air. _See_ Yeast.
+
+_Fertilised_—Completion of the act of fertilisation, _i.e._, fusion of
+the male element contained in the pollen tube with the egg cell of the
+ovule.
+
+_Fibrous_—Meaning a structure of fine loose filaments or hairs, _i.e._,
+young rootlets.
+
+_Fibro-vascular_—A compound tissue of fibres and vessels.
+
+_Filament_—A thread-like fibre.
+
+_Flaccid_—Want of firmness, soft and lax.
+
+_Fructification_—The fruit system of a plant.
+
+_Fuchsia_—A genus of exotic flowering plants having a petaloid calyx.
+
+_Function_—As applied to plant-life, meaning the use and lifework of
+the members of a plant.
+
+_Fungoid_—Growth like a fungus.
+
+
+G
+
+_Gamopetalous_—Petals united.
+
+_Gamosepalous_—Sepals united.
+
+_Genesis_—Creation, production.
+
+_Germinate_—The change of the seed from the dormant state to the active
+growing stage.
+
+_Gloxinia_—A genus of popular hothouse plants with large handsome
+flowers.
+
+
+H
+
+_Habitat_—The natural abode of a plant.
+
+_Herbaceous_—Applied to plants which do not form a hard woody stem.
+
+_Herbarium_—A collection of dried plants.
+
+_Hexagonal_—A six-sided and angled figure.
+
+_Hibernating_—Sleeping, a dormant condition.
+
+_Hilum_—The black scar on a bean seed.
+
+_Hippuris_—A genus of aquatic flowering plants.
+
+_Horizontal_—Parallel to the horizon level.
+
+_Hoya_—A genus of tropical climbing plants.
+
+_Hyacinths_—Bulbous plants.
+
+_Hydrangea_—A genus of flowering shrubs.
+
+_Hygienic_—Relating to the preservation of health.
+
+_Hygrometric_—Moisture and its influence.
+
+_Hygroscopic_—Applied to the film of water surrounding the particles of
+the soil.
+
+_Hypericum_—The generic name of the St. John’s wort.
+
+_Hyphæ_—Filaments or threads of the fungus spawn.
+
+_Hypogean_—Development of the cotyledons under ground.
+
+
+I
+
+_Impatiens_—The generic name of the balsam.
+
+_Impervious_—Not to be penetrated by water.
+
+_Insectivorous_—Catching and killing insects, plants that have this
+power and can absorb the decomposed insects.
+
+_Insoluble_—Substances that do not dissolve in water.
+
+_Intercellular_—Spaces between the cells.
+
+_Internode_—The space between two nodes.
+
+_Involucre_—A whorl of bracts.
+
+_Iodine_—A soluble substance extracted from kelp and used as a test for
+starch.
+
+
+L
+
+_Laburnum_—Yellow-flowered trees allied to the Pea family (Leguminosæ).
+
+_Legume_—The dehiscent fruit of the pea family, a pod.
+
+_Leguminosæ_—A family of plants having for their fruit a legume or pod,
+_i.e._, Pea, Laburnum.
+
+_Lenticels_—Minute pores in the bark.
+
+_Liane_—A hanging root or stem.
+
+_Liber_—The inner bark, same as phloëm.
+
+_Linnæa_—A genus of dwarf trailing plants.
+
+_Luscious_—Sweet and succulent.
+
+
+M
+
+_Magnesium_—The metallic base of magnesia.
+
+_Magnolia_—A genus of flowering shrubs and trees.
+
+_Mahonia_—A genus of evergreen shrubs belonging to the barberry family.
+
+_Martynia_—A genus of plants having capsules with long curved hooks.
+
+_Melampyrum_—A genus of dwarf flowering plants partly parasitic.
+
+_Membranous_—Thin and destitute of green colour usually applied to
+bracts.
+
+_Mesocarp_—The central layer of the pericarp.
+
+_Mesophyll_—The ground tissue of the leaf.
+
+_Metabolism_—Changes which take place in protoplasm and which it causes
+in other substances.
+
+_Microbes_—A term applied to one-celled plant atoms, like bacteria.
+
+_Micropyle_—A small pore in the coats of the ovule through which the
+pollen tube passes.
+
+_Modicum_—Moderate sized; a small quantity.
+
+_Monocotyledon_—A plant whose seed is furnished with one seed leaf.
+
+_Monœcious_—Applied to a plant when the stamens and pistil are in
+distinct flowers.
+
+_Monstera_—A genus of climbing aroids with edible fruit.
+
+_Mucilaginous_—Sticky, gumlike, secreting mucilage.
+
+_Mucuna_—A genus of Brazilian Leguminosæ, yielding the cowage
+(consisting of intensely irritating hairs), of the Materia Medica.
+
+_Mutualism_—Interchange of some advantage, botanically applied to the
+union of two dissimilar plants which live in _close_ contact with each
+other to their mutual benefit.
+
+_Mycelium_—The root-like colourless filaments of fungi.
+
+_Mycetozoa_—A term applied to the slime-fungi.
+
+
+N
+
+_Nectary_—A honey secreting gland or spur.
+
+_Nemophila_—A genus of dwarf annual flowering plants.
+
+_Nepenthes_—A genus of plants having as a prolongation of the midrib of
+the leaves, ascidia or pitchers.
+
+_Nocturnal_—Happening by night.
+
+_Node_—The exact point on the stem from which the leaf is developed.
+
+_Normal_—Regular, unaffected by any modification.
+
+_Noxious_—Hurtful or poisonous.
+
+_Nucellus_—The internal tissue of the ovule within which the embryo-sac
+is embedded.
+
+_Nutrition_—The process and function of taking in food for the purpose
+of growth and to replace waste.
+
+
+O
+
+_Orchis_—A genus of the orchid family growing in the soil.
+
+_Osmosis_—The passage of fluids through a membrane.
+
+_Ovary_—The ovule case, that part of the carpel that bears ovules.
+
+_Ovule_—The structure which after fertilisation forms the seed.
+
+_Ovum_—The egg cell of the ovule.
+
+_Oxalis_—The generic name of the wood sorrel.
+
+_Oxygen_—A gas, one of the constituents of the atmosphere.
+
+
+P
+
+_Palisade-tissue_—A tissue of oblong cells placed side by side at right
+angles to the flat surface of the leaf.
+
+_Papilionaceous_—Butterfly shaped.
+
+_Pappus_—A light hairy development from the calyx of some plants.
+
+_Parasitic_—The habit of growing upon and deriving nourishment from
+another plant.
+
+_Pellucid_—Shining and transparent.
+
+_Perennial_—Plants that live for an indefinite period.
+
+_Perianth_—A term used when there is no distinction between calyx and
+corolla.
+
+_Pericarp_—The ripened walls of the ovary constituting the structure of
+the fruit.
+
+_Persistent_—Applied to the parts of the flower that remain on for some
+time.
+
+_Petunia_—A genus of Brazilian Solanaceæ.
+
+_Philodendron_—A genus of aroids usually climbers.
+
+_Phleum_—A grass.
+
+_Phloëm_—The inner bark, containing sieve-tubes.
+
+_Phosphate_—A salt formed by the union of phosphoric acid with some
+base.
+
+_Phyllotaxis_—The law of leaf arrangement.
+
+_Physalis_—The generic name of the winter cherry.
+
+_Physiological_—Having reference to the function or life work of the
+plant.
+
+_Picea_—A genus of the Conifer family.
+
+_Pinetum_—A garden devoted to the culture of pine-trees.
+
+_Pinguicula_—The generic name of the butterworts.
+
+_Pinus_—A genus of the Conifer family.
+
+_Pistil_—The female part of the flower consisting of ovary, style, and
+stigma.
+
+_Pistillate_—Applied to flowers having the pistil only.
+
+_Pith_—The soft tissue in the centre of the stem.
+
+_Plumbago_—The generic name of the leadworts, small flowering plants
+and shrubs.
+
+_Plumule_—The first stem shoot of the germinating seed.
+
+_Poa_—A grass.
+
+_Poinsettia_—A genus of Mexican plants having bright scarlet bracts and
+small flowers.
+
+_Pollard_—A tree trunk with its branches cut short.
+
+_Pollen_—The fertilising or male part of the flower.
+
+_Pollination_—The act of conveying the pollen from the stamen to the
+stigma.
+
+_Polypetalous_—Separate or many petals.
+
+_Polysepalous_—Separate or many sepals.
+
+_Polytrichum_—The generic name of the hair moss.
+
+_Potassium_—The metallic base of potash.
+
+_Proboscis_—The feeling and feeding organ of an insect.
+
+_Prothallus_—The first growth when the spore of a fern germinates.
+
+_Protococcus_—A genus of unicellular plants forming a green stain upon
+trees, &c.
+
+_Protonema_—The first growth of the moss-spore.
+
+_Protoplasm_—A highly complex substance forming the essential part of
+all living cells, and to which all life growth is due.
+
+_Prototypes_—First forms of plant-life.
+
+_Psamma_—A genus of the grass family.
+
+_Pseudo-bulb_—A swollen stem common in the epiphytic orchids.
+
+_Pteris_—The generic name of the bracken fern.
+
+
+Q
+
+_Quiescent_—Inactive, dormant.
+
+_Quinine_—An alkaloid extracted from the cinchona trees.
+
+
+R
+
+_Radicle_—The first formed root when a seed germinates.
+
+_Rafflesia_—A genus of brown leafless parasites.
+
+_Receptacle_—That part of the stalk on which the flower is developed.
+
+_Resin_—A secretion from certain trees which hardens on exposure.
+
+_Respiration_—The process of breathing.
+
+_Rhinanthus_—The generic name of the yellow-rattle (a root parasite).
+
+_Rhododendron_—A genus of popular flowering shrubs and dwarf trees.
+
+_Root-cap_—A loose covering of tissue that protects the extreme point
+of the growing root.
+
+_Root-hairs_—The delicate unicellular hairs found on the young root.
+
+
+S
+
+_Salicine_—A substance obtained from the bark of willows, soluble in
+water and alcohol, and crystallising in bright white needles.
+
+_Salvia_—A genus of labiate plants.
+
+_Samara_—Winged fruit.
+
+_Saprophyte_—Plants that live upon decaying organic matter.
+
+_Sarracenia_—The generic name of the North American side-saddle plants.
+
+_Saxifraga_—A genus of dwarf Alpine plants.
+
+_Scales_—Rudimentary leaves.
+
+_Secretion_—Applied to substances like resin and honey, the production
+of assimilation and metabolism.
+
+_Sedum_—A genus of succulent Alpine plants.
+
+_Soluble_—Any substance that dissolves in water.
+
+_Spadix_—The inflorescence of the Aroideæ.
+
+_Spathe_—The bract of the Aroideæ.
+
+_Sporangium_—The spore-case of some of the cryptogamia.
+
+_Spurious_—False.
+
+_Stapelia_—A genus of succulent plants, very poisonous and fœtid.
+
+_Starch_—Colourless grains, a product of assimilation in the leaf.
+
+_Stigma_—The receptive part of the pistil.
+
+_Stipa_—A genus of the grass family.
+
+_Stipules_—Small outgrowths at the base of the petiole.
+
+_Stomata_—Minute pores in the epidermis of the leaf or green stem.
+
+_Sulphate_—A salt formed by the combination of sulphuric acid with some
+base.
+
+_Sycamore_—The plane tree of Scotland, Acer pseudoplatanus.
+
+_Symbiosis_—Mutualism, a living for one another, interchange of
+benefits by united growth.
+
+_Syncarpous_—United carpels.
+
+
+T
+
+_Tannin_—A substance widely diffused through the leaves and stems of
+plants, of an astringent character.
+
+_Tap-root_—A root that forms an unbranched tapering axis: _Ex._, carrot.
+
+_Tendril_—A coiled or hooked filament modified to assist plants to
+climb.
+
+_Tentacles_—The glandular and feeler-like hairs of the sundew.
+
+_Terminal_—At the apex or end.
+
+_Testa_—The skin of seed.
+
+_Tigellum_—The first stalk of the seed bearing the cotyledons.
+
+_Tillandsia_—A New World genus of perching or epiphytic plants.
+
+_Tissue_—A group of cells; having a common origin.
+
+_Tormentilla_—A genus of small creeping rosaceous plants.
+
+_Transpiration_—The giving off of water vapour from the surface of
+leaves and stems.
+
+_Tricyrtis_—The generic name of the toad-lily.
+
+_Tuber_—A fleshy root or succulent underground stem.
+
+
+U
+
+_Umbelliferæ_—A group of plants having an umbellate arrangement of the
+inflorescence or flower-head.
+
+
+V
+
+_Vallisneria_—A genus of aquatic flowering plants.
+
+_Valved_—Having valves, _e.g._, anther of the barberry.
+
+_Vapour_—Gas into which most liquids and solids are converted by heat.
+
+_Vasculum_—A little vessel or box for collecting botanical and other
+specimens.
+
+_Venation_—The arrangement of veins in a leaf.
+
+
+W
+
+_Weigelia_—A genus of flowering shrubs allied to Honeysuckle.
+
+_Whorl_—An arrangement of leaves or parts of the flower in rings.
+
+_Wort_—Sweet unfermented new beer.
+
+
+Y
+
+_Yeast_—A unicellular plant that sets up fermentation under certain
+conditions.
+
+ The Gresham Press,
+
+ UNWIN BROTHERS,
+
+ WOKING AND LONDON.
+
+
+
+
+Transcriber’s notes
+
+
+The text contains some inconsistencies in the usage of hyphens. Only
+those have been corrected where the majority was spelled otherwise. All
+corrections made are listed below.
+
+To represent formatting the following conventions are used:
+ _word_ means that “word” is in italics;
+ +word+ means that “word” is in small capitals;
+ =word= means that “word” is in bold.
+
+The asterism (⁂) on page 8 should be inverted, but this was not
+possible to achieve since no such symbol exists.
+
+Corrections
+
+ Page 20 In the list of illustrations hyphens removed from
+ “MONO-COTYLEDON” and “DI-COTYLEDON”, to match the captions of the
+ illustrations;
+ Page 21 In the list of illustrations “WHITE LILY PISTIL” changed
+ to “WHITE-LILY PISTIL” and “POLLEN-TUBE” changed to “POLLEN TUBE”,
+ to match the captions of the illustrations;
+ Page 22 In the list of illustrations “DIAGRAM OF TRANSFUSION” changed
+ to “TRANSFUSION DIAGRAM”, to match the caption of the illustration;
+ Page 22 In the list of illustrations “FLAVA” added behind “SARRACENIA”,
+ to match the caption of the illustration;
+ Page 42 “Another of these perching-plants is _Tillandsia Usnoides_”
+ changed to “Another of these perching-plants is _Tillandsia
+ Usneoides_”;
+ Page 62 “aërial” in “send down slender aërial roots” changed to
+ “aerial”, to match the spelling in the rest of the text;
+ Page 69 In “We may look upon the earth as being a sort of store-house”,
+ “store-house” changed to “storehouse” to match the spelling in the
+ rest of the text;
+ Page 100 In “in a skeleton leaf, the mid-rib”, “mid-rib” changed to
+ “midrib”, to match the spelling in the rest of the text;
+ Page 102 one occurrence of “called” removed from “belonging to this
+ great division are called called dicotyledons”;
+ Page 136 “to render the bud waterpoof” changed to “to render the bud
+ waterproof”;
+ Page 138 In “wood-sorrel is rolled into a spiral”, “wood-sorrel” is
+ changed to “woodsorrel”, to match the spelling in the rest of the
+ text;
+ Page 159 In “resembling the pine-apple plant”, the hyphen is removed
+ from “pine-apple”, to match the spelling in the rest of the text;
+ Page 202 “so that at length the seed-coats” changed to “so that at
+ length the seed-coat”;
+ Page 223 “PINE CONES” in the caption of the illustration, change to
+ “PINE-CONES” (in the list of illustrations too) to match the spelling
+ in the rest of the text and “fir-cones”;
+ Page 232 “have seeds with wings lightly twisted” changed to “have seeds
+ with wings slightly twisted”;
+ Page 238 “COCOS DE MER” in the caption of the illustration is
+ hyphenated (in the list of illustrations too) to match the spelling
+ in the rest of the text;
+ Page 246 “ivy-leafed toadflax” changed to “ivy-leafed toad-flax” to
+ match the spelling in the rest of the text;
+ Page 263 “the little epiphyte (mentioned in our first chapter),
+ _Tillandsia usnoides_” changed to “the little epiphyte (mentioned
+ in our first chapter), _Tillandsia usneoides_”;
+ Page 263 “by decomposing the carbon dioxide” changed to “by decomposing
+ the carbon-dioxide” to match the spelling in the rest of the text;
+ Page 280 “absorbs this carbon dioxide and effects” changed to “absorbs
+ this carbon-dioxide and effects” to match the spelling in the rest
+ of the text;
+ Page 337 “into technical phraseology these defininition” changed to
+ “into technical phraseology these definitions”;
+ Page 340 comma after “tuberous Umbelliferæ, earthnut” changed to
+ period;
+ Page 348 period added after “flowering plants and shrubs”.
+*** END OF THE PROJECT GUTENBERG EBOOK 79061 ***
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