First Studies in Plant Life in Australasia _ WILLIAM GILLIES, M.A. Us New York State Callege of Agriculture At Gornell University Dthaca, N.Y. Library iin Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924000616346 Leaves of blue gum showing the oil-dots (after Von Mueller). first Studies in Plant Jeife in Rustralasia WITH NUMEROUS QUESTIONS, DIRECTIONS FOR OUTDOOR WORK, AND DRAWING AND COMPOSITION EXERCISES. BY WILLIAM GILLIES, M.A. Co-Author of Nature Studies in Australia.” MELBOURNE ; CHRISTCHURCH, WELLINGTON, DUNEDIN, AND LONDON: WHITCOMBE & TOMBS LIMITED. LL. (® QK43] re Ay. 4707 “ Without a knowledge of plant life we may admire flowers and trees, but it is only as strangers, only as one may admire a great man or a beautiful woman in a crowd. But when one with even a slight knowledge of that delightful study goes out into the woods, or into one of those fairy forests which we call fields, he finds himself in the company of friends, every one of whom has some- thing interesting to tell.” —StR JOHN LUBBOCK. “* People think that when they have toiled for a long time, almost all their lives, that then they will come to the flowers and the birds, and be joyful in the sunshine. But no, it will not be so; for then they will be old themselves, and their ears dull and their eyes dim, so that the birds will sound a great distance off and the flowers will not seem bright.” RICHARD JEFFERIES. PREFACE, THis book is meant for boys and girls beginning the study of plant life. It is true that I have given, wherever possible, the reason for the facts stated about plant life: a branch of the subject which is generally kept back for a senior course. I have done this because I believe that the method of keeping beginners exclusively to the facts is false to the principles of true teaching. Anyone may see this who walks into the fields with a child and takes note of the questions he puts. If you tell a child that the leaves of an elm are alternate, stipulate, pinnate, with the blade unequally divided by the mid rib he will soon grow tired ; but if you lead him below an elm tree and show him that the peculiar shape of the leaves enables each leaf to catch the maximum of light, he will listen readily. Also, you have given him a key to the meaning of leaves and leaf-form that may bring him to your side with many other eager questions about other leaves. Almost unconsciously he has learned the purpose of a leaf, and this in itself helps him to understand a hundred things in the life of the leaf that were meaningless before. Similarly, if you tell the child that a snapdragon flower is personate and bilabiate, with didynamous stamens and a two-lobed superior pistil he will soon grow tired; but if you try to explain to him that the snapdragon’s curious mouth is due to the visits of bees, he will listen readily. Also, you have given him a clue to the meaning of a multitude of strange-shaped flowers; and the endless variety of form in these flowers no longer bewilders him. It is true that in approaching plant-life in this way we have often to say to the child: ‘‘I do not know.” Sometimes, too, we have to give explanations that may need to be revised with larger knowledge. But this is no reason why the child should not have the best answer to his questions that we can give. If the boy Copernicus had not been drilled in the Ptolemaic theory of the heavens, he would have had little chance of finding out the Copernican system. vi PREFACE Even the ignorance that we confess may often be of value to the child. When a teacher who loves his subject admits ignorance, he does it in such a way that it is a valuable stimulus to research on the part of his pupils. In a short time, they become fellow- workers with him, The atmosphere created by this method is one to quicken research and originality ; and here, indeed, we have its best feature. The old authoritative method of teaching Botany as a series of ascertained facts with all the qualities of certainty and finality, not only destroyed interest in all but a few minds, but gave no impulse to inquiry —no enthusiasm of research. The barrenness of much so called education lies in the training of young minds to receive passively certain teachings as final ; the truth being that there is no finality in science. The great discoverers were great because they verified and examined and experimented for them- selves; and we do them homage not for reaching finality but because they made progress. This is why such men are often impatient with the crowd of admirers who form clubs to study their work; good as such clubs are. ‘‘If I had been content,” says Ruskin, ‘‘to sit at another man’s feet all my life there would have been to day no Ruskin societies.” In no part of the world, too, is the investigating mind more needed than in this new Southern World of ours. The life-histories of many of our native animals and plants is still unknown. Fine work has been done by our pioneers in Zoology and Botany, and we are grateful for their work ; but the half has not yet been told. Every one who has looked into these things for himself has seen new paths of investi- gation stretching out in all directions ; and the boys and girls who are now being trained to observe are to be congratulated on the wide field that lies before them. Only those plants and trees have been used that are well known both in town and country. No plants have been mentioned that are known to botanists only, or that have no popular names. The practical aspects of plant-study for Australasian scholars have not been neglected. I have tried to show that the art of the gardener and of the farmer in manuring, watering, draining, rota- tion of crops, budding, grafting and the like are all copied from Nature’s methods, and are only to be fully understood when learned in this way. If to-day our fields are more productive than they were 50 years ago, it is because we have won Nature to the service of man by a loving study of her ways. It was with no thought of profit, indeed, that Linnaeus and his successors studied in garden and field. Hard-headed business men looked askance at what seemed. PREFACE vil to them elegant idleness ; and yet to-day the granaries of the world are more richly stored because men like these have bent over the ‘flowers of the field. These are the men to whom Nature loves to whisper her secrets, and it is to men of this stamp that Nature gives the power to make two blades grow where before there was but one. It is sober truth to say that if plant-life were well taught in our schools, the produce of Australasian fields would be doubled. To statesmen who are at their wit’s end to find revenue, this plan for doubling the revenue of a State may be commended. Much of the teaching in the book has been put into the ques- tions and exercises at the end of each chapter. Pains have been taken with these, because the information given in the book will be of little value unless there be constant personal observation, experiment and thought. One important result of plant-study will be an increase of interest in tree-planting. Only second to this will be the growth of a conscience in our people about the native trees that still remain to us. When people understand what a great tree means, and how even a tree fern takes 50 years to grow, they will no longer be the vandals they have been in the past. Every teacher must have noticed that a child speaks of a plant as if it could plan and feel and even think like a human being. If we are to meet the child on his own ground, we must to some extent adopt this way of speaking. This will do no harm if the child is gradually taught, as it grows older, that the plant’s power of action and change is limited by laws fixed by the Creator. It is worthy of note, however, that a plant is able to change its form and habits in ways not dreamt of by our fathers. One of our native geraniums is the same plant that one finds in Europe; but the finer climatic conditions have enabled it to change from an annual to a perennial. Striking changes occur when some plants are taken from the interior to the coast, or from the plains to the mountains. The changes made in flowers by the agency of insects are recorded in the rocks, and the transformations wrought upon flowers and vegetables by the gardener are before our eyes daily. Changes like these are due to the power that a plant possesses of adapting itself to its surroundings. What this power of adaptation is we do not know ; we can only say that the Creator has given to the plant the power to change within certain limits. A plant is not a musical box that can play its tunes in one way and in no other. The plant can play its tune with many variations according to its surroundings. vill PREFACE The changes made on flowers by the constant visiting of insects or by man’s agency are of great interest to children ; and such facts prepare them to understand the great fact that life in plant or in animal is not fixed, but, within certain limits, plastic. Many a reformer, grown weary in the task of lifting human nature, has got fresh heart from this discovery. The limits of change, narrow in the plant and animal, are wide indeed when we rise to him who has been made in the image of God. Two conditions have to be observed by him who would improve a plant. He must find out the laws of the plant’s life, and he must obey these laws. By doing this we are making our garden plants more beautiful year by year; and the day is coming when we shall attempt with the same reverent obedience to the facts to beautify the garden wherein the plants are men and women. The introductory chapter is meant for teachers, parents and senior scholars. The drawings are from the pencil of Mr. Wm. Huddlestone. W. G. CONTENTS. PREFACE : LIST OF ILLUSTRATIONS | INTRODUCTORY CHAPTER—A WALK ROUND MY ‘GARDEN I.—How SrEEps GERMINATE: Part I.—A Seed with Two Seed-Leaves . II.—How SEEDs GERMINATE : Pare IL. = Sead ith One Seed-Leaf Ill.—Tue Root: Part I.—How ka Root ‘Feeds hy Drinking IV.—TuE Root: Part II. What the Root ‘Beaks sei Avoids V.—THE Root: Part III. 2a dins “at Reps ‘Netue's 8 Rotation of Crops aya VI.—TuHE STEM: Part I.—What tite ee is ae ae VIL— ,, 33 », II.—Root-sap Tubes and Leaf- sap Tubes VIII.—Cuiimsine PLANts AND . PARASITES IX.—Tue Leaves: Part I.—How the Leaves’ Air- Food is made : ae X.—THE LKAVES: Part Tl. Siew Dead | ‘Stuff is turned into Living Food hae XI.—THE LEAVES: Part III.—Some Experiments XIL— ,, $5 », 1V.—Shapes and Vein Plans XIII.— ,, 53 », | W.—Reasons for Leaf Shapes XIV.—How LEAVES PROTECT THEMSELVES ... ys XV.—THE FLOWER: Part I.— What is a Flower? XV -45 56 », LI.—Parts of a Flower XVIL— ,, - » UL—,, " XVIIL— ,, ag >», LIV.—The Gouiainnls Debt to Insects XIX.—TuHE FLower: Part v. =Hepulen eal ‘Integulae Flowers XX.—THE FLOWER: Part VIL — Nore abet the: Rowers S Debt to Insects XXIL—Tue Fiowen: Part VII. —_Wind- Rartiliived Flowers XXII.—FrRvITS AND SEEDS: Part I.—How Seeds are Spread XXIII.—FRvuITs AND SEEDS: Part II.—How Seeds are Spread by Animals XXIV.—FRUITS AND SEEDS: Part IL ew ‘Beeds are carried by the Wind XXV.--How PLANTS MULTIPLY WITHOUT SEEDS XXVI.—How PLANTS HAVE BEEN IMPROVED BY MAN... XXVII.—How ONE SEASON PREPARES FOR THE NEXT ... SUMMARY INDEX TO TERMS AND PLANT N dates LIST OF ILLUSTRATIONS. P. puss dots of bluegum ea Fig. 1—French bean seed .. 2—Seedlings growing 3—Castor oil seed 4—Bean-half growing 5—Wheat seed AGE 6 & 7—Wheat seed germinating 14 8—Leaf of plant with one seed-leaf 9—Leaf of plant cwith two seed-leaves : 10—Root pressure : aes 11— Root sucking up water ... 12—Imitation plant cell 13—Outer skin of root 14—Tap root 15—Fibrous root... 16—Fleshy root . os 17—Roots from creeping stem 18—New bulb forming ¢ on old bulb .. 19—Oak-stem cut. ee ake 20—Shoots cut to show age ais 21—One year old stem.. 23—Grape vine shoot cut to show water-path 24—Danubian reed cut to show water-path 25—Palm tree zy nermian creeper "freak leaf ... 28—Sticky discs, | creeper... 29—Alternate air roots, J ape- nese creeper 30—Sucking roots, mistletoe 31—The dodder clinging and sucking 32— Australian scrub-vine aes 33—Rose branch in shade of north fence 5 34—Ditto in sun . 35—Inside ofaleaf _.. 36—Lower skin of a leaf 37—Feather 38—Feather-veined leaf 39—Oak leaf 40—Feather leaf cut 41—Pepper leaf . 42—Geranium leaf ses 43—Ma.llow weed leaf ... 44—Plane tree leaf 45—Fig tree leaf .. 46—Virginian cr eeper leaf 47—Ivy leaf (entire) 48— Spearhead leaf 49—Shield-like leaf 50—Alternate leaves 51—Opposite leaflets 52—Whorl of leaves 53—Compound leaf 54—Grass leaf 56—E1m leaf J apanese 15 16 20 21 PAGE Fig. 57—Gum tree leaves ... 81 58—Blackwood ... 83 59—Ivy leaf, upper 83 60—Ivy leaf, lower 83 61—Whittaker’s sundew 84 62—Clover leaflets by day and night ee 86 63—Folded leaflets... 87 64—Morning flower, fleshy leaves _... 87 65—Oil dots of bluegum leaf 89 66—Scotch thistle ee 90 67—Gorse seedling 90 69—Rib grass... 91 70—F lower umbel of i ivy . 93 71—Petalsofscarlet geranium 99 fla anthers and pistil of Scarlet geranium 102 72—Wild geranium 104 73—Tubular flower 111 74—Regular flower . 111 75—Irregular flower ... 112 76—Foxglove ... 113 77—Salvia ae 114 78—Peaflower 115 79—Honey tube... 120 83—Oak catkin . 125 84—Plantain 127 85—Flower of wheat . 128 86—Pistil of a grass 128 87— Maize plant : 129 94—Ripe fruit of geranium.. 131 95—Stork’s Bill, ripening seed cases - 131 96—Peaflower pod empty 132 97—Coconut .. 133 98—Oat awn Ss 134 99—Groundsel ... 137 100—Burr-medick 138 100a—Bathurst Burr 139 101—Sorrel weed 140 102—Poppy head ei 143 103—Dandelion head ... 143 104—Seed case of willow-herb 144 105— Plane tree, fruit ball... 145 106—Parsnip seed 145 107—Pine seed 146 108—Elm seed a -. 146 109—Rose stamens eS 121, 148 110—Pineapple leaves... 149 111—Raspberry bush rooting 149 112—Strawberry runner 151 113—Native ru: = 152 114—Scaly bulb ... 153 115—Solid bulb ... 153 ee Bu 157 117—Desert Pea 158 118— Budding 160 119—Grafting—... . 161 120—Compound leaf ofrose 164 121 Plane tree leaf cup 165 122—Leaf scars ... 122 123—Edge vein, gum leaf 7 Frrst STUDIES IN PLANT LIFE. A WALK ROUND MY GARDEN. This introductory chapter is meant for parents and teachers. 1. As I walk round the garden on this fine morning, I try to find out the secret of its charm. Much of the charm cannot be put into words at all; but here are one or two reasons for the keen pleasure that it gives. 2. My plants interest me because I have watched them from seed to seed. I have sowed and thinned, watered and planted; I have guarded them from weeds and from slugs; I have watched for the first flower and wondered: Will it be white or pink? I have bent over them to see the bees at work, I have shown them proudly to my friends; and in doing all this a part of my life has passed into these flowers. 3. On the face of a garden Nature writes her calendar as she writes ij nowhere else. Month after month inscribes its message on tree and plant; nay, in a well-stocked garden every week has its new feature that tells the passage of the year to the lover of flowers. There is a legend that the shade of Linnaeus, on returning to his old garden from the other world, guessed the date within seven days by 2 FIRST STUDIES IN PLANT LIFE looking at certain flowers that were just opening. The idea is not a fanciful one. Last year the goose- berry bush beside the summer-house broke into leaf on the 20th of July. This year, on the 22nd of the month, I walked down to the bush and found that the grey thorns were almost covered with a shimmer of green! That rhubarb plant burst through the ground on the 10th of August last year, and this year the clods were pushed aside on the 11th of the month! What wonderful timekeepers these plants are! The last week of September brought the green flowers to the elm, though as yet no leaf had shewn; and the same week saw the new green fruit-balls of the plane tree swinging side by side with the old, brown battered ones. Year after year, the willow is in full leaf in the last week of August; and on the last week in September the beautiful leaves of the plane begin to hide the winter outlines of the tree. Have you heard of the chesnut at the Tuileries that was called old Vingt Mars by the gardeners who had grown grey in its company. This stick marks the place where an African lily is buried. There is no sign of life to-day ; but, within a week, it will throw up a flower- stem! The flower is even now on the way to keep its tryst. George Eliot has the fine thought of God calling the bead-roll of the stars, and of the stars coming out in the evening sky, one by one. Even so, the flowers obey the heavenly summons. 4. Can you wonder that the Greeks conceived of this yearly marvel as the return of the Flower-goddess from the lower world? The myths of every land and the art of every eye have added their own charm to what is perennially charming, And one never tires A WALK ROUND MY GARDEN 3 of it as one tires of many things. Nay, since each spring adds a new memory to old memories, the new spring comes ever with a richer fragrance. The eyes become dim ; but we see with the eyes of younger days ; the ears grow dull, but we hear with the ears of the boy. , 5. And here we catch a glimpse of another secret of the garden’s charm. The birds sing from tree and covert, so that we think of them as our birds—and as a part of the garden. Even from the “bare, ruined choirs”’ of winter, we hear the birds rehearsing for the spring burst of song; and when the full chorus comes on some fine September morning, the call to the garden is irresistible. James Russell Lowell, in speaking of the early days of Harvard University— then a wattled fold on the edge of the wilderness, tells us that among the students were some red Indians who were to be trained as missionaries. They worked hard for a time at Greek and Latin; but the forest whispered to them and the first blue bird of spring whistled them back to the woods. “Oh, Sir,” Lowell hears them saying to their teacher, “ you hear we are called!” In the country, the magpie, in town, the thrush, are our blue birds that call us out of doors. For every man who has been brought up among trees or flowers there is some bird-note that will not be denied. ‘Oh, Sir, you hear we are called !” 6. They interest me—these plants, because some remind me of friends, and others take my thoughts abroad to far-off lands. I remember the day, ten years ago, when | brought home the little plant from which this rose bush grew. I often think of my friend when I look at its beautiful blooms. The dew on its. 4 FIRST STUDIES IN PLANT LIFE buds helps to keep fresh our friendship. This plant I brought from Lake Tyers, four years ago: it recalls a pleasant holiday. And here are a dozen pansies raised from seed sent to me by a friend in Scotland. Beside these are tulips from bulbs sent out straight from Holland. 7. This little scarlet pimpernel—the poor man’s weather-glass,* takes one straight to England. It has sprung up with the lawn-seed, and is trying to be at home in a strange land where rain-clouds are rare. The love lily of South Africa stands close to the belladonna lily that found its way from the Cape to England when James of Scotland was King. And here, on the border, is an acanthus that grew in Greece when sculptors were learning to give the charm of flower and leaf to their stately temples. On the fence beyond is the creeper that reminds us of the rich lands of Virginia, and, beside it, the smaller- leaved variety that came to us from Japan. 8. The scent of wall-flower draws us to a plant that reached England from the Mediterranean in the Middle Ages. This chrysanthemum carries the thought to a valley of China, and the dahlia beside it takes us to its native haunts in Mexico. It is in Mexico, too, that we find this sunflower at home. Yonder golden patch of poppies is from the foothills of California—the Californian poppyt. These sweet peas on the fence lead us back again from America to Europe, and we seek the old home of the sweet pea in the valleys of Sicily. This white peony is from Siberia. Did it catch its colour from the snow? It * So called because it shuts up before rain. + Eschscholtzia. A WALK ROUND MY GARDEN: 5 is three centuries since this lilac was carried from Persia to England. 9. That foxglove recalls the flowers that grow on the sunny side of an old moss-covered wall in Surrey, and these harebells that nod in the wind take us to a breezy down in Sussex. The tall poplar at the garden-foot takes the thought to Lombardy, and to the wide plains of Germany and France; and the plane tree on the road beyond carries one, as on a magic carpet, to the Levant. This looking-glass bush is from New Zealand, and that silky oak is from the coast of New South Wales. 10. Memories of childhood are stirred as we come to a border of violets. Cherished for itself, this beautiful flower is prized still more because it brings back the first garden of childhood and the first flower that was planted in it. Happy the child who is set over a little plot of garden ground! Whatever may happen in after-life, that first garden of childhood is a garden of Eden from which he can never be driven out. And now we pass a bed of cress, and I recall the awestruck boy who saw one morning his own name rising in living green letters from the dark earth.* 11. These green shoots breaking through the ground are daffodils. They come to us in August, but they also come to us with the winds of March, because it was then that Shakespeare saw them. It was then, too, that Wordsworth saw them. Here we have come upon another clue that leads us to the ‘secret of the garden’scharm. This flower is dear to us * Parents would be doing a great service to their children if to each child ‘they would grant a little plot of ground. This plot should be visited -occasionally, and encouragement given to the child’s first attempts at .gardening. 6 FIRST STUDIES IN PLANT LIFE because Shakespeare loved it, and that because Milton wrote of it. 12. But, indeed, our thoughts cannot stay within garden walls when we ask the poets to walk with us. We wander into spring fields powdered with daisies and golden with buttercups, and to forest-glades where the blue hyacinth is “like the heavens upbreaking through the earth.” There are cowslips among the grass and poppies in the corn, and from the woods comes a cuckoo’s call that was never heard in Australia. 13. Thus am I a citizen of the world when I walk in my garden. 14. And if the flowers take us to the ends of the earth, they also take us into times long gone by. Ages have gone to the making of a plant; and its history is written on its face if only we could read it. The smallest weed has passed through a thousand changes of soil and climate, of friends and foes, and only the All-knowing Creator could give the full story of the meanest flower that breathes. But to us, His sons and daughters, He has given the delight of being able to spell out this story here and there. There is not a line or spot on leaf or flower but has its meaning. This is the true language of flowers. Happy he who can read it! HOW SEEDS GERMINATE 7 I—HOW SEEDS GERMINATE.—Parr I. Teachers and parents are earnestly reminded of the great: importance of creating interest in each subject before a formal lesson on that subject is given . Before a lesson on Roots is given, a large number of roots of common weeds should be pulled up: and examined by the child. He should be asked to say what he sees in the root before he is allowed to see with the teacher’s eye; to say what he thinks before he gets the teacher’s thought ; to suggest lis own puzzles about the root before any puzzles are thrust upon him. Then, and not till then, should the orderly lesson be given. 1. A seed with two seed-leaves. ‘T'wo seeds lay on a shelfi—a seed of wheat and a French bean. They had been forgotten for four years, and they seemed dead as the dust that lay thick upon them. Spring-cleaning came round, and they were swept out with the dust, and cast upon a garden-bed. Now the earth was dry, and the seeds lay on the ground as lifeless as when they lay on the shelf. Then came a heavy rain, and washed soil over both seeds. A week of cold winds followed ; and the seeds lay still in the damp, cold ground. And then a warm wind blew; and, two days after, a strange thing happened. The earth was gently pushed aside, and a tiny green shoot thrust itself into the world of light and air ! At first it shot up quite straight (see fig. 7), and looked like a solid green stem; but, after a few days, it began to unroll. A long green leaf came out; and then another, and another. It was now clear that the little green shoot was not a solid stem, but a bundle of delicate leaves wrapped tightly round one another 80 that they could push through the earth into the air. B 8 FIRST STUDIES IN PLANT LIFE 2. But now the French bean also has cracked the earth, and is coming up in a green loop (See fig 4). In a day or two the loop has risen clear of the earth; but the outer coat of the bean is still clinging to the loop. A few days more, and the loop has straightened itself into a stem bearing two fleshy green leaves, that do not look lke proper leaves. Next time we pass, two little green leaves that look like true leaves have risen from between the two fleshy leaves ; and now the plant is fairly started in life. 3. By what magic did these dead-looking seeds, that had been forgotten for four years,* spring into beautiful green plants? The outsides of the seeds give no answer to the puzzle. Shall we look inside ? 4. What we saw inside a French Bean: the Plantlet. Soak some French beans for twenty-four hours. Examine a bean after it has been a few hours in the water, and you will find that the skin has puckered up into wrinkles, as if the bean’s clothes were too big for it. Be ~The skin has swollen faster than the Pate, ceoq 8004 that lies inside it. A few hours splitopentoshow later, the water reaches the seed within the skin, and the seed swells out and fills the skin so that it is smooth again. 5. And now use finger and nail gently and split open the bean. The seed-coat peels off, and the halves *The best seed-wheat is the wheat of the previous year. Each year added to the age makes the germination more uncertain. The stories of the germination of wheat found in Egyptian mummies are not true. HOW SEEDS GERMINATE 9 of the bean fall apart. Can these halves be the two strange green fleshy leaves that we saw on the top of the loop? They have the same shape, but are white. We shall see. Fastened to a point near the end of one of the halves, is a tiny object that looks like a little plant with the leaves bunched up. You look through your lens, and see two small leaves. They must be leaves, for you see the veins quite clearly. These, then, must be the second pair of leaves that we saw. They cannot be the first pair, for these were not veined. But all this is guess-work; so now let us make an experiment. 6. How to watch seeds while germinating. The simplest way of all is to grow the seeds in moist saw- dust. This provides moisture and air; and these, along with heat, are the three needs at this stage. The seeds can be lifted out now and then, examined, and then returned to the saw-dust. For small seeds, the Bee is a better plan: Get the top of an old lamp chimney, or any cylin- drical glass tube open at both ends. Roll some fresh white blotting-paper into a tube, and slip it into the glass tube. Fill in, then, with loose moist saw-dust. Place now the seeds between the paper and the glass ; pushing them into position with a blunt wire. Putin the half of the French bean that has the plantlet attached to it. Fix, now, the glass tube in a pot or Seedlings growing bebind glass. 10 FIRST STUDIES IN PLANT LIFE box of earth, and keep the earth and the saw-dust moist. By this plan you can watch the seeds grow- ing as easily as you can watch bees in a glass hive. 7. The scar on the seed. And now while we aze waiting for the seed to grow, let us look again at a whole French bean. You notice the rounded back and that the opposite side is hollowed and has a scar. (See fig. 4.) If you have ever helped to shell beans or peas you will guess at once that the scar is the point where the bean was fixed to the pod. 8. A seed with a large plantlet. Examine also peas and broad beans and then split them open. In all these cases the plantlet is small; but if you will open a castor-oil seed, you will find a plantlet as long as the seed itself. Remove the beautiful mottled outer skin of the castor-oil seed, and then, with knife or Fig) finger nail, break the seed gently into its Castor-oi1 halves. If you have done this carefully, ee you will now see on one of the halves the Plantict- stem, and above it the leaf of the plantlet. Stem and leaf together cover the whole space. Use now your lens and you will see distinctly the veining of the leaf. Note also the tiny leaf-ruff just above the stem. This is the first pair of true leaves of the castor-oil seedling. 9. The little root in the seed. Coming back to the split French bean, we must now look for the little root below the plantlet. This root is so placed that it comes out of the seed-skin by a little door near the sear. Allow a whole bean to germinate, and you will see the tiny white root pushing through this little HOW SEEDS GERMINATE 11 door close to the scar. As soon as the root is clear of the bean, it begins to point downwards. 10. The seed-leaves. Meantime the plantlet is growing larger. Ina few days the leaves begin to take a green tint, and the green colour spreads to the stem just below the leaves, and to the whole of the bean- half. The root continues white. Already we can see that our guess was correct. The bean- half is one of the green, fleshy leaves which we saw above the ground, and the little leaves of the plantlet are the true leaves. And Bean-half growing: all the seedling abovethe g9, we shall call slue roots is now becoming green. ne ae hewn halved that turn into green fleshy leaves—seed-leaves. We see now that the halves in split peas are just seed leaves that have been pulled apart. 11. And now the green stem gets longer and longer, and takes the form of a loop above the bean-half. It is clear that the loop is trying to lift the seed-leaf into the air, and so you must press in the blotting- paper so that the seed-leaf can get out. If you do this, you will see, in a day or two, the loop lifting out the bean-half which is now a green, fleshy leaf. We have now been able to watch every step from the 12 FIRST STUDIES IN PLANT LIFE swelling of the seed to the opening of the second pair of leaves—the first pair of true leaves. 12. The three needs in germination. We have seen that seeds need heat and moisture before they will grow. They also need air. Light is not needed, and indeed, seeds germinate faster when light is shut out. Exercises, experiments, etc.:— (1) Most seeds germinate like the French bean, but the seed- leaves of some plants remain in the ground. Make experiments with the garden pea, broad bean, sunflower, pumpkin, acorn, castor-oil seed, cress. Notes.—(a) In each experiment a scholar should be made responsible for watering, for marking dates, and so on. (6) Grow some sunflower seedlings in a pot to be ready for the experiment described in Chapter 9. (2) Suspend an acorn over water by a piece of string in the neck of a wide-mouthed glass jar. If the weather be warm, the evaporating water will moisten the acorn and cause germination. To show that light is not necessary, a second jar could be placed in a dark place. (3) Asa boy was stooping over a barn floor, a mass of hay fell on his back. How could the boy exert most force to free himself? Compare the method of the French bean seedling in bursting through the ground. (4) Some split peas were accidentally sown, and some came up. Explain how this could be. Composition exercise :—Tell the story of a French bean plant from the seed to the first pair of true leaves. Drawing exercise :—Draw a French bean, (a) dry, (0) ger- minating ; showing the progress of growth at intervals. Mark the date on each sketch. HOW SEEDS GERMINATE 13 I.—HOW SEEDS GERMINATE.—Parr II. 1. Seeds with one seed-leaf. We have watched the germination of the French bean, a seed that has two seed-leaves. Most of our garden plants have two seed-leaves, but the grasses, lilies and some other plants have only one seed-leaf. Now, no garden plant is so important as the wheat plant—the queen of the grasses ; and so we must look closely at the seed of wheat, and then watch how it germinates. 2. What is inside a Wheat-seed. Slice open a well-soaked wheat seed, using a sharp knife. The seed does not split into halves like the fe French bean, and so we must cut through. a Cut downwards from the hairy end to the a | wrinkled end. The knife passes through bite 29 white “flour,” and lays bare the plantlet Wheatseea lying between the wrinkled end and the show ‘o flour. The plantlet is a little disc of a dull (3), ob e white colour quite different from the white ‘of the flour. This disc is the seed-leaf ; and its business is to cover the plantlet and to feed on the flour. The true leaves cannot yet be seen, nor can the little root be seen. The flour is the food that gives the young plant a start in life before it can gather food for itself. The flour is stored up to feed the seedling just as the white of an egg is stored up to feed a chicken. 8. But here you say: “There is no flour in the French bean; how then does the seedling get its food.?”’ It feeds, I reply, on the thick seed-leaves. When you 14 FIRST STUDIES IN PLANT LIFE eat haricot beans you are taking the same kind of food as the French bean seedling. Split open an acorn, which is another seed that has no seed-flour. Note how small the plantlet is, and how great is the store of food in the two thick halves, and you will understand what a fine start the oak seedling gets in life. Take up the acorn after the seedling has grown for a time, and you will find that the plant has eaten all the food in the acorn halves. Test this also with a wheat plant. 4. How a Wheat seed grows. And now we can look at the wheat seedlings as they grow behind glass ; and we shall compare them with the French bean ‘seedling. A little white root is pushing its way out from the wrinkled end of one of the seeds. Next time we look, there are three roots, all coming from the wrinkled end, and a tiny green shoot has come out from the same place. Root and shoot have broken through the seed-leaf that sheathed them. In the French bean one root only came out from the seed; but in the wheat several roots come out. Another difference is that all of these wheat roots do not grow straight down like the first root of ee the French bean. Some of the roots grow tet (is Sideways as well as downwards. Again, the fhe thie ne main root of the French bean shows to the sere re. melee eye no hairs ; but in the wheat roots the hairs are so many and so large that you can see them without your lens. But both in French bean and wheat the green shoot grows straight up. 5. When we next look, we find that the top of the wheat shoot is of a darker green than the lower part of the shoot. Use your lens and you will see that the HOW SEEDS GERMINATE 15 lower part with the brownish-green is a sheath, and that the dark-green part is a new shoot that has broken out of this sheath. In a few days, this new shoot gives off a broad leaf, and, a little further up, another leaf. 6. The veins in the leaves. Take one of these wheat leaves and hold it to the light and you will see that the veins all run upwards, side by side. Take now a leaf—a true leaf, of the French. bean, and you will see that there is a network of veins. Remember this difference carefully; for it is one of the ways of telling whether Wheat seed germina a plant belongs to the family of ting, showing the 5 hairy roots and the plants with two seed-leaves or to second stage of the shoot. Comparewith the family of plants with one seed- fig. 4. Leaf of a plant with one seed-leaf leaf. All those that have the veins running up side by side, as in the wheat leaf, have but one seed-leaf; all those that have a network of veins, as in the leaf of the French bean, have two seed-leaves. 7. The Roots. Coming back now to the roots, we notice that the stout main root of the French bean—the tap-root, has thrown out slender side-roots (fig. 4). The tap-root has grown quickly downwards to get out of reach of drought, and the side-roots have been thrown out to seek food, and to help to fix the seedling in case of storm. They act like the tent ropes that fasten down a tent. Pull up one of the seedlings gently, and you will 16 FIRST STUDIES IN PLANT LIFE find that earth comes up with the roots. Even when you rinse the root, some earth remains. This is because the little hairs on the roots are sticky. In this way the roots get a firm hold of the earth. If you live near a river, you may have seen the roots of a tall gum tree laid bare. Where the bank is washed away you can often trace the great roots for an astonishing distance. Besides these great roots you now know that there are thousands of slender rootlets that Leaf of @ plant with two Cling to the soil. You wonder no pens longer that the tree stands firm in the storm. 8. The wonderful root-tip. The tip of the root does its work so cleverly that it has been called the brain of the root. It chooses its path as if it had the powers of an insect groping its way with delicate “feelers.” You must remember that this little delicate thread-like root cannot thrust the earth aside like a mole-cricket, or eat its way through the hard clods like the worm. It must find a way where there seems to be no way. It gets round an obstacle or squeezes through close clods in a most wonderful manner. Again, if there is the slightest moisture, it moves towards it as if drawn by some magnet.* The point of the root would soon be worn off by all this wear and tear, but for a little cap that protects the tip. This root-cap is constantly being renewed ; just * Of course there is no magic in this. The root cannot move towards the water till some of the moisture has reached the root-hairs. HOW SEEDS GERMINATE 17 as the point of a worn plough-share is renewed by the blacksmith. 9. How the root behaves when the tip is lost. The greatest danger to this wonderful root-tip comes, not from hard work, but from insects. Many insects, like the wire-worm, the mole-cricket, and the grub of the cockchafer, live as greedily on roots as a cater- pillar lives on leaves. The root-tip is therefore often eaten ; and it is a strange fact that when this happens the root seems to lose its way like an insect that has lost its “feelers.” It may grow longer, but it does not, as before, move downwards. But the plant must have downward-roots; and so new roots spring out of the injured root and grow downwards. Shift a downward-root with a blunt wire so that it points sideways. In a little time, it will begin to point again downwards. Repeat the experiment, having first cut off the tip, and watch what happens. Have you ever noticed that when the top shoot of a pine tree is. broken off, one or two of the side branches take up its. work and grow upwards? Compare with this what. happens to your injured root. Experiments and Exercises.— (1) Continue experiments on the seeds mentioned in the last. chapter. (2) Find an old tree that has thrown up suckers from the roots. Measure the distance from the stem to the furthest sucker, and compare with the height or reach of the tree. If the tree has “‘suckered” all round, you can, in this way, see the root-area. Note.—Pears, white poplars, elms and some plums often sucker freely. (3) Compare the stem of a pine tree with the tap-root of a dandelion or of a mallow weed. Composition Exercise.—Write an account of the Root-tip and. its work. 18 FIRST STUDIES IN PLANT LIFE Drawing Exercise.—(1) Make drawings of a wheat-seedling grown behind glass, at various stages, marking dates. (2) Draw side by side (a) a wheat leaf, (6) a French bean leaf, to shew the different veining. II—THE ROOT.—Parr I. 1. How the root feeds by drinking. The great tree was hungry, and the little root far out from the trunk was searching for food in the hot, dry ground. Now, there was in the earth the very food that the tree needed. This food was close to the root, nay was touching it, and yet the root could not lay hold of it. The great tree was starving in the midst of food, because the earth was quite dry. The tree could not eat, because the little root could not drink. 2. A great thunderstorm came, and the warm rain soaked down to the earth, where the little root waited. The food in the earth passed into the water, and the root drank eagerly. Along the little root to the great root, and from the great root to the trunk, travelled the precious food. Then it climbed up the stem, and ran along the branches; it flowed into the twigs, and shoots, and spurs; it pushed into the leaves, and into every vein of the leaves; and soon the whole tree, from the tiniest root to the topmost leaf, was full of new life! 8. The foods supplied to the tree by the root. ““But, do not the leaves feed the tree?” you ask, THE ROOT 19: Yes, by far the greater part of a treo’s food is got by the leaves; but the tree needs lime, iron, and other foods that can only be got from the earth.* The tree needs only a very small amount of this root-food, but: cannot live without it. If you tear off a fresh green leaf from a plant and put it in water, it will go on making food out of the air, but it has soon to stop; and one reason is that it can no longer get any root- food; and, without this root-food, it cannot use the air-food. The roots are not made for taking in solid food : they can take in fluids only; and, therefore, the food must be in a liquid form. This is one reason why the roots must have water. Another reason is that all the materials needed by the tree in its many parts are water-borne. And, so, without water, food-supplies. are soon cut off. 4. But now you exclaim: “ How can water climb up a great tree?” Yes, it is a wonderful piece of work. You will feel this if you carry a bucket of water up a long stair, and remember that a tree can quickly pull up many times this weight. Even a single sunflower can soon pull up a pailful of water. 5. How can water climb up atree? Well, you must know that the root, like every other part of the plant, is built up of tiny cells (See Fig. 13). The root-hairs, too, are just long cells by which the root. drinks. These hair-cells have very thin walls, so. that the water gets easily through into the cell. But, when the water has got inside the cell, it cannot get out again ; and when the cell gets'so full that it can hold no more, it squeezes some water into the next. * And nitrogen, phosphorus, potash, sulphur, &c. 20 FIRST STUDIES IN PLANT LIFE cell. This cell in the same way gets too full, and Squeezes some water into the third cell; and so on, up the root, and up the stem. Besides this root- pressure which pushes the water up the tree, there is another force that pulls the water up. This second force is caused by the evaporation of water through the leaves, and we shall hear more of it when we study the leaf. 6. Two experiments to prove that the root lifts water. How great the root-pressure is in Spring you may see if you cut a grape-vine a little above the root. You will be astonished at the strong flow of sap. It flows and flows as if it would never stop. Looking at the rush of sap, you wonder no longer that a dry dead- looking vine-stump can, in a few weeks, cover the side of a house with beautiful vine leaves. Cut also the stem of a young sunflower, or any of your seedlings that are growing strongly, and you will see a drop of water oozing out. 7. Another pretty experiment is the following: Take a young, strong garden balsam that is growing in a pot. Out off the stem squarely, near the earth. Take a short piece of rubber tubing and slip it over the stem, and tie firmly. Then pour a little Experiment toshow Water into the tubing to keep the She stump moist. Take now a piece THE ROOT 21 of glass tubing, and fit it into the rubber tubing. Tie tightly, and then, in order to keep the glass-tubing upright, fix it to a stake. The water, in a few hours, will rise in the tube and continue to do so for a day or two. The soil must be watered as if the plant were uncut. 8. How the water passes from the earth into the root. And now I am ready for the question which you have been waiting to put: “ How is it that the water passes from the earth into the root-cell, but cannot pass from the root-cell into the earth?” To understand this, take a large, long potato, and hollow it out carefully, as shewn in the Figure. Place in the bottom of this potato-tube a dessert-spoontul of sugar, and then place the tube in a tumbler that has a little water in it. Mark on the tumbler the level of the water, and note how, in a day or two, this water is drawn into the tube and up the tube. In a few days the water may be at the brim of the potato-tube. And now re- mihasiade oie verse the process. Empty the Cossack up water, potato-tube and tumbler, and put pure water in the potato, and strong sugared water in the tumbler. The water will now pass from the potato into the tumbler. 9. Now, what does all this mean? It means that the flow of liquid is always from the weaker to the stronger fluid. This is why the water, in both cases, flowed towards the sugared water. Now, the fluid in 22, FIRST STUDIES IN PLANT LIFE the root-cell is stronger than the fluid in the earth, and so the earth-fluid passes into the root-cell. 10. Why does too much salt in a soil hurt plants ? Water the earth in a pot containing some of your sunflower seedlings with a strong solution of salt. The outside fluid is now the stronger ; and so the fluid in the roots will pass out into the earth, and the seedlings will wilt. This will help you to see why most plants cannot grow in soils that contain much salt. At Mildura whole orchards have been ruined by soil containing too much salt. In good soils the fluid in the root-cells is always stronger than the earth-fluid ; and so there is nothing to check the flow into the roots. An easy experiment will make all this clearer. 11. A make-believe plant-cell. Fill a small wide-mouthed bottle quite full with water in which some sugar has been melted. From a clean sheep’s bladder cut out a cover for the mouth. Tie this firmly, and place the whole bottle on its side in a vessel of water. In a day or two take it out, and note how the bladder- lid has bulged out. The strong fluid inside the bottle has sucked in some oateceeg: of the weaker fluid. Place now the mamersea"2 8" bottle in a vessel containing a very strong sugar-fluid ; using more sugar than will melt. This causes fluid to pass from the sugar-fluid inside to the stronger sugar-fluid outside, and the bladder- lid no longer bulges. Now, if instead of a bottle with a bladder-lid, we could try a root-cell, we should see THE ROOT 23; ¢ it behaving in the same way. When you remember that each root-hair is one little cell, and that the plant—root, stem, leaves, and flowers—is built up entirely of small cells, you will see the importance of the experiments we have just been making. 12. What becomes of the fluid-foods received by the root? If you melt salt in water, and then leave this water in the sun, the water will disappear into the air and the sali remain. In the same way, most of the fluid taken in by the roots passes into the air through the leaves; but the mineral food remains in the tree. Sometimes a mineral that is not good for the plant finds its way in this manner into the leaves; but when the leaves fall the plant gets rid of these harmful or useless minerals. Exercises and Out-door Work :— (1) The sap gets thicker as it goes up a tree, owing to the escape of water by evaporation from the leaves. Show how this helps to lift the water from the roots to the leaves. (2) Seek opportunities of seeing how deep roots go. Railway cuttings and other excavations offer chances of study. In dry districts a tiny plant may have a root 20 inches long. Summer annuals especially have to make haste to tap the moisture which is beyond the reach of drought. Dig up carefully some summer weeds, and examine the roots. Composition Exercise :—Tell how a plant drinks through its roots, and how the fluid is lifted up to the leaves. Drawing Exercise :—Take up carefully a seedling. Try to get all the roots snread out as they were in the earth, and make a drawing. 24 FIRST STUDIES IN PLANT LIFE IV._THE ROOT.—Pazr II. 1. What the root seeks and avoids. The first use of a root is to fix the young plant in the soil; and the second use is to seek food in the soil. And so it has come to pass that the tiny white root points down- wards from the very first, just as the tiny green shoot strives upwards from the very first. The root there- fore has learned to shun the light, just as the green shoot has learned to seek the light. We can see how strong is this habit from the air roots of the ivy. Examine these roots, and you will find that they always grow away from the light and on the shady side of the stem. We can see how hard the root tries to escape the light in roots like that of the carrot, that actually shrink into the soil. Look also at the tip of a bramble shoot that has rooted, and you will see how strongly the root pulls the tip into the earth. 2. Why does the root keep near the surface ? But here you ask: ‘“‘ Since the root goes down, why does it not go farther down?” Well, there are several reasons. One is that the moisture comes from rain or dew that may not sink far. Another reason is that the deep soil may be too cold. A third reason is that the soil near the surface is better aired. A root, like a germinating seed, needs warmth and air as well as moisture. Trees sometimes, in hot weather, send their roots too far down into cold sodden sub-soil. Such trees suffer from ‘“ wet feet.” The monks of old knew this, and would place a large flat stone under the roots of their peaches to keep them from going THE ROOT 25 into a cold subsoil. Also, the surface soil is richer in plant food, and so the roots run sideways as well as downwards. 8. How roots and branches correspond. Can you tell me now why the feeding roots of a tree are most numerous at the points where the rain runs off the leaves? In a shower, you sometimes stand under a tree as you would stand under a great umbrella. Watch where the rain drops as it runs off the leaves. If you dig at these points, you will find that the tree has placed feeding roots just where the rain drops. But there is no hard and fast rule; for the roots go on farther if there be good moist soil beyond. Often a root will run out in this way until it is longer than the highest point of the tree. 4. How sodden ground hurts the root. The root must have moisture, but too much moisture is almost as dangerous as too little. When there is too much moisture the root cannot get air. An exploring root will avoid a sodden patch just as it will avoid a stone. A simple experiment will show the damage done to a plant by earth that is too wet. Place side by side in the open air, where they can get the rain, a well-drained pot of wheat seedlings and a jam-tin pot of wheat seedlings; both sown at the same time. Give exactly the same amount of water to each pot. The earthenware pot is porous to air, and any surplus water passes out at the side or through the hole in the bottom. The jam-tin cannot receive air through its sides, nor can it get rid of water when there is too much. Compare the growth of the seedlings in the pot and in the tin. When the wheat is about eight inches out of the ground, take the plants up carefully and 26 FIRST STUDIES IN PLANT LIFE look with a lens at the roots. On the well-drained roots you will find hundreds of tiny feeding hairs, while on the badly-drained roots these feeding hairs will be absent or few in number. No wonder the wheat in a wet patch of ground has a starved look ! 5. How the hairs on the root take in food. The hairs on the root are, aS we saw, delicate cells that suck in water. Now these hairs will not grow in soil that is kept constantly wet. Hence the poor growth of wheat in wet, badly- drained soil. In warm, loose, moist soil, on the other hand, the number of roots and rootlets and root-hairs is astonishing. Every particle of soil seems to be searched. ) a creeping stem rooting at the joints. Note.—Indicate the roots by faint lines. * See Chap. XXVII for annuals and perennials THE STEM 35. VIL—THE STEM.—Parr I. ! 1. It is rare to find a boy in England who can handle an axe, but nearly every Australian boy knows how to make the chips fly. But not every boy can read the story of the wood he is chopping. And yet it is a wonderful story. One man looks at a great. gum tree that has fallen to the axe and says. “It will burn well;” another says: “It will split into good palings;” athird: “It will make good railway sleepers;’’ and then comes a man who looks at the rings of the tree and says: “‘ Here is the diary that. the tree kept. It has been keeping this story of its life for a thousand years. Look!’”—and here he points to a place where the rings are all close together, “that was a time of drought when the tree made little growth; and here, where the rings are wide, is a time of good years when the sap ran free. For ten centuries the ’keets have come to its honey-pots in the time of flower ; magpies and crows innumerable have perched on its branches, and thirty generations of blackfellows have climbed up to the nest of the opossum.” Who would not learn to read a story like this ? 2. First, then, let us ask, What has the stem of a plant todo? It has two things to do: to hold the leaves and flowers up in the air, and to act as a channel for the sap. First of all we are to see how the stem holds the leaves and flowers up in the air. 3. The stem as a leaf-supporter. If you try to: count the leaves on a great tree you will soon stop: 36 FIRST STUDIES IN PLANT LIFE there are so many. It must be a stout stem that can carry all these leaves. And-each year there are more leaves, and the stem must become stronger. And so the stem gets thicker and thicker as the leaves grow more and more, until you cannot put your arms round the stem. And, as the tree grows older, all the middle part of the stem—the heartwood—becomes dead and hard. It is this hard, dead heartwood that enables the tree to hold up its great mass of leaves and to face the storm. Look at a great gum tree in a strong wind. The young saplings near it that have as yet no heartwood bend almost to the ground; but the old gum tree bends not at all. Not for a thousand years has the old gum tree bent to the wind. 4. Where the new stem-wood is placed.—Can you guess where the tree puts the new wood it makes during the growing season? In the middle? No: we have seen that the middle becomes dead and hard. Where then? On the outside of the old wood, and just below the bark. The living, active wood in a tree is to be found close to the bark. 5. The bark.—And the bark—does it also put the new bark on the outside? No: you can see that the bark must put its new growth on the inside, because, the outside gets old and cracked, and often, indeed, splits or peels off.* The bark is sometimes very elastic, and is able to stretch without breaking as the stem grows, but in most trees it splits or peels. In the elm it breaks into ridges, and in the stringy-bark gum it peels off. The outer bark may be very thick, as in the cork oak or the stringy-bark gum, or it may *The thin formative layer which, on one side, makes the new wood, and -on the other side, makes the new bark, is called the cambium (cambio, I change). THE STEM 37 be thin, as in the lemon-scented gum tree or the plane tree. As this bark peels off, fresh bark forms, and the tree is not hurt. Indeed, the tree is often healthier for losing this bark. The plane tree is able, in this way, to throw off the dust that gathers on the stem in summer; and this is one reason why it is so good a tree for our dusty streets. . 6. Sometimes, as in a young wattle or lemon-scented gum, the outer bark is so thin that a scratch of the finger-nail shews the green layer of the bark. Most trees, however, have a thick, dead outer bark to protect the tender growing new bark and new wood. You can now see that the living part of a tree—the new bark and new wood—lies between dead bark and dead wood. You will now understand how, by ringing, we can kill a tree without cutting the tree right through. All that we have to do is to cut through the bark to the new wood. You will under- stand also how it is that after a bush fire many of the trees are able, in a short time, to throw out new shoots. The living part of the tree was protected by the outer dead bark, and so new shoots can be made from the tree’s reserve stores. Our “bush” trees, you see, have to lay up stores, not for a rainy day, but for a day of fire. Many of you have seen, within a few weeks of the fire, a beautiful fringe of green running along the blackened branches. 7. Aone-year old stem. And now you are ready to see for yourself how wood and bark grow. ‘Take a one-year old shoot of any quick-growing wood like the banksian rose, and make a slanting cut with a sharp knife. In the centre you have the soft pith, fig. 38 FIRST STUDIES IN PLANT LIFE 20 (1), outside of the pith a ring of wood; and, outside of all, the bark. On the outside of the bark you Fic 19 Oak-stem cut across to show the annual rings. The new wood (sap-wood) is just below the bark. The rays running from pith to bark form the silver grain. find a thin skin which afterwards thickens; below this there is the green layer of the bark, and still farther in we have the inner bark. A two-year old stem. Take now a two-year old stem, and you will see (1) the pith, (2) the wood of the first year, (3) the new wood, (4) the bark.