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.