POPULAR BOTANY
<\.E.KNIGHT,™>EDWARD STEP
THE LIBRARY
OF
THE UNIVERSITY
OF CALIFORNIA
LOS ANGELES
THE LIVING PLANT FROM SEED TO FRUIT
A BEAUTIFUL UGANDA EI.OWKR (SPJTHODM NILOTIC^).
This Spathodea is a tree in the forests of Uganda, and of the equatorial province of the Egyptian Sudan and the
northern part of the Congo basin. An allied form is found in Western Equatorial Africa. The flowers, which grow in
bunches, are individually shaped like a Roman lamp; and when the tree is in full blossom it looks as though decorated
with flaming lamps.
POPULAR BOTANY
THE LIVING PLANT FROM SEED TO FRUIT
BY
A. E. KNIGHT
AND
EDWARD STEP, F.L.S
VOLUME I
WITH
721 BEAUTIFUL ILLUSTRATIONS
AND
18 COLORED PLATES
NEW YORK
HENRY HOLT AND COMPANY
PRINTED IN GREAT BRITAIN
VOL. I.
CONTENTS.
V.I
CHAPTER PAQB
INTRODUCTION. i
I. THE PROTOPLAST 1
II. THE PROTOPLAST AS HOUSE-BUILDER AND HOUSE-FURNISHER 24
III. CELL COMMUNITIES : A CHAPIER ON TISSUES 73
IV. THE ASCENDING SAP , 92
V. THE DESCENDING SAP . « . . 124
VI. SEED AND ROOT . 160
VII. NATURE'S WOODCRAFT : A CHAPTER ON STEMS 205
VIII. LEAF-BEGINNINGS AND LEAF-FORMS 245
IX. THE LEAF IN RELATION TO ITS ENVIRONMENT 278
COLOURED PLATES.
A Beautiful Uganda Flower (Spathodea niloticii) ....... frontispiece
Facing page
The Rosy-lipped Cattleya (Cattleya lablata) 33
Glory Pea (Clianthus dampieri) ............ 65
A Pitcher-plant (Nepenthes amesianci) 97
Western Banksia (Banksia occidentalis) 129
Variegated Adamia (Adamia versicolor) . . . . . . . . . .161
Scarlet Passion-flower (Tacsonia manicata) 193
Moutan Pseony (Pceonia moutan) ........... 225
Walker's Cattleya (Cattleya walkeriana) .......... 256
ILLUSTRATIONS IN THE TEXT.
PACE
Alenrone Grains, Crystalloids
and Globoids in . .53
Amoeba .... 9
Aristolochia, Reniform Leaf
of a Species of . . 268
Arrowhead. . . . 275
— Leaf of . . . .270
Aspen . . . .64
Bacilli : Single-celled Fungi . 12
Bamboo . . . 55,225
Banana, Flowers of v
Banyan . . . .193
Barley . 1
— Grain of, before Germina-
tion, and tbe Same
Germinating . . 170
— Grains of, Germinating in
the Ear . . . 1
Bean, Common, Star-shaped
Cellsof ... 26
Bee Orchis. , 3
PAGE
Begonia .... 276
Bell-animalcule . . .10
Bignonia, Pitted Wood Cells
from . .
Bindweed, Hedge
Birch . .
Birch -tree . .
Birttiwort . .
Blackthorn .
Bladderwort, Commo
— Flower of .
— Small . .
' Blood Portent "
Bog Moss . .
Bomarea carderi.
Bottle-tree .
Bramble . .
— and Honeysuckle
Brazilian Forest,
Scene in a .
. .32
. . 235
. 65,201
. .203
. . v
. .229
. 108
. . 106
. .109
.14
. .33
. . 132
. .222
. 199, 224
. , 238
Night
.143
Broomrape, Large
— Lesser . . :
— Tall
Brnnsvigia josephince .
Bryony, White .
— Black . . .
Bryophyllum calycinum
Buckbean . . . •.
Bundle, Fibro- vascular
" Bush-rope "
Buttercup, Bulbous
Butterwort, Common .
— Mexican
— Pale .
— Section through Leaf of
Cabomba .
Cactus, Ackermar.n's .
— Flowers of a .
— Giant .
Carrot, Wild
PAGE
. 187
. 153
. 155
, 151
, 219
231
237
252
35
208
220
179
108
102
103
140
281
47
27
67
177
PAGE
" Caterpillar, Vegetable " . 157
Cedar-tree, Cone of . .84
Celandine . . . .49
— Lesser . . . .182
Cell, Pitted (Diagrammatic),
Section of a Part of a . 32
— Single, Plant of a . .. 11
Cells,Porous,Diagram to illus-
trate the Disposition of
Layers of Secondary
Deposit in . . .32
Cephailis ipecacuanha, Annu-
lated Root of,and Flower 184
Ccphalotus follicularis. . 13n
Ceropegia sandersoni , . 240
Cherry, ' Five-ranked (Pen-
tastichous) Arrangement
' of Leaves of the. . 256
— Wild . . . .257
Chicory .... 48
Cinquefoil . . . .268
Illustrations in the Text, Vol. I.
PAGE
PAGE
PAGE
PAGE
Clematis, White. . - 234
Honey-locust-tree, Hetero-
Nepenllies, Pitcher of . 112, 113
Sarracenia. , . .117
Coast-guards, Vegetable . 181
phyllous Leaf of. . 280
Nuclear Division, Indirect . 74
— atkinsom . . .115
Conifer, Cell from the Bark
Honeysuckle . . .239
Oak . . . . .260
Screw-pine . . .190
of New Zealand . . 32
— Perfoliate, with Connate
— Acorns and Leaves of
Sea-holly . . . .186
Oordyceps, Clubbed . . 159
Leaves . . .266
Pedunculate . . 243
Sensitive Plant . . .21
Cordyceps spJiecocepfiala . 156
Hop Trefoil or Tellow Clover 92
— Seedling ... 28
Silk weed or Crow-silk . . 73
Cork Cells .... 14
Hop, Wild. ... 30
— The Greendale, Welbeck . 242
Slime-fungus . . 15, 16
Cotton-plant, Fruit of . 13
Horse-chestnut . 175,245,247
— The Winfarthing, near
Snake's Head . . .216
Cotton Thistle . . . 263
Horse-tail, Field. . . 128
Diss . . . .244
Snowberry . . .25
Cowbane . . . .70
. Parenchyma from the
Oak-tree . . . .23
— Oval Cell from Fruit of . 24
Creeper, Virginia . . 232
Stem of the. . . 78
Oak-trees, Woodland . . 59
Snowdrop-tree . . . 194
Crocus . . . .288
Hyacinth, Garden . . 218
Olive with Part of the Flesh
Soldanella . . .13$
Indiarubber . . 248
removed to show the
Solomon'** *->pal T?l f *>i ^
— Saffron . . . .218
Indiarubber-plant, Cystolith
Stony Centre . . 53
Rhizome of . .212
Crops, Norfolk or Four-course
from Leaf of . .54
Onion, Crystals in Cells of . 53
Sorrel, Flowers of . .56
Rotation of, First Tear 93
Ivy Berries . . .196
Onion Skin, Cells of . .18
South African Plant . . 4
do., Second Tear . 93
— destroying Oak . .191
Orchid, Aerial Roots of an
Sow-thistle, Common, Collen-
do., Third Tear . 94
Ivy, Flowers of . . . 192
Epiphytal . . .41
chyma of the . . 82
do., Fourth Tear . 94
— Ground . . . 269, 272
Phyllanthus angustifolius . 228
Spiderwort, Virginian, Beaded
Cuckoo-pint . . 45, 131
Jak-fruit . . . .39
Pillwort . . . 210, 213
Hairs of . . . 17
Cycad, Cones of a . . 89
Jessamine . . . i
Pimpernel .... 274
Spleenwort, Scaly . . 249
Cystolith .... 54
Juniper .... 277
Pine Cone . . . .189
Spurge, Caper . .77
Daisy . . . .273
Lady's Smock . . .253
— Fungus . . .69
Spurges .... 230
Dandelion . . . 204, 276
Laporlea, Leaf of a . . 278
Pine, Cone of Sabine's. . 66
Star of Bethlehem . . 217
Date Palm, Fruit of the . 135
Larch ... 80, 81
— Germination of the Seed
Stem, Dicotyledonous. . 209
Desmid . . . .26
Lattice-leaf . . .284
of a . . . .178
Transverse Section of
Diatoms . . . .29
Laurel, American . . vii
— Scots . . 58, 87, 202
a Four-year-old, (Dia-
Dittany, False . . .141
Leaf Butterfly ... 4
Stoma of . . . 126
grammatic) . . . 206
Dodder, Greater. . . 152
Lebanon, Cedars of . .83
Pine-trees, Roots of . . vi
Stitch wort, Greater . . 23G
Dog-rose . i
Lecanora parella . . 86
Pink, Oval Cell from Leaf of 24
Stomata .... 129
— Hip or Fruit of . .44
Lettuce, Garden, Ants held
Pitcher, Calif ornian . .116
Strawberry, Wild . . 223
Dragon . . . .140
fast by the Milk-sap of . 46
Pitcher-plant ... 7
Sugar Cane . .43
Drosera intermedia . .97
Lichen, An Alpine . . 88
— An Australian . . 6
Sundew, Cape . . .100
Dryad's Saddle . . .197
— Section through a Thallus
— Huntsman's Horn . . iv
— Intermediate. . . 95
Edelweiss .... iii
of .... 38
— Hybrid . . . .107
— Portuguese . . . 101
Elm, English . . .207
Lichens on an Old Wall . ii
— Masters' . . .111
— Round-leaved . . 90
Euphorbia, Longitudinal Sec-
Lily, Martagon . . .137
Plane-tree, Oriental . . 250
Sweet Briar . . .19
tion of a Portion of the
Lime . . .57, 279
Plume-thistle, Marsh . . 265
Teasel . . . . 267
Cortical Parenchyma of a 76
Liverwort . . . .134
Plum, Sclerenchyma from
Thread-moss, Swan's-neck . 136
Fern Fronds Unrolling . 255
— Section throueh Part of
the Stone of a, made up
Thyme, Wild . . .01
Fern, Elk's-horn . . viii
the Thallus of . . 134
of Lignified Cells . . 82
Toadstool, Glittering . . 163
— Lady . . .71, 167
London Pride . . .271
Poppy-heads . . .52
Toothwort . . 121,123
— Maidenhair, Prothallus of
Lotus, Sacred, Leaf of . 276
Potato-plant . . .212
Travellers' Joy, Cells of . 20
a Species of . . 169
Maize, Seed of . . . 173
Potato, Starch - grains in
Prosenchyma of. . 78
— Male .... 72
— on the Fourth Day of
Broken Cells of a. .42
Trumpet-leaf . . .us
— Walking . . . 251
Germination . . 173
of . . . .40
Tulip-tree .... 250
Ferns, Sporangia of . . 169
— in Vertical Section . 173
Primrose .... 127
Tumboa .... 241
Fly-trap, An Aquatic. . 122
— at a Still Later Stage . 174
Privet .... 269
Valllsneria spiralis, Cells
Fuchsia, Raphides of a
Mallow, Dwarf . . .274
Protoplasm ... 9
from Leaf of . .37
Species of . . .54
Mangrove .... 200
Rnfflesia arnoldi. . . 154
Vaucheria clavata . .13
Fungus, Earth -ball . . 162
Maple, Field . . .198
Ragwort . . , .261
Vegetable Sheep. . . 5
— Snake's-tongue . .158
— Root-section of a Young 180
Raspberry . . . .44
Venus' Fly-trap . 98, 99
Furze . . . .188
Marjoram . . . .60
Reed, Italian, Portion of
Vessels . . . .205
Garden, Night in the. . 139
Mistletoe . . .36, 150
Stem of . .76
Vetch, Tufted . . .258
Garrya elliptica. Flowers of . 90
— Cells from the . .34
Reedmace . . . 286
Violet, Sweet . . .254
Genista sagittalis . .228
Monkshood and Trefoil . 262
Reindeer Moss . . .75
Walking-leaf Insect — a Bogus
Godwiniz gigas . . . 282
Monstera deliciosa . 133, 285
Revolving Globe ( Vohox
Plant .... 2
Grass, Ravenna . . .209
Morel . . . .160
globator) ... 8
Walnut-tree . . .62
— Vernal . . . .264
— Common . . .164
Rhizomorph . . . 144
Water-lily, Giant . . 283
Grasses in Flower . . 211
Moss, Luminous. . . 142
Rhododendron . . 125, 128
Water-moss, Greater . , 165
Hair-moss .... 166
Thread-like Growth
— Section through Part of
Water-thyme, Cells of. . 22
Hare's-ear, Perfoliate
(Protonema) of . . 142
the Leaf of a . . 124
Wheat . . . .171
Leaves of . . . 266
Moss-plant, Fructification of a 168
Rhubarb . . . .176
— and Corn Poppy . .91
Haricot Bean on the Second
— Spore and Germinating
Roots, Some Forms of . 183
Willow, White . . 68
Day after Planting . 172
Spore of a . . .166
Rose, Christmas . . 195, 246
Woodruff . . ' . . 227
on the Fifth Day after
Mould, Green . . .22
— Hooks of Wild . . 233
Woodsia, Round-leaved . 169
Planting . . .172
Mushroom, Common . . 161
Rubber, Crude . .50
Wood-sorrel . . 51, 221
with the Cotyledons
— Honey-coloured . . 146
Rush, Club . . .226
Wrack, Channelled . . 148
laid open . . .172
Mushrooms, Luminous . 147
— Common, Star - shaped
Tarn, Chinese . . . 214
Heliamphora moans . . 119
— Tree-destroying . . 145
Cells from Stem of . 26
Tew 79
Hellebore, Stinking . . 259
Myxogaster . . .149
— Flowering . . .31
Tucca Leaf, Horizontal
Hemlock Water-drop wort . 6;
Nepenthes .... 114
Sand-dune on the Sussex
Section through the
HoUy BuTc, Lichen on .85
— mixta, Pitcher of . . ilC
Co«t . . . .185
Epidermis of a . , 130
Photo by]
FIG. 1. — JESSAMINE (Jasminum officinale).
[K. Step.
INTRODUCTION
OUR delightful poet
Cowley, in one of the
choicest of his essays,
tells of the desire he always
had to be "master of a
small house and garden,
with very moderate con-
veniences joined to them,"
in order that he might dedi-
cate the remainder of his
life "only -to the culture of
them and the study of
Nature."
We can all understand
this satisfaction and delight
in Nature ; yet many, per-
haps, while confessing to
a sincere admiration for all
that is beautiful, would
shrink from the study of
Botany, and look upon it,
maybe, as a dull science,
occupied only with desicca-
tions and dissections, and
the endless acquisition of
names. To such persons a
1
Photo by]
[E. Step.
FIQ. 2. — DOG-ROSE (Rosa canina).
A. typical representative of a great family which provides us with the
most important of our fruit trees, as well as some of our finest flowers.
ii INTRODUCTION
botanist is a dry-as-dust gentleman, after the pattern of the meagre
philomath in Miss Kendall's Dreams to Sell, who saw in Nature a soulless
something, without beauty and without sentiment: —
He loved peculiar plants and rare
For any plant he did not care
That he had seen before :
Primroses by the river's brim
Dicotyledons were to him,
And they were nothing more.
Photo by]
j. 3. — LICHENS ON AN OLD WALL.
Step.
Lichens are independent of the soil, and obtain their nutriment entirely from the air. They therefore
grow upon bare rocks, tree bark, and walls, drying up in the summer but reviving in the autumn.
Professor Dawson is, we believe, responsible for the saying : " I hate
Theology and Botany, but I love religion and flowers" ; and if by the term
Botany the professor meant only those dry-as-dust expositions of the science
which some of us know so well, then we are quite at one with him. But it
would seem that the professor's antipathy is to the science itself, as opposed
to the more aesthetic study of Nature : and here his laconicism may prove
misleading. " You study Nature in the house " (i.e. in dried specimens),
wrote Professor Agassiz, " and when you go out of doors you cannot find
her " — suggestive words, that unlock the secret of many a wearying failure.
Dr. Lindley well observes on this point : " Only to apply their names to
Photo 6yJ
FIG. 4. — EDELWEISS (Leontopodium alpinum).
[O. R. Ballance.
A Composite plant whose flowers are not in themselves conspicuous, but are rendered so by the Ions
set them off. It is now only to be found on points of the Europe
. _, oolly bracts which
Alps difficult of access. Very slightly enlarged.
INTEODUCTION
a few plants is a poor insipid study, scarcely worth the following ; but to
know the hidden structure of such curious objects, to be acquainted with the
singular manner in which the various actions of their lives are performed,
and to learn by what certain signs their relationship — for they have their
relations like ourselves — is indicated, is surely among the most rational and
pleasing of pursuits." Depend upon it, therefore, if the study of Botany has
become to any one a dead letter instead of a living word, it is because it has
been pursued apart from Nature, and hence the great purpose of the science
has never been truly
grasped.
The truth is there are
botanists and botanists.
There are some who have
an intimate acquaintance
with all the plants of their
neighbourhood — know them
at sight, and can name them
correctly when they are in
flower. They know them
indeed as flowers, but be-
yond the identification can
tell you little about them.
They delight in the beauty
and fragrance of the blos-
soms, and probably regard
them in the good old-
fashioned orthodox way, as
created merely to gratify
the eye and the aesthetic
sense of man. There are
others, with the collecting
mania strong upon them,
whose chief interest in the
plants of a new locality is to
discover how many blanks
in their herbarium they can
fill up. This kind of
botanist may know all about
names and localities and
the comparative rarity of his spoils, but probably little about the living
plant. Another type is the botanist of the schools, who knows all the
most advanced theories of plant physiology and tissues, but will probably
fail in the field to identify correctly the commonest weeds. And then there
are the specialists and splitters, the men who have an exhaustive knowledge
Photo &y] [E. J. Wallis
FIQ. 5. — HUNTSMAN'S HORN PITCHER-PLANT
(Sarracenia flava).
The long pitchers contain a liquid in which insects are drowned, tli
serving for the sustenance of the Plant. NORTH AMERICA
INTRODUCTION
of one group — or even one species, as
commonly understood ; their know-
ledge is very deep, but often very
narrow. Lastly, there is the all-round
botanist of wider sympathies, who,
although his knowledge may not go
so deeply as that of the specialist's,
probably gets more wholesome satis-
faction out of it, because he sees
vegetation more as a whole, and
realizes how it fits in with the genera]
scheme of things on this planet — its
connections with soil and climate, with
insect, bird, and beast, and with man
himself. He may realize what the
others are not likely to do, that this
living plant has habits, likes and dis-
likes, and little ways of its own just
as surely as every animal has. To
him the truth may be patent that
Photo by] [8. L. liastin.
FIG. 6. — BIRTHWORT (Aristolochia gigas).
Insects attracted by the carrion-like odour enter the
flower and are kept prisoners for hours in order to effect
the fertilization of the incipient seeds. GUATEMALA.
upon this living plant all other life
depends entirely ; even the entire
human race with all its achievements
and glorious history has been, and is,
indebted for its existence upon the
living plant.
The plant provides us with every-
thing we really need, makes the
earth habitable, makes the air breath-
able and the water drinkable ; sup-
plies us with food — not merely the
food of the vegetarian, but of the
flesh-eater also. If there were no
other reasons why man should con-
cern himself with an intimate know-
ledge of the living plant — what it is,
what it accomplishes for the world,
and how it does it — this one fact
should suffice ; and it is our justifica-
Pholo by~[ [//. E. Hill.
FIG. 7. — FLOWERS OF BANANA (Musa
paradisiaca).
The beginnings of the- familiar fruit. THOHCS.
INTRODUCTION
tion for placing before readers this elementary and necessarily superficial
statement of what the living plant is, what it does for us, and how it accom-
plishes its good work.
Where does the living plant obtain all the material that feeds and clothes-
the innumerable forms of animal life, and finally the hundreds of millions of
the human race ? The answer is, mainly from the atmosphere, partly from
the sunbeams, and a little from the earth. Collect a large heap of vegetationr
and burn it. You will find that all there is left is a thin layer of fine ashr
the mineral portion of the plant's materials. The rest has passed off into the
atmosphere from which
it was derived.
Every blade of grass,
every tiniest moss, as
well as the more notice-
able trees and larger
herbs, are doing this-
work for the animal
kingdom ; and there is
scarcely an inch of the
natural surface of the
globe that is not occu-
pied by one or other of
the vast variety of liv-
ing plants that have
adapted themselves for
life in all situations and
under all conditions. It
has been computed that
no fewer than two hun-
dred thousand distinct
species of the living
plant are known to and
have been described
and named by man, and
it may be taken that
11 these forms are necessary, in order that full advantage should be
taken of all the varying conditions under which life is at all possible.
A little warmth, a little moisture, and a little light are the minima of
the living plant's demands. At the other end of the scale they may be
found in the parched desert, where they must endure extreme heat,
extreme light, and almost an absence of moisture. They put in an
appearance on the scarcely cooled cinders from the latest volcanic eruption,
and thrive in the waters of hot springs having a temperature of 176° F.
For all these varied conditions a corresponding variety of form and habit
[F. C. White Co.
FIG. 8.— ROOTS OF PINE-TREES.
Denuded of soil by a flood. One of the many exig
plant is subject. JAPAN.
ies to which tli
Photo by]
FIG. 9. — AMERICAN LAUREL (Kalmia latifolia).
[Henry Troth.
Also known as Mountain Laurel and Calico Bush. A beautiful shrub allied to the Khododendron, with white
or rosy flowers an inch across. The stamens are held in little pockets until a bee visits the flower in quest of
nectar, when they spring up with force and corer the bee with pollen. NORTH AMEMCA.
INTRODUCTION
is necessary, and we find, therefore, the living plant conforming to a number
of principal types, and under these principal types almost endless differences
in detail. In the waters and on the damp rocks we have the primitive plants
of a single cell ; where there is the thinnest coating of soil, the moss ; where-
there is a thicker layer of humus, formed from the decay of other vegetation,
the ferns ; and where there are corresponding depths of permeable soil, the
flowering herbs, the shrubs, and the majestic trees. Then, to utilize and
make further utilizable the decayed and worn-out parts of the green plants,,
we have the fungus tribe, unable to produce for themselves from the
elements, but living as saprophytes on dead matter, and some of them a»
parasites upon the living.
Now, to an author it is,
of course, impossible to take'
his readers out of doors ;
but we trust that long be-
fore the last page of this-
work has been reached we
shall have fulfilled the hum-
bler task of awakening an
interest in the subject that
shall compel the reader to
go forth and make that
closer acquaintance for him-
self.
It may be added that
the study of Botany has
special advantages over
almost all other sciences,,
inasmuch as it is concerned
with objects which are found
in every region of the globe..
It is a study which relieves
the monotony of town life,
and adds interest to every
walk in the country. It
proposes nothing that could
cause distress to a sensitive
mind. It quickens the
observing powers of the
mind ; the habits of accu-
racy and caution, so needful
in every walk of life, grow out of the practice of putting Nature to the
question. Best of all, no one is excluded from the study : the poor are as,
free to pursue it as the rich.
[//. J. Shepntone.
-ELK'S-HOKN FERN (Platycerium grande).
One of the grandest of the ferns, with fronds five or six feet in length It
grows on the trunks or brandies of trees. KORTHHKN AUSTRALIA and ASIA.
fnoio by}
FIG. 11. — GRAINS OF BARLEY GERMINATING IN THE EAR.
In wet seasons, when harvesting has to be postponed, the ripe corn will germinate in the ear and ruii
the crop. Long roots are formed which make towards the earth.
POPULAR BOTANY
THE LIVING PLANT FROM SEED TO FRUIT
CHAPTER I
THE PROTOPLAST
IT is perhaps superfluous to ob-
serve that no links have yet
been found between living and not
living, between organic and inor-
ganic matter, and therefore between
plants and minerals. The doctrine
of spontaneous generation, by which
it has been attempted to supply
such a link, is based upon assump-
tion and not ascertained facts. The
most powerful plea that can be
urged for the doctrine is its an-
tiquity. The ancients had their
theory of spontaneous generation ;
though the ancients were not al-
ways right. It was Aristotle's belief
and teaching that frogs and snakes
sprang from mud and slime ; and
readers of Virgil (Georg. IV. 330-65)
will recollect the poet's recipe for
raising a swarm of bees from the
putrefying corpse of a two-year-
old bullock, by strewing broken
boughs and flowers of thyme and
cassia under the corpse. We must
2
[K. Step.
FIG. 12. — BARLEY (Hordeum).
Unripe and ripe flower-spikes. To the left are two de-
tached flowers (spikelets) with extended glumes. Below
them is a barley-corn, and to the right of it a fully expanded
flower showing the male and female parts. Between the
spikes are shown barley-corns in process of germination.
HUTCHINSON'S POPULAR BOTANY
confess that our faith in the philosopher's opinion, no less than in the
virtue of the poet's recipe, is somewhat weak. Observation teaches that
Life, which distinguishes the Mineral from the Vegetable and Animal
Kingdoms, does not spring up spontaneously. The principle of Life must
be there first, under whatever conditions; and hence it is safe to affirm
that the doctrine of " Life from Life," or biogenesis, is the true doctrine.
" Dead matter," said Lord Kelvin
before the British Association
some years ago, " cannot become
living matter without coming
under the influence of matter
previously alive. This seems to
me as sure a teaching of science
as the law of gravitation. I am
ready to adopt as an article of
scientific faith, true through all
space and through all time, that
Life proceeds from Life and
nothing but Life."
The German botanist Schlei-
den, taking the crystal as the
type of the most perfect form
of inorganic body, thus beauti-
fully contrasts it with a living
organism, the Barley-plant (see
fig. 12). "The crystal does not
spring at once a perfect Minerva
from the hand of Jupiter; the
matter of which it is formed
undergoes a constant series of
changes, the final result of which
is the completed shape of the
crystal. The crystal, too, has an
individual history, a biography,
but only a history of its becoming,
its origination. . . . Plants and
An example of protective resemblance to vegetable forms. ailimals form tllC most distinct
contrasts to this, and herein lies
that common nature, which induces us to comprehend them in one concep-
tion, as organic or living existence. ... In spring we commit the barley-
corn to its nurse, the earth ; the germ begins to move, starts from its
envelopes, which fall to decay. One leaf after another appears and unfolds
itself; then the flowers display themselves in a thickly crowded spike.
Called forth through wonderful metamorphoses, in each originates the germ
Fio. 13. — A BOGUS PLANT — THE WALKING-
LEAF INSECT.
Photo by] [E. Step,
FIG. 14. — BEE ORCHIS (Ophrys apifera).
A good example of the way in which some plants mimic animal forms. In this case the reason for
the resemblance to a bee is by no means clear. EUROPE and NORTH AFRICA.
3
HUTCHINSON'S POPULAR BOTANY
FIG. 15. — THE LEAF BUTTERFLY (Kallima).
When this butterfly settles upon a twig and closes its wings
together, it resembles a leaf.
[S. L. Bastin.
Fia. 16. — A SOUTH AFBICAN PLANT (Mesembryan-
themum truncatum),
This plant resembles a pebble. It is photographed in the midst
of five real pebbles to make the likeness clear.
of a new life ; and while this
with its envelopes becomes per-
fected into a seed, constant
changes in the plant, from below
upwards, are in progress. One
leaf after another dies and
withers. At last only the dry
and naked straw-haulm stands
there. Bowed down by the
burden of the golden gift of
Ceres, it breaks up and rots
upon the earth, while within
the scattered germ, lightly and
snugly covered by protecting
snow, a new period of develop-
ment is preparing, which, be-
ginning in the following spring,
continues on the unceasing
repetition of these processes.
Here there is nothing firm,
nothing consistent ; an endless
becoming and unfolding, and a
continual death and destruction,
side by side and intergrafted.
Such is the Plant ! It has a
history, not only of its forma-
tion, but also of its existence:
not merely of its origin, but of
its persistence. We speak of
plants ; where are they ? When
is a plant perfect, complete, so
that we may snatch it out of the
continual change of matter and
form, and examine it as a thing
become ? We speak of shapes
and forms ; where shall we
grasp them, disappearing
Proteus-like every moment and
transformed beneath our hands ?
... In every moment is the
Plant the ruin of the past, and
yet, at the same time, the po-
tentially and actually develop-
ing germ of the future ; still
THE PROTOPLAST . 5
more, it also appears a perfect, complete, and finished product for the
present " (The Plant}.
Matter, indeed, is too coarse and low a thing to imprison life. Life
uses up the virtue out of matter, and when for a space it looks as if
the matter lived, it is only for a little time, and the Life passes on to
use up fresh material. The former living plant or animal, as we saw
it, decays away ; but the Life has not decayed : it has changed its
place, and has made a step in its mysterious and immeasurable cycle —
Photo by]
FIG. 17. — VEGETABLE SHEEP (Raoulia eximia).
[E. J. Wallis.
A. Composite plant that grows on exposed hillsides, its tough stems and tiny flowers packed in a
compact mass like a great cushion of moss to resist the elements. It is often mistaken at a little
distance for a sheep. A native of NEW ZEALAND.
always unseen, unmeasured, and untouched. How different from the
inorganic crystal, which knows nothing of this ceaseless change and
progression ; which has no life-history to offer ; which, in fact, has never
been alive!
Wide, then, is the chasm, and very definite the line of demarcation,
between organic and inorganic bodies — between the Plant, which has
Life, and the Mineral, which is lifeless. Biology, indeed, which is the
science of life, concerns only the Animal and Vegetable Kingdoms — it has
no connection with the Mineral world. Botany and Zoology, the sciences
6 HUTCHINSON'S POPULAR BOTANY
that deal respectively with plants and animals, are its two main sub-
divisions; and Mineralogy is of necessity excluded. Of course it is only
with the first of these sub-divisions that we have to do : the subject
before us is Botany, not Zoology. The word " Botany," we may remark in
passing, is a Greek word, meaning any kind of grass or herb, and
botanike, in the same language, signifies the art which teaches the nature
and uses of plants. The dry look is sometimes taken off a subject when
the meaning of its Greek or Latin name is explained.
That any difficulty should be found in distinguishing plants from animals
might at first occasion some surprise. A cow is not mistaken for a cucumber,
nor an oyster for a water-lily ; and even when we take objects externally
Photo by]
FIG. 18. — AN AUSTRALIAN PITCHER-PLANT (Gephalotus follicularis).
[S. L. Bastin.
An example of a numerous class of plants that, growing in poor watery soil, are compelled to get their
food by trapping and digesting insects. WESTERN AUSTRALIA.
so much alike as a walking-leaf insect or the leaf butterfly and the leaf
it mimics (figs. 13 and 15), very little examination is needed to convince
us how essentially different they are. Many persons have been deceived
by the interesting Haastias and Raoulias of New Zealand (fig. 17), curious
plants allied to Gnaphalium, which form masses on the bare mountain tops
so closely resembling sheep at a very short distance that the most ex-
perienced shepherds are often deceived by their appearance. Some species
of Mesembryanthemum closely resemble pebbles, as may be seen by oui
photograph of a plant surrounded by real pebbles (fig. 16). Here also,
however, the deception vanishes on a closer inspection ; and the same thing
may be said of many orchideous flowers, whose remarkable resemblances
to objects in the sister kingdom have been often dwelt upon — as, for ex-
ample, the Bee Orchis (fig. 14). Nevertheless, in other cases real difficulties
Pfwto ny\
Fio. 19. — A PITCHER- PLANT (Sarracenia purpurea).
It lives partly on insects, which it traps and kills, and from their bodies it extracts the juice
necessary for its own growth. NORTH AMERICA.
7
8
HUTCHINSON'S POPULAR BOTANY
of distinction exist; and to prepare a definition either of an animal or a
plant, which shall be at once sufficiently full and sufficiently exclusive,
is in the present state of onr knowledge impossible. Probably, indeed, the
line of demarcation between the simpler forms of the two kingdoms will
never be absolutely determined.
Three important characteristics may, however, be said to distinguish
the higher animals — viz., the power of locomotion, evident sensitiveness, and
the possession of a special digestive cavity for receiving solid food : just
as the absence of these characteristics will be found to distinguish the
higher plants ; though even here exceptions are not wanting. Thus, among
the higher animals the oyster lacks
the power of locomotion, and the
tape-worm has neither sensitive-
ness nor a special digestive cavity ;
while among the higher plants
we find a power of locomotion in
the spermatozoids of Ferns, ex-
treme sensitiveness in the
Mimosas, and " a kind of external
stomach which digests solid food "
in the Pitcher-plants (figs. 18 and
19). The proposal gravely made
by a French savant to define an
animal as -im estomac servi par des
organes is, therefore, not to be
thought of; and the inadequacy
of the definition is more plainly
seen when we descend to the
lower forms of life. Here, not
only are locomotion and apparent
sensitiveness common among the
simpler water-plants, as Sphcerella
pluvialis * and Volvox globator (fig. 20), but the absence of a digestive
cavity is the rule rather than the exception in the lower animalcule
(Protozoa], of which the Amoeba and its immediate allies furnish good
illustrations. Indeed, we must ascend the zoonic scale as high as Vorti-
cella, the curious little Bell-animalcule (fig. 23), before we meet with even
the rudiments of a digestive apparatus.
Now, any one who would understand the complex forms of Life, whether
in the Animal or Vegetable world, does well to begin low down in the
scale by studying Life in its simplest forms; and unicellular, or one-celled,
plants supply excellent examples for the purpose. Allusion was made a
moment ago to Sphcerella pluvialis, one of the simplest forms of vegetable
* Protococcus viridis of Thome ; Hcematococcus pluvialis of Flotow, Prantl, and Vines.
Pholoby'i [A. Leal.
FIG. 20. — THE REVOLVING GLOBE
( Volvox globator).
Variously regarded as a plant and a simple animal. About
fifty of them in a row would measure one inch.
THE PROTOPLAST
Fio. 21. — PROTOPLASM.
A speck of the simplest form of living
Much magnified.
life ; a microscopic water-plant often to be
met with in rain-water cisterns, or as green
and reddish incrustations in damp places.
Sphcerella (fig. 24) is a plant of a single
cell ; and as we desire to speak a little of
the life-history of a single cell, it may be
well to take a nearer view of this tiny
organism.
If you take some rain-water from a
cistern into which the sun has been shining
for a few hours, and examine a drop of it
under the microscope, }'ou will probably
find that it is teeming with life. Minute
pear-shaped bodies of a green colour swim
rapidly about (fig. 24), propelling them-
selves along by delicate filaments of a
transparent substance, which branch out, two on each individual, from
a tiny red spot (termed the eye~spot), which might at first be thought to
be a head. The movement is due to the alternate shortening and lengthen-
ing of these filaments or flagella, which are so fine and transparent, and
lash the water so rapidly as to be scarcely visible. By-and-by the move-
ment becomes slower, and ceases ; the flagella disappear ; the green
bodies, as though ashamed of swimming about in their nakedness so long,
form little jackets for themselves of a substance hereafter to be described,
and sink to the bottom of the water, where they enter upon a new stage
of existence.
The active, motile stage is at an end ; the giddy childhood time is
passed ; an autumnal red has blended
with the fresh green hue of youth (for
the spent swimmers have partially changed
their colour) ; and the adult or stationary
stage has commenced. You continue to
watch one of these quiescent bodies. It
has lost its pear shape now, and has
grown larger. Presently a process of
rearrangement is seen to be going on
inside the little membranous sack.
The contents divide into two portions,
each of which again divides : and with
that there is a fresh formation of pro-
tective membrane, for each of the four
bodies must have its own cellulose in-
vestment, and — note this well ! — each
weaves its own. And now we have no
3
FIG. 22. — AMCEBA.
A. One of the simplest forms of animal life. B. The
same capturing an Actinophrys. Magnified about
80 times.
10
HUTCHINSON'S POPULAR BOTANY
longer one quiescent body, but four; so that when the outer investing
sack in which they are all contained gives way, they emerge as perfect
individuals. Each will have its own independent history ere long — per-
chance a very different history from that of the parent body ; for from
each may issue, not fully clothed individuals like themselves, but naked,
motile bodies, like those from which the parent was evolved, with pear-
shaped forms, and scarlet e37e-spots, and delicate filaments that possess
the power of contraction. Thus the round of life goes on.
But let us pause and ask, What are these changeful little bodies—-
these minute organisms, so simple
and yet so wonderful ? To which
of the two great realms of living
Nature do they belong ? Are
they animalculae. or plants ?
" Surely," it might be urged,
"they belong to the Animal
Kingdom — the little motile
bodies tell us that." Yet the
fact is otherwise. Those tiny
organisms are plants, true plants,
and their names must not be
sought for in any zoological cata-
logue. Their habits are, indeed,
strikingly similar in some re-
spects to those of many minute
animals ( Vorticella microstoma,
for example) : yet are they true
plants ; and the active little
bodies, with red eye-spots and
antennae-like prolongations, are
neither more nor less than the
motile cells or zoospores of our
single-celled plant, Spkcerella
pluvialis.
Yes, plants ; and each individual is a single cell, though it is only
after it acquires its coat of cellulose that it becomes a cell in the common
acceptation of the word. It is an unicellular plant, and so is distinguished
from the great mass of plants, which are multicellular, or made up of
many cells. And thus we are brought to a very interesting truth, and
one of vast importance to the student of Botany — viz., that every plant
in the wide world, from the highest to the lowest, consists either of a cell
or cells. We shall see farther on that the living matter (or protoplasm,
as it is called) is the essential part of the cell ; indeed, there is evidence of
this in the active spores of Sphcerella, which, prior to the formation
FIG. 23. — BELL-ANIMALCULE (Vorticella).
A microscopic animal belonging to the Protozoa, but plant-like
in appearance. Much magnified.
FIG. 24. — A PLANT OF A SINGLE CELL (Sphcerella pluvialis).
In the upper left-hand corner are seen the plants in t'he motile stage. To the right one more highly magnified
and showing the cell-wall (CM>), protoplasm (p), nucleus (n), and flagella (,/), arising from the clear part of the
protoplasm and piercing the cell-wall. Below to the left is a plant that has passed into the still condition : and
beside it one that has divided into four within the cell-wall.
11
12
HUTCHINSON'S POPULAR BOTANY
of their coats (properly, walls] of cellulose, were simply naked masses of
protoplasm. In many-celled plants, where cell-walls are always formed,
the .protoplasm may be used up in the thickening of the wall or transferred
to other parts of the plant : but in such cases what remains is still called
a cell.
The term cell appears to have been first used in a botanical connection
by the English microscopist, Robert Hooke. Writing in ,1665, he says :
u Our microscope informs us that the substance of cork is altogether filled
with air, and that that air is perfectly enclosed in little /boxes or cells,
distinct from one another." At that time, and for many years after,
the " little boxes " were considered the essential part of the plant : indeed.
FIG. 25.
BACILLI : SINGLE-CELLED FUNGI.
FIG. 26.
These microscopic plants belong to the division known as Schizomycetes or " Fission " Fungi, from their habit of
increasing their numbers by dividing into two. The first is the Comma Bacillus, which produces Asiatic cholera.
The second is the Bacillus of Bubonic Plague. Its long appendages are the flagella by which movement is
effected. Highly magnified.
it was not till the last century, when Schleiden, Schwann, and Mohl in
Germany, and Lionel Beale in our own country, proceeded to look into
the little boxes, that the maintenance of a contrary view became possible.
Then began, indeed, the study of Biology, the greatest though youngest
of the sciences, which has grown to such wonderful proportions in recent
years, though it must still be regarded as almost in its infancy.
Until the discovery was made that the protoplasm is the essential
constituent of the cell, our knowledge in vegetable physiology could
make but slow advances, and a great mass of facts connected with the
anatomical structure of plants which the microscope had brought to
light, though interesting in a general way, could have but little scientific
value. There was much, for instance, to gratify one's taste for the
marvellous in the statement that the surface of a square inch of cork
THE PROTOPLAST
13
*f-
FIG. 27. — FRUIT or THE COTTON-PLANT
(Gossypium).
Jach of the soft hairs of the cotton is a single cell
contains more than a million cells, and
that there are one billion two hundred
million in a cubic inch ; but the state-
ment by itself has little or no value
from a scientific point of view. When,
however, we are told (what neither
Hooke nor Leuwenhoek, nor any of
the older microscopists could have
told us) that each of these one billion
two hundred million cells originated
in a tiny speck of protoplasm, which,
after forming for itself — aye. and/rom
itself— as our little zoospore had done,
a delicate cell-wall, finer a thousand
times than the finest gossamer, had
proceeded to spread upon the interior
of that cell-wall layer after layer of
a new
sub-
stance,
w h i c h
we re-
cognise as suberin or cork, till the " little
box " was almost filled up — when these facts
were added, it may be said that our know-
ledge had indeed made great advances.
As allusion has been made to the wonder-
ful minuteness of the cells of cork (fig. 30),
it may not- be out of place to add a few
remarks on the comparative sizes of cells,
before we pass on to the consideration of
living matter or protoplasm. All cells, with
but few exceptions, are microscopically small ;
mere specks, indeed, and quite invisible to
the naked eye. If the task were proposed
to us of counting the honeycomb-like par-
titions in a thin section of the stem of a
lily, or the twig of an apple-tree, or a shred
of cucumber, or the petal of a rose — and
these delicate partitions are so many cells
— we should certainly beg to be excused :
for the microscope reveals the fact that they
are of such minuteness that many thousands
might lie, side by side and end to end, on
FIG. 28. — Vaucheria clavata.
A plant of a single cell, which is drawn out
into a tubular form.
14
HUTCHINSON'S POPULAR BOTANY
FIG. 29. — " BLOOD PORTENT " (Micro-
coccus prodigiosus).
A microscopic plant of a single cell, which averages
about cne-16000th of an inch across. One of the
Bacteria.
a surface no larger than one's thumb-
nail. As a rule, indeed, the cells of
all Flowering Plants are extremely
small, though certain organs may offer
remarkable exceptions. Thus the loose
cells (pollen-grains) contained in what
are known as the anther-lobes of flowers
are occasionally of an unusual size,
some measuring TVth of an inch in
diameter; though it should be added,
as a matter of comparatively recent
discovery, that the pollen-grains of a
large number of plants are now known
to be many-celled. In any case, the
size given is exceptional, and fre-
quently the grains do not exceed ^oVtyth
of an inch.
Some of the tiniest organisms
visible under the microscope are the unicellular Micrococci (a genus of
the Schizomycetes or " fission Fungi " *) — spherical plants whose diameters
vary from ^yiWoth to i s^^th of an inch
(fig. 29) : and along with these may
be placed those scarlet river-plants
(allied, doubtless, to our rain-water
Sphcerella'), many millions of which,
as Freycinet and Turrel tell us, might
swim without discomfiture in a drop
of water ! The Schizomycetes form
an interesting group, for they include
the Bacteria, Bacilli, and other formid-
able organisms, to which many of the
deadliest diseases are known to be
due.f The microscope has revealed
no minuter organisms than these.
Countless thousands of the dreaded
Kitasato bacillus (fig. 26), which is
parasitic in the human body and
* So called because they multiply by a simple
division of the body.
t llacillus antkracis is the probable cause
of anthrax in cattle, etc. ; B. tuberculosis of
consumption ; Spirochcete cholerce asiaticce of
FIG 30 —CORK CELLS Asiatic cholera (fig. 25) ; and various other
Theseparatece.lsmaybeseeneasilyinthisphoto.but *PedeS °f ^^ are ^SOciated with leprosy,
they are shown 125 times larger than the natural size. relapsing typllUS, lOOtrot, etc.
Photo hy]
FIG. 31. — A SLIME-FUNGUS (Stemonitis fusca).
The plasmodium stage, in which thousands of swarm-spores have united into a creamy ma
with a rolling motion prior to forming into sporangia. Natural size.
[E. Step.
lich moves
,».••*.
Phot° by} FIG. 32.— A SLIME-FUNGUS (Comatricha obtusata).
The ultimate stage (sporangia) of the remarkable organisms which are variously considered to be animals and plants,
are shown like pins sticking in the piece of rotten wood. Natural size.
16
HUTCHINSON'S POPULAR BOTANY
causes bubonic plague, could, it is said, find lodgment on a needle's
rjoint : while their rate of multiplication is so extraordinary that many
millions of millions may be produced from a single individual in a few
hours! It is estimated that one cubic inch of good soil will contain
something between fifty millions and four hundred millions of Bacteria,
and many of them are of the greatest value to the husbandman. Surely
we are here approaching the Infinite !
In contrast to the Schizomycetes may be mentioned the Xitdla, an
interesting fresh-water plant, which has cylindrical cells that measure
Photo by]
FIG. 33. — A SLIME-FUNGUS (Lycogala miniata).
[E. Step.
This is one of the largest of those members of the group that have separate sporangia (in others many sporangia are com-
bined to form cake- or cushion-like masses called aethalia). They are pink in colour, and are here shown of the natural size.
nearly two inches in length and ^ih of an inch in breadth ; or such one-
celled plants as the Vaucheria* (fig. 28) and Siphonoclada, where the
individual consists of a remarkable branched cell, greatly in excess of this.
Each of the soft hairs which cover the seed of the Cotton-plant (fig. 27),
and which are spun into cotton, is in reality a long cell. This may be
readily seen by unravelling a thread of reel-cotton and placing it under
the microscope.
* Vaucheria is a fresh- water alga. Perhaps it is hardly fair to compare the branched
nuiltinucleate body of Vaucheria with a simple cell.
THE PROTOPLAST
17
In commencing the study of cells an excellent object for microscopic
examination is the thin skin which covers the inside of the fleshy scales
of the common onion. The object depicted in fig. 35 consists of a small
fragment of this delicate membrane, mounted in balsam. Observe that
it is made up of a number of hexagonal or six-sided figures, on the
interior of which is an irregular granular substance. Each of these
hexagons represents a perfect cell; its sides are cell-walls, and the granular
matter in each is protoplasm.
Protoplasm in its natural
state is colourless and trans-
parent— so transparent as only to
be distinguished with difficulty
under the microscope. To make
it more apparent the specimen is
soaked in iodine solution, which
has the effect of staining living
protoplasm brown, while it tinges
with pale yellow the lifeless walls
of cellulose. The pale yellow is
hardly noticeable by lamp-light ;
but if a drop of strong sulphuric
acid is run under the cover-glass
at the time of preparing the slide,
the cell-walls become coloured
blue. It is by the use of these and
other reagents that the organic
elements of cells and tissues are
distinguished. The word " proto-
plasm " appears to have been first
used by Purkinje* in 1840, to
denote the formative substance of
the animal embryo, which he com-
pared with the soft cellular tissue
(cambium) between the wood and
the barkof trees. Mohl,afew years
later (1846), applied the term to
the contents of the vegetable cell.
It will be noticed that the protoplasm of each of the onion cells contains
a small spherical or oval mass, which takes a darker brown than the sur-
rounding matter when treated with iodine. The darker colour is due to
the greater density of the protoplasm at these points ; and these denser
portions envelope a sort of kernel— the nucleus (Lat. nux, a nut or kernel),
* The substance itself was first noticed and described by Roesel v. Rosenhof in his account
of the Proteus-animalcule, and was named sarcoda by Dujardin in 1835.
4
FIG. 34. — BEADED HAIRS OF VIRGINIAN
SPIDERWORT (Tradescantia).
Showing the rotation of the protoplasm
swollen part in the stream of protoplas
Greatly magnified.
their cells. Each
denotes a nucleus.
1-S
HUTCHINSON'S POPULATE BOTANY
-which consists of a net-work of threads (or JUyrUloB), embedded in a semi-
fluid substance known as nucleoplasm. The nucleus is not, however, a
necessary element ; protoplasm may live, and move, and do work when no
nuclei are present.
Once these cells were living cells — not, indeed, alive in every part.
for that could be said of nothing that lives ; but they were living cells.
Each cell was a life-unit, for the mysterious principle of Life was in
-each; and the protoplasmic contents of the cell, not the cell-walls, consti-
tuted the life-matter. Out of this apparently structureless matter the
cell-walls were formed, much as were the cellulose coats of our self-
dividing Sphcerella ; for in each case the protoplasm was the vital, active,
formative element of the cell. Did, then, these cell-walls cease to grow
when once they had been formed ? By no means. Yet their growth
was due, not to any principle of
Life within themselves, but to the
introduction of fresh particles of
cellulose among those already
existing. And these fresh particles
were formed and added by the
protoplasm.
The history of our fragment of
onion-skin is not singular. What
was once true of this little cluster
of cells, packed together in a space
no larger than a Lupin seed, is
true of all living organisms what-
soever, whether in the Vegetable
or the Animal world. The proto-
plasm is the essential part of the
cell. We would press this, even
at the risk of being tedious. It is a point of all-importance. The granular,
structureless contents of the cell, and not the wall of cellulose, constitute
the unit, the elementary part or cell. The protoplasm produces from itself
the cellulose ; the cellulose does not form the protoplasm. Cellulose, indeed,
is formed from three of the elements which enter into the composition of
protoplasm — namely, carbon, hydrogen, and oxygen. The formula is C(iH100,-,.
Here, then, is proof from chemical analysis. When our Sphcerella was at
rest at the bottom of the drop of water, the source of all the vital changes,
it will be remembered, was the protoplasm, not the membranous coat that
invested it. Through this delicate coat, it is true, was drawn in from the
surrounding water the lifeless material which was required for the nourish-
ment and growth of the plant ; but the interior substance was the active
.agent, the protoplasm was the drawing power ; indeed, the same work went
•on when the plant was a naked cell, without any cellulose envelope whatever.
FIG. 35. — CELLS OF O
.A fragment (much enlarged) of the delicate skin between the
firm layers of the onion bulb.
Photo by]
FIG. 36. — SWEET BRIAR (Rosa rubiginosa).
Although so varied in its parts— red stems and thorns, green leawe, and pink flowers— all are alike
composed of cells, built up by the protoplasts. EUBOPE.
19
[E. Step.
20
HUTCHINSON'S POPULAR BOTANY
FIG. 37. — TRAVELLERS' JOY (Clematis vitalba).
Young cells from the Stem, with walls of cellulose.
This loads us to another im-
portant phenomenon in cell-building
— the conversion of lifeless into
living matter. Deeply interesting
is the power which the protoplasm
possesses, not only of building up
formed material from itself, but of
transforming the lifeless material
which it draws to itself into living
matter ! There is nothing in the
whole range of Nature more wonder-
ful. A tiny speck of matter — viscid,
'*<$^%Z'^^^^J0' "S^Y transparent, and, so far as the
]^- xfT jlj highest powers of the microscope
I III Vw xi\ Can inf°rm ns' structureless— is able
JJA xXV JK^ss_-^'^ to produce matter like itself— living,
formative matter — out of the non-
living material by which it is sur-
rounded ! Yet the two are quite
distinct. The difference between the minute speck of protoplasm and that
which nourishes it is absolute. Nor does the one pass by delicate gradations
into the other. The change from the non-living to the living is instantaneous.
No less absolute is the distinction which exists between living matter and
the formed cellular material which is produced by it. The passage from
one state into the other is sudden and abrupt : matter cannot be said to
half live or half die. Thus a ceaseless round of change goes on— an endless
transformation of the lifeless and inorganic into the living but structureless,
and of the latter into formed material.
The wonderful movements of protoplasm have been often observed,
and perhaps no plant has been more studied for this purpose than the
Common Spiderwort or Flower-of-a-Day (Tradescantia virginica). If we
remove a single hair from a stamen of this plant by tearing off a portion
of the cuticle to which it is attached (thus avoiding injury to the hair
itself), and place the object in a drop of water under the microscope, we
may watch for ourselves two of the most characteristic movements of
protoplasm. Presuming that we have been fortunate in a choice of speci-
men, we shall find that the hair consists of three or four cells, of which
the shortest and broadest is at the base (fig. 34). In this cell the proto-
plasm will shortly be seen to be moving in several elliptical currents from a
common point, the nucleus ; while in the other cells it will be seen to
travel round the cell-walls, though the nuclei, as before, will be the
points of departure and return. The former kind of movement is known
as circulation, the latter as rotation.
Rotary movement may also be well seen in certain cells of the AVater-
THE PROTOPLAST
21
thyme (fig. 39) and the grass-like leaves of that river wonder, Vallisneria
spiralis- for here there are no stationary nuclei, but the whole of the
. protoplasm moves round and round. In some instances this movement is
found to take place in opposite directions in contiguous cells, observation
of this interesting fact being facilitated by the presence in the trans-
parent protoplasm of minute grains of a green colouring matter (chloro-
phyll), which are carried round with the stream, and thus discover its
course. The layers of living matter in which these corpuscles float are
frequently no more than ^^^th of an inch in depth ! What, then, must be
the dimensions of the green grains themselves ?
Probably enough has now been said, at least for the present, about the
remarkable properties of protoplasm. We have seen that the little specks
of germinal matter — the protoplasts, if you please — are the weavers of the
warp and woof of organisms — the builders, may we not say? — of all animal
and vegetable structures whatsoever. They constitute, indeed, " the
physical basis of life," and are the fabricators of every object that lives
or has lived !
Is it not wonderful to think of our little protoplasts even as the builders
of a single plant ? Conceive of them, for example, as the fabricators of a
Sweet Briar-rose. Here a number of them are busy at work in their
self -formed cells, and they
throw out material — as what ?
As incipient hairs. Here are
numbers more equally as busy,
and they are producing material
which will be built up into
woody fibre. Others, close at
hand, are constructing a wonder-
ful layer of ' similar cells, each
with its own protoplasm, its
own walls, its own cell-sap.
Thus in one part of the plant
we have our root-hairs ; in
another, our woody fibre ; and
in a third, some delicate tissue
of cells which is to aid in the
formation of a petal, a foliage
leaf, or perchance a seed. All
this, remember, in a single
plant ! Yet the little workers
are chemically alike in each
case; and all consist of the
same elementary substances.
y Photo by} [»'. Plomer Young.
And as With our sample FIG. 38.— SENSITIVE PLANT (Mimosa pudica).
22
HUTCHINSON'S POPULAR BOTANY
FIG. 39. — CELLS OF WATER-THYME
(Elodea canadensis).
Showing the directions of the currents of
protoplasm in the cells of the leaf.
Briar-rose, so is it with all plants. The chemi-
cal constituents of protoplasm are the same
wherever you find it ;. in the simple Fungus
(Penicittium glaucum) (fig. 40), which forms
the green mould on stale food, as in the complex
organism of a Trumpet-flower or an Orchid.
The foregoing may appear to be a sweep-
ing statement, involving as it does the
fundamental unity of all forms of vegetable
life ; but we may go much further than that
and say, with full sanction of modern Science,
that the protoplasm of the cells of which we.
and the entire membership of the Animal
Kingdom are built up, is essentially the same
as that which we have been considering in the
living plant. Formerly, the cell-matter of
animals was distinguished from that of plants
by the name of sarcode ; but when Max Schultze
and others established the fact that the matter was identical in animals
and plants, the distinguishing term was dropped, and now, whether we are
speaking of animal or vegetable organisms, the one word protoplasm is used
to denote its common nature. As a consequence of this identity of elemental
structure, no one can say with certainty where
the Vegetable Kingdom ends and the Animal
Kingdom begins. The simplest plants are
grouped under the name of Protophyta, and
the simplest animals form a corresponding
group known as Protozoa ; but in consulting
a modern natural history of plants and a
natural history of animals in turn, you will
find a number of species doing double
duty and appearing in each. Botanist and
zoologist alike claim them as their subjects.
The difficulty is increased by the fact that
many indubitable single-celled plants are in
their younger condition unhampered by the
wall of cellulose they secrete later, and with-
out which they are able to move freely, just
like similar organisms of undoubted animal
nature. The evolutionist, who contends that
FIG. 40.-GBEEN MOULD (Pern- an™al and Pknt llf° haVG had a common
cUlium glaucum), origin, gets over this difficulty by merging
which rapidly grows on stale food. Each Photophyta and Protozoa into a single group
branch end.m a chamof^pores, which fa!l ^^ Haeckel>s name of protista.
Photo by] [E. Step.
FIG. 41. — OAK-TREE (Quercus pedunculata).
Even the strongest and greatest of trees is built up of minute cells, which constitute its stout
trunk with its wood and bark, its leaves, flowers, and acorns. All the potentialities of this massive tree
were packed into the cells of the acorn. NORTHERN TEMPERATE REGIONS.
23
CHAPTER II
THE PROTOPLAST AS HOUSE-BUILDER AND HOUSE-FURNISHER
Moreover, the walls of the cells themselves are the work of <the protoplasts, and it is not a
mere phrase, but a literal fact, that the protoplasts build their abodes themselves, divide and
adapt the interiors according to their requirements, store up necessary supplies within them, and,
most important of all, provide the wherewithal needful for nutrition, for maintenance, and for
reproduction. — KERNEB.
THE subject of our last chapter was protoplasm, that wonderful sub-
stance which Beale calls the "vital element" of organic bodies,
and which Huxley has well denned as the " physical basis of life." We
now propose to advance a step further, and to speak of some of the
wonderful results of protoplasmic activity — in other words, of the cells
themselves (Hooke's " little boxes," if you please), as well as of the
changes which they undergo, and of the various substances elaborated
within them.
It will be evident to the least reflective mind that these changes must
be considerable, otherwise there would be no accounting for the infinite
diversities of form, structure, and properties which the Vegetable World
presents. For, since the most complex organisms are only the products
of cell formation and transformation, and all cells in their beginnings
are so much alike, the changes must be vast indeed that produce those
diversities — that give us, for instance, in one case a stalk of Wheat, in
another a spreading Oak, and in a third a Mushroom.
It will be remembered that
the resting spore of our rain-
water plant was almost round,
while the cells of the piece of
onion-skin were hexagonal, and
those of the staminal hair of
Tradescantia were in two cases
oblong, in a third almost spheri-
cal, and in a fourth triangular :
four distinct shapes in a less
number of minute objects — in-
ferential evidence, surely, that
the forms of cells may vary
greatly.
B
FIG. 42. — A : OVAL CELL FROM FRUIT OF SNOW-
BERRY. B : OVAL CELL FROM LEAF OF PINK.
a : NUCLEUS.
24
THE PROTOPLAST AS HOUSE-BUILDER
25
Photo l>y]
FIG. 43. — SNOWBERRY (Symphoricarpus racemosus).
[E. Step.
A plant allied to the IFoneysuckle, whose tiny pink flowers are succeeded by clusters of pure white berries.
"NORTH AMERICA.
The round shape occurs in most cells at a certain stage (not the earliest
stage, when they are contiguous at all points), but in few cases, compara-
tively, is this shape retained. The pressure of contiguous cells as growth
continues again effects changes, so that we get octagons and twelve-sided
forms, and sometimes cells of no definable shape at all. This may be
simply illustrated by getting several balls of soft clay and uniting them
by gradual and uniform pressure. The fruit of the Snowberry (Symphori-
carpus racemosus, figs. 4'2, 43) and the leaf of the Common Pink (Dianthus
caryophyllus) offer interesting examples of cells retaining the spherical — or
more correctly oval — form. The pulp enclosed by the outer membrane
of the berry of the first-named plant, even when full grown, consists of a
vast number of minute shining white granules, each of which is a perfect
and almost spherical cell.
The numberless departures from the rounded shape are not all due to
pressure, however. Some cells remain long and narrow through their whole
history, as those of the hairy seed-coat of the Cotton-plant, to which
reference has been made ; and others — to wit, the hairs om the leaves of the
Virginia Stock (Malcolmia maritima) and the Hop (Humulus lupulus) are
curiously branched. Stellate or star-shaped cells are also met with, being
found in the stems of many aquatic plants ; their rays are seldom very
regularly placed, and they vary in length on the same individuals. The
stellate cells shown in fig. 4.4, which, however, are not those of an aquatic
5
26
HUTCHINSON'S POPULAR BOTANY
plant, but of the Common Bean
(Vida faba), are fairly uniform.
The solitary stellate cell in the
next figure (fig. 45) is not so regu-
lar. It is a Desmid — one of a
remarkably beautiful family of
unicellular Algce. Good examples
of stellate cells are also afforded
by the stems of the Common
Rush (Juncus effusus, fig. 46), as
FIG. 44.— STAR-SHAPED CELLS OF COMMON BEAN, well as by the Flowering Rush
(Butomus wntbellatus), whose hand-
some rose-coloured flowers, rising above the
surface of the water on a stalk three or four
feet high, make it deservedly a favourite
with lovers of British water-plants (fig. 51).
Of more than morphological import-
ance are the facts to be next noticed.
"Endlessly diversified in the details of
their form and structure," says Professor
E. B. Wilson in his fine work on the vege-
table cells, "these protoplasmic masses
nevertheless possess a characteristic type
of organism common to them all ; hence
in a certain sense they may be regarded
as elementary organic units out of which
the body is compounded. The composite
FIG. 46. — STAB-SHAPED CELLS FROM STEM OF
COMMON RUSH.
FIG. 45. — A DESMID.
One of the simplest forms of green plants.
structure is, however, character-
istic of only the higher forms of
life. Among the lowest forms
at the base of the series are an
immense number of microscopic
plants and animals, familiar ex-
amples of which are the Bacteria,
Diatoms (fig. 49), Rhizopods, and
Infusoria, in which the entire
body consists of a single cell, of
the same general type as those
which in the higher multicellular
forms are associated to form one
organic whole. Structurally,
therefore, the multicellular body
is in a certain sense comparable
with a colony or aggregation of
rhnto 6yj
FIG. 47. — FLOWERS or A CACTUS .(Cereus).
. — ..
The Cacti grow in dry stony places, and have tough skins to prevent loss of moisture by evaporation. To protect
them from destruction by thirsty animals, their leaves have been- replaced by clusters of sharp spines.
27
HUTCHINSON'S POPULAR BOTANY
FIG. 48. — SEEDLING OAK.
The store of nutriment packed into the acorn is
sufficient to maintain the seedling until it has formed a
stern and leaves and the beginnings of its root system.
the lower one-celled forms — a compari-
son, however, which must be taken
with some reservation. The comparison
is not less suggestive to the physiolo-
gist than to the morphologist. In the
lower one-celled forms all -the vital
functions are performed by a single cell.
In the multicellular forms, 011 the other
hand, these functions are not equally
performed by all the cells, but are in
varying degree distributed among them,
the cells thus falling into physiological
groups or tissues, each of which is es-
pecially devoted to the performance of
a specific function." (Of this we shall
speak more fully in succeeding chap-
ters.) " Thus arises the physiological
' division of labour ' through which
alone the highest development of vital
activity becomes possible, and thus the
cell becomes a unit, not merely of struc-
ture, but also of function. Each bodily
function, and even the life of the
organism as a whole, may thus in one
sense be regarded as a resultant arising
through the integration of a vast num-
ber of cell activities ; and it cannot be
adequately investigated- without the
study of the individual cell activities
that lie at its root."
On looking at a young seedling —
say of an Oak (fig. 48) or Chestnut-
tree — the question naturally arises, How
is it that so small and tender a plant,
which may be bent with the finger,
is capable of growing into a might}7
forest-tree that shall defy the winter
storms of centuries? If the cells of
which the young plant is formed were,
in their beginnings, only so many little
specks of protoplasm, each surrounded
by a thin diaphanous wall of cellulose,
which the shake of a hand would cause
to dissolve away, by what mysterious
THE PROTOPLAST AS HOUSE-BUILDER
29
process has it attained even its present growth ? And, still more, how
will it develop into the strong-limbed giant which it is destined in future
years to become ?
The answer — in part, at least — lies in the wonderful property which
the protoplasm possesses, not only of building a primary investing wall for
itself, but of spreading on the interior of that wall successively new layers
of formed material (woody or otherwise in substance, as the case may
require) till the cell is all but filled up. This new material, which is found
in all Flowering Plants and in very many Cryptogams or Flowerless Plants,
is known as secondary de-
posit. The process which
goes 011 may be likened to
the formation of the furred
deposit (limestone) on the
inside of a kettle. The
kettle answers to the cell:
the water to the proto-
plasm ; the tin side of the
kettle to the primary cell-
wall ; and the hard lime-
stone accretion to the
secondary deposit.
Cellulose itself (C6H1005),
though it is the material of
which the primary cell-wall
is formed, is very seldom
found as a secondary de-
posit. The date-stone may
be cited as -an interesting
exception. The thickening
which takes place in the
interior of the cells of the
plum and cherry — we do
not speak of the stones of
those fruits — and in the pith of certain plants of the Pea family, is
a gum ; whilst mucilage, a kind of gum, is found in the cells which
form' the seed-coat of linseed, the apple, pear, etc. A very common and
important kind of secondary deposit is liguin, which, as might be guessed
from the name (Lat. lignum, wood), is found in all woody cells. The stones
and shells of many fruits are built up of such cells ; and woody tissue of
course abounds in the stems and branches of trees. Lignin, like all
secondary deposits, is derived from the protoplasm, which, as the cell-
wall increases in thickness, becomes more and more restricted in its
movements, until at last it is crowded out, if one may so say, and dies.
FIG. 49. — DIATOMS.
These are little boxes of pure flint deposited in the interior of micro-
scopic plants. Magnified 60 times.
Photo by]
Fio. 50. — WILD HOP (Humulus lupulus).
A hedgerow plant that climbs by twining round the stems of bushes. The male and female flowers are
on separate plants. This is the female plant. The flowers of the male are much smaller. EUROPE. J
30
IE. Step.
THE PROTOPLAST AS HOUSE-BUILDER
31
Great honour is put upon the
cell after death, however ; it is
dignified with a new name — a
name of sixteen letters — as
inelegant as it is long. The
lifeless structure becomes, in
fact, a sclerenchymatous cell —
the name implying that the
cell has had something hard
put into it ; for the term is
derived from two Greek words
— skleros, hard, and enchuma,
anything poured or put in.
Sclerenchymatous cells
occur in the gritty centre of
the pear, in the stones of the
peach, cherry, etc., and in the
shell of the common hazel-nut.
Lignin takes a deeper yellow
than cellulose when treated
with iodine, and it becomes
brown when treated with iodine
and sulphuric acid.
Suberin: or cork substance
(Lat. suber, cork), is another of
the secondary deposits of cells.
Like cellulose and lignin, it is
coloured yellow by iodine, but
it resists the action of sul-
phuric acid. Cork cells are
tough without being woody.
Parts of plants the fluids of
which require to be protected
from evaporation, are usually
surrounded by cork cells, as
the stems and older branches
of trees, in which the sap cir-
culates. In young and
quickly growing trees the
epidermis (outer skin) of the
stem, being unable to stretch
fast enough, often gets torn,
and then the busy protoplasts
cover the wound with a special
Photo 6y]
SteP-
FIG. 51. — FLOWERING RUSH (Butomus umbellatus).
A handsome waterside plant, three or four feet in height, with an
umbel of crimson flowers. EUROPE, ASIA.
HUTCHINSON'S POPULAE BOTANY
FIG. 53. — SEC-
layer of cork cells. The thick, rough,
cleft bark of a Spanish species of Oak
(Quercus suber) is the cork of com-
merce, of which the stopples for bottles
and casks are made. It is stripped off
without injury to the stem — which,
•>• indeed, soon gets covered with fresh
layers of corky cells, and in eight
or ten years the tree is again ready TION of a Part
FIG. 52. — CELL from the for stripping. The first peeling of a Pitted Cell
BaCkonifera ^docarp^ takeS PlaCG whe11 the tree is twentJ- (dia^ammatic)'
dacryoides). five or thirty years old, and great
care is always taken not to injure the inner bark.
Earthy or mineral substances, found in all plants, abound in some forms
of secondary deposit, and may be readily detected when any part of the
plant containing them is burned. The ash left after burning is commonly
known as " the ash of plants," and consists chiefly of silica, lime, and
magnesia. Silica (flint) is particularly plentiful in the grasses, canes, etc.,
the glassy appearance of the stems of such plants being due to the presence
of this mineral. Years ago, a melted mass of glassy substance — at first
supposed to be a meteoric stone — was discovered in a meadow between
Mannheim and Heidelberg in Germany ; but when chemically examined it
was found to consist of silex combined with potash. Upon inquiry it was
ascertained that a stack of hay, which had been recently destroyed by
lightning, had stood on the spot. The siliceous mass was simply the ash
that remained after the conflagration. One cannot reduce haystack burning
to a system for purposes of experiment,
but instructive results may be obtained
on a small scale by igniting
a piece of siliceous tissue on
platinum foil, after soaking
in nitric acid. If the ash is
then treated with the same
acid, it will show an insoluble
residue, and that residue is
flint.
It frequently happens
that the protoplasm deposits
secondary thickening only in
some parts of the cell-wall,
FIG. 55. — DIAGEAM to illustrate the
FIG. 54.—
PITTED
Wood Cells
from a Big-
nonia.
the other portions being left
bare. For this reason we
post in Porous Cells, (p) Pores. The
Broken Rings represent Successive
Layers of Secondary Deposit. The Pro-
toplasr
Thus, in what are Space.
get some curious varieties of toplasm occupies part~of the Central
cells.
THF. ROSy-UPI'KI) CATTI.KYA ( C,ittl<-ini lnl,inl«>.
Tliis beautiful Orchid is a native of Bra/il. where it grows on the trunks of trees. The magnificent (lowers measure
THE PROTOPLAST AS HOUSE-BUILDER 33
known as the pitted or dotted cells, the secondary deposit is spread upon the
cell-walls so as to leave little pits, open on the interior side of the cell, and
closed at the exterior by the primary cell-wall. These pits have the appear-
ance under the microscope of transparent specks (fig. 53). When several
dotted cells come together, it often happens that the pits of their con-
tiguous walls are coincident ; and the utility of this very beautiful arrange-
ment is at once evident : for even after the cells have attained a considerable
thickness, they are still permeable to the fluid from without, which is taken
in through these little pores and used up by the imprisoned but still living
and working protoplasts (figs. 53, 54, 55).
Ph»to by]
FIG. 56. — BOG-MOSS (Sphagnum acutifolium).
[E. Step.
The Bog-mosses grow in wet hollows where the soil is sour and too poor to maintain mosr plants. The decay oi the
older parts, pressed down by the newer growth, results in the formation of peat. COLDER TEMPERATE REGIONS.
In certain plants of the Cactus order (as Melocactus, Mamillaria, and
Opuntia), the wood is entirely composed of short spindle-shaped cells, in
which are elegant spiral bands of secondary deposit, looking, as Schleiden
neatly expresses it, " like little spiral staircases " (fig. 57). "We call these
spiral cells. The large elongated leaf-cells of the Bog-moss (Sphagnum)
(fig. 56) and the leaf-cells of many orchideous plants have spiral fibres
loosely coiled in their interior; but a better plant than either Orchid or
Bog-moss for studying these spirals is the Wild Clary (Salvia verbenaca), a
portion of the seed-coat of which makes an extremely interesting object
under the microscope. If a very thin slice of the outer coat, moistened with
a drop of water, be placed between the glass slides, the delicate fibres will
6
34 HUTCHINSON'S POPULAR BOTANY
be seen to break through the membranous cell-wall — a proof of their
remarkable elasticity. In most spiral cells that have been examined the
fibres wind from left to right ; and it has been suggested with some show of
reason that the direction of the twining stems of plants may have definite
relation to the direction of the spirals. This would certainly appear to be
the case in the Hop (Humulus hipulus), which is a right-handed climber and
always has right-handed spirals. Saccolabium guttatum, an East Indian
species of epiphytal Orchid, has fibres which wind in opposite directions, but
this is not a twining plant.
A fair idea of a spiral cell may be obtained by placing a coil of fine wire
in a tightly enclosing glass tube of the same length as the coil, and covering
up the ends with glass discs. In Nature the fibres are extremely delicate,
their diameters being in some cases less than T^^o^h of an inch ; and as a rule
FIG. 57. — CELLS FROM THE MISTLETOE (Viscum album).
1. Spiral cells. 2. Annular cells. 3. Reticulate cells.
they are quite transparent and colourless. Nevertheless, they may — and do-
— vary considerably in thickness ; and in most plants of the Lily order, and
also in the Elder (Sambucus), the coiled-up threads may be seen with the
naked eye. If the stem of a Lily be partly cut across and then gently
broken, the chances are that the broken pieces will be held together by some
of these delicate threads; and they will probably be found to be strong
enough to support the weight of one of the fractured pieces, if the piece in
question be not too large. It is wonderful to think that though some of the
cells which contain them measure only ^oVfjth °f an inch in diameter, the tiny
spirals may consist of several distinct threads ; indeed, the contiguous coils-
in some cases have been found to number more than twenty ! How carefully
Nature prepares her work even when the objects of her skill are invisible to-
the unaided human eye !
35
36
HUTCHINSON'S POPULAR BOTANY
The fibrous spirals in the leaf-cells of many Cone-bearing plants (Coniferce)
have been pressed into the service of man, being found to afford an excellent
substitute for wool and cotton. In 1842 a quantity of woven fabric of this
material was introduced in place of cotton in the hospital at Vienna, where,
after several years' experiment, it was renewed. Similar success attended
its introduction into prisons and hospitals at Berlin, Breslau, and other
places. When used in mattresses, it is found to last three times longer than
wool ; while for spinning and weaving purposes it has the strength of hemp,
Photo by]
FIQ. 59. — MISTLETOE (Viscum album).
[K. Step.
The well-known shrub that grows on various trees, chiefly Apple, parasitically. The possession of leaves, how-
ever, shows that it is not wholly a parasite. One-third of natural size. EUROPE, N. ASIA.
and so may be profitably employed in the manufacture of carpets and
blankets.
Sometimes the thickening of the cell-walls takes the form of rings, as in
the Mistletoe ( Viscum album) and many grasses ; and thus we get annular
cells — a name derived from the Latin annulus, a ring (fig. 57). Three or
four indiarubber rings fitted tightly in a short cylindrical lamp-glass give
the idea. Not infrequently the rings appear to have their beginning in
spiral fibres, which, in consequence of their rapid growth, get broken in
places, and so fall together in rings ; indeed, the transition from the spiral
to the ringed form has been observed in certain plants, notably in the
THE PROTOPLAST AS HOUSE-BUILDER
37
Opuntias, that well-known genus of the Cactus „ order to which the Prickly
Pear (0. vulgaris) belongs. They are plentiful enough, too, in the leaf -stalk
of the Common Ivy (Hedera helix}. Cells containing these composite fibres
are described as spiro-annular.
Another modification of the true spiral is found in reticulated cells
(Lat. reticulwm, a small net), where the bands of thickening are arranged
in a net-like manner on the interior of the primary walls. By this disposition
of the secondary deposit, little trenches are left at variable distances, which
appear under the microscope like more transparent lines. The Touch-me-Not
Balsam (Impatiens noli-tangere) and the Mistle-
toe (Viscum album,) furnish interesting exam-
ples of reticulated cells (fig. 57).
" It is scarcely possible," says Dr. Carpenter
in his Vegetable Physiology and Botany, " to
observe the number of different forms result-
ing from the varied combinations of the simple
elements, each of them probably having its
peculiar function in the Vegetable economy,
without being struck with the simplicity of the
plan by which Creative Design has effected so
many marvels, as well as with the extreme
beauty and regularity of the structures which
are thus produced. The comparison of such
specimens of Nature's workmanship as the
meanest plant affords, with the most elaborate
results of human skill and ingenuity, serves
only to put to shame the boasted superiority
of man ; for whilst every additional power
which is applied to magnify the latter serves
but to exaggerate their defects and to display
new imperfections, the application of such to
organized tissues has only the effect of dis-
closing new beauties, and of bringing to light
the concealed intricacies of their structure."
But it is time to pass from this subject. We trust that we have now
treated with sufficient fulness the more important facts connected with the
thickening of the primary cell-wall by means of secondary deposit ; and that
some definite idea has been conveyed of the manner in which cells — though
not all cells — are made strong and hard and capable of firm resistance. "We
will now consider some of the other substances produced in vegetable cells
as the result of protoplasmic activity.
In treating of the movements of protoplasm in Vattisnema, allusion was
made to the minute green corpuscles contained in the living matter of the
long grass-like leaves, and carried round with it in the cells. These little
FIG. 60. — CELLS FROM LEAF OF
Vallisneria spiralis.
Showing chloroplasts (the oval bodies
in the protoplasm.
HUTCHINSON'S POPULAR BOTANY
bodies are known as chlorophyll corpuscles or chloroplasts, and the green
colouring pigment chlorophyll — a name derived from the Greek chloros,
green, and phullon, a leaf. Many millions of such corpuscles exist in every
full-grown plant of Vallisneria ; though that circumstance alone is not our
warrant for returning to the subject. If chlorophyll were only distributed
in the tissues of a few water-plants, it would call for no special mention
here ; but the contrary is the case. As a matter of fact, these tiny bodies
of coloured matter constitute one of the most widely distributed of vegetable
substances, being found in all green plants; while their essential identity
with protoplasm gives them an especial interest. Chlorophyll corpuscles
have, indeed, been denned as specialized masses
of protoplasm coloured green, and no definition
could be more. clear, concise, and satisfactory. It
is thought that they possess a reticulated struc-
ture, and that the colouring matter occupies the
meshes of the network in a state of solution.
Chloroplasts are not found in animals, save, in-
deed, in some of the Flagellata, Planarians, etc.,
as a foreign product. The latter exception needs
to be recorded, since it was long held that the
chloroplasts contained in the tissues of the fresh-
and salt-water Sponges, and the fresh-water Polyp,
belonged to those animals.* Professor Weiss has
shown that they are really vegetable cells which
may be cultivated outside the animal body. " As,"
says he, "these green cells can form starch and
ultimately sugar, which transfuses out of the Algce
into the body of the animal, it is evident that they
are of real benefit to the animal, while the Algce
themselves can absorb certain substances out of
the animal cells. An analogous example occurs in
the Vegetable Kingdom in the case of the Lichens,
in which some green Algae are associated with a
Fungus. Every Lichen consists of the two
different organisms, and the green cells form, under the influence of light,
food substances which are made use of by the Fungus. In initial stages
the Fungus can be seen capturing, with its threads, the Algce cells
of which it makes use, and which are the working partners of the
concern " f (fig. 61).
Some minute marine-worms (Turbellaria), known as Convolwta, have
established a remarkable partnership with some of these green single-celled
* Chlorophyll corpuscles were found in fresh- water Sponges by Sir E. Ray Lankester,
and Mr. MacMunn found them in no less than nine specimens of sea Sponge,
t Proceedings of the Manchester Microscopical Society, 1892.
FIG. 61. — SECTION THROUGH
A THALLUS OF LICHEN
(Sticta fuliginosa).
Magnified 500 times.
- Skeen & Co.
FIG. 62. — JAK-FRTTIT (Artocarpus integrifolia).
A species of Bread-fruit, and valuable as food to the inhabitants of the districts in which it grows. INDIAN ARCHIPELAGO.
39
40
HUTCHINSON'S POPULAR BOTANY
A'lgse, which multiply to such an extent in their substance that the entire
animal is coloured green. After its larval stage the worm does not need
to trouble about food, for the plants manufacture and supply it with starchy
products. The plants in turn needing nitrogen, which is a rare commodity
in the sea, obtain it from the animal's waste. This partnership is not an
occasional or chance affair : both plant and animal have so thoroughly
entered into it through many generations that it has become fixed and
habitual, like the association of Algse and Fungus which has resulted in the
production of thousands of species of the compound plants we know as
Lichens. Professor Keeble has devoted a small volume entirely to telling
the story of the relations between these very dissimilar organisms.*
Under the microscope the chloroplasts have usually a globular appear-
ance, but instances occur in which they- are quite formless. In the
well-known Water-thyme (Elodea canadensis), so execrated by bargemen
and water-mill owners, they are
irregular in shape, some presenting
the appearance of circular flattened
discs, while others are spherical and
oval. Their diameters vary from
s^Voth to srnnrth of an inch. Of
the colouring matter diffused
through the corpuscles, we have a?
yet no certain knowledge, but th^
opinion still held by very many
that it is composed of two inde-
pendent colouring substances — a
golden-yellow and a blue-green — is
FIG. 63,-STARCH-GRAiNs OF POTATO. now abandoned by the highest
authorities. Those substances are,
indeed, the products of the decomposition of chlorophyll, but chlorophyll
itself is a single pigment.
One eminent analyst (Gautier) regards it as related to the colouring
matter of the bile ; another (Hoppe-Seyler) as a fatty body allied to lecithin,
which is a phosphoretted viscous substance entering into the formation of
the brain. But " it is extremely difficult," says Dr. Reynolds Green. " to
say what is the chemical composition of chlorophyll, on account of the
readiness with which it is decomposed. In all the processes which have
been adopted for its extraction it undergoes decomposition, and consequently
no definite conclusions as to its chemical nature can at present be arrived
at. It can be made to yield definite crystals by appropriate methods of
treatment after extraction, but it is probable that these crystals are a
derivative of chlorophyll, and not the pure pigment." The statement found
in many of the text-books that the chloroplasts are coloured blue by iodine
* Keeble, Plant-Animals: a Study in Symbiosis, 1910.
THE PROTOPLAST AS HOUSE-BUILDER
41
is misleading. Iodine denotes the presence of starch-grains, which often
occur— but by no meatis always — in the corpuscle.
Specially interesting is the fact that light is a necessary condition for
the formation of chlorophyll. Grow a plant in the dark, and its leaves will
be yellow and sickly ; bring it
forth to the light, and it will
become green and healthy.
Hence it will be readily gathered
that chlorophyll is seldom found
in the roots of plants. The roots
of the Common Buckbean or
Marsh- trefoil (Menyanthes trifoli-
ata) may be cited as a curious and
— in so far as underground roots
are concerned — perhaps an
unique exception ; but the green
aerial roots of some epiphytal
Orchids (fig. 64) contain this im-
portant substance. The white-
ness of celery is due to the
exclusion of light from the stem
and leaves, which are banked
round with earth as fast as they
grow. Hindrance is thus offered
to the formation of chlorophyll,
and by this mode of cultivation
the rank coarse taste of the plant
is completely removed, and the
mild sweet flavour which we as-
sociate with table celery is im-
parted to it. In its natural state
celery is a poisonous plant.
Doubtless the reader will have
noticed how quickly the pale
unfolding leaves of spring as-
sume their characteristic hue if
the weather be bright and sunny ;
and, on the other hand, how
slowly this change is effected
during a succession of dark
cloudy days. This fact is more remarkable in tropical countries than
in England. It frequently happens in America that clouds and rain
obscure the atmosphere for several days together, and that during this
time the buds of entire forests expand themselves into leaves. These
FIG. 64. — AERIAL ROOTS OF AN EPIPHYTAL
ORCHID.
42
HUTCHINSON'S POPULAR BOTANY
leaves assume a pallid hue until the sun appears, when, within the short
period of six hours of a clear sky and bright sunshine, their colour is changed
to a beautiful green. Mr. Ellis, an American writer, tells of a forest in one
of the northern States, the leaves of which, though fully expanded, were
almost white, no sun having shone upon the forest for twenty days. One
forenoon, however, the sun began to shine in full brightness, and the colour
of the forest absolutely changed so fast that the progress of the transforma-
tion could be watched. " By the middle of the afternoon the whole of this
extensive forest, many miles in length, presented its usual summer dress."
Often associated with chlorophyll is starch (C6H1005), which plays so
important a part in the nutrition of mankind. " Starch makes the man,"
said a lady lecturer half a century ago ; but she spoke of it in another
connection — namely, as the stiffening property in linen articles of male
attire. Starch was imported into this country
in considerable quantities during the sixteenth
and seventeenth centuries, when the enormous
ruffs inseparably connected with the Elizabethan
and early Stuart periods were in vogue. Gerarde
tells us that the best of this starch was obtained
from the Cuckoo-pint or Wake-robin (Arum
maculatum). "The most pure and white starch
is made of the roots of the Cuckoo-pint, but
most I hurtful for the hands of the laundress
that hath the handling of it ; for it choppeth,
blistereth, and maketh the hands rough and
rugged, and withal smarting." That dealer in
spells and philters, the notorious Mrs. Turner,
has the credit of introducing yellow-starched
ruffs into Britain, blue and white being the
fashionable colours hitherto. Mrs. Turner literally died in starch. In the
presence of many women of fashion she " made her exit on the scaffold at
Tyburn, rouged and dressed as if for a ball, and wearing an enormous ruff
stiffened with her own yellow starch."
The formation of starch is effected by protoplasmic bodies, which may
either be the chloroplasts already spoken of or leukoplasts (Greek leukos,
white, and plasma, something formed), which only differ from the former
in being colourless. Starch-making chloroplasts are found chiefly in the
leaves of plants; leukoplasts in the roots and tubers and certain other
parts which are hidden from the light ; yet the relationship between the two
is shown by the fact that leukoplasts turn green when light is admitted to
them for a sufficient time. They take a yellow or yellowish brown stain
when treated with iodine, and should be examined under a high power. The
starch-grains have the same chemical composition as cellulose (C6H1006), but,
unlike cellulose, are soluble in, water, and will take a blue or violet stain if
FIG. 65. — STARCH- GKAINS IN
BROKEN CELLS OF A POTATO.
FIG. 66. — SUGAR CANE (Saccharum officinarum).
A. giant grass whose cells are stored with canose or cane-sugar. The juices are extracted by pressure, and after passing
through purifying processes are crystallized. Cultivated from very early times. TROPICS.
43
44 HUTCHINSON'S POPULAR BOTANY
treated with iodine, which, cellulose will not. Their
formation may be thus described. The cells con-
taining chlorophyll, which are always near the
surface of the plant, absorb carbonic acid gas (C02)
from the atmosphere or water (the latter in the case
of submerged plants), and this gaseous compound
reacts with water (H20) in the chlorophyll corpuscles
under the action of light. The first organic product
as a result of this process is, in most plants, glucose
(C6H1206), or some other form of sugar. The sugar
has to be diffused along certain delicate cells * of the
plant, and as the process of diffusion is too slow to
keep pace with the process of construction, another
*8™Gy is brouSht into Pla^- The ^°roplasts, in
short, have the power of converting sugar into starch —
a power (we quote from Dr. Reynolds Green) which " is quite independent
of the colouring matter, being shared by other quite colourless plastids [the
leukoplasts already mentioned], which occur in other parts of the plant.
The transformation is apparently a process of secretion. Part of the
sugar consequently gives rise to numerous minute grains of starch, which
the plastid forms within itself, and deposits in its own substance. This
formation of a temporary store not only relieves the over-saturation of
the sap in the cell, but supplies the need of the protoplasm when the
formation of sugar from carbon dioxide and water is interrupted by the
failure of the daylight." It has been estimated that one hundred square
yards of green leaves can during five hours of sunlight manufacture one
pound of starch.
In this way, then, do green plants assimilate the carbon which they take
into their cells by absorption ; and as carbon usually
forms one-half of the dried plant by weight, the
statement will not appear extraordinary that starch
(or its physiological equivalent) is really the raw
material from which all the other organic substances
of the plant are elaborated.
Starch-grains are found in almost all plants, in
every part, but particularly in the roots, tubers,
seeds, and fruits, where they are stored up as reserve
food material : in fact, they supply the young plant
with food till it is in a condition to feed itself.
The roots of the Tapioca-plant (Jatropha manihot)
yield about 13| per cent, of this important sub-
stance ; the tubers of the Potato-plant (Solanum
FIG. 68.— RASPBEKBY tuberosum) nearly twice that proportion (figs. 63, 65) ;
(Rubus idceus). * The bast I tissue (vide Chapter III.).
THE PROTOPLAST AS HOUSEBUILDER
45
and the seeds of Wheat and Maize about 75 and 85 per cent, respectively.
The fruit of Artocarpus incisa —
The Bread-tree, which, without the ploughshare, yields
The unreaped harvests of unfurrowed fields ;
And bakes its unadulterated loaves
Without a furnace—
yields about 3^ per cent.
Starch-grains vary considerably in size, according to the plants in which
they are found. Some of
the largest occur in the
tubers of Canna edulis, and
measure ^^th of an inch in
diameter. This is the inter-
esting Tous-les-mois starch
of commerce. The grains
differ very much in form
also, but ovoid and lens
shapes are most common.
Spherical grains are found
in the tuberous roots of
plants of the Orchid family,
and rod and bone shapes
in the milk-sap of many
tropical Euphorbias. In the
Corncockle (Agrostemma
githago) they are spindle
shaped ; and angular starch
granules, .cemented together
to form ellipsoidal grains,
are found in the seeds of
the Oat (Avena) and Rice-
plant (Oryza).
Closely allied to starch
is inulin (C6H1005), which is
found in solution in many
roots, tubers, seeds, etc. —
particularly of plants of the Composite order. Thus it occurs in the
roots of Elecampane (Inula helenium}. Dandelion (Taraxacum officinale),
Chicory (Cichorium], and Feverfew (Matricaria parthenium) ; in the
tubers of the Potato-plant (Solanum tuberosum), Dahlia, and Jerusalem
Artichoke (Helianthus tuberosus) ; and in the seeds of the Sunflower
(H. annuus) and many other plants. The inulin of the chemist, which is
a soft, white, tasteless powder, is usually prepared from Elecampane or
the Dahlia. In its natural state inulin is distinguished from starch by
Photo by"] [E. Step.
FIG. 69. — CUCKOO-PINT (Arum maculatum).
A familiar hedgerow plant whose tubers are rich in starch. About one-
third the natural size. EUROPE, N. AFRICA.
46
HUTCHINSON'S POPULAR BOTANY
FIG. 70. — COMMON BEET (Beta vulgaris).
giving a yellow or yellowish brown
instead of a blue colour with iodine,
and by its inalterability under the
influence of ferments. It assumes
the form of beautiful sphere-crys-
tals on the addition of alcohol,
and is coloured an orange-red with
alcoholic solution of orcin, after
warming with hydrochloric acid.
An earlier occasion should per-
haps have been chosen to speak
of the sap of plants. We propose
in the following section to treat of
its composition only, reserving a
consideration of its functions for
future chapters. Cell-sap is the
fluid which the roots of plants absorb from the soil, or the leaves from the
atmosphere, and which contains in solution the true nutritious principles.
Water is the chief constituent of cell-sap, calculations showing that for
every two hundred grains of water absorbed and exhaled by a plant,
only one grain of inorganic matter is appropriated ; and for every two
thousand grains of water consumed, one grain of inorganic matter is
appropriated.
Young cells are usually well supplied with sap, which fills the spaces
(called vacuoles] occurring in the protoplasm. It is conveyed into the plant
by the roots, but not till it reaches
the leaves does it undergo any im-
portant changes. The proof of
this must be left for another
chapter, our present purpose being
simply to speak of the sap as a
substance found in vegetable cells
apart from the functions which
it discharges. Cell-sap may be
r!>s~4^ KH sweet or acid, clear or turbid,
%' .'f| nutritious or innutritions, so that
18 ^t^ *ts va^ue from an economic point
i& of view is often great. The re-
_\.\ freshing acid taste of most unripe
fruits is due to the sap. Citric
acid— a, familiar form of it— gives
sharpness to the juices of lemons,
FIG. 71. -ANTS HELD FAST BY THE MILK-SAP oranges, limes, and many of our
OF THE GAKDEN LETTUCE. commonest fruits, as the cranberry,
Photo by]
FIG. 72. — ACKERMANN'S CACTUS (Phyllocactus ackermanni).
[W. Rossiter.
This species has beautiful crimson flowers measuring from six to eight inches across. The stems are flat and leaf-like.
A native of Mexico.
47
48
HUTCHINSON'S POPULAR BOTANY
cherry, red whortleberry, and the " hip " of the Dog-rose (fig. 67) ; and it
exists, with an equal proportion of another acid — malic— in the cells of
the red gooseberry, the currant, the bilberry, the black cherry, the wood
strawberry, and the raspberry (fig. 68) ; while the latter is found alone in
apples, pears, etc. As these acids are much disliked by birds and mammals,
they serve as a protection to the young fruit, which would otherwise
get eaten before the seeds are ripe and ready for dispersion. As the seeds
mature, however, a
sweetening property is
added to the sap, and
so the visits of birds
and other fruit-eating
animals, whose presence
is now required, are
bountifully encouraged.
The acid juice of
Gymnema sylvestre, a
tropical Asclepiad, des-
troys or vitiates the
taste if the leaves be
chewed. Mr. Edge-
worth, who was the first
to draw attention to
this singular fact, states
that " after masticating
the leaf, powdered sugar
was like sand in the
mouth ; while a sweet
orange had the flavour
of a sour lime, the sour-
ness of the citric acid
being alone distinguish-
able. Only sweet and
bitter flavours are thus
destroyed. This indi-
cates that the action is not due to a complete temporary paralysis of the
nerves of taste. After a good dose of the leaf, sulphate of quinine tastes
like chalk. The effect usually lasts two or three hours." It has been
proposed to call the acid Gymnaic acid, after the plant.
The sweet pink cell-sap of the Common Beet (Beta vulgaris, fig. 70)
owes its sweetness to the presence of Canose (cane-sugar) dissolved in it.
The Prussian chemist Margraff was the first to discover this fact (about
1747), but it was not till the year 1809, when Napoleon forbade the importa-
tion of West Indian cane-sugar into France, that the discovery was turned
Pholo by] [E. Step.
FIG. 73. — CHICORY (Cichorium intybus).
A Composite plant with flowers of a distinctive bright blue. Its thick roots contain
inulin. EUROPE, N. AFRICA, N.W. INDIA
THE PROTOPLAST AS HOUSE-BUILDER
49
TO practical account. An Imperial sugar factory was then established at
Bambouillet ; pupils were regularly instructed in the process ; premiums
were offered for the best samples of the new sweetener ; and, in the course
of three or four years, the manufacture of beet-sugar was prosperously
•set on foot. Canose occurs abundantly in the Sugar-cane (Saccharum
ojficinarum) and
Sugar-maple (Acer
•saccharinum), and is
the substance found
in the nectaries of
flowers out of which
the bees make their
honey. Itis
secreted by the
protoplasm of the
cells composing the
nectaries, and the
quantity is at its
maximum during
the emission of the , •- • o ,•• ( . . *»^^
pollen, but ceases laSt^. ,«• •
when the fruit is
formed. Its pur-
pose is evidently to
attract insects or
small birds to the
plant, and thus to
secure pollination —
a subject 'of deep
interest, which will
be considered more
fully farther on.
Canose, or Cane-
sugar, must be care-
fully distinguished
from Glucose, or
Grape-sugar. The
formula of the first-
named is C12H220U, of the latter C6Hi209 ; and glucose', as we have already
seen, is a result of chemical rather than of protoplasmic action (p. 44). It
gives a bulky yellow precipitate with the reagent known as Fehling's
solution, which Cane-sugar does not.
No account of the peculiar juices of plants would be satisfactory which
excluded a reference to the milk-sap, or latex. This fluid, though clear
7
Photo by]
FIG. 74. — CELANDINE (Chelidonium majus).
IE. Step.
A plant that must not be confused with the Lesser Celandine, which is not related. The
Celandine is a member of the Poppy family. Its sap is milky but of a yellow colour.
EUROPE and W. ASIA.
50
HUTCHINSON'S POPULAR BOTANY
while in the uninjured tissues, instantly becomes turbid on exposure to the
atmosphere. The colour of the latex is usually milk-white ; but yellow, red,
and, in rare cases, blue milk-saps are met with. The microscope shows that
it consists of a colourless fluid wherein float myriads of minute globules,
which give the sap its opaque appearance. The Dandelion (Taraxacum
ofiicinale) and Celandine (Chelidonium majus) are familiar instances of latex-
yielding plants. The latter exudes a bright yellow juice if the leaf or stalk
be broken. Lettuces, again, when allowed to run up to flower, yield a white
milky fluid ; and both caout-
chouc (indiarubber) and the
opium of commerce are simply
the dried juices of two world-
known plants; caoutchouc being
obtained from Hevea brasiliensis,
a tall tree of tropical America,
and other trees, and opium from
the large Opium Poppy (Papaver
somniferum}.
The production of caout-
chouc by the various species
of rubber trees is not so much
that man may wear mackin-
toshes and tennis shoes, play
golf and have rubber tyres to
his cycle and motor-car, but
that the tree may be protected
from boring insects and other
afflictions. Mr. Belt makes this
clear by telling us* that rubber
trees which have been drained
of all their milk-sap get into an
unhealthy condition, and are
soon riddled by boring beetles.
A section through a lump of native rubber from the Niger. In this If a beetle Or a Woodpecker
condition it contains many impurities, being merely the coagulated , . , . i iii
sap as it has exuded from incisions in the tree. beglllS to bore into a healthy
tree, the latex is at once poured
into the wound, and its poison will drive off the bird, or kill and make
a prisoner of the beetle. So freely is this latex poured out to repair any
such injury, that it flows in a thin stream down the trunk and, soon
coagulating, produces a long, thin, elastic cord, which the natives use
for tying up bundles. This, no doubt, first directed man to the valuable
nature of indiarubber ; and who can properly estimate the importance of
that discovery ?
* Naturalist in Nicaragua.
FIG. 75. — CRUDE RUBBER.
PAofo &#] \_E. Step.
FIG. 76. — WOOD-SORREL (Oxalis acetosella).
One of the most charming of our native wild flowers. Its pure white flowers are streaked with hair-lines of purple. Its
trefoil leaves close down upon the stalk at night and during rain. Natural size. EUROPE, N. AFRICA, N. ASIA, N. AMERICA.
51
52
HUTCHINSON'S POPULAR BOTANY
Professor Kerner relates some curious facts to illustrate the protective
purposes of the milky juices of plants. These protective juices are not, as
in the case of the acid juices already referred to, required to keep off
birds and mammals, but to shield the plants, and particularly the floral
organs of plants, from the depredations of ants and other insects. Kerner' s
observations, recorded in his Flmvers and their Unbidden Guests, were confined
to two species of the
Lettuce family — Lactuca
angustana and the
Garden Lettuce (L.
saliva) ; and he thus
describes the effects of
the flow of juice on some
ants whose little hooked
\i ^F; feet had cut through
the epidermis of the
plants in certain places,
and thus induced the
flow: "Not only the
feet of the ants, but
the hinder parts of
their bodies, were soon
bedrabbled with the
white fluid ; and if the
ants, as was frequently
the case, bit into the
tissue of the epiderm in
self-defence, their
organs of mastication
also at once became
coated over with the
milky juice. By this
the ants were much im-
peded in their move-
ments, and in order to
The seed-capsules of the Opium-Poppy (Papaver somniferum). One to the right rid themselves of the
is cut open to show the divisions of the interior. The others show the open doors
Photo 6y]
Fm. 77. — POPPY- HEADS.
the roof which regulate the dispersal of the seeds.
annoyance to which they
were subject, drew their
feet through their mouths, and tried also to clear the hinder part of their
body from the juice with which it was smeared. The movements, however,
which accompanied these efforts simply resulted in the production of new
fissures in the epiderm, and fresh discharges of milky juice, so that the
position of the ants became each moment worse and worse. Many of them
now tried to escape by getting, as best they might, to the edge of the
THE PROTOPLAST AS HOUSE-BUILDER
53
FIG. 78. — CRYSTALLOIDS AND
GLOBOIDS IN ALEURONE
GRAINS.
leaf, and letting themselves fall from thence to
the ground. Some succeeded, but others tried
this method of escape too late ; for the air sdon
hardened the milky juice into a tough brown
substance, and after this all the strugglings of
the ants to free themselves from the viscid
matter were in vain. Their movements became
gradually fewer and weaker, until finally they
ceased altogether."
Latex-yielding plants increase in number as
we approach the tropics. The milk-sap is in
some cases extremely nutritious ; but mostly poisonous in the highest
degree. The juice of one species of Euphorbia (E. balsamifera^ thickened
into a jelly, is eaten as a delicacy by the inhabitants of the Canary Islands ;
and the Singhalese use the latex of the Ceylon Cow-
tree (Gymnema lactiferum) exactly as we do milk — a
fact which perhaps accounts for what Miss Gordon
Gumming calls their "invincible objection to cow's
milk." * The South Americans have their Cow-tree
also (Galactodendron utile), a native of Venezuela,
where it forms large forests. If a tolerably large
incision be made in the trunk of one of these trees,
it will yield a quantity of rich sweet milk, sufficient
to satisfy the hunger of several persons. " What
most interested us " (in the virgin forest near Para),
says Dr. Wallace in his Travels on the Amazon, " were
several large logs of the Milk-tree. On our way
through the forest we had seen some trunks much
notched by persons who had been extracting the milk. It is one of the
noblest trees of the forest, rising with a straight stem to an enormous
height. The timber is very hard, fine grained, and durable ; and is valu-
able for works which are much exposed to the weather. The fruit is eatable
and very good, the size of a small apple and full of a rich and very juicy
pulp. But strangest of all is the vegetable milk, which exudes in abundance
when the bark is cut. It has about the consistence
of thick cream, and but for a very slight peculiar
taste could scarcely be distinguished from the
genuine product of the cow." Some notches
* " This prejudice has been in a measure conquered in the
immediate neighbourhood of towns where foreigners require a
regular supply ; but (like the Chinese) no Singhalese man,
woman, or child seems ever to drink cow's milk, though a
little is occasionally used in the form of curds and eaten
with ghee, which is a sort of rancid butter." — Two Happy FIG. 80. — CRYSTALS IN CELLS
Years in Ceylon, by C. F. Gordon Gumming, vol. i. p. 113. OF ONION (Allium).
FIG. 79. — AN OLIVE WITH
PART OF THE FLESH RE-
MOVED TO SHOW THE
STONY CENTRE.
54
HUTCHINSON'S POPULAR BOTANY
having been cut in the bark of one of these trees with an
axe, " in a minute the 'rich sap was running out in great
quantities. It was collected in a basin, diluted with water,
strained, and brought up at tea-time and at breakfast
next morning. The peculiar flavour of the milk seemed
rather to improve the quality of the tea, and gave it as
good a colour as rich cream ; in coffee it is equally good."
Travellers would .doubtless be thankful if the milk-saps
of all plants were as nutritious as the milk-sap of the
American Cow-tree ; but it has been otherwise ordained.
Some, as we have already remarked, are 'extremely injurious.
The latex of the famous Javan Upas-tree (Antiaris toxi-
FIG. 81.— RAPHIDES carlo) is a deadly poison, and will produce large blisters
OF A SPECIES OF and painful ulcers on the person who incautiously touches
FUCHSIA. ^. jn the juice of the Mandioc-root (Manihot utilissima) —
from which the tapioca of our shops is prepared — the
Indian of Guiana dips his arrows to poison them ; and the juice of a South
African Spurge (Euphorbia caput-medusce) is used by the natives of Be-
chuanaland for the same purpose.
Sugar, inulin, and starch are largely used by the
protoplasm in the formation of cellulose for the cell-walls
in young plants ; as are also the fixed or fatty oils — olive,
rape, poppy, palm, etc. (see p. 58) — which swim, in the cell-
sap in the form of minute, shining yellow globules. These
plastic substances — all originating in protoplasm — are
stored up as reserve material in the cells of seeds, bulbs,
FIG. 82. — CYSTO- etc., though each has to undergo various changes before
tlie final conversion into cellulose is effected. Chief among
these changes is their transformation into the soluble sub-
stance glucose, or grape-sugar, already mentioned, which
is conveyed through certain conducting cells to that part of the plant where
new cells are being formed. How admirable is the wisdom directing this
complicated process ! Had the glucose been deposited in
the first instance, it must have undergone fermentation,
and thus would have become worthless before the plant
was ready to make use of it ; but the deposition of starch
(or its equivalent), which can remain unchanged for almost
any length of time, and which can at any moment be con-
verted into sugar, secures the desired object in the most
effectual manner.
The process is known as 'metabolism (Greek metabole, a
changing) — a term which is very comprehensive. It in-
cludes, indeed, not only all the chemical changes which
. , ' . , . -, , ,n ,,. ,
take place in the protoplasm, but the resulting phenomena
FIG. 83. — CYSTO-
LITH.
Crystals in a cell of Wal-
,_nut-tree (Juglans regid).
FIG. 84. — BAMBOO (Bambusa arundinacea).
The Bamboo is a gigantic grass, growing to a height of 50 or 60 feet. It is a native of the East Indies
anil China. In the latter country it is also carefully cultivated as one of the most useful of plants from which
the Gtunaman gets almost everything he requires.
55
56
HUTCHINSON'S POPULAR BOTANY
Phot
[E. Step.
FIG. 85. — FLOWERS OF SORREL (Rumex acetosa).
The Sorrels are not related to the Wood-sorrel, but to the Dock.
The similar names have been bestowed because both contain sharp
juices due to the presence of oxalate of potash in their tissues.
Slightly reduced. NORTHERN TEMPERATE and ARCTIC REGIONS.
as well. Thus the substances-
known as secondary or by-
products, such as volatile oils.
resin, tannin, pectin, acids, wax.
etc., are results of metabolism ;
so, too, are the substances called
degradation-pro ducts, which are
formed by the breaking down
and partial dissolving of organ-
ized structures. To this class
belong the mucilage of quince-
seeds and linseed, and many
kinds of gum, in some of which
— as the Gum Tragacanth — the-
organization of the cell-walls
used in their formation may
be detected. The gum named
is obtained from the Great
Goafs-thorn (Astragalus traga-
cantha}, a Levantine shrub, from
the bark of which it exudes
spontaneously at certain seasons
of the year, when it coagulates
and hardens and is then ready
to be collected.
How marvellous are these
changes when considered as the
results of protoplasmic activity !.
What miracle-workers are our
little protoplasts ! What a box
of wonders is every living cell L
" They may be regarded," as
Dr. Taylor pleasantly remarks,
" as so many organic chemical
laboratories, in which synthesis
is carried on even more vigor-
ously than analysis. Some are
starch manufacturers like Col-
man, as in the potato and other
tubers and bulbs ; some are per-
fume distillers like Rimmel, as
the cells in the leaves of Sweet-
briar (Rosa rubiginosa). Laven-
der (Lavandula), and Mints*
THE PBOTOPLAST AS HOUSE-BUILDER 57
(Mentha). Every cluster of cells has a work to do — sometimes special
kinds of work, but usually generalized kinds."
We would remark, further, that the reserve materials which we have
been considering (not the degradation- and by-products, but the nutritious
substances) fall naturally into two great divisions. The first division
comprises those substances which, like protoplasm, contain the elements
carbon, hydrogen, oxygen, nitrogen, sulphur, and perhaps, in- some cases,
phosphorus. They are essentially the plastic materials out of which the
protoplasm produces its wonderful transformations. Hence the name proteids
Photo fit/] \_E. Step.
Fia. 86. — LIME (Tilia).
The flowers of the Common Lime are here shown with their remarkable leafy bracts. EUROPE.
has been bestowed upon them, from Proteus, the fabulous old man of the
sea, who possessed the remarkable power of changing his form. The
substances comprised under the second division are distinguished from pro-
teids by the absence of nitrogen and sulphur, whence they are frequently
called the non-nitrogenous compounds.
The proteids include such substances as gluten, which forms a great part
of the corn-grains, and which is identical in its composition with albumen,
the basis of animal tissues ; legumin, which exists largely in the pea and
bean; and aleurow^-grains, which are abundant in oily seeds, and which
almost always enclose other bodies — namely, crystalloids and globoids
58
HUTCHINSON'S POPULAR BOTANY
(fig.. 78). The non-nitrogenous compounds, which invariably contain the
elements carbon, hydrogen, and oxygen, are starch, sugars, inulin, and
fatty oils.
A word as to the fixed or fatty oils. One of the most valuable of these is
olive oil, which is obtained from the Olive (Olea europeci), a shrubby tree
cultivated with great care in Spain, Italy, Syria, and other countries on the
shores of the Mediterranean Sea. The oil is contained in the drupe (fig. 79).
The Olive harvest in Italy and Spain produces £9,000,000 or £10,000,000 a
year. Palm-oil is obtained from the fruit of various Palms, and approaches
to the condition of ordinary fat ; so that it is well adapted for the manufacture
of candles. It constitutes an important article of food >in those countries
where Palms abound. The Flax-plant (Linuni) yields the valuable linseed-
oil, which is expressed from the seeds and largely used after distillation in
the preparation of paint. The pressed seeds from which the oil has been
partly extracted constitute the oil-cake often
given to cattle on account of its fattening pro-
perties. Rape-oil is extracted from the seeds of
the Rape-plant (Brassica napus), and is the oil
best adapted for the lubricating of machinery ;
while the seeds of a species of Poppy (Papaver
somniferum) supply the oil of that name ; and
those of the monkey-nut (Arachis hypogea) yield
the well-known ground-nut-oil, which is largely
used in India, Java, and Malacca both for light-
ing purposes and for food. The fatty oils may
be coloured black with osmic acid, or pink by
alkanna, and are soluble in ether.
Crystalloids, to which reference was made a
paragraph or so back, must not be confounded
with true crystals. They resemble them in ap-
pearance, but are essentially different, being capable of swelling up when
treated with certain reagents, which true crystals are not. They are to be
met with in most oily seeds, as the seeds of the Castor-oil-plant (Ricinus
communis\ and are not uncommon in the tuber of the potato. In the
latter they take a cubical form, and on being immersed in water split up
like a pack of cards, without dissolving (fig. 78).
True crystals (fig. 80) are far more plentiful in vegetable tissues than
crystalloids ; for which reason they call for more extended notice. Plants
of the Cactus tribe (Cadacece) usually contain a great quantity of oxalic
acid, which would be deadly to the plants were it not that they take up
from the soil a proportionate quantity of lime ; and this combines with the
acids in insoluble crystals. The Old-man Cactus (Cactus senilis) is computed
to contain as much as 85 per cent, of oxalate of lime ; and it often happens
with certain species of this tribe that their tissues become so loaded with
FIG. 87. — SCOTS PINE (Pinus
sylvestris).
A. section of tissue showing the resin
passage (in the centre).
60
HUTCHINSON'S POPULAR BOTANY
crystals as to render the plants quite brittle. Dr. Carpenter, in his work on
the microscope, relates that when some specimens of Cactus senilis, said to
be a thousand years old, were sent to Kew Gardens from South America
some half -century ago, "it was found necessary for their preservation
during transit to pack them in cotton like jewellery," so fragile were they
from the quantity of crystallized acid in their tissues.
Plant crystals are al-
ways formed of oxalate
of lime or potash. The
lime enters the plant as
sulphate of lime, and
when the sulphur — after-
wards used by the proto-
plasm in the manufac-
ture of new proteids
(p. 57) — has been separ-
ated by the protoplasts,
the lime combines with
the oxalic acid already
in the plant, and crystal-
lization takes place.
The crystallized acid has-
much the appearance of
Epsom salts, but it is
highly poisonous.
Never speak of the
formation of crystals as
" growth." This has
sometimes been done,
even by writers of con-
siderable reputation, but
it is a mistake. Only
living matter can be
FIG. 89. — MABJOKAM (Origanum vulgar e). truly said to grow ; and
One of the most fragrant of our herbs, whose masses of purple flowers cover CrVStals are not living;
acres of dry chalk-land. It belongs to the family of Labiates, or lipped flowers. J ,. ml
One- third of natural size. EUROPE, N. AFRICA, N. ASIA. matter. 1 lie prOC6SSeS
of crystal formation are
entirely different from the wonderful and all but miraculous life-processes of
protoplasm. The first are purely chemical in their nature, and may be success-
fully imitated in the laboratory ; the second are vital rather than chemical, and
defy imitation. A schoolboy may be taught to make crystals ; the most skil-
ful chemist cannot make a grain's- weight of living matter. " The processes
are absolutely distinct," says Professor Beale, " and the 'growth' of living
things implies Life, and such growth never occurs in the absence of Life."
.,
. t
V*
Photo by-]
IE. Step.
THE PROTOPLAST AS HOUSE-BUILDER
61
True crystals are found in the epidermal cells of the leaf of the Iris and
the Fiichsia. In the latter, they are disposed in little bundles, and look like
so many broken pieces of needle — whence the name raphides (Lat. raphis,
a needle) which is sometimes applied to them (fig. 81). Stellate crystals are
met with in the bark of the Lime-tree (Tilia) ; cubical in the Onion (Allium) ;
and sphere crystals in one of the Stinkhorn Fungi — viz. Phallus caninus.
A good slide for showing the cubical crystals of the Onion may be made by
soaking a little of the brown skin of the bulb in turpentine till it is quite
clear, and then mounting in balsam. In Switzerland, oxalate of potash is
FIG. 90. — WILD THYME (Thymus serpyllwn).
IE. Step.
A familiar wild plant with trailing stems, neat small leaves, and pale purple flowers. Like Marjoram a Labiate, and
aromatic. Slightly reduced. EUBOPE and N. ASIA.
prepared from the leaves of the Common Sorrel (Rumex acetosa] and Wood
Sorrel (Oxalis acetosella), so plentiful are the crystals in their tissues.
The cell-walls of the epidermis of some plants of the great Nettle order
(Urticacece) and a few others increase in thickness in a very peculiar manner,
the deposit taking the form of bladder-like growths containing carbonate of
lime. The cells of the Indiarubber-plant (Ficus elastica] and Common
Walnut-tree (Juglans regia) show these remarkable ingrowths very distinctly
(figs. 82 and 83). They have been christened cystoliths by the learned, a
name derived from the Greek kustis, a bag or bladder, and lithos, a stone.
Minute punctiform cystoliths, which reflect the light, are the cause of the
62
HUTCHINSON'S POPULAR BOTANY
white spots on the downy leaves of those curious shrubby plants, the
Boehmeria, a tropical genus of the Nettle order.
Closely allied with crystals are certain by-products of a more adven-
titious kind known as " vegetable stones." A large proportion of these are
formed and deposited in the tissues from the siliceous and calcareous sub-
stances which circulate with the sap. Thus, in the Bamboo, a round stone is
found at the joints of the cane, called " tabasheer " ; and in Java and other East
India islands, round and pear-shaped stones of carbonate of lime are some^
times found in the endosperm (the edible albuminous part) of the coco-nut.
Photo by]
FIG. 91. — WALNUT-TREE (Juglans regia).
[E. Step.
This photo shows the Walnut-tree in its winter condition, with the manner of its trunk divisions, and branch
and twig ramifications. From GREECE to the HIMALAYA.
In appearance they are almost lustreless, and not unlike a white pearl.
They are often as large as cherries and as hard as felspar. The natives of
the Celebes put high value on these vegetable opals, using them as amulets
and charms against disease.
Among the other substances which come under the category of by-
products may be mentioned the volatile and aromatic oils, so useful in
medicine and perfumery. Of these our naturalized and British plants
supply not a few, as every one knows who is acquainted with such old
favourites as Lavender and Rosemary, Spearmint and Peppermint, Thyme
FIG. 92. — HEMLOCK WATER-DROPWORT (CEnanthe crocata).
[E. Step.
A beautiful but highly poisonous plant that grows in marshes and by the waterside. About one-third of the natural
Size. EUROPE (BRITAIN to SPAIN and ITALY).
63
64
HUTCHINSON'S POPULAR BOTANY
and Marjoram, which all yield aromatic oils. Yet we must turn to hotter
countries for the perfumes most prized and coveted, and especially to the
inter-tropical regions. Thus Turkey (chiefly the Roumelian provinces),
Persia, and the Rajpootana States supply the fragrant attar-of-roses, which
is obtained by distillation from the petals of that flower. The quantity of
rose-petals required to furnish a teaspoonful of this princely perfume is
almost fabulous, and sufficiently accounts for the high price which the oil
commands. The London market is chiefly supplied from Roumelia, whose
average annual output is from thirty to forty hundredweight.* About
12,000 persons in this region depend entirely upon this source of income.
The Turkish attar is usually adulterated either with the oil of Geranium or
of the Indian Khus-khus Grass (Andropogon). There are two other kinds
of attar, both of Indian extraction — namely, the Jasmine and Keova, the
former being a production of the Large-flowered Jasmine (Jasminum
gratidiflorum), and the latter of the fragrant flowers of the Screw-pine
(Pandanus odoratissimus). Then we have oil of cloves and of cinnamon,
of cumin and of camphor, of lemons and of bitter almonds, of turpentine
and eucalyptus — all aromatic oils of more or less value ; while the peculiar
scent and great durability of russian leather is attributed to the employ-
Photo &y]
FIG. 93. — ASPEN (Populus trermda).
[E. Step.
The Aspen is one of the Poplars, but has its smaller, more coarsely toothed leaves on longer flattened leaf -stalks which
allow of the constant lateral movements for which the tree is famous. EUROPE, N. AFRICA, N. ASIA.
* It is said that 100,000 roses yield only 189 grains of attar !
(il.ORY I'KA (CliaiitliH* rlmnpifri).
,'ions of Australia and New Smith Wali-s. The pale jrr
iiintry. hut will succeed only in a hoi. dry, sunny sitna:
THE PBOTOPLAST AS HOUSE-BUILDER
65
Photo by]
Fia. 94. — BIRCH (Betula alba).
ihowing the delicacy of the twigs, the light character of the foliage, and the short cylindrical cones.
EUROPE, N. ASIA.
[E. Step.
ment, during the process of tanning, of a volatile oil obtained by the
distillation of Birch bark (Betula). The oil has a brown or black colour,
and a little of it poured on paper and allowed to dry gives to the paper
the scent peculiar to russian leather. On a future occasion, when the
odours of flowers in relation to insects will be our subject, allusion will be
made to Kerner's helpful classification of the aromatic oils, and some
further light will be thrown on this very interesting subject.
Professor Tyndall found that infinitesimal quantities of these essential
oils thrown off into the air enormously increased its power of absorbing
heat-rays of low tension ; and Dr. George Henderson, F.L.S.,* has suggested
that in this way these oils may often prevent injury from frost at one of the
most critical periods of a plant's life, namely, when it is setting its fruit. He
says, " In the low hills of the Punjab Himalaya, from 1,000 to 4,000 feet
above the sea and 10 to 20 miles across, in the end of March and in April,
when most of the plants are coming into flower, the blossoms are apt to be
blighted by late frosts, at least one would expect this ; but at that season
the air is filled with the odours of essential oils from these blossoms to such
an extent as to be at times (and especially on a still night, when frost most
often occurs) quite overpowering. My theory is that these essential oils
* Proceedings of Linnean Society, 1903.
8
66
HUTCHINSON'S POPULAR BOTANY
help to prevent radiation
at night, and thus preserve
the blossoms and allow the
fruit to set ; after all, it is
usually only a matter of four
or five degrees' fall of tem-
perature just at sunrise that
does all the damage."
We may add that the
oil of Birch bark mentioned
above is simply a form of
tannin, which is one of the
most widely distributed of
secondary products. Its
characteristic reaction is
that of forming insoluble
compounds with gelatine,
solid muscular fibre, skin,
etc., which then acquires
the property of resisting
putrefaction, as in the tan-
ning of leather. Kerner
has pointed out that its ex-
tremely bitter taste protects
the branches, cortex, and
fruits from being eaten.
The plants which furnish
most of the tannin of com-
merce are the Oak (chiefly
Quercus sessifolia, infectorid,
and pedunculata], Hemlock
Spruce (Abies canadensis),
Red Pine (Pinus contorta), and Water-smartweed (Polygonum amphibiiim).
Other by-products of metabolism — and the last that we shall here speak
of — are resins, waxes, and balsams, which naturally fall into one group.
Young buds are often coated with a balsam (i.e. a solution of resin in an
ethereal oil) to protect them from cold and wet during the winter and early
spring. The Horse-chestnut (sEsculus hippocastanum) and Balsam Poplar
(Populus balsamifera) offer familiar examples of these varnished buds.
Again, the stems of many plants of the Clove order (Caryophyltacece) are
plentifully supplied with a sticky solution formed of resin and gum, which
effectually forbids the approach of insects to the flower along that route ;
while resin-ducts are largely present in trees of the Terebinth and Cone-
bearing orders (Anacardiacece and Coniferce). The resin-producing capabilities
Photo by]
FIG. 95. — CONE OF SABINE'S PINE (Pinu
[E. Step.
sabiniana).
One of the finest of the Pine-cones, measuring 8 or 9 inches in
length. The tree is a native of California, where it grows to a
height of 50 or 60 feet.
FIG. 96. — GIANT CACTUS (Echinocactus).
[H. J. Shepstone
A native of Mexico. The spines are sufficiently long to be used as toothpicks. A similar plant, about seven feet high and
weighing a ton, was once received at Kew, but the injuries to its succulent flesh in transit were such that it did not
long survive.
G7
68
HUTCHINSON'S POPULAR BOTANY
Photo ly]
FIG. 97. — WHITE WTILLOW (Salix alba).
[E. Step.
The upright spikes are the female catkins. At the extremity of the shoot the new leaves are just emerged from the
leaf-buds. EUROPE, N'. AFRICA, ASIA..
of the Pine family are, indeed, phenomenal, one and a half or even two
pounds being frequently obtained from a single tree at each tapping
(fig. 87). The Maritime Pine (Pinus pinaster) is perhaps the most prolific
of all. It begins to yield abundantly when twenty-five or thirty years
old, and when the process is well managed will continue to yield for
a very long time. There are Pines at La Teste, in France, with as many as
sixty scars of places where they have been tapped, evidence that the
working of these trees goes back at least three centuries.
The production of resin by the Pines appears to be a protection from the
attacks of Fungi. It is most abundant in their trunks just above the roots,
from which many of the most deadly of the tree-fungi obtain access. To
the fact that roots of trees are often injured by the gnawing of rodent
animals many a noble tree falls a victim to fungus, the entire bark being
impervious to the attack of the fungus. This broken, a germinating spore
— probably brought in the fur of the mouse that gnawed the root — obtains
access to the layers of bast-tissue up which its mycelium can extend without
limit. Torn limbs offer a similar opening. In the case of the Scots Pine,
broken limbs rapidly have the wound closed by an outpouring of resin,
which coagulates and closes all the pores. Pine-trees in plantations often
have their roots torn by the spades of careless woodmen when cutting
drains. The fungus thus gains entrance, for the roots are deficient in resin,
THE PROTOPLAST AS HOUSE-BUILDER
69
but just above it is so abundant that further progress of the mycelium is
stayed. The Spruce and Weymouth Pine are not so rich in resin, and up
their trunks the mycelium of the deadly Forties annosus spreads rapidly,
causing the condition known as red rot.
Wax is another frequent vegetable production, especially in the torrid
zone, where many of the wax-bearing plants supply the natives with light.
This substance gives the bloom to the plum, cherry, and grape ; and " the
raindrops lie on the waxy surface of the Cabbage-leaf like balls of diamond,
from the total reflection of light at their points of contact." Wax is secreted
in the cuticle for the purpose of getting rid as rapidly as possible of the
water which is deposited on the surfaces of the leaves, or to prevent exces-
sive loss of water by transpiration — the latter an invaluable provision
in the Aloe, Cactus, and other fleshy leaved plants inhabiting the hot,
parched regions of the tropics. A further use is noticed by Kerner. He
tells us that the branches of many Willows which bear honey-laden flower
catkins are provided with wax-like coverings (combinations of fatty acids
with glycerine), so extremely smooth and slippery that would-be visitors to
the flowers (unserviceable, honey-thieving ants for the most part) strive in
vain to accomplish the ascent.
The delicate waxen bloom of many plants presents some curious forms
under the microscope. The bloom on the Rye, familiarised in a once popular
Photo by]
FIG. 98. — PINE FUNGUS (Pomes annosus).
[E. Step.
This fungus attacks Pine-trees chiefly through injured roots, and spreads thence up the trunk. The Scots Pine has an
abundant store of resin just above the roots which prevents the upward progress of the fungus. It is the cause of
" red rot."
70
HUTCHINSON'S POPULAR BOTANY
song, consists of dense ag-
glomerations of rods or needles,
and is a most interesting ob-
ject for examination. So, too,
is the wax coating of the leaves
of the Banana (A/itsa), which
consists of little rods that stand
erect on the cuticle like so
many Lilliputian posts ; while
the "frosting" of leaves is
made up of tiny granules of
wax.
It is worthy of remark how
much the production of these
and other secretions depends
upon the intensity of light and
heat. Plants that will grow
well enough in a climate very
different from that to which
they have been accustomed,
will, nevertheless, frequently
cease to form their peculiar
secretions, or at least produce
them in very diminished quan-
tities. This accounts for the
fact that the Tobacco grown
in this country is so vastly
inferior to that grown, say, in Cuba or Persia ; and to the same cause may
be traced the great scarcity in English-grown roses of the fragrant attar
already spoken of, which is comparatively abundant in the flowers cultivated
for that product in India, Persia, and Roumelia.
Most of the fragrant balms and balsams are the products of warmer
countries than our own — in fact, some of those of greatest repute are
obtained from places that are hot and dry, such as Arabia and Somaliland.
Thus, the Frankincense (Olibanum) of the Bible narrative is a resin obtained
from species of Boswellia which grow in Arabia. It is obtained by making
cuts in the bark of the tree, from which the resin is poured out to stop the
entrance of parasites. When dried by the sun the resin is scraped off.
Other resins coming under the head of Frankincense are Galbanum from
Ferula galbaniflua, a Persian plant, and Storax from Styrax offidnale in the
Levant. Myrrh is the most ancient of all these aromatic substances : it
is obtained from a plant known as Commiphora myrrha, a native of
Arabia, also found in Eastern Africa. Balm of Gilead is obtained from
Balsamodendron gileadense, a tree of Palestine ; and Ladanum is a sticky
Photo by]
[/?. Step.
FIG. 99. — COWBANE (Cicuta virosa).
An Umbelliferous plant that grows in watery places, and is highly
poisonous. About one-fourth the natural size. EUROPK. N. ASIA.
Photo ly] [E. Step.
FIG. 100. — THE LADY FERN (Athyrium filix-fcemina).
One of the most delicately graceful of our ferns. Its soft-textured fronds transpire water readily, and therefore it
grows where there is an abundance of free moisture in the soil. Here, by the wayside rill, shaded by overhanging
trees, is an ideal spot for it, to which it has added a considerable element of beauty. Distribution, world-wide.
71
72
HUTCHINSON'S POPULAR BOTANY
secretion from the leaves of
Cistus creticus, which is
gathered in the island of
Crete by dragging leathern
straps over the plants. The
Ladanum adheres to the
straps, and when they are
well coated it is scraped
off and used in the prepara-
tion of a perfume.
The scent of Lavender,
remarkably enough, is more
powerful in British-grown
plants than in those culti-
vated in the south of Europe,
its native habitat, much
light and heat being un-
favourable to the production
of the fragrant oil. Equally
curious is the statement —
the truth of which is
vouched for by Dr. Christi-
son — that the Cowbane
(Cicuta virosa) and Hemlock
Water-dropwort (GKnanthe
crocata], which are poisonous
in most districts of England,
are innocuous when grown
near Edinburgh ! The state-
ment seems hardly credible,
and though supported by so high an authority as Dr. Christison, should
be received — if received at all — with considerable caution. We do not
remember whether the statement has been tested — certainly we should
not expect Scottish stock owners to experiment with it upon their cattle,
for at intervals one reads in the newspapers that valuable beasts have
been killed through eating the plant. Too much care cannot be taken
in dealing with plants' [of this Natural Order — the Umbelliferse— for
though it yields us such valuable cultivated plants as Carrot, Parsnip,
Parsley, and Celery, it also includes Hemlock and other virulent poisons.
by] [E. Step.
FIG. 101.— THE MALE FERN (Nephrodium filix-mas).
One of the most robust of our ferns. In contrast to those of the Lady
Pern, its fronds are thick-textured, and it can grow in drier situations.
TEMPERATE REGIONS.
CHAPTER III
CELL COMMUNITIES: A CHAPTER ON TISSUES
Cell joined to cell, mysterious Life passed on
By viscous threads ; selecting in its course,
From formless matter, with mysterious touch
That seems a prescience, and that never errs,
Materials diverse, out of which to weave
The warp and woof of tissues.
in VERY plant, as already mentioned, consists either of a cell or cells, or
JDj of the products of their formation and transformation. When a
Rose-tree begins to grow, its growth is not effected merely — nor chiefly — by
the increase in size of already existing cells, but by the formation of cells
entirely new ; and this is true of all multicellular plants. Of course, cell
multiplication (as it is called) also takes place in unicellular plants. This we
saw to be the case with Sphcerella pluvialis ; but
in such instances the new cells become distinct
individuals ; they cease to form part of the
parent plant, and enter upon an entirely inde-
pendent existence.
Now, cells may multiply in four ways. Free
cell formation is one of these ; and we take this
mode of increase first, because it is the means
by which both the resting and zoospores of
Sphcerella are produced. The pollen-grains of
most Flowering Plants are formed in this way,
as well as many zoospores besides those of
Sphcerella. The process has been already de-
scribed at some length, and there is no need to
go over the ground again.
Sometimes, however, the entire protoplasm
of the parent cell, instead of dividing off into
several individuals, is used up in the formation
of a single new cell. This mode of cell forma-
tion, which is like a renewing of the youth of
the individual, is appropriately termed rejuven-
escence.
73
FlG. 102. SlLKWEED OR
CROW-SILK.
Portions of the filaments of six separate
plants. In the second three filaments ten
of the cells are seen to be in various
stages of conjugation.
74
HUTCHINSON'S POPULAR BOTANY
In a few forms of vegetable life the protoplasm of two or more cells
coalesces for the purpose of reproduction, and this is known as conjugation.
Here (fig. 102) are some cells of a little fresh-water weed, Zygnema
quinium, common enough in our ponds and ditches, and popularly known
as Silkweed or Crow-silk. Each of the pale yellow-green filaments represents
a separate plant, and is built up of a single row of cells ; but when conjuga-
tion is about to commence, the cell-walls of two distinct filaments that
happen to float in proximity form blunt projections from their sides, and
reach out to one another till they meet. Then, at the points of contact,
those portions of the walls which hinder communication between contiguous
cells dissolve away ; the sap at once occupies the passage thus formed ; and
the protoplasm from one of each pair of united cells, forcing its way through
the narrow channel, fuses with the protoplasm in the companion cell, and so
conjugation is effected.
But a far more common method of increase than any which we have yet
considered is that which is known as cell division. Increase in length of
FIG. 103. — INDIRECT NUCLEAR DIVISION (vide text).
every filamentary plant of Silkweed was due to cell division ; the cells of
the fragment of Onion-skin which we were speaking of in the previous
chapter multiplied in this way ; so did the star-shaped cells of the Common
Bean lately mentioned. Indeed, the vegetative organs of most plants (as
distinguished from the reproductive organs) are almost always so formed.
But what is cell division? To say that all normal vegetable growth
takes place by such means is no explanation of the process ; we are only
moving in a circle. Will you follow an attempt to illustrate the process
by means of a few diagrams ? We will suppose that the first sketch (fig. 102)
represents a row — or part of a row — of vegetative cells, of which the upper-
most is about to divide. Here (fig. 103) is this cell on a larger scale, with
its cell-wall (6) and its granular protoplasmic contents (c), in the midst of
which is drawn a circular disc to represent the nucleus (ri). Changes in the
nucleus intimate that the process has commenced. The nucleus elongates.
and its delicate fibrillce — delicate even under the highest powers of the
microscope — appear at this stage to interlace in a confusing manner. A
little later the tanglement is over, and the fibrillce are seen to be converging
to one or the other of the poles of the nucleus. Between these fibrillce
Photo by] [E. Step.
FIG. 104. — REINDEER Moss (Cladonia rangiferina).
One of the Commensal plants known as Lichens. In this country it grows among heather stems, scarcely noticeable in
•summer, but in winter it greatly increases in size. In the far north it is a plant of considerable importance, and, as its name
implies, forms a principal part of the food of the reindeer. Natural size.
75
76
HUTCHINSON'S POPULAR BOTANY
1 2 3
FIG. 105. — PORTION OF STEM OF
ITALIAN REED.
1. Outer covering of the stem or integument.
2. Pibro-vascular bundle. 3. Medulla or pith, (a)
Tissue of cells (parenchyma); (6) Bast-fibres;
(c) Pitted vessel ; (/) Spiral vessels ; (g) Annular
vessels ; (A) Soft loose cells of pith ; (.«) Sieve-
tubes or bast-vessels.
new and yet finer threads presently ap-
pear, each of which extends from pole
to pole, the figure now presented to the
eye being that of a miniature spindle in
the midst of the protoplasm, and this
spindle becomes more and more extended
till it stretches across the cell. Meanwhile,
along the fibres stream granules of proto-
plasm, which, gathering where the spindle
is widest (i.e. exactly •> midway between
the poles), unite to form a plate ; while
the specks of congested protoplasm which
constitute the ends of the spindle become
distinct and perfect nuclei. From the
plate thus formed is developed in time a
wall of cellulose, by which the entire
cavity of the mother-cell is divided into
two chambers ; and then, with the dis-
appearance of thefibrillce, the nuclei finally
part company, and cell division is accom-
plished.
Such, then, are the principal means of cell
multiplication — free-cell formation, rejuven-
escence, conjugation, and cell division; and this
leads us to another important subject — that of
cell fusion— with which we may link what little
there is to say about vegetable tissues, and then
close this division of our subject.
Any set of similar cells, governed by a com-
mon law of growth, forms a tissue, and two or
more cells, coalescing into a single individual
by the partial or entire breaking down of their
dividing walls, form a vessel. The latter process
is cell fusion. We have seen an example of
tissue already in the stellate cells of the Bean
(fig. 44) ; the fragment of Onion-skin shown in
fig. 35 was another example. The diagram now
given (fig. 105) offers examples both of vessels
and tissues, c, /, and g are vessels, a and h are
tissues of cells. The darkly shaded portion at b is
woody fibre, of which we shall speak again in a
moment. The subject need present no difficul-
ties, as the ground has been already cleared by
the remarks upon cell forms and structure ; but
FIG. 106. — LONGITUDINAL
SECTION OF A PORTION OF
THE CORTICAL PARENCHYMA
OF A EUPHORBIA,
Showing laticiferous or branched
laticiferous "cell" (7) in the midst
of the tissue.
CELL COMMUNITIES: A CHAPTER ON TISSUES
77
we trust the reader will follow the description closely, as the points to
be touched upon are of great importance. "We will consider vessels first.
To this end it may be well to take a backward glance for a moment. On
pp. 32 and 34 are illustrations of the spiral, annular, reticulated, and
pitted cells (figs. 54 and 57). Now, from all of these, vessels may be
formed. Place a lot of spiral cells on top of one another, and break away
the whole or greater part of
each of the partition walls,
and you will have a spiral
vessel (fig. 105, /). Do the
same with a number of
annular cells, or reticulated
cells, or pitted cells, and you
will have annular vessels, or
reticulated vessels, or pitted
vessels, as the case may be
(fig. 105, c and g). Of course
this could not be done in
reality, the vessels being far
too small ; but we use popu-
lar language. Hooke esti-
mated that a cubic inch of
oak contains upwards of
seven millions of vessels ;
and another of the old micro-
scopists, Leuwenhoek, com-
puted that the bole of an
Oak, only- four inches in
diameter, contains about
two hundred millions ! We
are not sure whether
Damory's Oak in Dorsetshire
is still standing; but this
tree not many years ago Photo 6y] ^- step-
measured eighty-four feet FlG- 107-— CAPEK SptJRGE (Euphorbia lathyris).
in circumference, and it
was then shown by a labori-
ous calculation that more
than 240 millions of miles of vessels were packed in a single foot's length
of the stem, and that if the vessels contained in the whole tree could be
placed end to end in a single line, they would have made a communica-
tion backwards and forwards between the sun and every planet in the
system ! The few thousand miles of piping which underlie London look
rather paltry in comparison with this.
A plant frequently grown in gardens, but locally wild in the south of
England. Its seed-vessels have been used as a'substitute for capers,
but they are of a poisonous nature. About one-twelfth of the natural
size. S. EUROPE.
78
HUTCHINSON'S POPULAR BOTANY
STEM OF THE FIELD
HORSE-TAIL (Equi-
setum arvense).
In certain cells of the Ferns and their allies the thicken-
ing deposit laid down on the inner surface of the cell-
walls takes the form of miniature ladders, on which
account the vessels constructed out of these cells (though
absorption of transverse septa is rare in Ferns) are called
scalariform, or ladder-like (Lat. scala, a ladder). As a
matter of fact, scalariform vessels are only modifications
of the reticulated form, from which they differ by the
partition -walls of secondary deposit being larger and more
FlQ. io8.— PAREN- regular.
CHYMA FKOM THE Spiral and annular vessels occur in the stems of most
Dicotyledons (plants with two seed-leaves), but only in
what is known as the primary wood, which forms the
first circle round the pith, and is called on that account
the medullary sheath (Lat. medulla, the marrow of bones) : whereas reticu-
lated and pitted vessels are found in the denser internal parts of the
woody layers (vide Chapter VII.). All of these occur in the leaf-stalks and
veins of leaves, and in certain parts of the flower, but never in the bark.
They keep the cellular tissue of the leaves stretched and extended, acting
like the ribs of an umbrella. In Monocotyledons (plants with only one
seed-leaf), they are placed in the interior of the woody bundles of the stem,
and sometimes you will meet with them in the root-fibres. In the mature
state they contain nothing but air ; but occasionally, in the spring, a portion
of the sap sucked up by the roots is pressed into them — a process on which
depends, for example, the "weeping" of wounded grape-vines (Thome'«
Lehrbuch, p. 30).
There is one other kind of elongated cell found in the
woody parts (nbro-vascular bundles) of many plants which
should not be passed over. "We have described it as " woody
fibre," but the scientific name for these vessels is bast-tubes
or bast-fibres (fig. 105, 6). Bast-tubes must not be confounded
with what are known as sieve-tubes or bast-vessels. The
former are long, pointed, and thick-walled, and occasionally,
though very seldom, they are branched. The sieve-tubes
or bast-vessels, on the other hand, consist of slender flexible
tubes, with their walls unmarked by secondary deposit
(fig. 105, s). The dividing walls of the cells of which
the last-named vessels are built are not entirely absorbed,
as are the partition-walls in the bast-fibres ; but they are
perforated in various places so as to resemble a sieve,
whence they are called sieve-plates, and the vessels, as we
have seen, sieve-tubes. Not infrequently the side walls of
adjoining tubes are also perforated.
vitalba). If two or three hollow cylinders, covered at each end
FIG 109 —PROS
EN CHYMA OF
79
80
HUTCHINSON'S POPULAR BOTANY
Phfto 6y] [E. Step.
FIG. 111. — LARCH (Larix europceus).
The Larch, alone among Conifers, sheds its leaves in
autumn. Here are shown the new leaves issuing in spring,
together with the male flowers. Native of ALPINE EUROPE.
with parchment, be placed together
lengthwise, and holes be driven
through the parchment covers so that
the cylinders freely communicate with
each other, a very fair idea will be
gained of a sieve-tube : the perforated
parchment covers will, of course,
answer to the sieve-plates. These
vessels retain their protoplasm, which
circulates through the sieve-plates,
and they evidently play an important
part in the life-history of the plant.
The German physiologist, Sachs, was
of opinion that much of the new
protoplasm is produced in the sieve-
tube, and this view is shared by Pro-
fessor Thome and other eminent
botanists. These also are the vessels
which play so important a part in the
diffusion of the sugar formed by the
chloroplasts in the leaves of plants.
In the leaves and outer bark of
many plants, thin-walled vessels of
various structure may be met with,
which usually run parallel with each
other and invariably contain bundles
of needle-shaped crystals. These are
closely related to the sieve-tubes, and
are known as utricular vessels. A very
large number of plants have them.*
The laticiferous vessels, which may
next engage us, though of much
interest from a physiological point of
view, need not detain us long. These
vessels, as their name implies, convey
the milk-sap or latex to the parts of
the plants which require, or, at least,
seem to require it ; for there is some
doubt as to the function of latex —
whether it is more than a by-product.
* According to Professor Thome (Lfhrluch,
p. 32), they occur in most Monocotyledons, and
in some Dicotyledons, being found exclusively
in the outer cortex or the foliar organs.
CELL COMMUNITIES: A CHAPTEE ON TISSUES
81
Like the vessels last mentioned, the
laticiferous vessels are closely allied
to the sieve-tubes, consisting of closed
tubes, cylindrical or angular in shape,
and usually with thin, transparent
walls. They are formed by the union
of cells, but not necessarily (and here
they differ from most vessels) by the
union of a single row of cells. They
appear to be bound by no rule of
growth, so that some very irregular
vessels are often seen which branch
out in all directions and form a copious
network, with free intercommunica-
tion. Their presence is limited, how-
ever, to a small number of plants ;
for the milk-sap of many latex-yield-
ing species is not contained in vessels,
but in long, branched, simple cells.
The Euphorbias (fig. 107), to which the
Spurges and South African Tapioca-
plant belong, abound in these cells.
We come now to tissues. The
sections figured (106-114) preclude the
necessity of any very detailed descrip-
tions. They show four kinds of tissue ;
but some courage is needed to declare
their names.
The tissue of cells shown in fig. 108
is known as
PARENCHYMA
(Greek parenchuma, the spongy sub-
stance of the lungs), and this is the
general name of tissues the cells of
which are arranged in rows, and
which are fairly equal in their dimen-
sions, being almost as long as they
are broad.
The tissue depicted in fig. 109 is
distinguished as
P.ROSENCHYMA
(Greek pros, beside ; encJiuma, some-
9
Photo by]
. Step.
FIG. 112. — LARCH (Larix europaeus).
The shoots grow downwards, but the cones bearing
the seeds stand more or less erectly.
HUTCHINSON'S POPULAR BOTANY
Fia. 113. COLLENCHYMA OF THE
COMMON SOW-THISTLE (Sonchus
asper).
thing poured or put in).* Its cells are
long and tapering, and dovetail into one
another, and these are the leading charac-
teristics of prosenchyma. Yet there is no
absolute dividing line between the two
kinds of tissue, parenchyma passing into
prosenchyma, and prosenchyma into paren-
chyma, by endless gradations.
The third tissue (fig. 113) has been named
COLLENCHYMA,
a word derived from two Greek words —
kolla, glue, and enchuma, a word explained
above. The gluey something poured or
filled in is usually most abundant in the
corners of the cells, and is added by the
protoplasts with the view of strengthening
the delicate walls. The substance forms,
one might almost say, the corner-stones of
their little dwelling-houses. Collenchyma
may be seen to advantage in the leaf-stalks of many Begonias, a trans-
verse section being the best for examination.
The name of the fourth kind of tissue is as tongue-tiring as the others,
but we have met with it before —
SCLERENCHYMA.
It will be remembered that the cells from the gritty centre of a pear
(p. 31) were sclerenchymatous cells ; and it was pointed out that the name
is given to thick-walled woody cells in which the protoplasm has been all
used up. The section of a plum-stone (fig. 114) shows the same thing.
Sclerenchyma comprises, indeed, those tissues the cells of which have become
much hardened by secondary deposit, and which contain no protoplasm.
It performs the mechanical office of support
and strength, and is emphatically dead tissue,
the very opposite of the tissue to which we
next invite attention, namely —
MERISTEM.
Meristem (Greek meristos, divided) is the
name given to growing tissue the cells of
which are continually dividing so as to pro-
* The word was formed on the model of " paren-
chyma" with little regard for derivation (Text-book,
of Biology,?. 409).
FIG. 114. — SCLERENCHYMA FROM THE
STONE OF A PLUM, MADE UP OF
LIGNIFIED CELLS.
83
84
HUTCHINSON'S POPULAR BOTANY
duce fresh tissue. Th
actively dividing cells have
thin walls, and no spaces be-
tween the cells : they are rich
in protoplasm, and always con-
tain a nucleus. From, cells
of this kind all permanent
tissues originate. They are
found, therefore, only in the
growing parts of plants, as
buds, the apex of roots, and
in certain parts of the stem.
Even sclerenchyma originated
in meristem.
Special cells or groups of
cells, so disposed as to form
cavities in the tissue, are en-
gaged in the formation of
the degradation- and by-pro-
ducts (p. 56), and to these the
name of glands has been
given. Thus we have resin-
glands, oil-glands, camphor-
glands, honey-glands, and
others that need not be par-
ticularized. They abound, for
instance, in the rind of the
orange and lemon, the odour
and flavour of which are derived from minute drops of volatile oil
stored up in vast numbers of these little cavities. Glands are frequently
external organs, and may be borne upon the ends of hairs, which are
then called glandular hairs. We find them, for example, in the Chinese
Primula. The margins and upper surface of the leaves of our English
Sundews (Drosera rotundifolia and D. intermedia) are provided with delicate
glandular tentacles (loosely called " hairs " in many text-books), which are
veritable insect-traps. The glands have the appearance of tiny dewtlrops,
but exude a viscid secretion, by which the thirsty and deluded visitors
to the plant are caught and retained — for a purpose which will be explained
in the next chapter.
The various kinds of vessels and permanent tissue may be conveniently
classed under three heads, which are easily remembered, the arrangement
being quite natural. If you take any ordinary leaf — say, the leaf of a Lime
— you will perceive that it consists of a thin outer skin, enclosing some
tough net-like veins and a lot of soft tissue which fills up the spaces between
Photo by] [E. Step.
FIG. 116. — CONE OF CEDAR-TREE (Cedrus libani).
A. very hard and solid cone of a purplish-brown tint. The scales
are thin, and overlap tightly. The seeds take about three years
to ripen. Natural size. MOUNTAINS OP SYRIA.
CELL COMMUNITIES: A CHAPTER ON TISSUES
85
the veins. The outer skin consists of a single layer of cells and is called
the epidermis (Greek epi, upon, and derma, skin). The veins are composed
in the main of bundles of vessels and long woody cells, and belong to what
is called the fibro-vascular system ; and the soft tissue which constitutes the
rest of the leaf is known as fundamental or ground tissue.
Here, then, we have the three great divisions under which all permanent
tissues and vessels naturally fall. Let us go over them again. First, there
is the epidermis, a thin cellular covering on the exterior of the plant;
secondly, the fibro-vascular system, consisting chiefly of wood-cells and
vessels, united in bundles, which extend from the roots to the leaves and
really form the skeleton or framework of the plant ; and thirdly, the funda-
mental or ground tissue, which occupies most of the space in the young
plant and consists chiefly of parenchyma. The lower plants — that is, the
Fungi, Algce, Liverworts (Hepaticce). and Lichens— have 110 fibro-vascular
bundles, and the Mosses (Musci) only contain them in a very rudimentary
form. Plants belonging to
the Cone-bearing order
(ConifercB), as the Pines,
Larches, Yews, and Cedars
(Pinus, Larix, Taxus, Ce-
drus), have wood-cells, but
no true vessels, their place
being taken by tracheides,
which are not continuously
open. In the higher plants,
the woodrcells of the fibro-
vascular bundles serve as
the channels by which the
crude sap, which holds in
solution the nutritious prin-
ciples, is conveyed from the
soil to the leaves. The ves-
sels are charged with air.
Before leaving this part
of our subject we ought to
mention that beneath the
single layer of epidermal
cells we have in the leaves
a layer of elongated cells
packed closely side by side
in a direction vertical to the
surface of the leaf, and these
are known as palisade cells,
and in the aggregate as
IE. Step.
FIG. 117. — LICHEN ON HOLLY BAKK.
This Lichen (Graphis elegans) consists of raised dark lines on the smooth
bark of the Holly-tree, which look much like the characters of some
Oriental alphabet.
HUTCHINSON'S POPULAR BOTANY
palisade-parenchyma. These palisade cells vary in length in different species.
Professor Haberlandt suggested that in certain plants the epidermal cells
act as ocelli, or primitive eyes, to the plant. The structure of these cells is
often lens-shaped, and consequently the rays of light which fall upon them
are brought to a focus. He found that by using such cells as lenses he
could obtain minute photographs of various objects, the image being
focussed upon the basal wall of the cell. When this fact became known in
England a few years ago, some of the more sensational newspapers made
capital out of it, and explained how plants could see, like animals, and they
published drawings that were supposed to be photographs of things " seen
through the eyes of plants." Of course, the plant has no nervous mechanism
that will enable it to see. For a human being to separate one of these cells
and use it as a lens by which to
obtain on the human retina a
diminished image of some object
is one thing ; for plants to be
able to see with that lens is
quite another matter. But ac-
cording to Haberlandt's inter-
esting hypothesis, the converg-
ence of the light-ra}^ that pass
into these lens-shaped cells
causes a differential illumination
of the protoplasm on the basal
walls of these cells, and sets up
a stimulus which results in the
leaf being moved into that
attitude in which it can ob-
tain the most suitable illumi-
nation for its work, in which
light plays so important a
part. Not only is this function being performed by the cells on the
upper surface of the leaf, but in a modified degree by those on the
lower surface.
It is believed that this convergence or focussing of the light results in
the more efficient illumination of the chlorophyll grains. Mr. Harold Wager,
F.B.S., who has made many experiments to elucidate the truth of this
matter, has shown that under the influence of this convergence the behaviour
of the chlorophyll grains is very marked. In a species of Mesembryanthemum
there are special lens-cells which are equally well developed on both upper
and lower surfaces. In Garrya elliptica, too, there are special lens-shaped
thickenings of the cuticle on both surfaces. It is worthy of note, as
supporting the above hypothesis, that, so far as observed at present,
epidermal cells of long focus are associated with long palisade cells, and the
[E. Step.
FIG. 118. — LECANORA PARELLA.
A Lichen growing on a rooflng tile. In such a situation it is evident
that the whole of its nourishment must be obtained from the
atmosphere. Natural size.
[E. Step.
FIG. 119. — SCOTS PINE (Pinus aylveatris).
In a pine wood the trunks grow very straight and tapering, due to the fact that a "canopy" of foliage is formed by
the upper branches which shuts out lisht from the lower branches and prevents their growth to any size. In the fore-
ground to the right of the photo will be seen a triplet. Three seedlings started so close together that as they have
increased in girth their lower trunks have been squeezed and amalgamated. K. EUROPE, ASIA.
87
HUTCHINSON'S POPULAR BOTANY
Photo 6y] [E. Step
FIG. 120. — AN ALPINE LICHEN (Gyrophora cylindrica).
A dull purplish Lichen with beautifully fringed margins, that grows on Alpine rocks. Slightly enlarged.
surface cells of short focus are connected with short palisade cells. The
whole subject, however, is in need of further investigation.
In the leaves of Gymnospermous plants — but not exclusively confined
to them — is found a particular form of tissue, known as transfusion tissue,
which has been the subject of considerable controversy. In the leaves of
Conifers and most Cycads it is nearly always found in lateral connection
with the vascular bundles, in some genera outside the phloem, and in others
opposite the xylem. The highly developed network of conducting tissue so
prominent in the leaves of Dicotyledons is entirely absent from those of the
Gymnosperms. "In order to compensate, therefore, for the lack of an
efficient conducting system in the leaf, recourse has been had to the de-
velopment of these peculiar tracheides (often accompanied by bast-cells of
similar shape), now known as ' transfusion tissue.' In Cycas and many
species of Podocarpue, in which the broad pinnae or leaves are traversed
by a single bundle, in addition to the normal transfusion tissue, a new
and accessory system has been developed, running from the bundle to
the margin of the leaf. This, however, ... is a purely secondary
modification of the mesophyll-cells, and bears only a functional relation
to "the normal transfusion tissue, having therewith no homology whatever.
In the pinna of Stangeria a dichotomizing system of closely placed veins
springs from the large central midrib. In the pinnae of all other Cycadsr
and in Podocarpus nageia, Dammara, and Ara/ucaria, among Conifers, a
system of parallel venation prevails, and here transfusion tissue is markedly
developed. The leaves of most Conifers are very narrow, and are traversed
by a single bundle, which, in all cases, is provided with well-developed
transfusion tissue. Ginkgo differs widely from all other Conifers in having
a dichotomizing system of ' bundles traversing its large, fan-shaped leaf,
CELL COMMUNITIES: A CHAPTER ON TISSUES
89
and has transfusion tissue present in connection with its rather widely
separated bundles, though more feebly developed than in most Conifers. . . .
It is well known that the bundles of the leaf of Cycads have a structure
peculiar to this order and not found in any other living group of plants.
Towards the lower surface of the lamina is placed the phloem ; next comes
the ordinarj7 xylem, which is formed by the cambium in a centrifugal
manner ; on the inner side of the secondary wood there may or may not
be a few elements of primary centrifugal wood, and then follows the
protoxylem consisting of narrow, elongated, spirally or reticulately thickened
elements. Farther, beyond the protoxylem, i.e. between this tissue and
the upper surface of the leaf, occurs another strand of xylem, primary in
origin, and of much greater development than that of the centrifugal
wood ; it is centripetal in
development, i.e. its ele-
ments are formed succes-
sively from the protoxylem
towards the upper surface
of the leaf ; it is charac-
teristic of the Cycadeae.
Typical transfusion tissue
occurs at the side of the
bundle, and this is seen to
be in intimate connection
with the centripetal xylem.
In the petiole the structure
of the bundles is the same,
though their orientation is
different. • In other Gymno-
sperms and all Angiosperms
this tissue is, so far as
hitherto observed, absent
from the vascular bundle." *
Here we conclude. We
have travelled together over
a good deal of ground, and
the physiologicalfacts which
have come before us must
* Mr. W. C. Worsdell, from
whom these remarks are quoted,
read a paper dealing with this
subject at length before the Lin-
nean Society in November, 1897 ;
the paper will be found in vol. v.
of the botanical Transactions of
that Society.
Photo by]
FIG. 121. — CONES OF A CYCAD.
[E. Step.
The Cycads were abundant in Jurassic and Wealden times, but are now
very few. They are believed to have been the starting-point from
which all our plants with conspicuous flowers (Angiosperms) originated.
90
HUTCHINSON'S POPULAR BOTANY
have convinced the reader that plants are very wonderful as well as very com-
plex organisms. We claim for them that they are not less wonderful than
animals — man alone excepted. Every individual — at least, among the higher
plants— is like a little city, athrob with life; in which a pulling down and
building up is ever going on ; in which there are lanes and alleys, and
broadways and aqueducts, and the daintiest of little houses. In one part of
the city are the starch factories ; in another, the milk-shops ; in another, the
sugar refineries. Here is the jewellers' quarter, where the crystals are
prepared ; here the per-
fumers', " where the most
fragrant scents are distilled ;
here the varnish-makers'
and colourmen's. Infinite
in variety, marvellous in
execution, is the work that
goes on ; and some of the
operations may be watched
under the microscope. We
may see the little artisans at
work — may enter with more
or less intelligence into what
is being done ; though how
the marvellous results are
produced we know not.
Here, indeed, we reach the
borders of the Unknown
Land, which Science has
never entered, and where
the mysterious facts of Life
lie hid. We screw on the
highest powers of the micro-
scope ; but the secret remains
a secret still. The things
formed are plain before our
eyes, and we may see them
forming ; we may note
effects, and even the pro-
cesses by which those effects are produced ; but behind all is the mysterious
principle called Life, and into this we may not enter. Again and again, as
we watch those viscid, transparent specks of structureless matter begin-
ning to move — as we see them throwing out their delicate strands, or
rotating slowly in their cells — we ask in awe and admiration, How is this ?
But the question falls in vain. The little protoplasts work on, but will
not answer.
Photo by] [E. Step.
FIG. 122. — FLOWERS OF GABBYA ELLIPTICA.
The long, pale yellow catkin consists of a series of cups, each containing
three flowers. The catkins are five or six inches long, and appear verv
early in spring. CALIFORNIA, MEXICO, etc.
91
CHAPTER IV
THE ASCENDING SAP
Now good digestion wait on appetite. — SHAKESPEARE.
IT has been pleasantly observed by one of our older physiologists that
the economy of the plant is analogous to that of a well-regulated
household. " The whole structure is composed of a number of different
organs or members having different parts to perform in the general
scheme ; and these parts or functions are so beautifully adjusted together
that, in every variety of circumstances in which the being is liable to be
placed, they shall still be executed in harmony and with one common
Photo by]
FIG. 124. — HOP TREFOIL OB YELLOW CLOVER (Trifolium procumbens).
Common in pastures and on roadsides. The pale yellow clusters consist of a number of flowers crowded together.
The downy stems will be found lying among the grass, etc., and often more than a foot in length. EUROPE
N. AFRICA, N. ASIA.
92
THE ASCENDING SAP
93
purpose. One organ pumps up the re-
quired water, another carries it, another
uses it in cooking, another gets rid of the
waste, another obtains the solid food, another
carries the cooked provisions to all parts of
the structure, another stores up the super-
fluity, another builds additions to the edifice,
while another prepares to send out a colony
furnished with supplies of food, and with
everything requisite to begin life for them-
selves " (Carpenter). This is very true ;
and we propose now to treat a little of
some of these interesting functions, on the
discharge of which depends not only the life
of the plant as a whole, but the permanence
of the species.
Now, all the operations carried on in a
plant are subordinate to the two great
functions of nutrition and reproduction —
nutrition, by means of which the life of
each individual is sustained ; and repro-
duction, which secures the continuance of
the species. For the present our remarks
will be confined to the former.
We may enter upon the subject at once
by asking, What is the food of plants ? — a
question which involves the further inquiry,
What are the constituents of protoplasm ?
For if, as we have seen, all vegetable cells
originate in protoplasm, and every plant
consists either of a cell or cells, or the pro-
ducts of their formation and transformation,
it stands to reason that the elements of
protoplasm must constitute a very large
proportion of the food of plants. Now, the
chief elements of protoplasm have been
already enumerated. They are six in num-
ber— carbon, hydrogen, oxygen, nitrogen,
phosphorus, and sulphur; but in order to
complete the list of nutrient substances,
we must add the elements iron, calcium,
potassium, magnesium, zinc, and, probably,
sodium and chlorine.
Of these elements carbon is by far the
FIG. 125. — FIRST YEAR OF NORFOLK
OR FOUR-COURSE ROTATION OF
CROPS.
FIG. 126. — SECOND YEAR OF NOR-
FOLK OR FOUR-COURSE ROTATION
OF CROPS.
94
HUTCHINSON'S POPULAR BOTANY
FIG. 127. — THIRD YEAR OF NOR-
FOLK OR FOUR-COURSE ROTATION
OF CROPS.
FIG. 128.— FOURTH YEAR OF NOR-
FOLK OR FOUR-COURSE ROTATION
OF CROPS.
most abundant. All the plants growing
upon the face of the earth absorb it in
large quantities. Their leaves take up the
carbon from the atmosphere in the form
of carbonic acid, and they grow and prosper.
Give them air purified from carbon, such as
we could thrive in, and they could not live ;
give them carbon dioxide with other matters,
and they nourish. Our floors, our tables, the
framework of the chairs on which we sit.
have derived all their carbon, as the trees
and plants derive theirs, from the atmo-
sphere, which carries away what is bad for
us * and at the same time good for them
— what is disease to the one being health
to the other. " So are we made depen-
dent," says Faraday, " not merely upon our
fellow creatures, but upon our fellow existers,
all Nature being tied together by the laws
that make one part conduce to the good of
another." f
Carbonic acid, or carbon dioxide as it is
now generally called, is present in the atmo-
sphere in the proportion of four parts in
ten thousand ; so that, in every thousand
cubic feet of air, we have not quite half a
cubic foot of carbonic acid — a proportion
somewhat startling when we remember that
this is almost the sole source of supply to
the entire vegetable kingdom; yet so great
is the volume of atmosphere which sur-
rounds the globe that, according to careful
computations, at least three thousand mil-
lion million pounds of solid carbon must
be contained in it— a quantity which is
probably far in excess of the weight of all
* Perhaps we should be more exact in saying that
it is the absence of oxygen, rather than the presence of
CO., which vitiates the air from the animal point of
view.
+ Some interesting experiments by Professor T. D.
Macdougal, of Minnesota, U.S.A., on the growth of
various plants in an atmosphere devoid of CO->, will
be found in the Journal of the Linnean Society
(Botany), vol. xxxi. 1896.
95
96
HUTCHINSON'S POPULAR BOTANY
Photo by-]
FIG. 130. — ROUND-LEAVED SUNDEW (Drosera rotundifolia).
IE. Step.
A larger species than the last, growing in similar situations and with the same habits. Reduced about one-third.
N. EUROPE, W. ASIA, N. AMERICA.
the plants which exist upon the earth. Submerged plants, having no
direct contact with the atmosphere, derive their carbon from the carbon
dioxide -dissolved in the water in which they live.
Carbonic acid is a gas consisting of two elements, oxygen and carbon,
combined in the proportion of two atoms of oxygen to one of carbon (C02) ;
and as the former is another of our plant elements, it is evident that carbon
is not the only nutrient substance taken up by the leaves. Yet by no means
all the oxygen required by the plant enters in through these organs. A
large proportion is obtained from the water absorbed by the root-hairs,
which, indeed, are the organs employed in conveying most of the food
substances to the plant ; and this taking in of inorganic nutrient matter by
the root-hairs is known as absorption.
Then there is hydrogen. Oxygen combines with hydrogen in a certain
proportion (H20) to form water ; so that when the roots are drinking up
water from the ground they are taking in two of the most essential elements
of the plant. It is probable, however, that a good deal of the hydrogen
supplied to the plant enters it in combination with nitrogen (another of the
essential elements of all plants) — in fact, as ammonia (NH3), that pungent
gas which gives strength to hartshorn and smelling-salts, and which is
dissolved in the water absorbed from the soil.
A PITCH KR PLANT (Nepenthe* <ime*ian<t).
These pitchers are an outgrowth from the tip of the leaf. They are hollow and provided will
The' liquid within is secreted by the walls of the pitcher, and insects which Ret drowned
re-absorbed for the nourishment of the plant.
i lid to keep out rain,
i it are digested and
THE ASCENDING SAP
97
The supply of nitrogen to plants in an accessible form is not nearly so
plentiful as the plant requires, and nitrogen-hunger is frequently experi-
enced by them. " Nor is the origin of this nitrogen deficit far to seek.
The nitrogen contained in the soil comes in the plant to form a con-
stituent of the organic nitrogen compounds, such as the proteins. The
plant dies and decays, or is eaten and the eater decays. . . . The organic
nitrogen compounds of the dead animal or plant are broken down by
the bacterial and fungous agents of decay into a series of simpler
forms which, acted on by yet other of the ordered army of saprophytic
micro-organisms, yield finally ammonia and nitrogen. The nitrogen
leaks away into the atmosphere and contributes to the 79 per cent, of
nitrogen gas which is contained in the air. The ammonia may leak
away also — as every dunghill testifies — or it may be fixed in the soil by the
agency of certain nitrifying micro-organisms. These bacteria convert the
ammonia into nitrates, and the nitrates so formed become available to
the roots of the green plant. On the other hand, the nitrates of the soil
may be seized upon by yet other, denitrifying micro-organisms and, becoming
converted into ammonia compounds, may be lost to the vital circulation.
The constant leakage of nitrogen from combined forms to the free and
inert form of nitrogen gas results in a shortage of nitrogen available for
the formation of the nitrogenous food of plants. We may thus speak of
the problem which besets all living organisms— that of obtaining adequate
supplies of organic nitrogen compounds — as the nitrogen problem, and we
may well believe that the
sum-total of life supported
on our planet is deter-
mined ultimately by the
amount of. available nitro-
gen present in the earth
and sea. Occasionally,
organisms are met with
which have solved the
nitrogen problem in a fun-
damentally satisfactory
manner. Among such
organisms are nitrogen-
fixing bacteria, leguminous
plants, and man. Each of
these organisms has evolved
methods of bringing back
into vital circulation the
nitrogen which has escaped
as nitrogen gas into the air."*
* Keeble, Plant Animals, 141.
10
Photo by]
[E. Step.
FIG. 131. — DROSERA INTERMEDIA.
A small Dragon-fly (Agrion puella) has been caught by the united
efforts of several leaves of the Sundew.
98
HUTCHINSON'S POPULAR BOTANY
The other elemental food substances are also found in the soil, and are
either dissolved by the water or by an acid sap excreted by the root-hairs.
This sap is a very necessary provision, as some of the substances essential
to vegetable life and growth are insoluble in water, and but for its timely
services the greater number of plants would be literally starved, and in
a short time disappear from the face of the earth. The powerful action
of this acid excretion may be shown by means of a simple experiment.
Let the perfectly smooth surfaces of two slabs of marble be spread with
sand to the depth of a quarter of an inch, and in one of the sand layers
sow some seeds of mustard and cress. Place both ,the slabs in a fairly
warm place and a good light, and water them occasionally till the plants-
on the seed-sown bed have
grown for a short time. On
cleaning off the sand from
the slabs it will be found
that the one which had the
sand only will be as smooth
as ever, while the other will
be covered with minute
grooves — a kind of rough
etching of the root system.
In other words, the root-
hairs will have eaten their
way in the marble, channel-
ling out passages for them-
selves by means of the acid
sap. This experiment will
show how it is that large
trees are able to sink their
roots deep into the solid
rock,- which may be literally
split to pieces by the subsequent growth of the tree's embedded roots.
The nutrient substances are never taken up indiscriminately by the
plant. Not least among the many marvels of plant life is the mysterious
power vested in the root of selecting from the surrounding fluid the sub-
stances which it requires and rejecting others. Thus if you plant a pea
and a wheat-grain together in the same soil, the former will take care to
make the most of whatever of lime and its compounds the water of the
soil contains : while the latter, rejecting these, will absorb for itself the
silex or flinty matter. How this comes to pass we do not know, and
the wisest of savants can assign no reason ; but a power of selection
undoubtedly exists.
From the fact itself we may learn a good deal. It is evident, for
instance, that the soil which is planted year after year with the same
FIG. 132. — VENUS' FLY-TRAP (Dioncea muscipula).
The action of the leaves as an insect-trap was known as far back as the
days of Linnaeus, but regarded only as an extreme example of vegetable
irritability. It was not until Darwin had explained the Sundew that
attention was drawn to the real purpose of Dionaea's movements.
tA. J. Wallis.
FIG. 133. — VENUS' FLY-TRAP (Dioncea muscipula).
The first known of these insectivorous plants. Unlike the slow-moving tentacles of Drosera, the two lobes of the leaf
close with a snap the moment an insect touches one of the three spikes in the centre of a lobe. When the leaf is
closed, the spines on the margins interlock like the teeth of a rabbit-gin. NORTH CAROLINA, U.S.A.
100
HUTCHINSON'S POPULAR BOTANY
crops will soon be im-
poverished, and at last
become permanently
unproductive for plants
of that description.
A field that is sown
with Wheat for a suc-
cession of years will at
length lose all its flinty
matter, and will then
be useless, not only as
a wheat-producing soil,
but also for the grow-
ing of all cereal grasses
and silica-containing
plants.* On the other
hand, the very same field
may abound in nutrient
substances perfectly
adapted to vegetation of
another kind. Farmers
nowadays are well ac-
quainted with these
facts, and by a carefully
selected succession of
different crops — a rota-
tion of crops, as it is
called — and a scientific
system of manuring, they provide against the otherwise inevitable exhaus-
tion of the soil. The well-known Norfolk or four-course rotation is a case
in point (figs. 125-128). This consists of root- crops, Barley (Hordeum), Clover
(Trifolium), and Wheat (Triticum), which are dealt with in the following
manner : " The farm is broken up into four portions. The first undergoes
thorough tillage and is planted with Boot-crops, which need especially potash
and lime, and having short roots, take their food near the surface, or are
surface feeders. Division 2 has Barley, which takes up very little lime and
potash, but much silica, and is also a surface feeder. Clover, in division 3,
takes much the same food as the root-crops, but is a subsoil feeder — that
is, sends its roots deeply into the ground. The Wheat, in division 4, is
also a subsoil feeder, but, like Barley, takes up much silica." Next year, and
every succeeding year, the position of the crops is changed ; and thus, at
* Perhaps this statement needs a note. It has been shown that silica is not absolutely
necessary for the growth of cereals ; other important constituents would be exhausted long
before the silica— e.g. nitrogenous matter, or phosphates.
Photo by] [S. L. Bastin.
FIG. 134. — CAPE SUNDEW (Drosera capensia).
A native of South Africa, which has green, leaf-like footstalks, indicating that
it draws more nourishment from the air than the other species.
THE ASCENDING- SAP
101
the end of four years, ea.cn part of the soil will have had each kind of
plant growing on it, and the order for the four years will stand thus : —
YEAR.
DIVISION 1.
DIVISION 2.
DIVISION 3.
DIVISION 4.
First .
Root-crops
Barley
Clover
Wheat
Second .
Barley
Clover
Wheat
Root-crops
Third .
Clover
Wheat
Root-crops
Barley
Fourth .
Wheat
Root-crops
Barley
Clover
In former times it was a usual thing to give rest to the land by allowing
it to lie fallow at certain intervals, and though our scientific agriculturists
have now discovered other means of replenishing the soil, the practice has
by no means died out.
The importance of this sys-
tem of fallowing was known
to the ancients, for Virgil in
his first Georgic mentions it,
and suggests as an alternative
that the husbandmen should
follow the Barley crop by sow-
ing leguminous plants, thus
anticipating, or at least fore-
shadowing, the very modern
discovery of the nitrification
of the soil by the roots of
these plants, or rather by the
bacteria that attach them-
selves thereto. He says:
" You shall sow the golden
Barley whence formerly you
had borne away the luxuriant
Pulse in their rattling pods,
or the slender produce of the
Vetch, or the bitter Lupin's
fragile stalks and rattling-
straw."
It is remarkable that to the
present day the Germans
grow Lupins on very poor
land every third or fourth
year, solely for the purpose
Of ploughing them in for the
n+' +>IP cm'l • o-nrl
OI ine SOU , ana
FlG" ^'-
(Drosophyllum
A sub-shrubby plant of the Peninsula and North Africa. The ten-
tacles do not close over their prey, as in the Sundew. The natives
hang these plants in their rooms in lieu of fly-papers.
102
HUTCHINSON'S POPULAR BOTANY
it is reckoned that no less than 500,000,000 pounds of nitrogen are thus
obtained from the air annually by this method of cropping in that
country.
Marshy places are usually very deficient in certain of the nutrient
elements, as nitrogen, potash, and other salts, and plants which grow in such
neighbourhoods, being often hard put to it to obtain a sufficiency of food,
take to crime for a liveli-
hood. Finding, we know
not how, that gnats and
flies and other species of
the great class of Insects
contain in their bodies the
aliment which is so deficient
in the soil, the plants actu-
ally prepare traps for the
capture of these winged
creatures, which they kill
and eat without compunc-
tion.
Many have found a
difficulty in receiving the
statement ; nor is a little
scepticism surprising. One
such plant is the little
Round-leaved Sundew
(Drosera rotundifolia, fig.
130), whose round leaf-
blade bears about a couple
of hundred red tentacles,
each ending in a globular
head from which a clear
drop of gum exudes and
glistens like a drop of
dew. These sticky glands
close round the insect
prisoners, and these move-
ments are accompanied by
the excretion of a digestive ferment comparable with animal pepsin, which
dissolves all the nitrogenous constituents of the victim, just as the gastric
juice of our bodies would dissolve an oyster.
There are three British species of Sundew, all of which are insecti-
vorous. The round-leaved (Drosera rotundifulia) is perhaps the prettiest, and
it is to be met with in many places growing amid wet Sphagnum Moss.
Equally plentiful is the Intermediate Sundew (Drosera intermedia), with
FIG. 136. — MEXICAN BUTTEBWOBT (Pinguicula caudata).
The Butterworts catcli small insects by means of a viscid secretion from
the glands of the leaves. One of these glands, viewed sideways and
enlarged, is shown above. The other figure shows the head of the gland.
Photo 6y] [*.
FIG. 137. — PALE BUTTEKWORT (Pinguicula lusitanica).
The smallest of our native species, found chiefly in the bogs of the south-\vest of England and West Scotland.
It has pretty lilac-tinted flowers. The leaves are less than an inch in length. Its headquarters are in the
PENINSULA and WESTERN PRANCE
103-
104
HUTCHINSON'S POPULAR BOTANY
Photo by] [J. J. Ward.
FIG. 138. — SECTION THROUGH LEAF OF BUTTERWOKT.
A thin slice from the leaf is here shown highly magnified to make clear
the position of the stalked glands. They are seen to arise from special
cells of the epidermis.
oval leaf-blades (fig. 128).
On another page is a picture
of an African species,
Drosera capensis, the Cape
Sundew (fig. 134), which was
introduced from the Cape
of Good Hope in the year
1875. Its pretty purple
flowers are borne on a leaf-
less stem or scape,* which
is longer than the leaves
but not quite so hairy. In
almost every part of the
world one or more species
of the family may be found.
Australia has its twin-leaved
Sundew (D. binata] and
many others ; India its
Drosera lunata, with curious
moon-shaped leaves ; Africa its few-flowered Sundew (D. paucifloroi), as well
as the Cape species already described; the long-leaved Sundew (D. longi-
folia) is spread over Northern Europe, Canada, arid Brazil ; while the
United States have a pink- and purple-flowered species (D. filiformis],
which is insectivorous like all the rest.
The margins of the leaf contract so that the leaf-blade is converted into
a cup, and into this receptacle the glands pour out a fluid that has the power
of digesting the soft parts of the insect, and the enriched fluid is then
reabsorbed by the cells of the leaf, and through them distributed to the
plant as a whole. This process of digestion and absorption takes about
two days, and when it is completed the leaf again expands. A remarkable
feature of the plant's behaviour when an insect has been captured is the
knowledge of locality shown by the tentacles: from all parts of the leaf
the tentacles bend to the particular spot where the captive is, every tentacle
co-operating to prevent the possibility of escape. The information must
be transmitted from cell to cell in some way not understood.
The Droseras are very partial to rump-steak, and devour it greedily
when they get the chance — that is to say, when they are under experi-
ment; but cinders, and bits of moss and quill, and tiny balls of paper,
they will have nothing of. Drops of milk and dissolved isinglass do not
appear to come amiss to them, but tea they determinedly eschew, and
will not deign to bend their tentacles even a hair's breadth if you sprinkle
a little of the refreshing beverage on their leaves. Insects, however, are
* A leafless stem, springing from the base of a plant and bearing only a flower or flowers,
such as is seen in the Primrose, Cowslip, Hyacinth, etc., is a scape.
THE ASCENDING SAP
105
their special favourites, and the wing of a fly or the leg of an ant will
meet with almost instantaneous recognition.
Nearly allied to the Droseras is the dainty little Portuguese Sundew
(Drosophyllum lusitanicum) (fig. 135), which is also a true insect-eater, though
the glandular hairs distributed plentifully over its grass-like leaves are
not endowed with the motile power of the Droseras. In this respect it is
more akin to the Catchflies and London Pride, which catch insects by means
of the glandular hairs with which their stems are covered. This plant is
remarkable as having its habitat, not in marshy places, but on sandy shores
and dry rocks ; in which respect it resembles many of the Australian
Sundews, which grow and thrive in the most arid soil. The villagers in the
neighbourhood of Oporto hang the plant in their cottages, using it instead
of fly-paper.
More wonderful
than either Droso-
phyllum and Drosera,
and belonging to the
same order (Drose-
racece), is Venus'
Fly-trap (Dioncea
muscipula), a native
of North Carolina
(fig. 132). Candour
compels us to state
that it bears no better
character than its
unnatural cousins,
unless, indeed, its
very proficiency in
crime may be looked
upon as a redeeming
feature. Its leaves
spread in a circle
round the crown of
the root, and either
lie flat upon the
ground or gently
elevate themselves
above the soil. They
consist of two very
distinct parts— a pho'° 6y]
stalk and a blade. FlG- 139- — COMMON BUTTEKWORT (Pinguicula vulgaris).
The stalk is a flat A muc^ larger species, common in the mountain districts of the North. Its
leaves are two or three inches long, and the flowers violet on purple scapes.
green, leafy expan- N. EUROPE, N. ASIA, N. AMERICA.
106
HUTCHINSON'S POPULAR BOTANY
sion, the veins of which are coarsely netted, and it is joined to the
blade by a very narrow neck. The blade consists of a roundish, thick,
leathery plate, having strong, hidden, parallel veins, which spread nearly at
right angles from the central vein or midrib to the margin, and is bordered
with a row of strong, stiff, tooth-like hairs. "When young, the two sides of
the blade are placed face to face, and the teeth cross each other; after-
wards, when full grown, the sides spread flat, or nearly so, and the teeth
then form a firm spreading border. On
each half of the blade stand three delicate,
almost invisible bristles, uniformly arranged
in a triangle ; and these are the true sensitive
organs of the plant. Let but one of the
bristles be touched, and the two sides of the
blade spring together with considerable force,
the marginal teeth crossing each other so as
to enclose securely any small object which
may have caused the irritation, be it insect,
straw, or seductive morsel of steak. Wonder-
ful to relate, no other part of the leaf is
sensible to external impressions. In vain is
the back of the leaf disturbed, or the smooth
glandular surface pricked and tickled ; unless
you jar one of the bristles, no irritability is
excited, and the blades remain immovably
open. The moment the shock is communi-
cated through one of the bristles, the collapse
is effected, the leaf assuming altogether the
appearance of an iron rabbit-trap when it has
closed upon its prey ; and if, at this time, an
attempt is made to open the leaf, it is vio-
lently resisted, in consequence of the rigidity
of the parallel veins.
Like the Sundews, Dioncea feeds upon the
insects which it catches, for it possesses, like
them, the power of digestion. Dr. Burdon
Sanderson, in a lecture delivered at the Royal Institution in 1874, thus
referred to the digestive power of this plant : —
" When we call this process digestion, we have a definite meaning.
We mean that it is of the same nature as that by which we ourselves,
and the higher animals in general, convert the food they have swallowed
into a form and condition suitable to be absorbed, and thus available for
the maintenance of bodily life. We will compare the digestion of Dioncea
with that which in man and animals we call digestion proper, the process
by which the nitrogenous constituents of food are rendered fit for
FIG. 140. — FLOWKR OF BLADDER-
WORT (Utricularia vulgaris).
This type of flower is called personate. The
lips are closed, as in the flowers of Snapdragon
and Calceolaria, only bees being able to force
them apart, in order to reach the nectar in
the conical spur.
Photo W IE. J. WaUit.
Fia. 141. — HYBRID PITCHER-PLANT (Nepenthes obrienana).
The midrib continues beyond the apex of the blade, as a tendril, but also develops into a pitcher-shaped hollow with a
distinct hd, which can be raised or lowered by the plant. The interior walls secrete a fluid, formerly supposed to
be pure water, but now known to possess digestive powers.
107
108
HUTCHINSON'S POPULAR BOTANY
absorption. This takes place in the stomach. It also is a fermentation —
that is, a chemical change effected by the agency of a leaven or ferment
which is contained in the stomach juice, and can be, like the ferment of
saliva, easily separated and prepared. As so separated, it is called pepsin.
" Between this process and the digestion of the Dioncea leaf the resem-
blance is complete. It digests exactly the same substances in exactly the
same way — i.e. it digests the albuminous constituents of the bodies of
animals just as we digest them. In both instances it is essential that the
body to be digested should be steeped in a liquid, which in Dioncea is
secreted by the red glands on the upper surface of the leaf ; in the other
case by the glands of the mucous membrane. In both, the act of secretion
is excited by the presence of the substance to be digested. In the leaf, just
as in the stomach, the secretion is not poured out unless there is something
nutritious in it for it to act upon ; and, finally, in both cases the secretion is
acid. As regards the stomach, we know what the acid is — it is hydrochloric
acid. As regards the leaf, we do not know precisely as yet, but Mr. Darwin
has been able to arrive at very probable conclusions."
These ferments are now known as " enzymes," and those that digest
proteids are distinguished as
" proteases." Of the proteases
three kinds are known, under
the names of pepsin, trypsin, and
erepsin. Pepsin, as Sanderson
points out, acts only in an acid
solution, but trypsin and erepsin
are most active in alkaline
liquids. Professor Vines and
others have shown the presence
of one or other of these en-
zymes in the germinating seeds
of a variety of plants, and de-
monstrated the probability of a
protease of some kind being pre-
sent in all plants at one stage or
another of their development.
It appears that the digestive pro-
cesses are essentially the same
in both animals and plants.
The Butterworts (Pingui-
cudci) constitute another genus
of insectivorous plants. One
FIG. 142,-CoMMON BLADDEBWOBT species, Pinguicula vulgaris,
( Utricularia vulgaris). better known as the Bog-violet
Above, one of the bladders is shown greatly magnified. Or Large ButterWOrt, is Common
THE ASCENDING SAP
109
Photo by]
FIG. 143. — SMALL BLADDEKWOBT (Utricularia minor).
inch Ic
A portion of the plant is shown natural size. The pitchers are about one-twelfth of
short stalks. Widely distributed.
IE. Step.
ad are on
in the North of England, while other species are found in different parts of
the United Kingdom. Pinguicula is a Latin word, a diminutive of pinguis
(fat) ; and the name has been given to the genus because its leaves are
greasy to the touch. Like the Droseras, Dioncea, and Drosophyllum, all the
Butterworts are fly-catchers and fly-digesters ; and the large circular glands,
supported upon foot-stalks of varying lengths, which thickly cover the
upper surface of the leaves, are the fatal traps. The incurved leaf edges
are devoid of glands, and appear to serve the double purpose of prevent-
ing insects from being washed away by the rain and of retaining the
secretion, which might otherwise flow off the leaf and get wasted. When
an insect alights or is blown on the leaf, "it gets entangled in the sticky
secretion, and it is killed, and speedily killed, by the secretion adhering to
and closing up the spiracles by which the insect breathes" (Sanderson).
Perhaps it is hardly to be wondered at that the Pinguicidas, like the
Droseras, have connections outside their own immediate family. The Butter-
worts and the Bladderworts are, in fact, first-cousins ; and who has not heard
of the carnivorous doings of the latter? Our illustration shows the Common
or Greater Bladderwort ( Utricularia vulgaris), an inhabitant of ditches and
deep pools (figs. 140, 142). The plant is common enough in this country.
Notice carefully the many little bladders attached to the leaves, a character-
istic of all the Utricularias. These bladders are of curious structure. Each
has an aperture closing with an elastic valve, which is of much thinner
texture than the vesicle to which it is attached. It opens inwards, and
110
HUTCHINSON'S POPULAR BOTANY
small aquatic animals, incautiously entering the little door, like the fly in
the nursery poem, " ne'er come out again."
" The entrance into the bladder has the appearance of a tunnel net, always
open at the large end but closed at the other extremity. The little animals
seemed to be attracted into this inviting retreat. They would sometimes
dally about the open entrance for a short time, but would sooner or later
venture in, and easily open or push apart the closed entrance at the other
extremity. As soon as the animal was fairly in, the forced entrance closed,
making it a secure prisoner. I was very much amused in watching a
Water-bear (Tardigrada) entrapped.
\ It went slowly walking round the
\ bladder, as if reconnoitring, very much
\ like its larger namesake ; finally it
1 ventured in at the entrance, and easily
I' 'J , — x_^ opened the inner door and walked in.
The bladder was transparent and quite
empty, so that I could see the move-
ments of the little animal very dis-
tinctly, and it seemed to look around
as if surprised to find itself in so ele-
gant a chamber ; but it was soon quiet,
and on the morning following it was
entirely motionless, with its little feet
and claws standing out as if stiff and
rigid. The wicked plant had killed it
very much quicker than it kills the
snake-like larva. Entomoskraca, too,
were often captured — Daphnia, Cyclops,
and Cypris. These little animals are
just visible to the naked eye, but under
the microscope are beautiful and inter-
esting objects. The lively little Cypris
is encased -in a bivalve shell, which
it opens at pleasure, and thrusts out
its feet and two pairs of antennae, with
tufts of feather-like filaments. This little animal was quite wary, but
nevertheless was often caught. Coming to the entrance of a bladder, it
would sometimes pause a moment and then dash away; at other times
it would come close up, and even venture part of the way into the
entrance, and back out as if afraid. Another, more heedless, would open
the door and walk in, but it was no sooner in than it manifested alarm, drew
in its feet and antennae, and closed its shell. But after its death the shell
unclosed again, displaying its feet and antennae. I never saw even the smallest
animalcule escape after it was once fairly inside the bladder" (Mrs. Treat).
FIG. 144. — PITCHER OF Nepenthes tnixta.
Note the corrugated rim, and the long spines down
the front of the pitcher.
Photo by} [J. J. Ward.
Fia. 145. — MASTERS' PITCHER-PLANT (Nepenthes mastersiana).
A beautiful hybrid with deep claret-coloured pitchers, four and a half inches long, with ribbed margin to the mouth,
and sharply toothed wings down the front.
Ill
112
HUTCHINSON'S POPULAR BOTANY
A critical and microscopic examination of the contents of the bladders
will show, not only that the habits of the Utricularia come nearer to the
animal than that of any other of the carnivorous plants, but that the
bladders with which they are furnished are, in truth, so many little
stomachs, digesting and assimilating animal food.
Besides containing Bladderworts of the British type, the West Indies
possesses some of a type not found in this country. During his stay
in those islands, Charles Kingsley came upon certain specimens, grow-
ing out of the damp clay, which " were more like in habit to a
delicate stalk of flax, or even a bent of grass, upright, leafless or all but
leafless, with heads of small blue or yellow flowers, and carrying, in one
species, a few very minute bladders about the roots, in another none
at all. A strange variation from the normal type of the family," con-
tinues the eloquent canon, " yet not so strange, after all, as that of another
variety in the high mountain woods, which,
finding neither ponds to float in nor swamp
to root in, has taken to lodging as a para-
site among the wet moss on tree-trunks ;
not so strange, either, as that of yet
another, which floats, but in the most un-
expected spots — namely, in the water which
lodges between the leaf-sheaths of the
wild Pines [Tillandsia], perched on the tree-
boughs, a parasite on parasites * ; and sends
out long runners, as it grows, along the
boughs, in search of the next wild Pine
and its tiny reservoirs."
We must not quit this subject without
offering a few remarks on the Pitcher-
plants. If the little bladders of Utricularia,
which measure scarcely an eighth of an
inch in length, are so many stomachs,
digesting and assimilating animal food,
what shall we say of the pitchers of
Nepenthes and Sarracenia, which fulfil a
similar purpose, and occasionally measure,
in the case of Nepenthes eduurdsiana
twenty inches from lid to leaf attachment,
and in that of Sarracenia flava upwards
Pho,o by] [s. L. Bastm. of three feet in height '? The pitchers
FIG. 146,-PiTCHER OF Nepenthes. reallv form Parfc of the leaf structure; those
The first known of these plants was Nepenthes in Nepenthes and 8a,rracmia are peculiar
distillatoria, from Ceylon, which had much , . . , , . ,
narrower pitchers than the above. The interior * ^One of these IS parasitic m the botanical US6
of this pitcher is shown in fig. 147.
of the term.
THE ASCENDING SAP
113
developments of the petiole, or leaf-stalk,
their lids (where lids are formed) probably
constituting the blade.
We may begin with the Sarracenias,
popularly known as Indian Cups, Side-
saddle-flowers, and Trumpet-leaves. In fig.
152 we have the beautiful but treacherous
Sarmcenia flava, which bears a magnificent
flower of a rich canary-yellow, sometimes
measuring as much as eight inches in
diameter. The long trumpet-shaped erec-
tions are the leaves, which have been united
at their margins to form pitchers (though
some regard these pitchers as hollow leaf-
stalks), and which usually contain a fluid —
not rain-water — of a bland and somewhat
mucilaginous taste. In the photograph
(fig. 151) is shown a mass of organic matter
at the base of the tube, consisting of clotted
flies in all stages of digestion and decay.
Professor Asa Gray, the distinguished
American botanist, studied these plants
closely, and has given an amusing account
of what takes place inside the long pitchers
when once they have been entered by
insect visitors. " After turning back the
lids of most of the leaves," he writes, " the
flies would enter, a few alighting on the
honeyed border of the wing, and walking upward, sipping as they went
to the mouth, and entering at the cleft of the lower lips; others would
alight on the top of the lid, and then walk under the roof, feeding there ;
but most, it seemed to me, preferred to alight just at the commissure of the
lips, and either enter the tube immediately there, feeding downward upon
the honey pastures, or would linger at the trunk, sipping along the whole
edge of the lower lip, and eventually near the cleft. After eating (which
they generally do with great caution and circumspection), they begin again
to feed, but their foothold, for some reason or other, seems insecure, and
they occasionally slip, as it appears to me, upon this 'exquisitely soft and
velvety declining substance. The nectar is not exuded or smeared over
the whole of this surface, but seems disposed in separate little drops. I
have seen them regain their foothold after slipping, and continue to sip,
but always slowly and with apparent caution, as if aware that they were
treading on dangerous ground. After sipping their fill they frequently
remain motionless, as if satiated with delight, and, in the usual self-
11
Photo by] [S. L. Bastin.
FIG. 147. — PITCHER OF Nepenthes.
The pitcher is here cut through to show what
happens to insects when they venture inside.
114
HUTCHINSON'S POPULAR BOTANY
congratulatory manner of flies, proceed to rub their legs together, but
in reality, I suppose, to clean them. It is then they betake themselves to
flight, striking themselves against the opposite sides of the prison-house,
either upwards or downwards, generally the former. Obtaining no perch
or foothold, they rebound off from this velvety microscopic chevaux de
/rise, which lines the inner surface, still lower, until by a series of zigzag
but generally downward falling flights, they finally reach the coarser and
more bristly pubescence of the lower chamber, where, entangled somewhat,,
they struggle frantically (but by no means drunk or stupefied), and
eventually slide into the pool of death, where, once becoming slimed and
saturated with these
Lethean waters, they cease
from their labours. After
continued asphyxia they
die, and after maceration
they add to the vigour and
sustenance of the plant.
This seems to be the true-
use of the limpid fluid, for
it does not seem to be at
all necessary to the killing
of the insects (although it
does possess that power) ;
the conformation of the
funnel of the fly-trap is
sufficient to destroy them.
They only die the sooner,
and the sooner become liquid
manure."
In the Nepenthes we have
another family of irreclaim-
able insect feeders. Each
of the pouch-like prolonga-
tions of their leaves is — like the tall cups of the Sarracenias — a kind of
external stomach which digests solid food. Here is a beautiful hybrid
Nepenthes inastersiana] which is to be found luxuriating at Kew (fig. 145),
Its pitchers measure three or four inches in length, but in most of the
Nepenthes they are larger. A Bornean species, probably Nepenthes villosa,
noticed by Dr. Hooker, "has pitchers which, including the lid, measure
a foot and a half, and the capacious bowl is large enough to drown a
small mammal or bird." These Nature-made water-vessels (or their contents)
have proved, indeed, in more instances than one, the salvation of travellers,
in places where streams are few and droughts a common occurrence.
Though the pouches of Nepenthes distillatoria are comparatively plain, in
Photo by] [S. L.
FIG. 148. — Nepenthes.
A small portion of the inner wall of a pitcher, showing the digestive glands
by means of which the plant utilizes the drowned insects. Magnified.
FIG. 149. — Sarracenia atkinsoni.
A hybrid between the American Pitcher-plants known as the Trumpet-leaf an
pitchers are covered with a network of red veins.
115
\E. J. Walli
the Huntsman's Cup. The green
116
HUTCHINSON'S POPULAR BOTANY
many species these singular structures are richly marked and show both
beauty and variety of form. Observe, for example, the exquisite Nature-
painting on the bowl and lid of Nepenthes mixta, and the curious corrugated
rim with which it is provided (fig. 144). This rim is not merely ornamental.
It strengthens the mouth of the pouch and keeps it distended ; and more-
over, it secretes the honey by means of which insects are attracted to the
plant and eventually into the death-pool below.
Another interesting species of pouch-like fly-catcher, though not
belonging to the Nepenthes, is the diminutive and almost stemless New
Holland Pitcher-plant (Cephalotus follicularis), a native of Western Australia,
where -it* was discovered by the French naturalist, Labillardiere, more than
seventy years ago (fig. 154). Dr. Tait has found that the acid secretion of
certain glands on the inner surface of the pouches of this plant will digest
shreds of albumen and insects, and therefore that the plant is truly
carnivorous ; and certainly the pitchers are wonderfully adapted for the
capture and retention of their living prey. The corrugated rim " ends
abruptly on the inner margin in a row of inflexed teeth," and " below the
rim is a ledge extending round the inside of the pitcher, with its acute edge
projecting downwards into the cavity, forming a kind of contracted neck.
This is called the conducting shelf. Below this, again, the upper two-thirds
of the walls are smooth and glandular.
At the lower margin of this smooth sur-
face an oblique curved elevation extends
oil each side, and below all is the bottom
of the pitcher, which is smooth and
without glands. The surface of the con-
ducting shelf is furnished with hairs
projecting downwards."
Dr. Macfarlane found that, by first
giving Nepenthes insects for the purpose
of stimulating the flow of digestive
fluid, he could get it to reduce fibrin
to the condition of jelly in less than
an hour.
A reflective person is apt to inquire,
Why were insectivorous plants ever given
a place in Creation ? and it certainly does
seem strange that objects in the Vegetable
World should be made the instruments
Photo byj [^s. L. Bastin. °^ destruction to objects in the sister
FIG. 150.— CALIFOBNIAN PITCHER kingdom ; though we have long been
(DarUngtonia calif arnica). reconciled to the existence and necessity
The entrance to the pitcher is here covered by a ,. .. , . . . „ , . mi
hood. Insects crawling along either platform find OI an Opposite COndltlOll OI thlllgS. That
themselves just under the entrance. Its habits , , . , , i -i , i •
are similar to those of Sarracenia. ants and apnides snould thrive and grow
THE ASCENDING SAP
117
fat by feeding on the sappy tissues of
plants appears to us a natural and even
justifiable provision, but that the plants
should retaliate by setting traps for their
tormentors is not so easily accounted for ;
and we are immensely shocked when we
find that not a few of them actually feed
upon their captive enemies. Is not this,
we cry —
A sort of retrograding ?
Surely the fare
Of flowers is air,
Or sunshine sweet.
They shouldn't eat
Or do aught so degrading.
But what these wilful children of Flora
should do, and what they actually do,
are of course two very different things ;
and when all is told, and poets and
moralists have had their say, the stubborn
fact remains that certain plants do feed
on insects ; and that nitrogen, potash, etc.,
may be obtained from other sources than
the soil, and be absorbed into the plant by
other organs than the root. At the same
time it should never be forgotten that the
root is the chief organ of absorption — that
is, of all the nutrient elements save carbon
— and, moreover, that insectivorous plants
occupy but a small corner of the Veget-
able Kingdom. As already remarked,
they have apparently taken to this method
of obtaining nitrogenous food because
there is so little of it in the soil where
they grow.
Although the plants in this case have
completely turned the tables upon their
persistent enemies, the animals, it is in-
teresting to note that the latter again retaliate through some of their
members. One of the Lemurs is known to raid the larger species of
Nepenthes for the sake of the dead insects, and even the insects send at
least one representative to reduce the spoils of the plant. Mr. F. G. Scott
Elliot says: "Near Fort Dauphin, in Madagascar, 1 found great quantities
of Nepenthes madagascariensis. Almost every pitcher was one-third to two-
Photo by] ' [S. L. Bastin.
Fio. 151. — Sarracenia.
A pitcher cut open to show the interior and the
black mass of organic matter at the bottom, result-
ing from the plant's digestion of captured insects.
118
HUTCHINSON'S POPULAR BOTANY
thirds full of corpses, but in some of them large, fat, white maggots, all
of a very unprepossessing appearance, were quite alive and apparently
thriving. These must have been the larvae of a blowfly similar to that
which has been mentioned by others as inhabiting Sarracenia. At the
same place a white spider was very often to be seen. Its web was spun
across the mouth of a pitcher, and its body was quite invisible against
the bleached remains inside. It had suited its colour to the corpses within,
in order that it might steal from the Nepenthes the due reward of all its
ingenious contrivances ! "
"We have dealt at some length with these insect-eating plants, but we
have not yet exhausted the list. One other that had formerly been re-
garded merely as a root-parasite has of late years been at least suspected
of getting some of its food by predatory courses. "We refer to the
Toothwort (Lathrcea squamaria], a rare but interesting plant. During about
eleven months of the year it leads a subterranean existence, fattening upon
the sap of the elm and hazel, to whose
roots it is attached by suckers. About
March it makes its presence known
above ground by sending up short,
thick, fleshy flowering stems almost white
in colour, but usually tinged with violet.
The flowers are thickly crowded on the
greater part of this stem, but below them
are a number of curled fleshy scales —
really leaves, but not much like the
ordinary forms of leaves. On the under-
side there are peculiar and complicated
chambers which are only accessible
near the turned-down tip of the leaf ;
but though this appears not to be a
sufficiently obvious way in. the Tooth-
wort has learnt the weakness of its
victims. It is the nature of many of the
smallest creatures to look out for hidden
retreats in which they can enjoy a moist,
cool atmosphere ; and so it is stated that
many animalcules and the very smallest
forms of insect life explore these laby-
rinths, and mostly fail to find the way
out again. It is not asserted that the
Toothwort pours out a digestive fluid,
FIG. 152.-
(Sarracenia
°Ut
Grows to a height of two feet; yellow in colour, °f. Protoplasm from the liv-
the lid netted with purple veins. NORTH AMERICA. mg Cells which extract the SOf t parts
A Pitcher-plant allied to Sc
[E. J. Wallis.
FIG. 153. — Heliamphora nutans.
rracema, and of similar habits. It has white or pale — rosy flowers. A
native of MOUNT RORAIMA, GUIANA.
119
120
HUTCHINSON'S POPULAE BOTANY
of the victims, for they have found only the hard parts of the prisoners
remaining after a short period of incarceration.
The accompanying photographs of the Toothwort have peculiar interest,
because they were taken in a Surrey lane where John Ray (1628—1705)
recorded the plant as growing in his time. The plant photographed is in
all probability a direct descendant of the plants he noted. Figs. 155, 157.
It may be asked. How is it that the fluid from the soil is able to force its
way through the membranous cell- walls of the root-hairs and to pass upwards
into the plant ? The question suggests another, namely, How is it that water
is drawn up into a piece of loaf-sugar or a sponge ? though by fencing the
first question in this manner one is only suggesting a solution to the tail-end
of the difficulty, nor this, unless something is known of capillary attraction.
But how is it that the fluid of the soil gains entrance into the closed
cells ? A merely verbal explanation, however clear, would be dry and unen-
lightening. We might talk about endosmose and exosmose and the power
of passing through porous diaphragms for hours, and still fail to convey
a definite impression on the subject. An experiment in this case will
save a world of laborious explanation. For this experiment nothing more
is required than a bowl of distilled
water, some sugar in solution, a small
length of glass tubing, and a couple of
pieces of bladder to close up the ends.
The experiment is performed in
the following manner : Close up one
end of the tube with a piece of bladder
and pour in the solution of sugar ; then
close up the other end, and immerse
the whole in the bowl of water. It
will presently be found that the bladder
at both ends has become distended, in
consequence of an increase of volume
of the fluid in the tube, the increase
being due to an inflow of the distilled
water in which the tube is immersed.
This transmission of fluid through a
porous partition from the exterior to
the interior is called endosmose (Greek
endon, within ; osmos, impulsion). On
applying a little of the distilled water
to the lips, it will be found to have
acquired a slightly sweet taste, a small
portion of the sugary solution having
passed Out through the bladder. Here,
, . . -, ,
then, is evidence that two currents,
Photo by] IS. L
FIG. 154. — Cephalotus follicularis.
Interior of a pitcher of this little Australian Pitcher
plant
The entire plant is shown in fig. 18.
the dead insects.
Note
THE ASCENDING SAP
121
Photo by-]
FIG. 155. — TOOTHWORT (Lathrcea squamaria).
A parasite upon the roots of Elm and Hazel. The leaves are represented by hollow scales
enter; and it is believed they are digested and absorbed.
of which the inward flow of water is the chief, have been set up. With
these results in view, substitute in imagination a root-hair for your
glass tube,' and for your bladder the exterior cell-walls of the hair, and
the experiment will have been made to some purpose.
That there is a slight outivard flow of sap from the plant, in addition
to the more important inward passage of water and its concomitants, may
be shown in another way. If a plant be grown with its roots in water,
the surrounding fluid is soon found to contain some of the peculiar sub-
stances contained in the descending sap. Thus a Pea or Bean will dis-
engage a gummy matter, a Poppy will communicate to the water an
opiate impregnation, and a Spurge will give it an acrid taste. This
passage of the sap through the cell membranes, from within outwards
is called exosmose (Greek exo, outside ; osmos, impulsion).
Once the fluid from without has entered the root-hairs, it diffuses from
cell to cell till it reaches the nbro-vascular system — that wonderful
arrangement of vessels and woody cells which forms the framework or
skeleton of the plant ; and so it mounts and mounts, chiefly by way of the
wood elements, from root to stem, from stem to branch, from branch to
slender twig, till it reaches the leaves — as little changed during its whole
122
HUTCHINSON'S POPULAR BOTANY
passage as the water which passes through a pump. The wind which rocks
the trees and plants to and fro assists in this process, and the leaves also
assist, though in quite a different manner. The latter, indeed, are the
busiest organs of the plant, as we shall see in the next chapter, when we
shall consider their wonderful structure and functions.
The rate at which the watery sap courses up the stem may be gathered
from Kingsley's vivid description of the Liantesse (Schnella excisci), a West
Indian Water-vine, whose singular stem, hanging in loops twenty feet high,
he likens to a chain-cable between two
flexible iron bars. At one of these
loops, "about as thick as your arm,"
writes the Canon, ",your companion, if
you have a forester with you, will
spring joyfully. With a few blows of
his cutlass he will sever it as high up
as he can reach, and again below, some
three feet down; and while you are
wondering at this seemingly wanton
destruction, he lifts the bar on high,
throws his head back, and pours down
his thirsty throat a pint or more of pure
cold water. This hidden treasure is,
strange as it may seem, the ascending
sap, or rather the ascending pure rain-
water which has been taken up by the
roots, and is hurrying aloft to be elabo-
rated into sap, and leaf, and flower, and
fruit, and fresh tissue for the very stem
up which it originally climbed ; and
therefore it is that the woodman cuts
the Water-vine through first at the top
of the piece which he wants, and not at
the bottom ; for so rapid is the ascent
of the sap that if he cut the stem
below, the water would have all fled upwards before he could have cut it off
above " (At Last, p. 159).
The " pure rain-water " mentioned by Kingsley is not really pure, for
it contains mineral elements from the soil dissolved in it. The plant
requires this mineral matter to mix with the gases taken in from the
atmosphere, that all may be elaborated into sap in the leaves. But the
percentage of mineral constituents is very low, so that a vast volume of
water must be given off as vapour through the stomata, and this increases
the pulling action which helps the upward flow.
So much for the ascending sap.
FIG. 156. — AN AQUATIC FLY-TRAP
(Aldrovanda).
A small rootless plant that Darwin called "a minia-
ture aquatic Dionsea." A single whorl of leaves is
here shown, together with an enlargement of a single
leaf. EUROPE, INDIA, AUSTRALIA.
Photo by]
FIG. 157. — TOOTHWOKT (Lathrcea squamaria).
The plant consists of the flower-stems only, which make their appearance in early spring. They are here shown fully
extended, but on a scale about one-third less than actual size. EUBOPE and ASIA," N. and w.
123
CHAPTER V
THE DESCENDING SAP
And now returning through the knotty stem
By broader routes, a copious, nutrient stream.
WE saw in Chapter III. that an ordinary foliage leaf consists of three
distinct kinds of tissue, which may be popularly described as the
veins, the fleshy substance between the veins, and the thin enveloping skin.
Here is a microscopic view of the transverse section of part of a Rhodo-
dendron leaf (fig. 158). Upwards of twenty layers of cells are packed in the
thickness of this single leaf — a fact to arrest attention. The double line of
cells lettered a belongs to the epidermis of the upper side of the leaf; 6
shows the fibre-vascular bundle of a vein in cross-section ; c the par-
enchyma of the ground tissue,
easily to be recognised in the
actual leaf by the chlorophyll
corpuscles contained in the cells ;
d are air cavities between the cells,
botanically known as intercellular
spaces • and the single row of cells
'li&WVf UfWQWWtffi h at the bottom of the section be-
longs to the epidermis of the under
side of the leaf.
But some cells have yet to be
spoken of which play a most im-
portant part in the life of the
plant, and to which particular at-
tention should be given. A pair
of these cells are lettered / in the
drawing. They project from the
lower line of epidermal cells, and
form the two lips of a little mouth,
which communicates with one of
the intercellular spaces (d) ; more-
over, they contain chlorophyll,
which the epidermal cells do not.
To speak of these projecting cells
FIG. 158. — SECTION THROUGH PART OF THE
LEAF OF A RHODODENDRON.
124
THE DESCENDING SAP
125
as " lips " is not fanciful, for
the orifice between them is a
veritable mouth, and the name
which physiologists apply to
such openings is stomata, which
is simply the Greek word for
" mouths " (figs. 160, 162, 163).
The stomata, indeed, are
little mouths or crevices in
the epidermis, caused by the
separation of certain cells in
the course of growth; and
these cells form the "lips" of
the mouth, and are known as
guard-cells. Each is shaped
like a crescent, their points or
horns meeting to form the
stoma or mouth ; and it is by
means of these peculiar struc-
tures that the plant tran-
spires. The tiny openings
establish a communication
between the atmosphere and
the air chambers or inter-
cellular spaces in the interior
of the plant, the passing in
and out of gases being regu-
lated in a beautiful manner
by the guard-cells.
Fig. 164 represents a minute piece of the epidermis of the Madder-plant
(Rubia tinctoria^ in which three of the stomata are plainly shown ; but far
better for examination is a beautiful plant of the Daffodil order— Amarylli-
daceaa — known by the very ugly name Hippeastram. It is a variety of
H. ackermanni, one of the largest flowering species' of the genus. As a
rule the clefts vary in length from -j^^^h. to rWircn^h °f an inch, and so
abundant are they on some leaves that a square inch of tissue may contain
as many as 250,000 of them. They are met with only in those parts of the
plant where they are actually needed, for our protoplasts work on economic
principles, never wasting their forces. Hence you will look in vain for the
stomata on leaves which grow under water,* or on the under surface of
* Water stomata, however, are found in some plants. " These are situated over the ends
of small masses of specially modified parenchymatous cells (glandular cells), in which vascular
bundles terminate, and which are known as water glands." Water stomata give off water and
various substances in solution. — Text-book of Biology, p. 92.
Photo by-] \E. Step.
FIG. 159. — RHODODENDRON (R. arboreum).
This magnificent tree, a native of the Himalaya, is quite hardy in
some parts of southern England, and reaches great proportions. The
clump photographed is about twenty feet in height.
126
HUTCHINSON'S POPULAR BOTANY
floating leaves — the very place where they are most plentiful in land plants.
Plants of the Cactus tribe (Cacteae) and some tropical Euphorbias — whose
leaves, like those of the Cacti, hereafter to be spoken of, have been meta-
morphosed into spines and thorns for protective reasons — develop their
stomata on the fleshy succulent stems. From roots — if we except the
green-celled aerial roots of a few epiphytes, such as the Tree-orchids of the
tropics — they are entirely absent. In the interesting Polar-plant (Silphium
laciniatum) the stomata are about equally distributed on both sides of the
broad flat leaves — a very necessary provision, because of the peculiar position
of the leaves, both faces of which are in every case equally illuminated by
the sun. This is the case with most, if not all, plants with vertical leaves.
A curious fact, not unconnected with
our present subject, has been brought
to light by Dr. M. C. Cooke, in relation
to Bomarea carderi, a handsome climbing
plant of Colombia. The plant has long
lance-shaped leaves, and Dr. Cooke has
pointed out that the under surfaces of the
blades of these leaves are exposed to the
light, owing to a twist in the leaf-stalk
(fig. 167). To give additional interest to
the discovery, a competent physiologist,
Mr. W. S. Gilburt, to whom specimens
were submitted, ascertained that the entire
structure of the leaves is reversed, in
order to fulfil the conditions of their re-
versed position ; the under surface being
smooth, and presenting the usual character-
istic epidermal cells of an upper surface ;
while the true upper surface is fitted to
do duty for the former. No satisfactory
reason has yet been assigned for the twist-
ing of the leaf-stalk, and if ever the phenomenon is accounted for it
will probably be by one who has studied the plant closely in its native
habitat.*
It has -been shown that the presence of light is most essential to the
development of perfect and vigorously acting stomata. This fact — with
other related facts — has been well illustrated in the case of one of the
commonest of the Liverworts, Marchantia polymorpha (fig. 169). The young
plant, when first separated as a kind of bud from its parent, exhibits no
stomata or roots.f "It has been ascertained by repeated experiments," says
Dr. Carpenter, "that stomata and roots [really 'rhizoids'J may be caused
* Freaks and Marvels of Plant Life, pp. 196, 197.
t More correctly rhizoids. Rhizoids corresponds to the root-hairs of Flowering Plants.
FIG. 160. — STOMA OF SCOTS PINE
(Pinus sylvestris).
The breathing pores of plants are called stomata
or mouths. In this section of a leaf of Scots
Pine, the open stoma on the surface is seen to
connect with spaces between the cells of the leaf-
tissue. Magnified.
127
128
HUTCHINSON'S POPULAR BOTANY
to develop themselves in either of the two sides ;
the stomata * being always formed on the upper
surface, under the influence of light, and the . . .
[rhizoids] proceeding from the lower towards darkness.
But if the surfaces be reversed after the reproductive
organs have been developed to a certain point, so that
the stomata be directed towards the ground, and the
. . . [rhizoids] be made to rise into the air, the little
plant will right itself, by twisting itself round, so as
to bring its surfaces to their former position. Further,
when plants of a higher description are grown in dark-
ness, the stomata are developed very imperfectly, or
Part of section through leaf , not at all. Thus we have an example of the very im-
fts0gia?d%dLf.leS3ia^ifiedh portant effects of the stimulus of light upon the veget-
able structure, not only in covering its actions, but in
influencing its development" (Vegetable Physiology and Botany}.
We have said that the stomata are the organs through which the plant
transpires. The condensation of water on the glass surface of an ordinary
fern-case is a familiar instance of transpiration ; though doubtless some of
,the vapour is due to evaporation from the soil. By placing a piece of
cardboard, through which a small hole has been made for the insertion of a
well-developed leaf-shoot, over the mouth of a tumbler of water, and covering
the whole (leaf-shoot and tumbler) with a bell-glass, evaporation will be
prevented, and the watery deposit forming on the inside of the glass will
soon furnish proof that water is transpired from the leaves. Hence the
necessity for keeping the roots of plants well supplied with water ; for if the
loss by transpiration be greater than the quantity supplied by the roots, the
conducting parts (as the stem and branches) quickly suffer; and when at
length the evaporation from the more delicate organs can no longer be
compensated, they lose their stiffness or turgidity, hang down from their
own weight, and wither. The flagging of leaves, so
often noticed in the potting and bedding-out of plants,
is due to the same cause. The delicate root-hairs, by
which alone absorption of the soil is effected, get de-
stroyed in the process of transplanting, and thus the
upward flow of crude sap to the leaves is temporarily
arrested. In cases of this kind, transpiration should be
artificially checked by shading the plants from the light
till such time as new root-hairs have been found, when
absorption will again take place.
FIG. 163.— FIELD
HORSE-TAIL. * Qr^ rather, stomata-pores. They are really pores in the outer-
Section through part of stem mogt j r of tissues /for tjie thallus has no true epidermis), and each
of Equisetum arvense, show- . , . . . . . ... . , . , .
ing a stoma and its connec- pore leads into an air chamber much larger than itseli, in which is
tions. Magnified. contained the assimilating tissue of the thallus.
WESTERN HANKSIA (Sankna occidental™).
A representative of the Order Proteaceae. There are numerous species, confined to Australasia. The Western Banksia
is found only in South- West Australia. The flowers are without petals, and great numbers of them unite to form heads
as shown. But the shrubs are chiefly valued in cultivation on account of their ornamental foliage, which is dark-green
above but covered with white or red down on the underside.
THE DESCENDING SAP 129
Thus we see how important a part the leaves play in connection with the
upward flow of sap. Transpiration, which is carried on chiefly through the
stomata, not only gets rid of the superfluous water, but sets up a rapid
movement of the crude sap from the root to the leaves, drawing it upwards,
somewhat as the oil is drawn upwards in the wick of a burning lamp. This
giving-off of water by plants is often of considerable benefit to the regions
in which the plants are found. " It is a well-known fact," says Dr. Nathaniel
"Ward, the inventor of the Wardian case, " that many hilly countries have
been rendered quite sterile, in consequence of the indiscriminate destruction
of their trees, the roots of which, taking up more water from the deep-seated
springs than the plants require for their own use, distil the surplus through
the leaves upon the ground, forming so many centres of fertility. ' Spare
the forests, especially those which contain the sources of your streams, for
your own sakes, but more especially for that of your children and grand-
children.' " * Needless to add, the quantity of water given off in the manner
described renders the solutions denser in the leaves
than in the stems — a point that will come before us
again presently.
Before leaving this subject of stomata we
should call attention to the analogous structures in
the bark, known as lenticels. As the stem or branch
of a woody plant grows, the epidermis with its
stomata gets too small for the increasing diameter of
the part. It cracks longitudinally and dies, becom-
ing dead bark, but connection between the air out-
side and the intercellular spaces of the cambium
within is maintained by means of the lenticels, FlG- 164.— STOMATA.
through which carbonic acid gas passes outwards &S ?^rt^0S^),le^£
and oxygen inwards. These lenticels may be noticed three 8tomata-
on the twigs of trees as little prominences, differing in tint from the sur-
rounding bark. In the Birch and Cherry they are especially noticeable as
transverse lines.
Much more devolves upon the leaves than the giving off of superfluous
moisture. We have seen that the crude sap, which contains in solution the
nutritious principles, undergoes but little change during its passage from
the root to the leaves ; and also that the substances thus introduced into
the plant are, without exception, inorganic compounds. Yet these compounds,
if they are to be of any service to the plant, must be converted into organic
matter, in order that this, in turn, may form the plastic material or protoplasm
out of which new vegetable structures, such as cells, vessels, etc., maybe
built up. In other words, the food must be assimilated by the plant ; and
this necessity pertains not merely to the nutrient substances absorbed from
the soil, but also to the carbon dioxide derived from the atmosphere.
* On the Growth of Plants in Closed Cases, etc., pp. 10, 11.
12
130
HUTCHIXSON'S POPULAR BOTANY
Assimilation, indeed, is found to consist essentially in the decomposition
of carbon dioxide and the formation of some kind of sugar — possibly glucose
(C6Hi20G), possibly canose (C12H22On) — in the chlorophyll corpuscles. Allusion
was made to this some pages back, where it was pointed out that the cells
containing chlorophyll— which are always near the surface of the plant —
absorb carbon dioxide from the atmosphere or water (the latter in the case
of submerged plants), and that this gaseous compound is decomposed in the
chlorophyll corpuscles under the action of light. It was also stated that the
first organic compound as a result of the process is, in most plants, a form of
sugar.* The importance of the leaves
in the economy of Vegetable Life will
be seen at once, when it is added that
these are the organs chiefly concerned
in the work in question.
YTou may illustrate the process by a
simple experiment. Let the stem of any
pond-weed of convenient size be placed
in water which holds carbon dioxide in
solution (a little spring water will be
pretty sure to contain a sufficiency for
the purpose), and exposed to sunshine.
What follows ? From the cut surface
of the stem, bubbles of gas are given
off at regular intervals. The liberated
,^l_. — -, If^?' }£*</ bubbles consist of oxygen. Probably
f&'V5rfy V:: • .•'"'•' you now perceive what has taken place.
Some of the carbon dioxide has been
absorbed by the leaves of the plant,
and there decomposed, under the influ-
ence of light, the oxygen having been
given back to the water as useless. This
setting-free or evolution of oxygen from
plants is popularly known as " breath-
ing " or respiration, but the term, in this
application of it, is altogether erroneous, the process being one of exhala-
tion and simple evaporation. Plants do respire, just as animals respire,f but
* It has been proposed to apply the term photosynthesis instead of assimilation to this
process. "As the activity of the chlorophyll apparatus is so essentially dependent upon
light," says Dr. Reynolds Green, "the process of construction of carbo-hydrate substances
from carbon dioxide and water, which is its primary object, may appropriately be called
photosynthesis. This term has certain advantages over the older expression, the assimilation
of carbon dioxide, as the term 'assimilation' may preferably be reserved for the process of
the incorporation of the food materials into the substance of the protoplasm " (Introd. to
Veg. Phys. 1900).
t That is, by giving out carbon dioxide and watery vapour and inhaling oxygen. A plant
placed in pure carbon dioxide would soon be suffocated, just as would an animal.
FIG. 165. — HORIZONTAL SECTION
THROUGH THE EPIDERMIS OF A
YUCCA LEAF,
Showing stomata.
131
132
HUTCHINSON'S POPULAR BOTANY
the giving off of oxygen in the manner described is not respiration. We
htwe been watching one of the consequences of assimilation.
Mark, we say, "consequences." The true act of assimilation— in this
case the appropriation of carbon— has taken place out of sight in the leaves,
•which, as already stated, are the organs chiefly concerned in this important
function. The process itself is only imperfectly understood, though enough
has been discovered to stimulate inquiry. Undoubtedly the first stage in the
"building-up process is the union of C0.2 and H20 to form the starting-point
for a carbo-hydrate ; and the first carbo-hydrate which can be detected in
the leaves is, as we have been pointing out, some form' of sugar. The leaves
are chemical laboratories, wherein
the little green corpuscles of proto-
plasmic matter produce results that
have baffled our Kolligers and Fara-
days, though every year the Plant
World is yielding up fresh secrets
to the patient workers of to-day.
The exceeding difficulty of the in-
vestigation may be gathered from a
remark by Mrs. Somerville, that
'; although it may be inferred that
chemical action is the same within
the vegetable as it is in the inorganic
world, yet it is accomplished within
the plant under the control of the
occult principle of plant life." *
Under certain conditions cells and
tissues containing chlorophyll have
their power of assimilation arrested
for a time, though the cells continue
to respire. Dr. A. J. Ewart has made
an extensive series of experiments
on various plants bearing upon this
point (see Journal of the Linnean
Society, vol. xxxi. pp. 364-461). The
agents or circumstances producing this suspension of function are stated
by him to be " dry heat, moist heat, cold, desiccation, partial asphyxi-
ation, etherization, treatment with acids, alkalies, and antipyrin, accumu-
lation of the carbo-hydrate products of assimilation, immersed in very
strong plasmolytic solution, and prolonged insolation. The inability to
assimilate is, if the cell remain living, only temporary, being followed
sooner or later by a more or less complete recovery of the power of
assimilation."
* Molecular and Microscopic Science, vol. i. p. 168.
FIG. 167. — Bomarea carderi.
Owing to a twisting of the leaf-stalk the lower surface of
the leaf is brought above, and the whole of the struc-
tural arrangements are altered to correspond with this
change of position.
THE DESCENDING SAP
133
In the leaves are manufactured the
starch-grains, proteids, etc., of which
some account has been already given,
and which are required, not only for
the present growth of the plant, but
also as reserve food material. But
these substances are solid and insoluble
in water, a circumstance which pre-
vents their passage from cell to cell ;
and they have therefore to undergo
further changes before they are dis-
missed from the leaves. Starch, for
example (C0H1005), is converted, by
means of a ferment called diastase, into
the soluble substance sugar* (C6H1206),
which, becoming part of the assimilated
nutrient sap, is distributed through
the plant, to be again fixed in the
form of starch at particular places, as
in the grains of cereals, the tubers of
the Potato, etc. The proteids are also
changed, the agents in their trans-
formation (known as proteolytic enzymes)
being pepsin and the various trypsins.
But we spoke of respiration. What
is it ? If the term is a misnomer as
applied to the evolution of oxygen
from plants, in what does true respira-
tion consist? The question may be
answered by a simple experiment. Soak
in water for twenty-four hours, to
induce germination, a quantity of peas,
then place them in a jar, disposed in
single layers between pieces of moist
blotting-paper. The mouth of the jar
is closed by a tightly fitting cork, which
is withdrawn after an interval of a
few hours. Now take a lighted taper
and plunge it into the vessel. In-
stantly the flame is extinguished. You
guess the cause ? While confined in
the jar the peas have been evolving carbon dioxide, and in carbon dioxide
* I.e. glucose or grape-sugar. The formula for canose or cane-sugar, sometimes called
sucrose, is Cn
Photo by\ [£. Step.
FIG. 168.— Monstera deliciosa.
The fruit-spike of this Mexican plant. The seeds "are
embedded in a luscious pulp, which has a flavour
similar to that of pine-apple. The leaves have large
perforations in their tissues.
134
HUTCHINSON'S POPULAR BOTANY
FIG. 169. — LIVERWORT (Mai
chantia polymorpha),
Showing the stalked antheridial
receptacles.
no flame will live. That the vessel is charged with
this gas may be proved in a simple manner. Into
another jar pour some lime-water. When carbon
dioxide and lime-water are brought together, the
former combines with the lime and forms an in-
soluble carbonate of lime, which imparts a white
cloudy appearance to the liquid. If, then, we
next tilt the jar containing the peas over the
other vessel, the carbon dioxide, which is heavier
than the air, will be poured into the lime-water,
and the result just described will be witnessed.
It would be easy to demonstrate further that
the germinating peas have absorbed a volume of
oxygen nearly equal to the volume of carbon dioxide given out; indeed,
the absorption has really preceded the evolution of the latter, and is
the cause of it. In other words, the oxygen has found its way into the
living cells of the peas, and by decomposing, with the active assistance
of the protoplasm, some of the complex carbon-containing compounds, has
liberated the carbon dioxide. What is known as oxidation, a burning of
organic material, has taken place — the very process which goes on in
animal bodies, and which is called respiration. The germinating peas
have, in fact, been breathing, not through any special respiratory
organs, as is the case in animals, but breathing nevertheless ; and what
is true of the subjects of our experiment is true of the living parts of
almost all plants. Eespiration is as necessary to vegetable as it is to
animal life, and in both the great kingdoms breathing and living may be
taken as synonymous terms. True, in certain of the lower forms of
vegetation, such as the Yeast-plant (Saccharomyces cerevisice) and Bacteria
(Schizomycetes), a process of fermentation goes on which appears to
obviate the necessity for respiration ; but the exceptions only give
emphasis to the rule. In the Algce and Mosses (Musci), again, respiration
is comparatively feeble ; still, they breathe, and whenever a free supply of
atmospheric oxygen is denied, they are suffocated and die.
As we ascend the scale of Life, respiration becomes more and more
vigorous, and is often attended by a sensible liberation of heat, particularly
in certain parts of the plant and at certain periods. For this reason the
Soldanelias, a small genus of pretty Alpine
P plants, are able to melt a way through the
^s^^:fl^^cc:acc^^^ hardest crust of snow, their slender flower-
stalks pushing upwards to the light and air
as effectually as if they were so many fire-
heated awls.
Fm. 170.— SECTION THROUGH PART We m add before passing from this
OF THE THAI/LUS OF LIVERWORT, J . 111
showing a stomate and air chamber. subject, that m many— pro bably in all—
FIG. 171. — FRUIT OF THE DATE PALM (Phoenix dactylifera).
A native of Africa and Tropical Asia. One of the most valuable of trees, as whole tribes practically live upon
its iruit, wiucii is Dome by the female trees only. Some idea of tne abundance of Iruit may be gathered from this
photograph, which shows only a small portion of the tree.
135
136
HUTCHINSON'S POPULAR BOTANY
flowers there is a distinct rise of temperature at the period of open-
ing, a fact the truth of which may be demonstrated by a thermometer
in the case of inverted tubular and bell-shaped flowers, the air in. which
is not only warmed, but, being little disturbed by the surrounding atmo-
sphere, retains its warmth. Kerner (Natural History of Plants) has recorded
the results of some experiments in this direction which are very interesting.
The temperature inside the spathe of one of the Brazilian Aroids, the hand-
some large-leaved Monstera deliciosa, was found to be 38° centigrade, when
the temperature of the outer air was only 25° ; the spathe of another Aroid,
4 '/
Si ', *
[E. Step.
FIG. 172. — SWAN'S-NECK THREAD-MOSS (Mnium hornum).
One of the most beautiful of our mosses, forming deep and extensive carpets of golden green, above which nod the
spore-capsules on their arched thread-like stalks. It may be found on sandy woodland banks, fruiting in the spring.
Arum cordifolium, was 35-39° at the same air temperature ; while Arum.
italicum, a plant extremely common in the region of the Mediterranean,
closely resembling our common Cuckoo-pint, actually exhibited a temperature
of 44° when the thermometer in the external air only registered 15°. This
was at the period of the opening of the spathe, which was noticed at the
time to give forth a peculiar fragrance, like wine. Here, then, we have
a plant the temperature of whose respiring flowers exceeds that of blood-
heat !
The evolution of light from plants is also thought to be connected more
THE DESCENDING SAP
137
or less remotely with respiration — i.e. with
the combustion of carbon compounds in
living cells. Many theories, however,
have been advanced to account for the
phenomena of luminosity, and the paucity
of our knowledge on the subject may be
gathered from the fact that the very
existence of the phenomena — at least,
in the higher plants — is to this day gravely
questioned by many botanists. In our
opinion the evidence in favour of the
alleged occurrences is too accumulative
to be resisted ; though doubtless they are
due to other causes than those which pro-
duce the phosphorescence in plants of
lower organization, as we hope presently
to show.
The great naturalist Linnaeus was the
first — at least in modern times — to record
an observation on the subject, his atten-
tion having been drawn to it by his
daughter, Christina Linne. Walking in
her father's garden one hot June evening,
she observed the flowers of Tropceolum
majus (the Garden Nasturtium) give forth
sparks or flashes. The phenomenon was
repeated on successive evenings, and also
in the mornings before sunrise, when
not only her father, but other men of
science were present. One of these gentle-
men, a well-known electrician named
Wilcke, believed the flashes to be electric ;
and this appears to be the opinion of
most writers who have investigated the
subject since ; though some believe that
the scintillations are only apparent, and
class them among optical illusions. The
fact that the flashes are invariably ob-
served at times when the air is dry and
charged with electricity, is, however, ail
argument — and a pretty strong one — in
favour of the former view.
Perhaps no flowers exhibit this phenomenon in a more remarkable
degree than those of the plant noticed by Linnaeus ; though the common
Photo by] ' IE. Step.
FIG. 173. — MARTAGON LILY (Lilium
martagon).
One of the plants whose flowers are said to be
luminous. EUROPE, ASIA
138
HUTCHINSON'S POPULAR BOTANY
Marigold (Calendula vulgaris), African Marigold (Tagetes erecta), Martagon
Lily (Lilium martagori), and Sunflower (Hdianthus) are also highly luminous.
The remarkable scintillations first observed by Christina Linne have
now been witnessed by so many credible and competent observers, that
it is singular their reality should be longer doubted. M. Haggren, a
Swedish naturalist, observed them frequently, and when at work in his
garden employed a man to watch the flowers and to make signals whenever
the flashes occurred. They
both saw the light con-
stantly, ' and at the same
moment, playing round the
flowerheads of the Mari-
gold. This was in the
months of July and August,
the phosphorescence being
only seen at sunset or for
half an hour after, and never
on rainy days or when the
air was loaded with vapour.
A microscopic examination
of some of the flowers, to
discover whether some small
insects or phosphoric worms
might not be the cause of
the light, soon convinced
our naturalist that such a
theory was untenable.
Nothing of the kind was
found, and he came to the
conclusion that the flashes
were electric. His own
theory, however, that the
electric light was caused by
the pollen of the florets,
which in flying off was scat-
tered upon the petals, is
hardly to be taken seriously.
In the year 1835 Mr. J. R. Trimmer, of Brentford, was an eye-witness
of the phenomenon, of which he sent an account to the Magazine of
Botany. In this case, also, everything points to electricity as the exciting
cause. The writer was walking in his garden in the. evening, where many
Nasturtiums were in bloom, his thoughts far away from the subject of
phosphorescence, when vivid flashes from those flowers attracted his notice.
The flashes were the most brilliant he had ever observed, and at the
Photo by} [S. L.
FIG. 174. — THE SOLDANELLA (Soldanella alpina).
This pretty alpine plant is shown under the snow, which by its own
evolution of heat it is able to melt, and so make its way to the light.
EUROPEAN ALPS.
FIG. 175. — NIGHT IN THE GARDEN.
An attempt to show the luminosity of the Nasturtium (Tropceolum majus), which many observers have vouched for
as appearing in certain conditions of the atmosphere.
139
140
HUTCHINSON'S POPULAR BOTANY
same time — a fact to be specially remarked — the sky was overcast with a-
thunder-cloud.
Seven years later (August 4th, 1842) the phenomenon was observed by
a Mr. Dowden and three others, at nearly the same time of the day and
under similar climatic conditions. In other words, the flashes were seen at
about eight o'clock in the evening, after a week of dry weather. " By
shading off the declining daylight, a gold-coloured lambent light appeared
to play from petal to petal of the flowers, so as to make a more or less
interrupted corona round the disc." The flowers examined were a double
variety of the Common Marigold.
In quite recent years more than one naturalist has recorded his personal
observations of the phenomenon. Thus Canon Russell, writing to Science
Gossip in September, 1891, says : " On the evening of June 16th, 1889r
I happened to be taking a
stroll round the rectory
garden, and passing by a
fine plant of the Common
Double Marigold, of a deep
orange colour, I was struck
by a peculiar brightness in
the appearance of the
flowers. After watching for
a few seconds, I observed,
to my great surprise, that
coruscations of light, like
mimic lightning, were play-
ing over the petals. Think-
ing that I might be only the
victim of an ocular illusion,
I brought out other mem-
bers of the household, and
asked them to report exactly
\ ^1 what they saw. Some per-
ceived the flashes readily
enough, but others only
slowly and after patient
observation, all eyes not
being equally sensitive to
such rapid vibrations of
light. These performances
commenced about 8.30 p.m.,
and continued for perhaps
an hour. I afterwards ascer-
tained that much later on,
IE. step,
Fio. 176.-DBAGON (Arum dracunculus).
This South European species differs from the Cuckoo-pint in producing
a stem above ground, which is spotted with purple. The leaves, too,
are broken up into large lobes in a pedate manner. The spathe and
spadix are purple, and give out a fetid odour.
THE DESCENDING SAP
141
it was almost dark, the whole
plant seemed to glow with a sort of
pulsing phosphorescence."
The Common Nasturtium was
also luminous in a less degree, the
luminosity in this case extending to
the leaves, which, it is further stated,
gave off " a blue vapour of extreme
tenuity." " I put a leaf of Nasturtium
on the stage of a microscope," con-
tinues the canon, "and, having
focussed it for the central spot from
which the nerves branch off, under an
inch and a half objective, I brought
it into a room nearly dark. Looking
at it then through the microscope,
I found that the leaf could be dis-
tinctly seen almost by its own light.
The appearance of the luminous
vapour floating over its surface (like
moonlight over rippling water) was
strikingly beautiful. The whole leaf
seemed to twinkle with points of
light— the main ribs radiating from
the common centre shining out like
a silver star. These effects are best
witnessed after a day of hot sun-
shine." .
Canon Russell's discovery of phos-
phorescence in the leaves of Tropce-
•olum introduces a new feature into the inquiry, and is of much interest.
Moreover, the fact that the luminosity remained in or on a leaf which had
been detached from the plant and removed to quite a different spot, and
that it was visible alike in daylight, dusk, and lamplight, might be held to
dispose once and for ever of the optical illusion theory ; for how could such
a theory be sustained in view of the persistence of the phenomenon ? And
yet it is strange that so few have beheld this manifestation.
So far the references have all been to orange-coloured flowers ; and it
will be remembered that Coleridge wrote :
Tis said at Summer's evening hour,
Flashes the golden- coloured iiower,
A fair electric flame.
The False Dittany (Dictamnus fraxinella} — of which there are several
garden varieties, white, red, and purple — may be said to occupy an unique
FIG. 177. — FALSE DITTANY (Dictamnus
fraxinella).
From glands on the flower-stalk this plant exudes an
etheric oil which is volatilized in warm weather, and if
a light is applied beneath the flower the vapour takes
Many modern experimenters, however, have failed
to get such a demonstration.
fire.
142
HUTCHINSON'S POPULAR BOTANY
place among luminous plants (fig. 177). To quote
from Erasmus Darwin :
What time the eve her gauze pellucid spreads
O'er the dim flowers, and veils the misty meads,
Slow o'er the twilight sands or lealy walks,
With gloomy dignity Dictamna stalks ;
In sulphurous eddies round the weird dame
Plays the light gas, or kindles into flame.
FIG. 178. — LUMINOUS Moss In plain prose, the plant secretes a fragrant essential
(Schistostega osmundacea). Q^ ^n great abundance : and in warm weather this
The so-caiied luminosity is a false exudes anci volatilizes, so that the air becomes
appearance due to the reflection of .,.',.
light from certain ceiis. impregnated with it. and is rendered not only very
fragrant, but also highly inflammable ; insomuch
that, if a naked flame be brought near the plant, the oily vapour takes
fire. This discovery, like that of the luminosity of Tropceolum, was made
by the gifted daughter of Linnaeus, and has been verified since by Dr.
Hahn, the result of whose investigations is given in the Journal of Botany
for 1863. His first experiments were unsuccessful, but on bringing a
lighted match to a nearly faded blossom, he saw " a reddish, crackling,
strongly shooting flame, which left a powerful aromatic smell, and did not
injure the peduncle." Since then he has repeated the experiment several
times, and a careful microscopic examination of the plant has shown that
the inflammable etheric oil is contained in numerous minute reddish brown
glands, located in the flower-stalks.
Other instances of luminosity in Flowering Plants — which, however,
must be more quickly passed over — are afforded by
the latex or milk-sap of a species of Euphorbia (E.
phosphorea), which is said to shine with a phos-
phorescent light on warm nights in the ancient
forests of Brazil, and by the roots of certain plants,
as the fragrant Khus-khus (Andropogon) and other
grasses. A luminous rootstock referred to in the
Proceedings of the Royal Asiatic Society for April,
1845, is perhaps that of the Khus-khus grass.
After a wet cloth bad been applied to its surface
for an hour or two it gleamed in the dark "with all
the vividness of a glow-worm " ; and though the
lustre faded away as the specimen dried, it was
revived on the application of fresh moisture, nor
did it appear to lose its luminous property after
frequent applications. The sap of the Cipo, a South
American Vine, is said to be so highly luminous
Greatly magnified. that, when injured, it seems to bleed streams of
FIG. 179. — THREAD-LIKE
GROWTH (PROTONEMA) OF
LUMINOUS Moss.
FIG. 180. — NIGHT SCENE IN A BRAZILIAN FOREST.
A Mushroom (Agaricus gardneri), like some others of its tribe, here gives out a soft but brilliant light. The light
is of pale greenish hue, and equal in brilliancy to that of the larger fire-flies.
143
144
HUTCHINSON'S POPULAR BOTANY
living fire. " Large animals have been noticed standing among its crushed
and broken tendrils, dripping with the gleaming fluid, and surrounded by
a seeming network of fire."
Passing now from the Flower-
ing Plants, we come to the non-
flowering or Cryptogamic, to which
the Mosses, Seaweeds, Fungi, etc.,
belong. Here we meet with some
very striking and unmistakable
instances of luminosity, though in
some of these, doubtless, the phe-
nomenon is connected rather with
the process of assimilation or
decomposition than with electrical
conditions of the atmosphere. We
have seen that assimilation com-
mences with the decomposition of
carbon dioxide in the chlorophyll
corpuscles, and that this takes place
under the action of light. Light
is therefore absolutely essential to
the successful discharge of the
functions which are carried on in
green tissues; and hence the very
interesting adaptations for increas-
ing light intensity in plants which
grow in caverns and grottoes and
in the twilight depths of the sea.
Certain caves of Central Europe
have long been celebrated for their
luminous Mosses. On entering one
of these caves, the eye is at once
attracted to the floor of the cham-
ber, which gleams and sparkles
with minute points of golden-green
light. The ignorant beholder might
imagine that he had stumbled upon
a store of hidden emeralds, but
any hopes of sudden enrichment
fostered by such a thought will be
quickly dissipated ; for the treasure
FIG. 181. — BHIZOMOKPH. is °nly gnome's treasure at best.
On bringing the supposed prize to
the light, it is found to consist
Photo by]
[E. Step.
Strands of mycelia of the Honey-coloured Mushroom (Ar-
millaria mellea), which has often been observed to give out
light.
THE DESCENDING SAP
145
Photo by]
FIG. 182. — TBEE-DESTBOYING MUSHROOMS.
[E. Step,
Their rhizomorphs or mycelia ascend the tree beneath the bark and cause destruction of its tissues. The species
represented are the Sulphur-tuft (Hypholoma fasciculare) and the Honey-coloured Mushroom (Armillaria mellea).
of nothing but lustreless earth and yellowish grey fragments of stone,
dotted over with tiny, dull green, feather-like Moss-plants (fig. 178), as well
as with multitudes of delicate branching threads, which are simply more
Moss-plantSj but in an earlier stage of development. It is from these slender
filaments — or, rather, from the spherical and microscopic cells at the ends
of their branches — that these deceptive and beautiful scintillations arise.
In fact, the little semi-transparent globes, each of which contains a few
grains of chlorophyll, act like the lenses of a cat's eye, refracting the
scanty incident light where it strikes the globes, and producing a bright
disc on each as the result (fig. 179). By this means the light is concen-
trated on those places where the chlorophyll is situated, and, in spite of
the surrounding gloom, the granules are able to discharge their special
functions in an entirely efficient manner. The nama of this very curious
luminous Moss is Schistostega osmundacea.
There are other Mosses (e.g. Hooker ia splendens) which exhibit the same
phenomenon, though in a less marked degree ; nor are these special
organizations confined to the Musci. They are to be found in many of the
Sea-wracks and other submarine plants ; though the deep-sea Algae are more
often distinguished by an optical phenomenon of another kind. The popular
13
146
HUTCHINSON'S POPULAR BOTANY
idea that as you descend deeper and deeper into the ocean, and the light
of day vanishes, a fiery yellow first succeeds, then a flaming red (the
"watery sea-hell" of Schleiden), then dark crimsons and purples, and
finally an impenetrable black, is partially, though not entirely, correct ; and
the circumstance has an important bearing on our present inquiry. Strictly
speaking, the colour of sea-water — in reflected as well as in direct light, and
at all depths where the light can reach it — is blue, a fact which is scien-
tifically accounted for by the high refrangibility of blue rays, which
enables them to pass easily
through the water, while the
red, orange, and yellow rays,
which are far less refrangible,
are absorbed. Yet red and
yellow rays are absolutely
essential to plants contain-
ing chlorophyll if carbo-
hydrates are to be formed
and life and growth main-
tained * ; and the question
naturally arises, How do the
deep-sea Algce, which are
deprived of all but the blue
rays, compensate themselves
for this deprivation ? The
answer to the question affords
a striking instance of the
resourcefulness of ^Nature.
No marine plants inhabit
a deeper zone than the
Floridece or Eed Seaweeds,
and it is b}^ means of
the pigment which gives
them that colour that the
deficiency is remedied. This
pigment, which is known
as phyco-erythrin (Greek phukos, seaweed ; eruthros, red), is fluorescent in a
high degree, and has the remarkable property of changing the blue rays
which visit the plant into yellow, orange, and red ones; so that the
chlorophyll granules contained in the underlying tissues are enabled to
carry on their functions in a regular manner, decomposing carbon dioxide
and forming organic substances just as do the green Algce which float
uptfn the surface of the water. In fact, the arrangement is quite as perfect
and efficient as is the lens arrangement in luminous Mosses.
* The blue rays are said to be actually destructive of vegetable protoplasm.
Photo by] [E. Step.
FIG. 183. — HONEY-COLOURED MUSHROOM.
A couple of examples of this fungus from the group shown in fig.
182, but here photographed natural size.
FIG. 184. — LUMINOUS MUSHROOMS.
aong them the European Agaricus olearius — have long been known to give out light in the darkness.
147
148
HUTCHINSON'S POPULAR BOTANY
We come now to the Fungi. Here we meet at once with examples of
luminosity which are undoubtedly due to phosphorescence. Phosphorescent
Fungi are abundant, for instance, in the coal-mines of Dresden, where they
are even said to be dazzling to the eye. Hanging in festoons and pendants
from the uneven roofs, twisting root-like round the pillars and covering the
walls, they give to these otherwise dreary excavations the semblance of
fairy palaces. " I saw the luminous plants here in wonderful beauty,"
says Mr. Erdman, a Commissioner of Mines, " and the impression produced
by the spectacle I shall never forget. It appeared, on descending into the
mine, as if we were entering an enchanted castle. ' The abundance of
those plants was so great, that the roof and the walls and pillars
were entirely covered with them, and the beautiful light they cast
around almost dazzled the eye. The light they give out is like faint
moonshine, so that two persons near each other could readily distinguish
their bodies."
These spreading masses of luminous vegetable matter were formerly
looked upon as a distinct species of Fungus, and were classed with a few
others of similar root-like form in the group Rhizomorpha ; but they
.-
Photo by]
FIG. 185. — THE CHANNELLED WHACK (Pelvetia canaliculate).
[E. Step.
A brown seaweed tha
tide. On many
that grows profusely on the rocks between tide-marks, and twice a day is left dry by the receding
of the higher rocks it is completely dried up by the sun during the period of low water,
but fully recovers on the return of the tide.
THE DESCENDING SAP
149
are now
known to
be simply
the my-
celi a of
various
species of
Agari c,
the large
fungi to
which our
c o mmon
edible
Mushroom
b el ongs.
A small
portion of
one of
these rhiz-
omorphs,
with the
mushroom
which is
its fruit,
or spore-
bearing body (sporophore), is shown in figs. 181 and 183. The phosphores-
cence of the rhizomorph is said to be due to slow decay and oxidation,
either in the mycelia or fructification of the Fungi; and Sir Joseph
Hooker found that alcohol, heat, and dryness soon dissipate it. That
eminent botanist frequently saw the luminous mycelia in the dead wood
used for fuel by the natives of Northern India, and has furnished
some remarks on the subject in his interesting and informing Himalayan
Journals.
Ayaricus olearius, a Fungus common in the South of France, is also
highly luminous. It grows in the dark crevices of the Olive-stems in
November and December, when the gills under the pileus or cap are said to
shine as brightly as a glow-worm. It has been proved to emit light only
when alive. Under experiment it has been found to cease to do so at once
when deprived of oxygen. Equally remarkable is the Brazilian . species of
phosphorescent Agaricus (A. gardneri) — a parasite on the Pintado Palm —
the light of which is of a pale greenish hue, and equals in brilliancy that of
the larger fire-flies ; while Borneo can boast a closely allied species, also
parasitical on trees, the greenish luminous glow of which has been likened
to the glow of the electric discharge. Australia appears to be exceptionally
FIG. 186 — A MYXOGASTER.
One of these little-known but wonderful organisms (Brejeldia maxima) is here shown in the plasmodium
tage, when it has the appearance and consistency of cream. At a later stage it gathers into cushion-
" ion the ] "
with a purple-brown crust, under whi<
plasmodium breaks up into dust-like spores.
150
HUTCHINSON'S POPULAR BOTANY
rich in these fairy lamps, most of which belong to the same great genus,
Agaricus, though the prevailing colour of their light is white. One species,
found by Drummond in the valley of the Swan River, deserves particular
mention, if only on account of its size and weight. It measured sixteen
inches in diameter and a foot in height, and weighed about five pounds.
Even these statements, however, are eclipsed by the account of the Spruce
log which the Rev. M. J. Berkeley saw, and which was literally ablaze on
the inside with the white plasmodium of some unidentified species of Myxo-
gaster* When some of the luminous matter was " wrapped in five folds of
paper, the light penetrated through
all the folds on either side as brightly
as if the specimen was exposed," albeit
the luminosity had been already going
on for three days !
M. Tulasne, who made some careful
experiments in vegetable phosphor-
escence, found that the light from
luminous Fungi was extinguished in
vacuo or non-respirable gases, and
from this he inferred that " it is due
to a slow combustion without heat,
arising from a chemical combination
of the oxygen of the atmosphere, in-
haled by the Fungus, with a substance
peculiar to the plant."
Whether this is the true explana-
tion of the phenomenon, we do not
pretend to say, and those who may
desire to pursue their inquiries on the
subject will do well to consult the
learned paper by M. Tulasne in Ann.
des Sci. Nat. (1848), or Dr. Phipsori's
little book on Phosphorescence, in which
has been brought together. Neverthe-
less, we think it has been pretty clearly demonstrated that luminosity
in the lower plants is connected almost exclusively with one or other
of those two important functions, assimilation and respiration — the former
in the case of cave-growing Mosses and deep-sea Algce; the latter in
the case of certain Fungi which lodge their spores in decaying wood ;
whereas the luminosity which has been observed in the higher plants,
and which appears to be confined to white, yellow, orange, and scarlet
* The Myxogasters appear as small incrustations on dead leaves and twigs, and vary in
colour from black to bright orange. They form an anomalous group of Fungi, or as some say
of Protozoa, low forms of animal life.
Fia. 187. — MISTLETOE (Viscum album).
Leaves, buds and fruit are here shown. A photograph
of a larger portion of the plant will be found on page
36 (fig. 59).
much curious information
[£. Step.
FIG. 188. — TALL BROOMEAPE (Orobanche elatior).
The Broomrapes are a remarkable genus of plants that are parasitic upon the roots of other plants, from which
they obtain all their nourishment. Having no use for leaves, these are reduced to thin dry scales. This is our
tallest species, and about three feet in height. It is parasitic upon the roots of Hardheads (Centaurea scabiosa).
EUROPE, X. ASIA.
151
152
HUTCHINSON'S POPULAR BOTANY
flowers, is presumably due to electrical conditions of the atmosphere,
and, in that case, it ought perhaps to be classed among abnormal
phenomena.
But it is time to conclude this long digression, and to return to our more
immediate subject — the sap of plants.
The true sap, which conveys the elaborated food material from the
leaves to the root, etc., is very different from the crude, thin, watery sap
which ascends from the root to the leaves.
A curious fact, illustrative of this differ-
ence, is, that the latte'r is nearly or quite
harmless in those plants whose proper
juices have the most virulent properties.
Thus, according to Carpenter, "the in-
habitants of the Canary Islands draw off
the ascending sap, which serves as a
refreshing drink, from the interior of
the stem of Euphorbia canariensis, a tree
of which the descending sap is of a very
acrid nature, resembling that of the
Common Spurge (E. peplus) of this
country, but much 'more powerful." It is
important to bear this distinction clearly
in mind. The crude sap ascends, as we
had seen, chiefly by way of the wood
elements of the vascular system ; while
the elaborated sap, avoiding the wood
elements, passes down the sieve-tubes,
the cellular tissues of the bark,* and,
possibly, the laticiferous vessels, though
it is now a question whether the latter
play an important part as distributors.
Thus we have an ascending and a de-
scending, a crude and an elaborated sap,
and each pursuing independent routes
through quite distinct parts of the plant.
When the experiment has been tried of
removing a ring of bark from a tree —
* The elaborated sap containing the nitrogenous
organic substances (i.e. the soluble results of proteid
FIG. 189.-GKEATEK DODDEK conversion) descends by way of the sieve-tubes,
(Cuscuta europcea). and> P^haps, the laticiferous vessels, while that
containing the non-nitrogenous organic substances-
A twining leafless parasite that commences growth . . , , {• . .
in the earth, but soon attaches itself to its victim (sugar, etc.) passes downwards through the par-
by suckers, and then gives up its roots. enchyma.
THE DESCENDING SAP
153
say, an Oak or Elm — growth below the
ring has almost immediately ceased,
conclusively showing that the flow of
assimilated nutrient sap to that part of
the stem has also ceased, and therefore
that the way of the sap's descent is the
bark. A branch of an ordinary fruit-tree
may be made to bear specially fine fruit
simply by binding it tightly with a ring of
stout wire ; for by this means the down-
ward flow of elaborated sap is checked,
and the fruit gets the benefit of all the
food produced by the leaves of the branch.
The fact is well known to gardeners, and
much of the prize fruit shown at exhibi-
tions is produced in this way. The upward
flow of crude sap of course goes on with-
out interruption through the uninjured
wood-vessels ; and thus the leaves above
the ring are duly supplied with raw
material from the soil, out of which to
elaborate new descending sap.
Plants which have neither leaves nor
roots are of course unable either to draw
up a supply of crude sap or to elaborate
the juices required to sustain life. They
therefore resort to nefarious practices, and
live, like ' the feudal barons in the days of
King Stephen, by plundering their neigh-
bours. Of this sort are the Dodders
(Cuscuta), the Broomrapes (Orobanche), the
Balanophorales, the Rafflesiales, and a
great many more of the plants so well
named parasites. We will say nothing of
the Mistletoe (Viscum album), which is,
comparatively speaking, a mild offender,
and, moreover, possesses true leaves (fig. 187). The germination of the
Dodder (fig. 189) is effected, like that of plants in "general, in the earth,
and without requiring the presence of other plants. The embryo —
which, unlike the embryos of most Flowering Plants, has no external
reserve of food material to feed upon — is nourished, in its first develpment,
at the expense of the albuminous matter within itself. The slender and
elementary root pushes its way into the earth, and the young, red, thread-
. like stem rises above it. If it^finds no other living plant near it, it dies ;
Photo by] [E. Step.
FIG. 190. — LARGE BBOOMBAPE
(Orobanche major).
Parasitic chiefly on roots of Furze and Broom.
Grows to a height of two feet. EUROPE,
N. AFRICA.
154
HUTCHINSON'S POPULAR BOTANY
but should it succeed in finding one, it surrounds the stem, and from the
points of contact proceed suckers which contain conducting tissue, and this
tissue attaches itself to the conducting tissue of the host, and sucks the
juices which the host has elaborated. Then the root of the Dodder becomes
obliterated, and dies, and henceforth the plant lives by its suckers alone.
"Whilst it was not a parasite," says the eminent French botanist, De
Candolle, " it rose vertically ; as soon as it became one, it was no longer
tempted to direct itself either vertically or towards the light. Its shoots
dart from one plant to another, and thus are conveyed to new victims
when the old ones are exhausted. Often the seeds germinate before they
FIG. 191. — Rafflesia arnoldi.
Except for its hidden roots which permeate its victim, there is nothing but this enormous flower — thr
and the largest blossom known. It is found in the forests of SUMATRA.
feet across,
quit the capsules, and the new plant immediately becomes a parasite ;
this is particularly observed in the Cuscuta monogyna, which attacks the
Vines in Languedoc." *
Fig. 189 shows the Greater Dodder (C. europcea), which Gerarde describes
as " a strange herbe, altogether without leaves or roote, like unto threds,
very much snarled or wrapped together confusedly, winding itselfe about
bushes and hedges, and sundrie kindes of herbes." This species is very
partial to the Hop-plant (Ilumulus). Other species attack the Flax-plant
(Linum usitatissimum). Clover (Trifolium), Thyme (Thymus), and Furze or
Gorse (Ulex europceus).
* Cyclopaedia of Natural History, vol. ii. p. 262.
a.nt/4 ••
"v • --
W/mmF^x
mm^s&£
^m . w- • ^ ^ 7 f ^JK. fp m. r 0 v,' .S i '/» •* ' *»^ J
IP fM^g
•Jv.,,, Ji?i$V
' - ' '"
FIQ. 192. — LESSER BKOOMBAPE (Orobanche minor).
Parasitic on the roots of various plants, especially Clovers. The stems are more slender and the flowers less
crowded than in the other species.
155
156
HUTCHINSON'S POPULAR BOTANY
In the meek garb of modest worth disguised,
The eye averted and the smile chastised,
With sly approach they spread their dangerous charms,
And round their victim wind their wiry arms.
The Broom-rapes (Orobanche), which are marked
by the absence of chlorophyll, carry on their
thievish practices underground by fastening on the
roots of trees and shrubs, so that when they rise
above the soil, and put forth their spikes of dingy
flowers, only the instructed botanist would suspect
them of the crimes which lie at their door. The
Balanophorales and Bafflesiales, which embrace
some seven or eight families, are also destitute of
chlorophyll, and support themselves in much the
same way as the Broom-rapes, by becoming parasitic
on the roots of green-leaved woody plants. They
belong chiefly to the tropical parts of Asia and
America ; but a few species are found in South
Africa, and two or three belong to Australia and
the Mediterranean area. The last-named group (the
Rafflesiales) includes that vegetable wonder,
Rafflesia arnoldi, the largest flower in the world,
of which we must give some account (fig. 191).
The plant was discovered about ninety years
ago by Dr. Arnold, a botanist of some note, while
exploring with Sir Stamford Raffles' party in the
interior of the island of Sumatra. The news of
the discovery was conveyed by Dr. Arnold in a
letter to a friend, and it will be better to quote
from his account than to give the facts in words of our own. The
doctor says: "Here [at Pulo Lebbas, on the Manna River, two days'
journey inland of Manna], I rejoice to tell you, I happened to meet with,
what I regard as the greatest prodigy of the vegetable world. I had
ventured some way from the party, when one of the Malay servants came
running to me with wonder in his eyes, and said : ' Come with me, sir,
come ! A flower — very large — beautiful — wonderful ! ' I immediately went
with the man about a hundred yards into the jungle, and he pointed to a
flower growing close to the ground, under the bushes, which was truly
astonishing. My first impulse was to cut it up and carry it to the hut.
I therefore seized the Malay's parang (a sort of instrument like a wood-
man's chopping hook), and finding that the flower sprang from a small root
which ran horizontally (about as large as two fingers or a little more), I
soon detached it, and removed it to our hut. To tell you the truth, had I
been alone, and had there been no witnesses, I should, I think, have been
FIG. 193. — Cordyceps
sphecocephala.
A West Indian fungus that attacks
insects, especially a large species
of wasp (Polities) here shown to
have succumbed to the attack.
THE DESCENDING SAP
157
fearful of mentioning the dimensions of this flower, so much does it exceed
every flower I have ever seen or heard of; but I had Sir Stamford and
Lady Baffles with me, and a Mr. Palsgrave, a respectable man, resident at
Manna, who, though all of them equally aston-
ished with myself, yet are able to testify as to
the truth.
" The whole flower was of a very thick sub-
stance, the petals and nectary being in but few
places less than a quarter of an inch thick, and
in some places three-quarters of an inch ; the sub-
stance of it was very succulent. When I first saw
it, swarms of flies were hovering over the mouth
of the nectary, and apparently laying their eggs
in the substance of it. It had precisely the smell
of tainted beef. The calyx consisted of several
roundish, dark brown, concave leaves, which
seemed to be indefinite in number, and were un-
equal in size. There were five petals attached to
the nectary, which were thick, and covered with
protuberances of a yellowish white, varying in
size, the interstices being of a brick-red colour.
. . . Now for the dimensions, which are the most
astonishing part of the flower. It measures a full
yard across, the petals being twelve inches from
the base to the apex, and the space between the
insertion of one petal and the opposite one being
about a foot. Sir Stamford, Lady Baffles, and
myself took immediate measures to be accurate
in this respect, by pinning four large sheets of
paper together, and cutting them to the precise
size of the flower. The nectarium [or hollow
central bowl of the flower] would, in the opinion
of all of us, hold twelve pints, and the weight of
this prodigy we calculated to be fifteen pounds."
The plant grows parasitically on the roots of a
species of Vine (Ciss'iis), and consists, besides this
remarkable flower, of a mycelium-like tissue.
The Cuscutas and the Orobanches, the Bala-
nophorales and the Bafflesiales, by no means ex-
haust the list of vegetable parasites. There are
the Fungi, that comprehensive group in which
are included not only most of the mildews, rusts,
smuts, blights, etc., whose pernicious ways are
unpleasantly familiar to farmers, nurserymen, and
robert
158
HUTCHINSON'S POPULAR BOTANY
fruit-growers, but also that singular genus the Cordyceps^ several species
of which are parasitical upon insects, spiders, and their allies. Fig. 193
shows a West Indian Cordyceps (C. sphecocephala), which attacks a species
of Polistes or wasp. The wasps may frequently be seen flying about with
plants of their own length projecting from their bodies. Other well-known
species of the same family are Cordyceps entomorrhiza and militaris, which
sow themselves in — and derive their nourishment from — the bodies of larvae
or pupae buried in the soil or among dead leaves. A New Zealand species,
C. rcbertsii, popularly known as the "Vegetable Caterpillar," sometimes
reaches a height of eight inches (fig. 194).
In reviewing the ground traversed in this and the preceding chapter,
Photo by] IE. Step.
FIG. 195. — SXAKE'S-TONGUE FUNGUS (Cordyceps ophioglossoides).
This Cordyceps attacks another fungus — the Hart Truffle (Elaphomyces variegatus) — in our pine-woods.
we think it will be conceded that the analogy between the economy
of the Vegetable and a well-regulated household has been sufficiently
established. We have observed the admirable manner in which the
multitudinous cells and vessels perform their allotted functions in
the general scheme, and the harmony of action which exists between the
several parts. We have seen how certain organs pump up the required
water, and others carry it ; how some are employed in getting rid of the
waste, while others elaborate the nutrient material, and others, again,
distribute the elaborated food through the plant, or store up the superfluity
for future use.
Such, in brief, is the economy of the Plant. We have but touched the
fringe of the subject ; but what a subject it is ! How vast and inexhaus-
tible ! How incomprehensible and fathomless !
Photo by]
FIG. 196. — THE CLUBBED CORDYCEPS (Cordyceps capitata).
IE. Step.
This is a much larger species with stouter head (spore masses). Like the Snake's-tongue, it is a parasite upon
another species of Hart Truffle (Klaphomyces granulalus), a subterranean fungus of spherical form that would be
difficult to find but for the presence of the Cordyceps above ground,
159
CHAPTER VI
SEED AND ROOT
Then rise the tender germs, upstarting quick
And spreading wide their spongy lobes, at first
Pale, wan, and livid ; but assuming soon,
If fanned by balmy and nutritious air,*
A vivid green. COWPER.
" r MHE nature of everything," says Lord Bacon, " is best considered in
-*- the seed" — an aphorism which contains a truth of very wide
application, though it is only quoted here because the first part of our
subject is the seeds of plants. That the nature of the Plant is best
seen in the seed is a truism which perhaps every physiologist would be
willing to admit, and we shall probably be as ready to make a similar
admission after weighing a few of the facts with which it is proposed
immediately to deal.
When the reign of the Frost-spirit is over, and the earth is brought
once more under the mild and vivifying influence of the spring, a large
proportion of the seeds confided to the ground, either recently or at the
end of the preceding autumn, swell, and release from their envelopes the
precious germs which they have held in ward during the intervening
months, and which, endowed with a life of their own, soon imbibe freely
their nutriment from the atmosphere and the soil. Such is, in essence, the
phenomenon of germination, the simplicity of which is perhaps not less
wonderful than the results achieved are manifold and surprising. We say
" in essence," for when we come to consider the phenomenon in detail, a
surprising variety confronts us. Let us consider a few examples.
The majority of Fungi are propagated by minute dust-like spores, which
_ differ from seeds in containing no
embryo or young plant, but simply a
^T^"X tiny mass of living matter. Kick a
^•pr ripe puff-ball — the dusty powder that
flies out consists of thousands of these
spores. Or if we select as our type
the Common Mushroom (Agaric as carn,-
FIG. 197. — MOREL (Morchella esculenta).
A spore of this edible fungus, and another in process The Poet miSht h^e added, " And fostered
of germination. by the light-dispensing sun."
160
VARIKGATRD ADAMIA (Mania eerricolor).
shrubs, members of the Saxifrage family, and near allies of the Hydrangeas. The spe
beautiful of the (terms. At first the unopened buds are nearly white, then become nli
fully-opened flower i- purple and violet. It is a native of China.
Kiired is
diile the
SEED AND ROOT
161
Photo by]
FIG. 198. — COMMON MUSHROOM ( Agaricua campestris).
[E. Step.
The mushroom is not the fungus but its fructification, the plates or gills under the cap (ptteus) producing millions of
microscopic spores which have the power under suitable conditions of reproducing the thread-like mycelium which is
the working stage of the fungus. About one-fourth of the natural size.
pestrix, fig. 198), the spores are borne on the under side of the frail
umbrella-like cap (the pileus) on minute stalks. A powerful microscope
is needed to examine them, as individually they are quite invisible to the
naked eye. When these spores fall to the ground they begin to swell,
and presently put out cellular threads of wonderful tenuity, which grow
and branch, and continue growing and branching, till they form a beauti-
ful white flocculent mass — the " Mushroom spawn " of our markets — from
which new Mushrooms may be raised. Thus the spore does not develop
at once into a perfect Mushroom, with thick stem and spreading disc-
shaped fructification; there are two distinct stages of development. The
close pile of whitish threads — botanically known as- the 'mycelium— appears
first ; and then, out of the mycelium, arises the fructification or Mush-
room, consisting of stalk and cap. It is important to bear these successive
stages of development in mind.
When demolishing old houses, one frequently finds on the damp rafters
or underneath the planks the mycelia of other Fungi, spreading from a
centre nearly equally in all directions, and so delicate that a breath might
dissipate them; but even in quite new houses one may meet with the
terrible " dry rot" that will soon make havoc with the timber, and reduce
it to tinder. In the species common in woods and meadows, it is the
fructification alone which attracts our notice. In the latter case, indeed,
14
162 HUTCHINSON'S POPULAR BOTANY
the mycelia are for the most part hidden, either in the soil or in the bark
of trees ; while the fruit-bearing organs assume the brightest colours, and
flaunt themselves with gay effrontery. They appear in all conceivable
forms (figs. 199-201), graceful and grotesque, elaborate and simple, geo-
metrical and irregular. You may meet with them as cups and bottles, as
horns and trumpets, as umbrellas and canopies, as finger-rings and strings
of beads, as eggs and egg-cups, as globes and discs, as solid leathery lumps
Photo by] [£. 8tept
FIG. 199. — EARTH-BALL FUNGUS (Scleroderma vulgare).
Often mistaken for a Puff-ball or even Truffle. The skin is thick and the contents at first a hard blue-black mass,
which ultimately breaks up into minute spores, which are set free by the rupture of the corky shell. In this condition
it is known as the Devil's Snuff-box. Odour strong and unpleasant. The upper example is cut through to show
interior.
and hollow spherical cages ; and the wonder excited by this inexhaustible
variety of forms is not lessened when we remember that the beginning of
each was a tiny spore, smaller than the dust-motes that gyrate in the sun.
With this brief glance at the development of a Fungus spore, let us
take a forward step, and consider, with equal brevity, the round of life
in one of the Mosses. The Mosses (Musci) contain chlorophyll, and there-
fore occupy a more important position in the Vegetable World than the
'Photo by] [S. Si
FIG. 200. — THE GLITTERING TOADSTOOL (Coprinus micaceus).
All the Coprini are very fragile fungi, rapidly melting soon after they come to maturity. Their black spores are
distributed in the form of ink. The Glittering Toadstool is so called because it is sprinkled with minute specks which
reflect the light, and look as though the cap had been dusted with powdered mica.
163
164
HUTCHINSON'S POPULAR BOTANY
Fungi; they form, indeed, a sort of link between the higher and lower
plants. When one of the microscopic spores ejected by an adult Moss-
plant has fallen into congenial soil, and begins to germinate, its innermost
coat (for it is double-coated) protrudes, and develops into thread-like branch-
ing filaments (the protonema), recalling the mycelia of Fungi, but dis-
tinguished from mycelia by containing chlorophyll in their cells (fig. 204).
From these filaments arise the leafy shoots of the new, but not yet perfect
Moss-plant, which is botanically known as an oophyte (i.e. egg-plant) ; and
this, when fully de-
veloped, produces the
male and female organs
of the plant — the anthe-
ridium and archegonium,
as they are called — on
the successful discharge
of whose functions future
fructification depends.
In fact, the antheridium
is filled with myriads of
minute spiral bodies
(somewhat analogous to
the pollen of flowers),
which it ejects upon
the archegone, and so
brings about fertilization
(fig. 203). As a result
of this process, we get
the full-grown Moss-
plant, with its urns and
hoods (sporangia and
calyptrcv), as shown in
drawing (fig. 206) ;
urns being full of
new spores — the life-
germs of a future gener-
ation.
Do not think that the simple Moss-plants are undeserving of your
notice. They will well reward the most reverent and painstaking study —
indeed, few objects are so fraught with interest, whether to the microscopist
or the outdoor naturalist. We know the remark is often made, in tones of
careless disparagement : " They are only Mosses ! " But he who speaks
thus lightly has no true sense of the beautiful, and certainly can never have
taken the trouble to examine these delicate organisms. E-uskin's touching
tribute to their lowly ways and tender beauty, which forms one of the choicest
Photo by-]
[E. Step.
FIG. 201. — COMMON MOREL (Morchella esculenta).
the
the
Esteemed by epicur
has been burnt by a
3. It appears in spring, usually on spots where the earth
jipsy fire. The spores are produced on the surface of the
honeycombed head or pileus.
SEED AND EOOT
165
Photo ly] [E. Step.
FIG. 202.— GREATER WATER-MOSS.
Fontinalis antipyretica is found chiefly in running streams, attached
to stones and wood. Very few of the true Mosses are aquatic.
passages in Modern Painters,
might be commended to all
such, and we offer no apology
for quoting the famous pas-
sage : " Meek creatures ! " he
calls them, "the first mercy of
the earth, veiling with hushed
softness its dintless rocks ;
creatures full of pity, covering
with strange and tender honour
the scarred disgrace of ruin,
laying quiet finger on the
trembling stones to teach them
rest. No words, that I know
of, will say what these Mosses
are. None are delicate enough,
none perfect enough, none rich
enough. How is one to tell of
the furred and rounded bosses
of beaming green — the starred
divisions of rubied bloom, fine-
filmed, as if the rock-spirits
could spin porphyry as we do glass — the traceries of intricate silver, the
fingers of amber, lustrous, arborescent, burnished through every fibre into
fitful brightness and glossy traverses of silken change, yet all subdued and
passive, and framed for simplest, sweetest offices of grace ? They will not
be gathered, like the flowers, for chaplet or love-token : but of these the wild
bird will make its nest, and the wearied child his pillow. And as they are
the earth's first mercy, so they are its last gift to us ; when all other service
is in vain, from plant and tree, the soft Mosses and grey Lichen take up
their watch by the headstone. The woods, the blossoms, the gift-bearing
grasses, have done their part for a time ; but these do service for ever.
Trees for the builder's yard, flowers for the bride's chamber, corn for the
granary, moss for the grave."
A still higher scale of Vegetable Life is reached in the Ferns. The
spores of ferns are contained in a capsule or sporange (fig. 207), dense clusters
of which form, when ripe, those brownish patches or incrustations on the
under sides of the fronds, familiarly known as- the " fructification,"
botanically as sori. Each of the brown patches is, in fact, a sorus, and
consists of a dense cluster of sporangia, or spore-containing vessels (fig. 208).
When the spores have escaped from these vessels, and begin to germinate
in the moist earth, they do not put forth delicate filaments like the Fungi
and Mosses, but each produces a small green leafy expansion, which is
known as the prothallus (fig. 209). From the under side of the prothallus
166
HUTCHINSON'S POPULAR BOTANY
slender root-hairs are given off; and along with these, the antheridia and
archegonia — minute organs of reproduction, homologous with, though
simpler in structure than, those of Mosses. It is only when fertilization has
taken place that the egg develops into a new Fern-plant.
Thus far we have confined ourselves to spores, which are the chief means
of multiplication in the lower plants, and which, as already pointed out,
contain no young plant or embryo. Spore-plants have no evident flowers,
and their organs of fructification were
obscure to the early botanists, on which
account they were' called Cryptogams,
or Hidden-marriage plants, from the
Greek kruptos, hidden, and gamos, mar-
riage. They form, indeed, one of the
two great sub-kingdoms into which all
plants are divided ; the other sub-king-
dom comprising the Seed-plants or
Phanerogams (Greek phaneros, evident,
and gamos). To the Spore-plants or
Cryptogams belong the Protophytes
(unicellular forms of vegetable life,
whether containing chlorophyll or not),
Algoa, or Seaweeds, Fungi, Liverworts,
Mosses, Ferns, Horsetails, Club-mosses,
Water-ferns, and Selaginellas ; and to
these we shall revert at greater length
in later chapters ; the Seed-plants or
Phanerogams embrace all the rest.
Bearing in mind what has been said
about spores, let us now observe the
process of germination in true seeds.
On planting a grain of "Wheat or
Barley in suitable soil, the first change
to be noticed is the swelling of the
grain, and this is followed before very
long by the appearance of a root—-
the primary root — and several indepen-
dent root-fibres (fig. 210), the former
dying before it has grown to any
length. The stem, which originates in
what it known as the plumule, appears
later. The plumule is a bud consist-
ing of several leaves on a reduced axis,
FIG. 204. — SPORE AND GERMINATING & . .
SPORE OF A MOSS-PLANT and lts outer sheath, in which the rest
(Gymnostomum ovatum). of the plumule is still enclosed, emerges
FIG. 203. — HAIR-MOSS (Polytrichum
commune).
(a a) Antheridia. (5 6) Hairs and sterile filaments
(paraphyses).
167
168
HUTCHINSON'S POPULAR BOTANY
first. Meanwhile, the root-fibres (which are really adventitious roots pro-
ceeding from the base of the plumule) continue to grow, taking a down-
ward direction, while the stem begins to force its way towards the light
and sun Why the stem should take an upward course, contrary to the
force of gravity, is not known, but the fact is interesting. Our ignorance
of the ultimate causes of many other occurrences quite as common is not
less complete. Why are fluids incapable of resisting a change of shape?
We cannot tell. Why does the earth attract the
bodies on its surface, or the sun attract the earth ?
Still we are at a loss. We are 'familiar with facts,
and are able to deduce what are called physical laws
from them, but of the ultimate causes of the phe-
nomena themselves we know nothing.
On removing a germinating grain of Barley from
the ground, the young stem will be found to be sur-
rounded at its base by a sheath (fig. 210), which is
called the seed-leaf or cotyledon, and which should
be particularly noticed. We shall refer to it again
in a moment. The grain contains starch and gluten,
and remains for some days adhering to the base of
the young plant — a reservoir of nutriment. As
growth proceeds this food supply diminishes, being
conveyed to the seedling and used by it for evolv-
ing new protoplasm and cell-walls ; nor is germina-
tion, properly speaking, at an end till the whole is
used up, and the empty husk loosens from the plant.
The proportions of starch and gluten (gluten, it
should be remembered, is one of the proteids) vary
in the different kinds of plants of the Grass order
(Wheat, Bice, Maize, Millet, etc.), and on these rela-
tive proportions depend the alimentary properties
of the various cereals.
Similar in some respects to the germination of
Barley, though strikingly dissimilar in others, is the
germination of a bean (figs. 212-14). In this case a
primary root, formed by the direct growth and
elongation of the embryo root or radicle, strikes
down into the earth, and gives off lateral branches or secondary roots,
which in their turn may send out a third series of branches, and so on
(fig. 213). Meanwhile, the plumule or young stem, with its bent, yellow-
green tuft, elevates itself above the soil, and straightens as it rises ; while
the tuft itself, expanding under the influence of solar light and heat, is
seen to consist of two perfectly formed leaves— the first foliage leaves of
the plant. Until these leaves are able to take in food from the atmosphere
FIG. 206. — FRUCTIFICA-
TION OF A MOSS-PLANT
(Polytrichum gracile),
In section, showing the two
loculi, or spaces, filled with
SEED AND EOOT
169
and to elaborate starch, etc., for themselves,
the plant is dependent upon the supply
contained in its two seed-lobes or cotyledons,
which, unlike the single cotyledon of a
Barley grain, form the chief substance of
the seed.
The young plants of Mustard (Brassica
alba). Cress (Lepidium), Poppy (Papaver),
etc., which are not thus liberally endowed,
are thrown upon their own resources at a
very early age, and have to work for their
living almost directly they have broken
from their shells. In such cases the cotyle-
dons rise above the ground very soon after
germination has commenced, and at once
perform the functions of true leaves— developing
chlorophyll and taking in carbon dioxide in a
business-like and energetic manner. In this
way the plants are kept alive and vigorous till
ordinary leaves are produced.
By soaking a Bean in warm water for a
short time, the thick double skin or testa, with
which it is surrounded, may be easily removed,
and the two large fleshy lobes, which are the
cotyledons of the embryo, may then be separated
without difficulty, and the plumule and radicle
laid bare (fig. 212). Before stripping the
seed, the small black scar or hilum should be
noticed ; as well as a minute aperture at one
end of it, the micropyle, from which a small
quantity of water may be expressed if the moist
seed be squeezed between the finger and thumb.
When the testa has been removed and the
cotyledons thrown open, the root of the germ-
plant will be seen to be directed towards this
aperture.
On stripping a seed of Maize (Zea mays), a little
examination will show how small a portion of the
seed the single cotyledon occupies. Indeed, when
the whole of the embryo plant, consisting of
plumules, radicle, and cotyledon, has been picked
out of the white floury matter in which it is
embedded, it will be found that the bulk of the
seed remains (figs. 215-217).
FIG. 207.— SPORANGIA OF FERNS.
(a) Maidenhair Fern (Adiantum capillus-veneris),
with spores escaping, (fe) Royal Fern (flsmunda
regalis). (c) Bristle Fern (Trichomanes radicans).
FIG. 208. — ROUND - LEAVED
WOODSIA ( Woodsia hyperborea).
Tart of a frond with five clusters of
sori. Below, a single sorus, consisting
of a cluster of sporangia.
FIG 209. — PROTHALLUS OF
A SPECIES OF MAIDENHAIR
FERN SEEN FROM BELOW.
170
HUTCHINSON'S POPULAR BOTANY
Thus in the one case the embryo forms the entire kernel of the seed ;
and in the other it is surrounded by a mass of albuminous tissue or endo-
sperm, and occupies but a small part of the kernel. On this account, seeds
of the latter kind are called albuminous, while
those which, like the bean, contain no sur-
rounding nutrient matter, are said to be
exalbuminous. The terms are somewhat mis-
leading, however, as the substance contained
in the seed is not identical in chemical com-
position with animal albumen. It has charac-
teristic differences in various plants. Thus it
is mealy or farinaceous in cereals ; fleshy in
the Barberry (Berberis) and Heartsease (Viola) ;
oily in the Poppy (Papaver) and Coconut
(Cocos nucifera) ; mucilaginous in the Mallow
(Malva) • cartilaginous in the berry of the
Coffee-plant (Coffea); and hard and white like
ivory in the Negro's Head Palm (Phytelephas
macrocarpa). The endosperm of this palm
forms the " vegetable ivory " of commerce.
In some seeds a part of the albuminous
substance owes its origin to layers of cells
outside and different from those which produce
the endosperm, and hence it is given the dis-
tinguishing name of perisperm. In seeds of the
Water-lily family (Nymphceacece) , for example,
the embryo plant is embedded in endosperm,
which occupies the narrow end of the seed,
while the rest of the albumen consists of
perisperm. Ripe seeds of the Cannas (Can-
nacece), again, have no endosperm at all,
the whole of the nutrient substance being
perisperm.
For important reasons of classification the
number and position of the cotyledons of seeds
should always be carefully noted. We have
seen that the spores of Fungi, Mosses, Ferns,
and other cryptogamic plants never have
cotyledons— they are not true seeds. We
have also seen that grains of Barley and
those organs, provide but one with each
embryo ; while both the Bean and Mustard seed have ttvo. Therefore,
looked at with reference to the germinating body, the plants above
enumerated are of three kinds : those entirely destitute of cotyledons,
FIG. 210. — A GRAIN OF BARLEY
BEFORE GERMINATION, AND THE
SAME GERMINATING.
Maize, though possessing
Photo by]
FIG. 211. — WHEAT (Triticum vulgar e).
Showing the ears of wheat in various stages of ripeness.
171
[Henry Irving.
172
HUTCHINSON'S POPULAR BOTANY
FIG. 212. — A HARICOT BEAN ON THE SECOND DAY
AFTER PLANTING,
And the same with the cotyledons (c c) laid open to show the plumule (p).
The radicle (r) is partly hidden behind the left-hand cotyledon.
Grass, Rush, Sedge, Palm, Lily, Orchis,
and Arum orders — in fact, the greater
number of plants with parallel-veined
leaves — are Monocotyledons ; while most
plants with net-veined leaves, whose name
is legion, are Dicotyledons. The two great
classes of Flowering Plants (Monocotyledons
and Dicotyledons) have other characteristic
differences, many of which will be found
referred to in succeeding chapters. Thus
or Acotyledons ; those with
only one cotyledon, or
Monocotyledons ; and those
with two cotyledons, or
Dicotyledons. The import-
ance of this classification
will be apparent when it
is added that by far the
greater number of known
plants v fall under one or
another of these three
divisions. Sea-weeds,
Fungi, Liverworts, Mosses,
Ferns, and all other crypto-
gamic plants belong to the
first division — they are
Acotyledons ; plants of the
FIG. 214. — THE SAME WITH THE COTYLEDONS
LAID OPEN.
FIG. 213. — A HARICOT BEAN ON THE
FIFTH DAY AFTER PLANTING,
Showing the plumule breaking its way through
between the cotyledons.
the parts of the flower of a
Monocotyledon are usually
arranged in threes or sixes —
three petals, three sepals, three
stamens, and so on ; while the
floral organs of a Dicotyledon
are generally arranged in fours
or fives. The structure of the
stem in each is also essentially
different.
SEED AND ROOT
173
FIG. 215. — SEED OF MAIZE
(Zea mays).
The testa removed to show the
embryo, consisting of plumule,
radicle, and cotyledon embedded
in mealy perisperm. [Note. — The
embryo has been partly lifted
out from the perisperm in order
to show the several parts more
clearly.]
The seeds of a small number of Flowering
Plants — chiefly parasites, as the Dodder (Cuscuta) —
have no cotyledons ; but these must be regarded as
instances of vegetable degeneration, and such plants
are classed among Phanerogams for other and
sufficient reasons. Young plants of the Fir and
Pine order (Coniferce) sometimes have as many as
twelve or even fifteen seed-leaves, and thus form
a small class by themselves, to which the name
Poly cotyledons has been given, though the term
would hardly be accepted by present-day syste-
matists. Instances have been recorded of Dicoty-
ledons with three cotyledons (!), but such cases are
abnormal, and should be classed among freaks of
nature. Seedling Maples have manifested this
peculiarity, and a speci-
men of a tricotyledonous
Oak may be seen in one of the museums of
economic botany at Kew.
Many curious facts have been discovered
by Darwin with reference to the movements
of plants, and not the least curious are those
which relate to the movements of the cotyle-
dons and roots of seedlings. Of the young
plants which he examined, the cotyledons in
some cases kept up a continuous movement in
a vertical direction ; in others they oscillated
from side to side, the seed-leaves always acting
together— save, indeed, in a solitary instance,
where one cotyledon rose while the other fell, the
plant which exhibited this exceptional movement
being a species of Wood-sorrel.
The young growing rootlets likewise exhibited a
constant slow movement from side to side,* their
tips, which displayed the most exquisite sensitiveness,
enabling them to avoid destruction and threatened
injury, and to feel their way downwards between the
particles of the soil. " A radicle," says Darwin in his
Movements of Plants, " may be compared with a
burrowing animal, such as a mole, which wishes to
penetrate perpendicularly down into the ground. By
continually moving his head from side to side, or
circumnutating, he will feel any stone or other FlG 2i7_THE SAME IN
* The path is really a spiral— a circumnutation. VERTICAL SECTION.
FIG. 216. — MAIZE ON THE FOURTH
DAY OF GERMINATION.
The testa' has been removed.
174
HUTCHINSON'S POPULAR BOTANY
obstacle, as well as any difference in the hardness of the soil, and he will
turn from that side ; if the earth is damper on one than on the other side,
he will turn thitherwards as a better hunting-ground. Nevertheless, after
each interruption, guided by the sense of gravity, he will be able to
recover his downward course, and to burrow to a greater depth."
Note, too, how the sensitiveness of the root and rootlets struck Mr. James
Rod way during his study
of plant life in the forests
of Guiana: "Roots are
undodbtedly able to dis-
tinguish suitable from un-
suitable food, and though
they may be poisoned now
and then, this is nothing
strange, as the same thing
happens to man. Their
sensitive tips go wandering
in every direction, branch-
ing here and there in
search of proper food.
As long as the soil is
uncongenial they press
forward, and only when a
good feast is discovered
do they throw out that
broom-like mass of fibres
so conspicuous on the
banks of rivers and creeks.
A barren subsoil is care-
fully avoided by keeping
to the surface, while in
the rich river bottom the
sour, water-logged alluvion
is equally distasteful. On
the sand-reef the tap-roots
FIG. 218. — MAIZE AT A STILL LATER STAGE,
Showing the primary root which has broken through the coleorhiza (cr).
and two adventitious roots growing from the base of the young stem.
go down fifty feet
more, and spread most
evenly to glean every particle of food contained in the water that has
percolated to these depths. On the mountain, again, every chink and
cranny between the rocks is explored, the roots sometimes .penetrating
through narrow crevices into hollows where water has accumulated, and
spreading their network of fibres over the roof, down the walls, and
into the pools. In some cases it appears as if the roots smell the water at
a distance, and move straight onwards until they reach it. Some epiphytes
IE. Step.
FIG. 219. — HORSE-CHESTXUT (Msculushippocastanum).
The lower branches of a well-clothed tree showing the pyramidal spires of blossom, which are here about one-twelfth of the
actual size. The flowers are white, splashed and spotted with red and yellow. Native of the mountain regions of S.E. EUROPE.
175
176
HUTCHINSON'S POPULAR BOTANY
that push their aerial roots down the trunks of trees in the forest hang them
quite free when above the water, only allowing them to branch out when
they reach the surface. In the first case moisture is obtained from the rain
and the dew as they trickle down the little channels in the bark, while in
the other a reservoir of water is below, and the plant seems to know it."
It is the tip of the root just in advance of the growing point that appears
to possess the intelligence. It seems to know when a stone blocks its pro-
gress that it is no use trying to get through. It turns aside from the obstacle
and goes round it, but persists in pursuing its original direction in spite of
this detour. Darwin compared the root-tip to a brain/
An extremely curious instance of the motiiity of young roots is furnished
by an Indian species of Loranthus, nearly related to the Mistletoe ( Viscum
album), and, like it, a parasite on trees. The fruit contains bird-lime — a
peculiar viscous, tenacious, and elastic substance — and when the berry
loosens from the plant, it
sticks to whatever it falls
upon. The seed is em-
bedded in the viscid pulp,
and germination com-
mences in the following
manner. " The radicle,"
says Mr. N. E. Brown,
': at first grows out, and
when it has grown to
about an inch in length,
it develops upon its ex-
tremity a flattened disc ;
the radicle then curves
about until the disc is
applied to any object that
is near at hand. If the
spot upon which the disc
has fastened is suitable,
the germination continues,
and no locomotion takes
place ; but if the spot
should not be a favourable
one, the germinating em-
bryo has the power of
changing its position.
This is accomplished by
the adhesive radicle rais-
ing the seed anfl advancing
•. . arlrkfV,OT. c^nf r»v fr*
^ co anOtner Spot, Ol, tO
IE. step.
Fio. 220.— RHUBARB (Rheum rhaponticum).
Well known as a kitchen-garden plant whose leaf-stalks are used in tarts,
etc. It is a native of Siberia, whence it was introduced about 350 years ago.
SEED AND ROOT
177
make the process plainer,
the disc at the] end of the
radicle adheres very
tightly to whatever it is
applied to : the radicle
itself straiglitens, and
tears away the viscid
berry from whatever it
has adhered to, and raises
it in the air. The radicle
then again curves, and
the berry is carried by it
to another spot, where it
adheres again. The disc
then releases itself, and
by the curving about of
the radicle is advanced to
another spot, where it
again fixes itself. This,
Dr. Watt says, has been
repeated several times, so
that to a certain extent
the young embryo, still
within the seed, moves
about. It seems to select
certain places in prefer-
ence to others, particularly
leaves. The berries on
falling are almost certain
to alight upon leaves, and
although many germinate
there, they have been observed to move from the leaves to the stem, and
finally fasten there " (Gardener's Chronicle, 1881).
Though the direction of the roots is normally downwards, it would appear
from experiments begun by Colonel Greenwood more than fifty years ago
that they will grow in any direction in which they can find food. The
colonel placed a number of Horse-chestnut seeds in flower-pots, which he
suspended in an inverted position on wirework, and watered the seeds from
above. The main-root which each seed sent down into the air presently
died ; but the branch-roots, which had not taken a downward course, continued
to grow, and the plants nourished. He had thus stumbled upon the fact that
the seedlings of the Horse-chestnut have a primary root whose downward
determination nothing can pervert. This downward root is as peculiar to
the seedling as the seed-leaves are, but the branch-roots will grow in any
15
Photo by] [E. Step.
FIG. 221. — WILD CAKROT (Daucus carota).
One of the most graceful of the smaller Umbelliferous plants. From its
hard, dry, stick-like roots the thick, fleshy garden-carrots have been evolved
by cultivation. EUROPE, X. AFRICA, N. ASIA.
178
HUTCHINSON'S POPULAR BOTANY
direction. The experiment did not end here. For upwards of twenty years
Colonel Greenwood preserved one of the plants in its inverted position,* by
placing it on a flat stone and exchanging the flower-pot, when the branch-
root grew too long for it, for a chimney-pot full of earth ; and so adding
another and another, as occasion required, till the column was seven feet
high. Then he turned the root over a wall
into a similar column of earth on the other
side, thus permitting it to take, for the
first time, a downward direction. When
at last this much-abused organ reached
the ground, the colonel removed both of
the artificial columns ; and the plant, with
a naked, arching root, fourteen feet in
length, was left to its own resources
(Athenceum, 1864).
Seeing that roots are such wonderful —
we had almost said versatile — organs, it
may be interesting to look a little at their
structures. The root-section shown (fig.
224) is that of a young Maple (Acer
campestre). Notice particularly the layers
of rather long cells (a) at the extremity of
the root. These constitute the root-cap.^
and form a sort of protecting shield to
the dense cluster of smaller cells hidden
immediately within the end of the sheath,
which form the growing-point of the root.
All the wear and tear to which these
delicate-growing cells would be subject is
borne by the sturdier root-cap ; while the
growing-point makes some compensation
for the services thus rendered by fabri-
cating new cells for the sheath on its inner
side, as its outlying cells become worn and
withered in the rough pioneer work which
they perform. In the centre of the root
is a bundle containing woody vessels —
the vascular cylinder or stele — which consti-
tutes, in conjunction with the rest of the
vascular system, the mechanism by means of which the crude sap is carried
upwards to the leaves, there to be elaborated into nutrient material. In
nearly every species of plant there is but one of these steles in -each
root, but in a few — chiefly palms— the roots are polystelic. The tissue of
* Inverted as regards the root. t The pileorhiza of some botanists.
FIG. 222. — GERMINATION OF THE
SEED OF A PINE (Pinus).
Photo by]
[Henry Troth.
FIG. 223. — BULBOUS BUTTERCUP (Ranunculus bulbosus).
These plants produce special roots whose office is to draw the stem structure from which they originate down with
them, to prevent their elevation above the surface. The same phenomenon has been observed in the Carrot, Evening
Primrose, Martagon Lily, Monkshood, Dandelion, Daisy, and other plants.
179
180
HUTCHINSON'S POPULAR BOTANY
rather thickened cells (endoderm) surrounding the stele is parenchyma (pm),
which forms a strong padding and hermetically closes the central cylinder,
thus preventing the passage of air while allowing that of water. It is known
as the root-sheath. In most plants with biennial and perennial roots the root-
sheath serves the further purpose of a repository for food material — starch,
fat, sugar, or whatever other supplies may be needed for the next period of
vegetation. Surrounding the tissue is a mass of cells (the cortex) consisting
of thinner-walled parenchyma, in which also reserve materials are deposited ;
and then, last of all, we have the epidermis (e), with its unicellular root-
hairs (/), those delicate organs by which the plant dissolves — and through
which are absorbed — the inorganic substances which constitute, with water,
the crude ascending sap.
As a protection against field-mice, insect larvae, and other underground
animals, many food-storing roots develop poisonous and disagreeable sub-
stances in their tissues, in the way of noxious alkaloids, fretid gum resins,
and other products well known to druggists ; and it has been observed that
such roots are very seldom attacked. Protected roots of this kind will be
found in Soapwort, several species of Gentian (Gentiana punctata, lutea, and
pannonica), as well as of the thick and poisonous main-roots of Monkshood
(Aconitum napellus}, the massive roots of the Rhubarb (Rheum officinale}, and
many Umbeliiferce.
The fact that the root is often a storehouse of nutritious food substances
has an important morphological bearing, almost all departures from a slender
tapering form — at least in the young root —
being chiefly due to it. The Carrot and
Turnip, for example, are simply the primary
roots of Daucus carota and Brassica rapa
swollen up with reserve material (figs.
228-233; see p. 183). These primary or
main roots are known as tap-roots ; though
various qualifying names— such as conical,
fusiform, or spindle-shaped, and napiform
or turnip-shaped—are given, according to
the special form which the tap-root
assumes. Occasionally the tap-root divides
into two or three forks, as in the poisonous
Mandrake (Mandragora officinalis), where
they have a fancied resemblance to the
human form — though this is not the
origin of the name of the plant. In days
of popular ignorance and credulity the
Mandrake was looked upon with super-
FIG. 224,-Roo^criON OF YOUNG stitioug awe by all classes? and itg roots
(Lettering explained in the text.) were said to be endowed with animal
— -re.
SEED AND ROOT
FIG. 225. — VEGETABLE COAST-GUARDS.
Lyme-grass, Sea-sedge, Marram-grass, and Sea-holly are most useful plants on sandy shores, as their roots and under-
ground stems hold the loose sand together, and prevent it being washed away by the sea or driven inland by the wind.
See also fig. 237.
feelings, and to shriek when torn from the earth ! It was, therefore,
accounted dangerous to disturb them.
Fibrous roots are seen in the Grasses, Buttercup (Ranunculus, fig. 223), etc.,
the name being given to branch-roots which are very slender. The fibres
sometimes penetrate to a greater depth than people are inclined to suppose,
particularly when the subsoil is hard and dry, and the plants are needing
more abundant nourishment. Even in rich garden soil the roots of Wheat
(Triticum) have been traced to a perpendicular depth of five or six feet.
This, however, is nothing in comparison with the depth to which some tap-
roots will penetrate. One hundred and ten feet is the computed length of
the tap-root of a Baobab-tree (Adansonia digituta) in Adanson's account of
Senegal ; but this, we need scarcely add, is exceptional. '
In the fibrous roots of many plants we find peculiar swellings and thicken-
ings, which serve (like the different forms of tap-root) as reservoirs of
nutritious matter ; and these may all be described as tuberous roots (fig. 226).
Care must be taken, hoivever, not to confound a tuberous root with a tuber, which
last is not a root at all, but a fleshy underground stem (cf. Chapter VII.).
In Pelargonium triste the tubercles or swellings give the fibres a beaded
182
HUTCHINSON'S POPULAR BOTANY
appearance, and hence the root is described as moniliform or necklace-shaped
(fig. 230) ; while in the Common Dropwort (Spiraea filipendula] the fibres
bear irregularly shaped knobs or nodules towards the ends ; and this kind of
root is distinguished as nodulose (fig. 235). Both forms are fairly common.
A far less frequent form is the annulated (fig. 236), in which the fibre-
expansions have a ring-
like appearance. Of this
we have an excellent ex-
ample in the well-known
Brazilian plant, Cephaelis
ipecacuanha, which yields
the valuable drug of that
name. Ipecacuanha
formed the basis of the
medicine with which the
Dutch physician, Adrien
Helvetius, treated
dysentery so successfully
in the seventeenth
century; and he had
cause to bless the root.
The fame of the cele-
brated medicine spread
to the Court of France,
and Louis XIV. gave the
fortunate doctor a
thousand louis d'ors to
reveal the secret of its
composition.
Testicular and fascicu-
lar roots have also been
looked upon as varieties
of the fibrous form by
some writers ; though
others — certainty with
less reason — have re-
garded them as variations
of the divided form of
tap-root. Perhaps it would be more fitting to place them in a group
by themselves, for they seem rather to form a link between those
classes than to belong exclusively to either. The peculiarity of the
testicular root (fig. 227) is that some — usually two — of its divisions become
fleshy and enlarged so as to form more or less egg-shaped expansions ;
while in the fascicular root the clustered rootlets become swollen along
Photo by]
FIG. 226. — LESSER CELAN
A good example of a plant
storage in them of food matf
[E. Slei
ficaria}.
hose fibrous roots become tuberous by the
terial. One of the earliest and commonest of our
sprin
flowers.
FIGS. 227-235. — SOME FORMS OF ROOTS.
Testicular Root.
Moniliform Root.
Tuberous Root.
Napiform Root.
Thickened Tap-root.
183
Fusiform Boot.
Tuberous Fascicular Root.
Fibrous Root.
Nodulose Root.
184
HUTCHINSON'S POPULAR BOTANY
their length, and look like a bundle of spindle-shaped (fusiform) roots
(fig. 229).
We might tabulate the chief forms of subterraneous roots in the following
manner : —
fl. Conical.
-J2. Fusiform.
' (.3. Napiform.
FIBROUS
BOOTS
"f
1. Non-tuberous.
Tuberous —
a. Moniliforin.
l>. Nodulose.
c. Annulated.
fl. Tuberous Fas-
QUASI- cicular.
FIBROUS-* Tuberous Tes.
ROOTS- I ticular.
Many perennial plants of the rosette type, which like to keep their
leaves flat on the ground to be safe from extirpation by browsing animals,
develop a special set of roots whose function is to pull the plant down into
the soil to counteract the growth of the root-stock, which would lift them
above the proper level. These hauling roots go down into firm soil and
take hold of it ; then by contraction they pull the whole plant down
sufficiently. But how do these special roots
know when the proper level for the root-
stock has been reached ?
Certain plants with spreading fibrous
roots subserve a useful purpose by binding
together the loose sand on the seashore, and
raising those banks which, as in Norfolk,
defend the country from the encroachments
of the sea. Of this sort are the Lyme-grass
(Elymus arenarius), the Sea-sedge (Carex
arenaria), the Marram (Psamma arenaria),
and the beautiful Sea-holly (Eryngium
maritimum).
The Marram, mentioned above, was the
subject of an Act of Parliament in Queen
Elizabeth's time, the purpose of the Act
being to encourage the cultivation of this
grass and prevent its destruction. Its
preservation is still carefully provided for
by the " bank-reeves."
The dunes on the shores of Holland and
Denmark have been an object of care by
the Government for an even longer period
than have the English dunes ; and there,
also, resort is had to the cultivation of
grasses and creeping plants, while burrowing
and grazing animals are rigidly excluded.
FIG. 236.— ANNULATED ROOT OF In certain parts of France and North
Cephaelis ipecacuanha, AND FLOWEK. America, again, similar means for resisting
SEED AND ROOT
185
Pholoby-]
FIG. 237. — SAND-DUNE ON THE SUSSEX COAST.
IE. Step.
This photograph, taken from the landward side, shows how the Marram (Psamma arenaria) holds the loose sand
together. The wind scoops out hollows in the surface where unprotected by this grass ; but the immense bank as a
whole keeps its form and its protective power, owing to the network of underground stems and roots which prevent
any serious shifting, whilst the tough aerial stalks intercept much of the sand that would otherwise blow away.
the encroachments of shifting sands have been extensively employed
for many years ; and the method has been greatly improved upon and
developed.
So far back as 1780, M. Bremontier, an eminent French engineer, devised
the means (first suggested, it is said, by a priest of Mimizon) of fixing the
dunes. The practical value of his theories, which were adopted by the
Government, has been fully established by the experience of a century. An
American savant, Mr. G. B. Emerson, bears this testimony : -1 1 visited, in
1872, the region saved by Bremontier, and examined the work he had done,
and its effects. The whole country, for more than a hundred miles along
the Atlantic coast of Gascony and from four to eighteen>landward, had been
covered with sand-hills. . . . The process of ruin had been going on for
centuries, and some of the sand-hills were hundreds of feet high. In the
midst of this recovered region I stopped a day or two at a beautiful town,
where a hundred thousand persons from Paris and other cities of France,
attracted by the genial climate and the health-giving atmosphere of the pine
forests, had passed the winter. I walked and drove along the sandy roads,
186
HUTCHINSON'S POPULAR BOTANY
visited a monument to Bremontier, erected by his brother, ten miles or more
inland in the redeemed territory, and saw in many places deciduous trees —
oaks, ashes, beeches, and others — growing luxuriously under the protection
of^the pines. One cannot help feeling while enjoying this the justice of our
countryman Marsh, who counted Bremontier, and Eeventloy, who conducted
a similar work in Denmark, as amongst the greatest benefactors of their
race."
Bremontier' s mothod is briefly this : A continuous wooden paling about
four feet high is erected
parallel with the shore-line,
and about a hundred yards
back from high-water mark,
a space an inch wide being
left between the boards.
As the sand is not raised
like dust, but glides along
near the surface, it piles
up in front of the paling,
and passing through the
crevices, is deposited behind.
This goes on till the boards
are buried, when they are
raised one at a time, and
the operation is continued.
By repeating the process
again and again the dune
steadily rises in height and
assumes a slope of from
seven to twelve degrees in
front, and much less on the
land side. On setting the
first fence, tufts of Psamma
arenaria are planted in
front, and in a belt eight
times wider than the
obstacle opposed. These
tufts are in quincunx order, and closer together near the paling. Those
outside stop some of the sand, those farther up stop more, and thus an even
slope of the desired angle is secured and maintained. The tufts are set in
winter, and between them are sown seeds of the same plant, and of Triticum
junceum, Artemisia, Cakile maritima, Scdsola, Ephedra, and other maritime
plants. These grasses, etc., grow upward as they are buried, and thus the sand
is bound together in a fine network of fibres. Then, at a fit time, the surface
is sown broadcast with a mixture of seeds of the Maritime or Cluster Pine
Photo by] IE. Step.
FIG. 238. — SEA-HOLLY (Eryngium maritimum).
An Umbelliferous plant with blue flowers and leathery, spiny leaves
that helps to keep the sea-shore sands from shifting.
m&-..
.
/i
•
* :/.".' "• %; V ' -"
P*olo6y] LE.Sttp.
FIG. 239. — BROOM (Cytisus scoparius).
A valuable wild shrub with pliant stems and beautiful bright yellow flowers. It grows upon poor 'sandy soils. to wh|ch,
, with the aid of the nitrifying bacteria on its roots, it imparts a considerable amount of fertility
CANARIES, ETC.
187
188
HUTCHINSON'S POPULAR BOTANY
(Pinus pinaster), the Common
Broom (Cytisus scoparius\
Dwarf Furze ( Ulex nanus) and
Marram (Psamma arenaria).
These sprout and come up
together, the tender shoots
of the pine growing well
when screened by the other
plants. Thus the land is
saved.
The planting of the same
grass on the dunes of Cape
Cod, in the State of New
York, has been practised
since colonial days ; and
similar conservative measures
were ordered by law upon
the beaches of Long Island
as early as 1758. On the
Florida coast, the Bermuda-
grass (Cynodon dactylori) has
been successfully used in
fixing loose sands. Its roots
creep to a great distance,
with short nattish leaves,
sending up flowering shoots
a few inches high at intervals,
which bear seed and spread.
It runs over the sand in zig-
zag form, with joints at each
angle six or eight inches apart, from each of which a root strikes into
the ground, soon forming a most effectual network of roots through the
loosest sand.
Roots which issue from the stem, as distinguished from those which
result from the development of the radicle, are spoken of as adventitious.
We have seen that the roots of Barley are of this description, and it is
noteworthy that the greater number of Monocotyledons exhibit the same
kind of growth. The well-known Pandanus-trees or Screw-pines, of which
there are many species, are remarkable for their adventitious roots, which
continue to be given off by the stem long after it has appeared above the
ground (p. 242). These aerial roots, which are furnished at their extremities
with special cup-like root-caps in which to catch the rain and dew, grow
downwards in the air till they reach the ground, when the cups fall oif, and
the denuded organs proceed to act in the ordinary manner of underground
Photo by] IE. Step.
FIG. 240. — FURZE ( Ulex europceus).
A stiff spiny shrub, often confused with Broom, and sharing the
useful fertilizing properties of that plant, but more catholic as
regards the soils it grows upon. Except in the seedling stage it has
no leaves, which have all been converted into spines. EUROPE,
CANARIES, AZORES.
SEED AND EOOT
189
roots. The slender-stemmed plant, which is often top-heavy with its
massive crown of leaves, derives welcome support from this very curious
arrangement.
As incidental reference has just been made to aerial roots, perhaps this
is the most fitting place to offer what little we have to say about those
interesting organs.
Plants which grow within the inter-tropical regions show a very
conspicuous tendency to develop roots above-ground ; and the phenomenon
is not confined to one family or order, but has been observed in plants very
far removed from one another in the system of Nature. Moreover, the
objects for which such roots are produced may vary greatly. Thus, some
roots (like those of the Pandanus-trees just mentioned) answer the purpose
of supports. The Paxiuba (Iriartea), a tall, erect, smooth-stemmed Palm
with a large crown of curiously cut leaves, found in the Amazon region, is
remarkable on this account. " Its great singularity," says Dr. Wallace, " is
that the greater part of its roots are above-ground, and they successively
die away, fresh ones springing out of the stem higher up, so that the whole
tree is supported on three or four stout straight roots, sometimes so high
that a person can stand between them
with the lofty tree growing over his
head. The main-roots often diverge
again before they reach the ground,
each into three or more smaller ones,
not an inch each in diameter. Though
the stem of the tree is quite smooth,
the roots are thickly covered with large
tuberculous prickles. Numbers of small
trees of a few feet high grow all around,
each standing on spreading legs, a
miniature copy of its parent."
Then there are feeding aerial roots.
A large number of tropical Orchids,
epiphytic on old trees, besides possess-
ing naked air-roots which subserve the
purpose of attachment, have others
which are modified for the absorption
of nutriment from the surrounding
atmosphere — indeed, in a few cases
the Orchid has no green leaves (e.g.
Polyrhiza) ; the roots do everything.
These modified roots hang down from
the stem or branch of the tree to
which the plant is anchored, in white
thread-like bunches, the whiteness
Photo by] IE. Step.
FIG. 241. — PINE CONE.
A cone of the Cluster Pine (Piniis pinaster), a tree
that has been of great value in reclaiming land from
the sea. One-half the natural size.
190
HUTCHINSON'S POPULAR BOTANY
being due to a papery membrane which envelops the green chlorophyll-
containing cells of the true roots. This covering is composed of perforated
cells, and acts like a sponge. " "When it comes in contact with water in
the liquid state," says Kerner, ': or more especially when it is moistened
by atmospheric deposits, it imbibes instantaneously its fill of water. The
deeper-lying living green cells of the root are thus surrounded by a fluid
envelope and are able to obtain from it as much water as they require."
Moreover, this porous tissue possesses
the power of condensing aqueous
vapours and other gases ; so that a
Tree-orchid is absolutely independ-
ent of its host for nourishment.
It will be evident from the above
facts that the papery envelope has
a twofold use. In the dry season it
reinforces the safeguards provided
by the root against too profuse
transpiration on the part of the
living green cells in the interior;
" and in the wet season," as Kerner
remarks, " it provides for the con-
tinuous supply of the requisite
quantity of water." The air-roots
of many Aroids and Tree-ferns
answer much the same purpose;
but this is not the case with the
peg-like aerial roots of Ivy (Hedera
helix), which are simply intended for
mechanical support. The nourish-
ment required by the Ivy is obtained
in an entirely honourable manner
by its leaves and underground
roots ; and the rather rough treat-
ment which the plant has received
from some writers on account of its
supposed parasitical tendencies is,
to say the least, unfortunate. One poet charges it with having " hid the
princely trunk, and sucked the verdure out on't " ; but the ''prejudice on
which the accusation is based has no foundation in fact.
The aerial roots of Ivy are, in short, an arrangement by means of which
the plant clings and climbs ; and though it is doubtless true that they
penetrate into the bark of trees, their object is not plunder, but the obtaining
a more secure anchorage. But on the other side, it must be admitted
that many a fine tree is killed by the Ivy robbing it of light and air —
FIG. 242. — SCKEW-PINE (Pandanus utilis).
A native of Madagascar, whose aerial roots have cup-shaped
extremities. From its saw-edged leaves are made sugar-
bags and the familiar " mats " used by fishmongers and
poulterers. Height about sixty feet.
Photo 6y]
[E. Step.
FIG. 243. — IVY (Hedera helix) DESTROYING OAK (Quercus robur).
The Ivy, whose thick stem is here seen twining around the trunk of the Oak, is innocent until it has reached the upper
branches of its host. Then, by developing numerous bush-like branches, it shuts out the light and air, and starves
the Oak. Many a fine tree is killed in this manner, owing to the neglect of a little care in our woods.
191
192
HUTCHINSON'S POPULAR BOTANY
smothering it, in fact, by its profuse branching when it has reached the top
of the tree.
Of plants which attain to the dignity of trees, none perhaps exhibits
stich a prodigality of adventitious air-roots as the time-honoured Banyan
(Ficus indica, p. 193). It is of this tree that Milton finely says : —
The bended twigs take root, and daughters grow
About the mother tree ; a pillared shade
High over-arched, and echoing walks between.
There oft the Indian herdsman, shunning heat,
Shelters in cool, and tends his pasturing 'herds
At loop-holes cut through thickest shade.
The parent tree, in fact, gives off aerial roots from its branches, as small
tender fibres, which, increasing in length and thickness, presently reach the
earth and pierce their way into it. The parts above-ground continue to
grow thicker and thicker, till they attain the girth of large trunks, when
they themselves become parent trees by sending out new branches from the
top, and these in turn send down aerial roots, which undergo similar
Photo by}
IE. Step.
FIG. 244. — FLOWERS OF IVY (Hedera helix).
The Ivy does not flower until it has surmounted its support, and the five-pointed leaves of the climbing stem have
been succeeded by the lance-shaped leaves that mark its growth as a bush. The wide-open flowers are much visited
by honey-loving insects of many kinds. EUROPE, N. AFRICA, ASIA.
SCAKI.KT HASS1ON-FI.OWKR (Tac
The Tacsonias diffe
from the Comr
represented i
on-flowers (Pa
of Peru, and i
*i,fl(trn) in having
shown one-half the
icatn).
long tube to the calyx.
SEED AND ROOT
193
modifications and perform
similar functions, till the
original tree has become a
grove! The vigorous
growth of these trees may
be gathered from the fact
that one of their seeds,
which had been deposited
by a bird on the crown of
a Palm-tree, not only began
to germinate in that strange
situation, but actually sent
down a root through the
stem of the Palm, thus des-
troying its host and sup-
planting it !
Apropos of this subject,
we must say a word or two
about the parasitical vagar-
ies of the Brazilian Balsam-
tree (? Clusia rosea), with
handsome pink and white
flowers and large shining
leaves, which is thus referred
to by Dr. Wallace: "It
grows not only as a good-
sized tree out of the ground,
but is also parasitical on
almost every other forest
tree. Its large round whitish fruits are called ' cebola braba ' (wild onion)
by the natives, and are much eaten by birds, which thus probably convey
the seed into the forks of lofty trees, where it seems most readily to take
root in any little decaying vegetable matter, dung of birds, etc., that may
be there ; and when it arrives at such a size as to require more nourish-
ment than it can there obtain, it sends down long shoots [? aerial roots] to
the ground, which take root, and grow into a new stem. At Nazare there
is a tree by the roadside, out of the fork of which grows a large Miicuja
Palm, and on the Palm are three or four young Glusia-trees, which no
doubt have Orchidece and Ferns again growing upon them." If we sup-
pose (arid the supposition is not extravagant) that these Ferns, at the
time when Dr. Wallace visited the spot, supported and nourished on their
fronds some creeping Moss-plants or Liverworts, we shall then have a
four-ranked succession of guest plants — epiphytes on epiphytes, and on
these epiphvtes, and again epiphytes on them !
16
FIG. 245. — BANYAN (Ficus indica).
Showing the aerial roots which develop into stout props and trunks,
which enable the horizontal branches to grow indelinitely and cover
194 HUTCHINSON'S POPULAR BOTANY
Mr. James Rodway has much to say of the Clusias and their deadly
work. " Woe betide the forest giant when he falls into the clutches of the
Clusia or fig," he writes. " Its seed being provided with a pulp, which is
very pleasant to the taste of a great number of birds, is carried from tree
to tree and deposited on the branches. Here it germinates, the leafy stem
rising upward and the roots flowing, as it were, down the trunk until they
reach the soil. At first these aerial roots are soft and . delicate, with
apparently no more power for evil than so many small streams of pitch,
[E. Step.
FIG. 246. — SNOWDROP-TREE (Halesia tetraptera).
A. beautiful North American shrub, growing to a height of fifteen or twenty feet, and representing the order Styracaceae.
Its drooping bells are produced in spring before the leaves are fully expanded; They have not so close a resem-
blance to the Snowdrop as the name suggests.
which they resemble in their slowly flowing motion downwards. Here and
there they branch, especially if an obstruction is met with, when the stream
either changes its course or divides to right and left. Meanwhile, leafy
branches have been developed, which push themselves through the canopy
above and get into the light, where their growth is enormously accelerated.
As this takes place the roots have generally reached the ground and begun
to draw sustenance from below to strengthen the whole plant. Then comes
a wonderful development. The hitherto soft aerial roots begin to harden
and spread wider and wider, throwing out side branches which flow into and
195
196
HUTCHINSON'S POPULAR BOTANY
amalgamate with each, other until the whole tree-trunk is bound with a
series of irregular living hoops.
" The strangler is now ready for its deadly work. The forest giant,
like all exogens, must have room to increase in girth, and here he is
bound by cords which are stronger than iron bands. Like an athlete
he tries to expand and burst his fetters, and if they were rigid he
might succeed. But the strangler is like a python, and almost seems as
if provided with muscles. The bark between every interlacing bulges out
and even tries to overlap, but the monster has taken every precaution
against this by making its bands very numerous and wide. We can
almost see the struggle, and knowing what will be the result, must pity
the victim.
"As the tree becomes weaker, its leaves begin to fall, and this gives
more room for its foe. Soon the strangler expands itself into a great bush,
almost as large as the mass of branches and foliage it has effaced. Its
glossy leaves shine in the sunlight, and it seems to glory in its work. Every
branch is clean and sleek ; not a lichen or fungus can find shelter anywhere.
It has got on the shoulders of the forest giant, but does riot intend to
support in its turn even the tiniest dwarf. If we could forget its murderous
work, how we should admire it ! Take the Clusia insignia, for example.
Here we have one of the most beautiful shrubs in the world. Its thick
leathery leaves shine as if polished, and its green sleek branches alwajTs
look clean and healthy. As it sits crowing, as it were, over its victim,
the contrast between them is most striking. Perhaps the forest giant is
dying — the few leaves
remaining are yellow
and sickly. No flowers
have been produced
for two or three seasons,
and even the branches
look shrivelled. There
is not the least hope
of recovery ; it only re-
mains, therefore, to sub-
mit to the inevitable, to
die and give place to
the strangler." Here
again, however, we have
no parasitism in the true
sense — the Clusias are
merely climbers ; they
strangle, but do not feed
upon the trees which
support them.
Photo by]
FIG. 248. — IVY BERRIES (Hedera helix).
IE. Step.
The flowers are shown in fig. 244. The flat-topped fruits are greenish -black,
one- third of an inch across, and contain from one to five seeds.
SEED AND EOOT
197
Pfio/o by]
FIG. 249. — DRYAD'S SADDLE (Polyporus squamosus).
[E. Step.
A Fungus parasitical upon various trees. Each pileus is from six inches to two feet across, of an ochreous ground
tint, more or less covered with fringed red-brown scales.
Aerial roots, unless they are epiphytal, are usually more or less circular
in section, though they are liable to flatten out in growth if they are of the
nature of clinging or supporting roots. Parasitic roots offer more variety,
and may be rounded, flattened, wart-like, ribbed, disc-shaped, netted, etc.,
according to the special character of their work and the peculiarities of
their environment. Some epiphytal Orchids, in addition to their white cord-
like hanging roots, have others of a strap-like form, which adhere so firmly
to the trunks of the host trees, that it has been found impossible to loosen
one of the straps without tearing away a portion of the bark. " In other
species of tropical Orchids," * says Kerner, "the roots are not flat from the
beginning, but become so when they come into contact with the bark.
A root is often to be seen which arises as a cylindrical cord from the axis,
then lays itself upon the bark in the form of a band, and farther on lifts
itself once more, resuming at the same time the rope form. . . . Complete
coalescence takes place between the bands and the bark, and the union is
extremely close." It is affirmed by the same writer that, when the seeds of
any of these tree-growing Orchids " are transferred to loose earth devoid
* E.g. Sarcanthus rostratus.
198 HUTCHINSON'S POPULAR BOTANY
of humus, they perish soon after germination ; whereas when sown on the
bark of a tree, they not only germinate, bnt grow up with ease into hardy
plants."
Many interesting cases are recorded of plants which, though in their
normal state exhibiting no peculiarity of root growth like Banyan, Orchis,
or Pandanus, yet have put forth adventitious roots from the most unlikely
places when circumstances of an extraordinary nature made special demands
upon their powers. It is affirmed of the Field Maple (Acer campestre)
Photo by] \_E. Step.
FIG. 250.— FIELD MAPLE (Acer campestre).
The green flowers and leaves are shown of the natural size. The former are succeeded by winged fruits, similar to
those of Sycamore, but with the two wings horizontal. EUROPE, N. and W. ASIA.
that if you plant it upside-down the buried stem will put forth roots,
and that the tree sustains no injury by such treatment. Not every plant
is able to accommodate itself thus nicely to circumstances ; yet there
can be no doubt that a similar latent vegetative power exists in a great
number of plants. Take the Silver Birch (Betula alba) for an example.
Some sixty years ago one of these trees was blown down in the Birch wood
of Culloden, "and fell," says a writer in Science Gossip, "right across a
deep valley or ravine, which it completely spanned ; and the top branches
took root on the other side. From the parent stem no less than fifteen
Photo by] [JS. Step.
FIG. 250. — BRAMBLE (Rubus fruticosus).
One of the many forms of this very variable shrub. The fruits have formed, but are at present hard and red,
the drupes not having yet developed the juiciness and black colour that marks the ripening of the contained
seed. EUROPE, N. AFRICA, N. and W. ASIA.
199
200
HUTCHIXSON'S POPULAE BOTANY
trees grew up perpendicularly all in a row " ; and thirty years later, when
the gentleman who furnishes these particulars visited the spot, they were
still vigorous and flourishing. It is matter of common knowledge also,
that the foliar organs of many plants possess the power of putting forth
roots — a subject to which we shall refer more particularly when we come
to speak of leaves.
Every one must have observed, too, one way in which the Bramble
propagates itself. The long arching shoot grows until its tip reaches the
ground, into which it pushes, and then instead of leaves puts out a cluster of
white roots. When these are well developed one of the buds grows into a
stout stem, which shoots straight up into the air. In this way are formed
those impenetrable thickets of Bramble that stud our commons and the
outskirts of woods.
It might be thought
by those who are fa-
miliar with pictures of
West Indian Mangrove
swamps that the singu-
lar curved roots of those
trees, standing high
out of the water, are
adventitious ; but the
case is otherwise. They
are true normal roots,
resulting, curiously
enough, from the ger-
mination of the seed
while the fruit is still
attached to the parent
branches. "In the
economy of Nature,"
says Dr. William Hamil-
ton, " the Mangrove
performs a most impor-
tant part, wresting
annually fresh portions
of land from the
dominion of the ocean,
and adding to the do-
main of man. This is
effected in a twofold
manner : by the pro-
FIG. 252.— MANGROVE (Ehizophora mangle). gressive advance of
The trunk stands out of the swamp, supported by its curved, leg-like roots, a 1 -, -, ,
condition due to the seed developing roots before it drops from the tree. tneir TOOtS, and. DV tne
SEED AND ROOT
201
Photo 6y] IE. Step.
FIG. 253.— BIRCH (Betula alba).
This tree being blown down in a gale continued to send out new branches which took a vertical direction, also
sending new roots into the soil.
aerial germination of their seeds, which do not quit their lofty cradle till
they have assumed the form of actual trees,* and drop into the water
with their roots ready prepared to take possession of the mud, in advance
of their parent stems."
An old English navigator — that able, trustworthy writer, William
Dampier — thus describes the tree : " The red Mangrove groweth commonly
by the seaside, or by rivers or creeks. It always grows out of many roots,
about the bigness of a man's leg, some bigger, some less, which, at about
six, eight, or ten feet above the ground, join into one trunk or body, that
seems to be supported by so many artificial stakes. Where this sort
of tree grows it is impossible to march, by reason of these stakes, which
grow so mixed one among another, that I have, 'when forced to go
through them, gone half a mile and never set my foot on the ground,
stepping from root to root." Kingsley describes a Mangrove swamp as a
desolate pool, round which the Mangrove roots form an impenetrable net.
As far as the eye can pierce into the tangled thicket, the roots interlace
* Hardly " trees." It would be more correct to say, " till they attained to a considerable
202
HUTCHINSON'S POPULAR BOTANY
with each other, and arch down into the water in innumerable curves, by
no means devoid of grace, but hideous just because they are impenetrable.
The natives are quite at home in such places, however, leaping or climbing
from root to root with ease and agility, though never daring to trust their
weight on the treacherous marshy ground.
Many of the larger trees of India are famous for their buttress roots.
Miss Gordon Gumming, who spent two years in Ceylon, was struck with
the extraordinary size and height of these roots, which, as she says, " are
thrown out on every side like buttresses, evidently <to enable the trees to
resist the rushing of floods. The buttresses are so high that full-grown
men could stand in one compartment unseen by their neighbours in the
next division." In the park of the Government Agent's house at Kurene-
galla, Miss Gumming
saw many majestic trees
supported by their own
wide-spreading roots,
which covered the
ground for a very wide
radius, forming but-
tresses like low walls.
" The most remarkable
of these," she writes,
" are the Kon- and Labu-
trees ; there are also
great Indiarubber-trees,
whose roots, though not
forming such high walls,
are equally remarkable
and labyrinthian."
The roots of the
Lum-tree, a forest giant
which grows on the
island of Ualan, really
deserve a place by
themselves, and a special
term would have to be
invented to accurately
describe their form.
Dr. Hartwig considers
them to be without a
parallel in the Vegetable
World. Each of the
Lum-tree's roots runs
above-ground to a con-
Pholo by]
FIG. 254. — SCOTS PINE (Pi
[E. Step.
Growing on the edge of a sand-pit, the loose earth has yot washed uway, allow-
ing a good view of the upper root-system of this Conifer.
• '
Photo by] IE. Step.
FIG. 255. — BIRCH-TREE (Betula alba).
Its lightness and grace have earned it the name of " the Lady of the Woods." It is a tree that demands plenty of light,
and therefore is only to be found on the outskirts of woods or in the open. EUROPE, N. ASIA, and N. AMERICA.
203
204
HUTCHINSON'S POPULAR BOTANY
siderable distance, and " is surmounted by a perfectly vertical crest,
gradually diminishing in size as the root recedes from the trunk, but
often three or even four feet high near the base. These crests, which
are very thin but perfectly smooth, regularly follow all the sinuosities
of the root, and thus form, for a considerable distance round the tree,
a labyrinth of the strangest appearance. Large spaces of swampy
ground are often covered with their windings, and it is no easy matter
to walk on the sharp edges of their vertical bands, whose interstices
are generally filled with deep mud. On being struck, the larger crests
emit a deep sonorous sound, like that of a kettle-clrum." They are not
true aerial roots, nor even epigeous roots, but rather roots of a sub-
terraneous origin, which have been pushed through the yielding oozy
soil in order to obtain the oxygen which is absent in the water-logged
soil. The Marsh Cypress in a similar manner sends up woody growths
from its buried roots^in! order to conduct oxygen to them.
Photo by]
FIG. 256. — DANDELION (Taraxacum officinale).
[E. Step.
All the florets in this familiar Composite flower have strap-shaped corollas, thus differing from Composites like
the Daisy, which has only the outer row strap-shaped. Owing to its buoyant seeds, the Dandelion is widely
distributed, being found in all cold and temperate regions.
CHAPTER VII
NATURE'S WOODCRAFT: A CHAPTER ON STEMS
Sap-laden stems, of forms grotesque and weird,
That creep, and climb, and twine, and hang in air.
WHAT is a stem ? The term in popular language is confined to those
parts of the plant which rise above the ground, but popular ideas
are not always satisfactory or exact. We have seen that roots also may rise
above the ground ; and is not a tuber an instance of a stem which grows
beneath the soil ? The popular definition, then, will not answer. Of
botanical definitions, Professor Thome's is. perhaps, as
satisfactory as any. " The stem, in its various forms,"
he says (Lehrbuch, p. 49), " is that part of the plant
which bears the leaves, flowers, and fruits." This is, on
the whole, a sufficient definition.
Before treating in detail of these " various forms," it
would be well to make a few remarks on the structure
of the stem. When dealing, on a former occasion, with
the cells and vessels of plants, we named and described
the three great classes into which all permanent tissues
may -be divided — viz. Fundamental or Ground Tissue,
the Fibro-vascular System, and Epidermal Tissue ; and
we saw that each of these classes is represented in
every well-developed foliage leaf. The annexed diagram
(fig. 257) has been prepared with the view of illustrating
the manner in which these tissues and vessels are
distributed through the stem of an ordinary dicotyle-
donous plant. The figure, indeed, represents an actual
model which was made for us for lecture purposes, and
which consists of a column of wax, not unlike an altar
candle, but furnished with eight large wicks instead' of
one, the wicks being arranged in a circle, at about
equal distances from each other. Fitting closely round
,i i • •,. , J FIG. 257. — VESSELS.
the column is a cylinder ot stout paper.
We will suppose that this column represents the erect
and very young stem of a Flowering Plant— say a Sun-
205
206
HUTCHINSON'S POPULAR BOTANY
flower stem : the paper cylinder surrounding it will then answer to the
epidermis ; the eight many-threaded wicks to eight separate fibre-vascular
bundles ; and the wax itself will represent the ground tissue. Bear in
mind that the fibre-vascular bundles ("nerves" or "veins") of the leaves
are always in connection with the bundles of the stem, insomuch that the
latter are often regarded merely as lower portions of the leaf bundles ;
while a whole bundle formed by such union is said to be common — that isr
common both to leaf and stem.
If it were possible for the wicks to increase continually in thickness,
it is evident that they would at length meet, and form an unbroken circle
round the innermost portion of the wax ; and this is precisely what takes
FIG. 258. — TRANSVERSE SECTION OP A FOUR-YEAR-OLD DICOTYLEDONOUS
STEM (DIAGRAMMATIC).
(m) Medulla or pith, (mr) Medullary rays, (s) Medullary sheath. (X) Xylem (wood). (P) Bast or phloem. (C Cambium.
ring. (K) Cortex. (E) Epidermis. The eight fibro-vascular bundles (Jv) are united by wood and bast (a>6) formed by thfr
cambium between the bundles. The figures 1, 2, 3, 4, refer to the years of growth of the wood.
Photo 6jr] IE. Step.
FIG. 259. — ENGLISH ELM (Ulmus campestris).
An ancient tree that has been broken in a storm ; but its abundant vitality has enabled it to partially make
good the defect by new growths. The English Elm is considered a variety, or perhaps hybrid, of the Wych Elm
(Ulmus montana). It is reproduced by suckers, as it rarely, if ever, produces fertile seed.
207
208
HUTCHINSON'S POPULAR BOTANY
place with the woody bundles in the stems of dicotyledonous trees, such as
the Oak, Beech, Elm, etc., though the completion of the circle is accelerated
by the formation of new bundles between those already existing. The
wood of timber-trees of several years' growth is nothing more than a mass
of such bundles closely packed together, and surrounding that part of the
ground tissue which is known as the medulla, or pith. Locked in as the
pith then appears to be, communication is nevertheless maintained with the
bark by means of narrow prolongations of the pith, which, in transverse
sections of the stem, have the appearance of lines diverging from the
centre. These, as having their rise
in the medulla, are known as medul-
lary rays. They constitute what
cabinet-makers call the " silver grain "
in wood.
But how do the woody bundles
increase in size ? The question is
not easy to answer — at least, with-
out bringing to our aid a good many
technical terms — yet we do not des-
pair of making the process plain.
Here (fig. 260) is represented in
transverse section a fibro-vascular
bundle from the stem of an herba-
ceous plant ; let us examine it. The
narrow end, A, is that which, in a
complete transverse section of the
stem, would be directed towards the
centre or pith, while the wide end,
5, would of course be nearest the
bark (fig. 258). The whole bundle is
embedded in ground tissue (gt). Now
notice how the vessels are arranged
in the bundle. Those adjoining the
pith, and represented by darkly lined
circles in the midst of other tissue,
are annular vessels (a) ; immediately above them, embedded in similar
(that is, woody) tissue, are spiral vessels (sp) ; and higher still are pitted
vessels of various sizes (pv], surrounded by greatly thickened wood cells.
Within the brackets lettered G we have a tissue of delicate growing
cells known as the cambium layer ; and above the cambium layer an assort-
ment of sieve-tubes, bast-fibres, and pareiichymatous wood-cells, of which
the innermost constitute the soft, and the outermost the hard bast.
The soft, thin-walled, growing cells, or cambium (a name derived from
the Latin cambio, I exchange), really divide the bundle into two parts, of
Fio. 260. — FIBRO- VASCULAR BUNDLE.
Diagram of a transverse section of bundle from an her-
baceous plant. (A) Wood or xylem, consisting of (a)
annular and (sp) spiral vessels surrounded by cells of the
primary wood ; and (pv) pitted vessels in the midst of
denser woody cells. (B) Liber or phloem, consisting of
(6') hard bast and (b") soft bast, (gt) G-round tissue.
NATURE'S WOODCRAFT: A CHAPTER ON STEMS
209
FIG. 261. — DICOTYLEDONOUS STEM.
Diagram of transverse section. The eight fibre-vascular
bundles are seen embedded in the ground tissue (<?0- (»>)
Medulla or pith, (or) Cambium ring.
which the inner (A) is called the
wood or xylem (Greek xftlon, wood
or timber), and the outer (B) the
liber* or phloem (Greek phloios,
bark) ; and it is to these growing
cells that all increase of the woody
bundle is due. They are filled,
indeed, with protoplasm, and in
the growing season are constantly
undergoing division to form new
cells, by which means new wood is
added to the outside of the xylem,
and new liber to the inside of the
phloem. All the woody bundles of
the stem are, in a way, united by
the cambium, which forms an un-
broken ring in the stem, those
portions of the ring which lie be-
tween the bundles being known
as interfascicular cambium (fig. 261, cr). As the cambium remains dormant
during the winter, and the cells which it forms in the spring are larger
than those of the autumn, the extent of its work each year may be easily
traced — indeed, the concentric rings of wood in the trunk of a dicotyledo-
nous tree are the abiding records of its annual and annular labours, and
furnish means of forming a fairly accurate computation of the age of the
tree. The interfascicular cambium
serves the double purpose of
lengthening the medullary rays (see
fig. 258 1 and adding fresh phloem and
xylem between the original bundles.
In fact, it assists in completing the
circles of the liber and wood, thus
making the stem one solid whole.
It should be added that all
Flowering Plants do not have the
nbro-vascular bundles arranged in
the manner above described. In
Monocotyledons — Palms, Lilies,
Grasses, etc. — they are scattered
irregularly in the stem ; nor are
* The name liber was applied by the
Romans to the inner bark or rind of a tree FlG' 262.-RAVENNA GBASS (Erianthus
, f ravennce).
used for paper. Our word 'library traces
, , , .; r J A transverse section of this Monocotyledon showing the
OaCK tO It. closed nbro-vascular bundles embedded in ground tissue.
17
210
HUTCHINSON'S POPULAR BOTANY
these bundles provided with vitally active cambium ;' so that when
cease to grow (at an early stage in the history of the plant) the stem
also ceases to increase in thickness. The section of a stem of Ravenna
Grass (Eriantkus ravennce), which is shown in fig. 262,^ contains a portion
of one of these closed nbro-vascular bundles. Flower^ess Plants, or Crypto-
gams, usually do not contain them at all ; but where they are present they
sometimes form an irregular and broken ring near the outside of the stem,
as in the Ferns, and in other cases constitute the axis of the stem, and are
solitary. The Pillworts (Pilularia, fig. 267), a family of flowerless plants
specially partial to
marshy and inundated
ground, offer interest-
ing examples of axial
fibro-vascular bun-
dles. All the Flower-
ing Plants, and those
among the Crypto-
gams which have
these bundles in their
stems, also contain
them in the roots ; so
that a system of ves-
sels extends from root
to leaves in each
plant, and forms, as
we were seeing in
Chapter III., the
skeleton or framework
on which the plant is
built up.
The external forms
of stems exhibit even
greater variety than
the external forms of
roots. Some stems
are very much like roots, not in their forms merely, but also in their habits.
We allude to those which grow underground — to rhizomes, tubers, bulbs,
and corms.
Rhizomes, of which the Flag (Iris}, Solomon's Seal (Polygoncttum,, figs. 265
and 269), and Lily of the Valley (Convallaria majalis) offer familiar examples,
are subterranean stems of horizontal growth, which give off roots below and
leaf- and flower-bearing shoots above. Such stems are always spoken of
as roots by the old writers. Gerarde, for example, refers to the rhizome of
the Iris as " gladen rotys " in the following curious recipe for a cosmetic :
FIG. 263.— PILLWORT (Pilularia globulifera).
Transverse section of stem showing axial fibro-vascular strand. P is the paren-
chyma, surrounded by the dark ring of xylem, outside of which is the bast (-B) with-
in the bundle sheath. Outside this again are the cortex and epidermis.
Photo by\
IE. Step.
FIQ. 264. — GRASSES IN FLOWER.
The flowering stem of a grass is a wonderful structure. Fine as it is, it is hollow: and when one considers its
height and the pull of its branches upon it, its strength is enormous. Seen when the flowers are just open,
it is a thing of great beauty. Were it less common it would receive more attention — and admiration.
211
212
HUTCHINSON'S POPULAR BOTANY
FIG. 265. — RHIZOME or SOLOMON'S SEAL.
The cut-off base of this year's stem is shown just behind
the growing point. Behind it the scars left by the decay
of earlier stems.
" Do take ij parties of the poudre of
gladen rotys [Iris roots], and the iij
part of the poudre of ellebre [Helle-
bore], that some men clepen cloff-
ynge, and medele both these poudres
togider in honey. A plaster of this
wole purge and dense the face of
frekels, also it will resolve the pockys
and whelkys of the face."
Rhizomes haye a very important
function in that they enable plants to form vigorous colonies, which are
not only able to hold their own against the attacks of a competitive
species of plant, but enable the ovules of its individual stems to be more
certainly fertilized than would be the case were the individuals scattered.
A familiar instance is seen in the way the Common Daisy, having taken
advantage of a small bare spot on a lawn, proceeds to enlarge its
territory by sending out offshoots all around. Had it grown as a
single plant the summer growth of the neighbouring grasses would have
deprived it of light and air ; but if unchecked by the gardener the
Daisy patch extends, and, amalgamating with other patches, would soon
extirpate the grass. It is this method of spreading, too, that enables
the useful Marram of the sand-dunes to hold the loose sands together.
Other examples of this habit in common plants will be found in
the Dog's Mercury and the Stinging
Nettle.
Tubers are most conveniently
studied in the Potato-plant (Solatium
tuberosum, fig. 266). A potato is, in
fact, a true stem, and its "eyes" are
buds, each of which is capable of
producing a new plant. Thomas
Heriot (a fellow-voyager with Sir
Walter Raleigh, who was the first
to introduce the potato into this
country) describes the tubers as
"round, some as large as a walnut,
others much larger. They grow in
damp soils, many hanging together
as if fixed on ropes." The Jerusa-
lem Artichoke (Helianthus tuberosus)
and the Chinese Yam (Dioscorea
batatas, fig. 268) are other familiar
FIG. 266,-PoTATo-PLANT, examples of edible tubers.
Showing underground portion of stem with tubers and n JL i j.
root-fibres. Bulbs are subterranean stems not
NATURE'S WOODCRAFT: A CHAPTER ON STEMS
213
unlike buds, with thick, fleshy scales folded round a conical axis (fig. 273).
Corms are somewhat similar, but their scales are thin, few, and mem-
branous ; and the axis of a corm is much thicker than the axis of a
bulb (fig.. 272). The Crocus, Cyclamen, and Gladiolus offer good examples
of the corm ; and instances of bulbs are furnished by the Lily, Onion, Star
of Bethlehem, Snakes-
head, and Hyacinth.
Both these forms of
underground stem are
storehouses of food
material, husbanding
the strength and energy
acquired by the plant
during one season for
the exigencies of the
next. The reserve of
food is largely drawn
upon by the plant at
the time of flowering,
but if flowering be pre-
vented, a very consider-
able saving of expendi-
ture is the result ; while
the bulb, which is con-
tinually receiving fresh
supplies of nutriment
from the leaves, is found
to be larger at the end
of the growing season
than at the commence-
ment. A Lily, or other
bulbous plant, by having
the buds cut out year
after year just before the
period of flowering, ac-
Cumulates an abnormal
£ £ l
OI lOOCl-
Photo z>y]
step.
FlG- 267.— PILLWORT (Pilularia globulifera).
Scarcely to be distinguished from grass at a glance. It has a long, thread-
like, creeping rhizome from which long, slender leaves arise singly or in pairs,
• i , , i , -, and between their bases are the spherical spore-cases. EUROPE, NORTH OP
material (starch) ; and THE ALPS.
when at last the plant
is permitted to flower, it is able to compensate itself for former deprive-
ments by making an exceptionally grand display. Herein lies the secret
of the size and beauty of many " florists' flowers."
Many of these bulbous plants grow in places where, for many months,
owing to the absence of rain, the land is a desert. Deep in the ground
214
HUTCHINSON'S POPULAR BOTANY
where they have withdrawn all their living material, they are preserved
from drying up, and when the rainy season begins they at once become
active above-ground, and the desert becomes a garden of brilliant flowers.
Such a transformation may be witnessed in the Karoo, in South Africa.
Among its plants the Brunsvigia is conspicuous by reason of its umbels of
scarlet flowers, which, it is said, may be seen at the
distance of a mile.
Among certain plants with underground stems a
kind of motion occurs, to which it may be worth while
to make a brief allusion. Some plants, for example,
appear one season in a spot at a little distance from
that which they occupied in the previous season, and
thus appear to travel, the shifting of position being
effected by means of the sucker-like subterranean
stems annually formed by the parent, which projects
them to a certain distance and then perishes. The
corms of many plants of the Iris order (Iridacece) ex-
hibit a similar property, each forming a new corm at
its apex every year, which feeds upon the parent
till the latter is quite dry. Growth goes on in this
way, year by year ; the corms continually rising, not,
indeed, " by stepping-stones of their dead selves," but
by stepping-stones of their dead parents, " to higher
things," till the surface of the earth is reached. Then
the corms become dispersed by the scratching of birds
and small mammals, and each in its new position sends
a thick shoot deep into the soil, through which the
material of the above-ground corm is conveyed to
form a new one at a suitable depth, or, by the produc-
tion of special roots, the corm is pulled down to the
proper level.
Yet the above instances of vegetable progression
have, after all, nothing very remarkable about them,
N^ the so-called motion being strictly analogous to the
progression of an ordinary aerial stem by the forma-
tion of fresh branches year after year. True motion
does, however, exist in a large number of above-
ground stems, such as the tips of the runners or
stolons of the Strawberry-plant (Fragaria, fig. 278) and
the growing points of the stems of the Ivy (Hedera), Raspberry (Rubus
idceus), etc., which Darwin, Sachs, and others have observed to rotate just
as do the cotyledons and rootlets of the Bean (Vicia faba\ Pea (Pisum
sativum\ Wood-sorrel (Oxalis acetosella), etc. Circumnutation is, indeed,
a general characteristic of aerial stems.
Fia. 268. — CHINESE
YAM (Dioscorea batatas).
The tubers are a valuable
food, used like the Potato.
215
216
HUTCHINSON'S POPULAR BOTANY
Aerial stems present a far greater variety of forms than those which
grow beneath the soil. In some cases the trunk is simple and unbranched,
as in the Palms, when it is called a caudex ; in others — to wit, the stems of
most woody trees and shrubs — the branches are numerous. A stem that
is weak and not woody, and which perishes annually down to the root, is
herbaceous. Then there are root-shaped stems and knotted stems ; ascending
stems and trailing stems;
twining stems and climb-
ing stems ; and all these
may — and do — assume
a bewildering diversity
of forms — cylindrical,
triangular, quadrangu-
lar, ribbed, compressed,
etc. How singular, for
example, is the mode of
growth of those glorious
tropical climbers, the
Bauhinias ! Here (fig.
275) is a drawing of
part of the stem of a
Demeraran species,
which the natives call
" bush-rope " and the
sailors " land-turtles'
ladders," and which
offers as neat an exam-
ple of Nature's wood-
carving as one could
wish to see. It is prob-
able that the undulating
central part of such
stems protects the sap-
conducting tissues of the
plants against strain.
The edges of the stem
are almost straight, and
form a sort of frame-
work to the sinuous middle part ; so that, as Kerner says, " in the case
of a longitudinal tension the frame only is affected at first," and " the
tissues in the centre can still uninterruptedly conduct the sap to and from
the branches which arise from its broad surface " (Natural History of Plants).
" Often three or four of these bush-ropes," says Dr. Hartwig, " join tree to
tree, and branch to branch ; others descending from on high take root as
Photo by] IE. Step.
FIG. 270. — SNAKE'S HEAD (Fritillaria meleagris).
A native Lily that grows in moist meadows. Its dull purple flowers are
chequered with light and dark tints. The photo, which is two-thirds of the
natural size, includes the rare white variety. EUROPE, W. ASIA.
NATURE'S WOODCRAFT: A CHAPTER ON STEMS 217
Photo by\
FIG. 271. — STAR OF BETHLEHEM (Ornithogalum umbellatum).
One of the most beautiful of the smaller liliaceous flowers. The grass-like leaves have a white line down the centre,
and the white flowers come up in a loose cluster (corymb) of from six to ten. It is naturalized in places here, but
is a native of Europe south of Belgium. About one-third of the natural size.
soon as their extremity touches the ground, and appear like shrouds and
stays supporting the mainmast of a line-of-battle ship : while others send
out parallel, oblique, horizontal, and perpendicular shoots in all directions.
Frequently trees above a hundred feet high, up-rooted by the storm, are
stopped in their fall by these amazing cables of Nature, and are thus
enabled to send forth vigorous shoots, though far from their perpendicular,
with their trunks inclined to every degree from the meridian to the horizon.
Their heads remain firmly supported by the bush-ropes ; many of their
roots soon refix themselves in the earth, and frequently a strong shoot
will sprout out perpendicularly from near the root of the reclined trunk,
and in time become a stately tree."
The Buttress-trees of the virgin forests of Central America, again, have
very peculiar stems. They are provided, as their name implies, with
buttresses from six inches to a foot thick, which project from the stems
like walls to a distance of several feet, thus affording room for a comfortable
hut in the angle between them. Then there are the Pao-Barringudos of
218
HUTCHINSON'S POPULAR BOTANY
FIG. 272. — SAFFRON CROCUS (Crocus
sativus).
Corm and section of same, (a) Old corm ;
(6) new corm ; (c) bud.
the Brazilian forests, whose stems bulge
out in the middle like enormous barrels ;
and the Delabecheas or Bottle-trees of
/ \ ni~)}''~'C tropical Australia, which have the same
lumpish mode of growth (fig. 277), to say
nothing of the Caulotretus or Monkey-
ladders, and the numberless other tropical
tree-climbers, whose singular varieties of
stem-form — flattened and warty, ridged
and contorted, net-like and interlacing—
are the wonder of travellers. We shall
return to some of these tropical curiosities
presently when considering the means by
which slender and weak-stemmed plants
maintain an erect position.
Mention was made a moment ago of " woody trees and shrubs." an
expression which recalls the old and somewhat vague classification of
Flowering Plants into herbs, shrubs, and trees. Botanists differ very
considerably in their definitions of these three forms, and it is hardly
necessary to discuss the points of difference ; probably most persons have
a tolerably correct idea of the main distinctions upon which the classifica-
tion is based. Herbs are plants of com-
paratively small size, usually with soft and
succulent stems, which die down to their
base every year. The crown or root-stock
itself may survive, and produce either a
fresh plant year after year, when the herb
is said to be perennial, or only the follow-
ing year, and then it is biennial. If the
herb dies completely — roots and all — in
the first year, it is an annual. Perennial
plants with branching ^uoody stems, which
do not attain to the dignity of trees, or,
in other words, do not exceed about
twenty feet in height, are shrubs; while
perennials of larger growth, if character-
ized by a distinct primary stem or trunk,
may be fairly classed among trees. No
hard-and-fast dividing lines can be drawn
between these three forms, however, herbs
passing into shrubs, and shrubs into trees,
by endless gradations.
It may be remarked in this connec-
tion that the modifying effect of climate
FIG. 273. — GARDEN HYACINTH
(Hyacinthus orientalis).
Section of bulb, showing the overlapping leaves
of which it is composed.
Photo J>y~\
[J- T. Newman.
FIG. 274. — Brunsvigia Josephines.
A singular bulbous plant of the Karoo in South Africa, where for many months no rain falls. In the rainy season
they at once become active, and send up their umbels of scarlet flowers, developing their leaves later.
219
220
HUTCHINSON'S POPULAE BOTANY
on the size of plants of the same genus, and even of the same species,
is in some cases extremely curious. Heat is a great stimulus to growth,
and many plants which attain to the dignity of trees in tropical and
sub-tropical countries will degenerate into mere shrubs when grown in
more temperate regions. Speaking generally, the farther north we go
the more stunted is the vegetation ; but the
difference observable in plants of the same
species even when growing in neighbouring
countries is frequently very marked. A striking
illustration of the above' facts is afforded by
the Willows (Salix\ some of which in this
country are timber-trees of considerable dimen-
sions, while in the Arctic regions their repre-
sentatives seldom attain the height of nine
inches ! Salix herbacea, myrtilloides, pyrenaica,
and reticulata, all species found in the ice-
regions of North America, arrive at maturity
and bear their flower-catkins when they are
scarcely six inches above the ground ! Some
of these small trailing forms we have on our
own moors and heaths.
To come back to the stern. The points on
the stem where leaves are given off and buds
formed are called nodes ; the spaces between,
internodes. Recently Professor L. Celakovsky,
of Prague, has propounded a new theory re-
specting the building up of the stem. As just
stated, the view formerly held by botanists was
that the internode consisted of all that section
of the stem lying between two nodes, but in
Celakovsky's opinion this view requires some
qualification when applied to dicotyledons. Ac-
cording to a notice of this theory by W. C.
W[orsdell] in the New Phytologist, the Bohemian
botanist divides stems into two classes — holo-
cyclic and mericyclic. Holocyclic stems consist
of a series of joints or internodes placed one
above another, each occupying the entire
diameter of the axis and terminating at the node in a leaf. As each
leaf arises from that portion of the apex which becomes the stem-joint
to which it belongs, we may regard, he says, the leaf along with the
latter as a morphological unity, and term it a Sprossglied (shoot segment).
The entire monocotyledonous embryo (apart from the root) represents a
first such Sprossglied, the hypocotyl being its holocyclic Stengelglied (stem-
Fio. 275.— "BUSH-ROPE."
Portion of stem of a Bauhinia.
NATURE'S WOODCRAFT: A CHAPTER ON STEMS
221
joint). Holocyclic articulation is characteristic of monocotyledons. The
mericyclic stem differs materially from the holocyclic, the stem-joints or
internodes being arranged side by side (juxtaposed) as well as superposed ;
and therefore occupy only a portion of the diameter. Thus, in the case
of leaves arranged spirally on a stem, the internode is only a segment of
the diameter extending from one leaf to that which comes exactly above or
below it. This arrangement of leaves is made clear in the next chapter,
but for our present purpose it may be said that according to the number
of leaves in one complete turn of the spiral round the stem, so there is
FIG. 276. — WOOD-SORREL (Oxalis acetosella).
IE. Step.
The plant is sensitive to atmospheric changes. The leaflets fold down close to the leaf-stalk at night and on the
approach of rain. A slight jar of the leaf-stalk will produce the same effect. If a plant is put into a dark
cupboard the leaflets will assume the nocturnal pose, and if then brough t out into full daylight will spread out at once.
a corresponding number of segments or internodes juxtaposed in its
diameter, and all beginning on different levels. When the leaves form
a whorl, as in the Bedstraws (Gcdium) and Woodruff (Asperula), there
will be as many internodes as leaves, but all begimring and ending at
the same level. We cannot go into all the details here ; but we may say
in brief that whereas the former theory of Braun and Sachs regarded the
stem as a pre-existing basis on which the leaf is developed, Celakovsky
holds with Fleischer and Hegelmaier that the leaf is first formed and
develops from its base a Stengelglied or internode.
A hollow and unbranched stem, the internodes of which are separated
222
HUTCHINSON'S POPULAR BOTANY
by thickened nodes, as in the Grasses, is a culm- while a pithy stem
without thickened nodes is a calamus. We have good examples of
this sort of stem in the Rushes. Our English Grasses, it must be con-
fessed, give but a poor idea of the dignity of a culm, and one must
make a journey to India, or South China, or the Eastern Archipelago,
where the colossal Bamboos abound, in order to obtain a truer idea.
Every one of those polished jointed stems is a culm. Sometimes as many
as a hundred of them " spring from a single root, not seldom as thick as
a man, and towering to a height of eighty or a hundred feet " (Hartwig).
Miss'Gordon Gumming tells
us that in Ceylon these
giant Grasses " peep above
ground during the rains,
about July, and shoot up
at the rate of twelve inches
in twenty-four hours. The
Malacca Bamboo [Bambusa
maxima], which is the
largest known species, con-
tinues growing till it attains
a height sometimes con-
siderably above a hundred
feet, with an average
diameter of nine inches."
Picture for a moment the
grace of our meadow
Grasses, united with the
lordly growth of the Italian
Poplar (Populusnigra), and
we shall have a faint idea
of the beauty and dignity
of this form of stem.
Branches occasionally
take remarkable and mis-
leading forms. The dark
green leaf-like expansions of the Butcher's Broom (Ruse us aculeatus) are
really branches — flattened branches or cladodes — on which the little
greenish flower is borne. This is one of the most curious of our native
plants, and the only woody monocotyledon indigenous to British soil. In
the southern half of Britain it is common locally in woods where the
surface soil is clay, sand, or gravel, and on windy heathlands one is pretty
sure to meet with it. The cladode shown in fig. 283 is not a cladode of
the Butcher's Broom, but of a Jamaica shrub, Phyllanthus angustifolius,
which belongs to quite another family and order. There is also a small
FIG. 277. — BOTTLE-TREE (Delobechia rupestris).
A native of tropical Australia.
224
HUTCHINSON'S POPULAR BOTANY
genus of evergreen shrubs, consisting of only four species, which bears
its flowers in much the same manner ; indeed, they have received on that
account the appropriate name of Phyllocladus, from the Greek phullon, leaf,
and klados, a branch. They belong to the Cone-bearing order (Goniferce)
and are natives of Borneo and New Zealand. Somewhat analogous to the
leaf branches of this family are the flat two-edged membranous branches
of the Arrow-jointed Genista (G. sagittalis, fig. 284), a not uncommon plant
in English gardens.
Branches which are arrested in their growth to form hard points are
known as thorns or spines. Thus the thorns of the Hawthorn (Cratcegus
oxyacantha, Blackthorn (Prunus spinosa, fig. 285), Spiny Rest-harrow
(Ononis spinosa), etc., are simply metamorphosed branches ; for they
contain, like true branches, fibro-vascular bundles. Under cultivation the
thorns often disappear, and fruitful branches are borne in their stead — a fact
which suggests the interesting inquiry, What .is the purpose of thorns in
the economy of Nature ? Dr. Burnett offered an ingenious answer to this
question upwards of seventy years ago, though possibly even he is indebted
[E. Step.
FIG. 279. — BRAMBLE (Rubus fruticosus).
A. portion of a branch laden with its juicy fruit — the ever-popular Blackberry.
MOUTAX P.-KOXY (P
The Moutan, sometimes called Tree Paeony. differs from the Common Paeony in having much branched shrubby stems, and
double, and vary in colour from white through all shades of red. It is a native of China, where it is widely cultivated.
NATURE'S WOODCRAFT: A CHAPTER ON STEMS 225
for the thought to a still earlier botanist. " In open tracts of country,
the very circumstance of the sterility of the soil must prevent the pro-
duction of many plants ; and of those which grow, few will be enabled
to perfect many seeds. It is necessary, therefore, to protect such as are
produced from extermination by the browsing of cattle, otherwise not
only would the progeny be cancelled, but also the present generation be
cut off. And what more beautiful and simple expedient
could have been devised than ordaining that the very
barrenness of the soil, which precludes the abundant
generation by seed, should at the very same time, and by
the very same means, render the abortive buds (abortive
for the production of fruit) a defensive armour to protect
the individual plant, and to guard the scantier crop which
the half-starved stem can bear ? That such an armature is
produced by the abortion or partial development of buds
and branches, there is abundant proof. For not only are
thorns found in every stage, varying from their simple
dormant or winter state, when, if opened, they contain
the rudiments of leaves, through leaf-bearing spines to
rigid thorns on the one hand, or leaf-clad branches on
the other ; but the very organs, i.e. buds, which, when the
plant is half-starved, are partly developed as spines, and
partly only as branches, become, when an abundant
supply of nourishment is provided, altogether leafy
branches : the buds have all been wholly developed, none
have degenerated into thorns, and the plant is tamed.
The Common Rest-harrow (Ononis arvensis) is a familiar
example immediately in point, for of it there are two
well-known varieties called 0. spinosa and 0. inermis, from
the circumstance of this being smooth and destitute of
thorns, while that is covered with them. These two
varieties I have often seen growing together on the same
heath ; the one well-clad with its offensive and defensive
arms, and furnished with few leaves to tempt the appe-
tite of cattle ; the others, upon or near to which a care-
less cow had dropped a profusion of manure, replete with A portion o£ the culm
leaves and blossoms, but wholly destitute of thorns, and showieaedSenodes tbick"
just in such a state as to furnish an agreeable repast to
the animal by which it had been so richly endowed."
The wonderful way in which stems seem able to adapt themselves to
circumstances, terrene, climatic, and otherwise, is even more strikingly
illustrated in the tropical Spurges (Euphorbiaceae). These adopt the forms
and habits of the Cactese, an order of plants from which they are widely
separated, developing the same succulent tissue (a provision against rainless
18
FIG. 280. — BAM-
BOO.
226
HUTCHINSON'S POPULAR BOTANY
seasons), a tough leathery membrane to retard evaporation, and formidable-
spines as a protection from browsing cattle. Sometimes these spines get
into the breasts of buffaloes and other large animals, causing inflammation
and even death, and the wild asses of the desert are often lamed by them.
Compare the stems of the two species of African Spurge (Euphorbia
grandicornis and E. abyssinica) shown in fig. 286 with the slender European
species (Euphorbia splnosa).
Weak-stemmed plants, which object to the low earth-
trailing life that satisfies a Strawberry-plant or Creeping
Buttercup, resort to all manners of devices in order to
grow upwards. Thus the Ivy (Hedera helix) climbs by
means of its short and multitudinous aerial roots — it is.
a root-climber ; the Bramble (Rubus fruticosus) and the-
Wild Rose (Rosa arvensis] — hook climbers — develop prickles
on their stems, whose curved points enable the plant to
cling to whatever will help its ascent ; the Traveller's
Joy (Clematis vitalba) and Garden Nasturtium (Tropceolum-
majus] — leaf climbers both — gain the desired end by means
of their leaf-stalks, which they twist round the nearest
support; the Vine (Vitis vinifera) and Virginia Creeper
! (Vitis quinquefolia] mount upwards by help of tendrils,
J which, in the plants named, are metamorphosed branches
!' with adhesive discs, but in others — as the Sweet Pea.
(Lathyrus odoratus), Yellow Vetchling (L. aphaca}, Smilax,
and (possibly) White Bryony (Bryonia dioica) — are meta-
morphosed leaves and stipules.* Ercilla volubilis, a
Chilian climber, attaches itself to any available support
by means of adhesive discs borne directly upon the
branches just above the axils of the leaves. Lastly,
the stem itself may entwine the supporting object, when
its spiral course is in some plants always to the left (e.g~
the Convolvulus, Black Bryony, and the Scarlet Runner
Bean), in others always to the right, as the Hop (Humidus
lupv/lus) and Honeysuckle, albeit external conditions have
no influence on the maintenance of these directions. The
climbing proclivities of the Hop are greatly facilitated
by the development of innumerable anvil-shaped hooks-
on the ridges of its hexagonal branches.
Plants whose shoots twine always to the right — i.e. clockwise — are-
called dextrorse climbers ; while those whose shoots take the opposite direc-
tion— i.e. counter-clockwise — are described as sinistrorse climbers. " It is a.
matter of indifference to the direction of these movements/' says Kernerr
* Some are of opinion that the so-called climbing stipules of the Bryony are really
extra-axillary branches.
FIG. 281. — CLUB
RUSH (Scirpus
pungens),
Showing triangular stem
or calamus ; also flowers.
FIG. 282. — WOODRUFF (Asperula odorata).
The leaves are borne in whorls, and there are as many internodes as leaves, but all begin at the same level.
Woodruff in drying gives off an odour resembling that of new-mown hay. EUEOPE (except Peninsula), N. AND w. ASIA.
227
228
HUTCHINSON'S POPULAR BOTANY
283. — PtiyUanttms angustifol
A leaf-like branch, bearing flowers.
FIG. 284. — Genista
sagittalis,
Showing two-edged
membranous branch
and twigs.
" whether we allow light,
warmth, or humidity to
operate on this side or
that ; the particular species
always twists in the same
direction, the Hop towards
the right, the Convolvulus
[and Dodder] towards the
left. More than this, even
if the twining portion is
continuously bound in an
opposite direction, the re-
sult is all the same ; the
plant cannot be coerced
into any other path, and will not depart from the direc-
tion peculiar to it. It continues to twist and twine
according to an innate tendency inherited from generation
to generation, and we can only refer the different directions
of twisting to internal causes, to the peculiar constitution
of the living protoplasm in each particular plant." It has
been asserted by Darwin that the Bittersweet (Solanum
dulcamara), a trailer rather than a twiner, is both a left-
handed and a right-handed climber when growing near
slender stems. Kerner, however, affirms that in many species
of climbing plants whose stems, like that of the Bittersweet,
increase in thickness from year to year, " the twining is
not very conspicuous," and adds of the plant in question
that it forms a kind of link " between plants with twining
and those with interweaving stems."
Travellers tell us that we must go abroad in order to
obtain just ideas of the habits and eccentricities of climbing
and twining plants ; and the accounts which they bring
us from the far-off forests of the Amazon and West Indies,
from India and the South Pacific Islands, are well calculated
to kindle a desire to go thither. They tell us of foot-
tangling Mamures,* with creeping stems and fan-shaped
leaves, which interlace with wire-like branches of other
plants hanging from above. " You look up and around,
and then you find that the air is full of wires, that are
hung up in a network of fine branches to half a dozen
different sorts of young trees, and interwined with as
* Carludovica, a genus of monocotyledonous plants, most of which
are climbing and palm-like, and all of which are tropical. The genus is
included in the order Cyclanthaceae.
NATURE'S WOODCRAFT: A CHAPTER ON STEMS
229
many different species of slender creepers. You thought at your first
glance among the tree-stems that you were looking through open air ;
you find that you are looking through a labyrinth of wire-rigging, and
must use the cutlass right and left at every five steps" (Kingsley). Some
of these climbers are " twisted in strands like cables ; others have thick
stems contorted in every variety of shape, entwining snake-like round the
tree-trunks, or forming gigantic loops and coils among the larger branches ;
others, again, are of zig-zag shape, or indented, like the steps of a
staircase, sweeping from the ground to a giddy height " (Bates).
Herb disputes with herb, shrub with shrub, and tree with tree, for
every cubic foot of air and soil. It is one grand struggle for existence.*
Nor do the weakest always go to the wall. By employing artifice the
slender clinging plant
sometimes destroys the
strong -limbed self-sup-
porting giant; the un-
fittest rather than the
fittest thus surviving in
the struggle. This is
well illustrated in the
Marcgravias, and par-
ticularly in Marcgravia
umbellata, which abounds
in the woods of Jamaica,
and which assumes such
a variety of forms in the
process of growth that
it is often- mistaken for
different plants. At its
first appearance it is
but a poor, thin, weak-
stemmed climber, bear-
ing a few heart-shaped
leaves ; but it is also
provided with aerial
roots, and by means of
these it attaches itself to
the sturdy trunk of any
tree that is conveniently
contiguous, and mounts
* An Indian Grass— Pani-
cum arborescens— whose stem
is no thicker than a goose-quill, FlG 285.— BLACKTHORN (Prunus spinosa).
rises as high as the tallest trees ^ ^ ^ ^ to be modified b_ancheg by their bearing the
in this Contest lor light and air. flowers. The leaves have not yet appeared. EUROPE.
230
HUTCHINSON'S POPULAR BOTANY
and mounts through the dense leafy gloom of the forest till it reaches some
region of unobstructed light, overtopping the foliage of the tree by which
it climbed. With that it changes its tactics, the whole plant being trans-
formed as by the touch of a magician's wand. The stem rapidly strengthens
and increases in size, flattening and moulding itself over the larger branches
of its supporter ; and presently it sends down numerous slender, dependent,
and individual branches from the upper part, at the same time throwing off
its now useless lower leaves
and roots. Last of all, the
plant'' separates from its
host — leaving the tree per-
haps in a dying state — and
becomes a self-supporting
withy shrub, capable of
producing flowers and nec-
tar, and, in due season,
abundance of ripe fruit.
Another extraordinary
climber is one of the Climb-
ing Palms. " Though no
thicker than your finger,
it will be found," says
Mr. P. H. Gosse inOmphalos,
u almost a quarter of a mile
in length. This is a kind
of Cane {Calamus *) ; its
slender jointed and polished
stem is encased in the
closely sheathing and tubu-
lar bases of the leaves,
which are spiny on their
midribs, spiny on their
pinnae, and horridly spiny
on the long and tough
whip-lash in which the
point of each leaf termin-
ates. This lengthened
cord is studded, at intervals of a few inches, with whorls of stout and
acute prickles which are hooked backwards, and perform an important
part in the economy of the plant. We see how it sprawls along the
* The Calami supply most of the walking-canes of commerce, of which some twenty
millions, valued at about £40,000, are annually imported. Mr. Gosse was a careful observer,
but " almost a quarter of a mile " is a surprising length for any of these Calami. The
statement needs confirmation.
FIG. 286. — SPURGES (Euphorbia).
To the left is Euphorbia imndicornis, in the middle E. abyssinica, to
the right E. spinosa; the first two African, the third European.
[E._Step.
FIG. 287. — WHITE BKYONY (Bryonia dioicz).
A hedgerow climber, belongins to the Cucumber family. It climbs by the aid of tendrils which contract into
spirals. It is the only British representative of the family, and here it is restricted to the South. EUROPE, NORTH
AFRICA, WEST ASIA.
231
232
HUTCHINSON'S POPULAR BOTANY
ground a few yards, then climbs up a tree, runs over the summit,
descends on the opposite side to the
ground, mounts over another tree, and
thus pursues its worm-like course. Now
as the pinnate leaves are put forth at
every joint, the formidably armed nagellum
affords a secure hold-fast to the climbing
stem, which otherwise would be liable to
be blown prostrate by the first gust of
wind ; the recurved hooks, however, catch
in the leaves and twigs of the trees, and
effectually maintain the domination of the
prickly intruder."
Writing of a forest in the interior of
Shag Island, in the Hauraki Gulf, four
miles from the mainland of New Zealand,
Froude, the historian, says : " We turned
from the path into the forest, forcing our
way with difficulty through the thicket.
Suddenly we came on a spot where three-
quarters of an acre, or an acre, stood bare
of any kind of undergrowth, but arched
over by the interwoven branches of four
or five gigantic Pokutukama-trees, whose
trunks stood as the columns of a natural
hall or temple. The ground was dusty and
hard, without trace of vegetation. The roots
twisted and coiled over it like a nest of
knotted pythons ; while other pythons,
the Rata parasites [Metrosideros robusta]
wreathed themselves round the vast stems,
twined up among the boughs, and dis-
appeared among the leaves. It was like
the horrid shade of some Druid's grove."
" Without trace of vegetation " — those
words are significant. Though the state-
ment is a negative one, it tells of a warfare
of vegetation, too — but a warfare that is
accomplished. The victors are the Pokutu-
kama-trees and the Ratas, which alone
survive. How many youthful plants —
Blackwood-trees, Ti-trees, Acacias, Tree-
ferns, and so forth — have been crushed out of being by these vegetable
pythons !
Photo by] \E. Step.
FIG. 288. — VIRGINIA CREEPER (Vitis
quinquefolia),
Showing leaves and tendrils. The tips of the
tendrils develop into clinging discs when they
come in contact with any firm substance.
NATURE'S WOODCRAFT: A CHAPTER ON STEMS
233
To much the same purpose speaks a recent traveller, Mr. James
Rodway. Species of Loranthacece — the Mistletoe family — propagated by
birds, are parasitic on the forest trees of Guiana. "As the parasite gets
strong, its long extensions spread from branch to branch, and from twig
to twig, everywhere extending octopus-like arms provided with sucking-
discs, which adhere to and bleed the tree in a hundred different places.
Branch after branch is
dried up. but as the
loranth has many strings
to his bow, this does not
hurt him much. There
are always more to con-
quer, and unless the tree
stands alone, which is, of
course, impossible in the
forest, he rarely comes
to grief. It is not to
his advantage that the
tree should die quickly,
and therefore the longer
it can support him the
better. However, even
the most sturdy giant of
the forest suffers greatly
from such continual de-
pletion, and may be so
weakened as to lag
behind in the race for
life, with the ultimate
result that it is smothered
by its fellows."
C ir cumn utation,
which has been shown
to be so general in the Photo by] IE. step.
growing ends of stems, FIG. 289. — HOOKS OF WILD ROSE (Rosa canina).
is seen to excess in the
climbing organs of weak-
stemmed plants, and is the means by which they are enabled to feel about
(if one may so say) in search of support. Thus the apex of the stem of a
Hop-plant (Humidus lupulus), fourteen inches in length, has been known to
sweep round in a circle nineteen inches in diameter in quest of something
to lay hold of, and the long shoot of a tropical Asdepiad, observed by
Darwin, beating this record, described a circle five feet in diameter. As
the weather was hot, the plant was allowed to stand on the naturalist's
For the purpose of resting its Ions' weak stems on stronger shrubs in climbing,
the Wild Rose develops its prickles into flat curved hooks.
234
HUTCHINSON'S POPULAR BOTANY
study table, and he watched with interest the long shoot sweeping this
grand circle, night and day, in search of some object round which to twine.
Oeropegia sandersoni, a closely allied plant (fig. 29G), exhibits the same in-
teresting phenomenon.
The movement, which
has received the name
of circumnutotion, is,
indeed, related to, if
not identical with, that
which enables a shoot
to climb upwards — a
fact of which it is easy
to satisfy oneself by
bringing the circumnu-
tating shoot of a Hop-
plant in contact with
any upright object that
would serve as a sup-
port, when the shoot
will at once begin to
entwine about it.
Kerner suggests that
such movements may
be caused by the action
of co-operating proto-
plasts in certain rows
of cells on the circum-
ference of the shoot ;
though what it is that
impels them to this
work he does not pre-
tend to say. To him it
is "just as puzzling as
the stimulus to the pro-
duction of partition-
walls in the interior
of a cell " — and that,
as we have shown, is
one of the sealed
mysteries of biological
science.
"We will conclude this chapter with some remarks on the sizes of stems.
In prehistoric ages the Animal World had its giants both on land and sea,
of which the rocks bear witness in the fossil remains of mastodon and
Photo by] IE. Step.
FIG. 290. — WHITE CLEMATIS (Clematis montana).
The Clematis climbs by twisting its leaf-stalk round any support that ccmes
handy. These stalks harden like wire, and are attached to the woody stems long
after the leaves have fallen.
Photo Z>y] [E.
FIG. 291. — HEDGE BINDWEED (Calystegia sepium).
This beautiful weed climbs by twining its entire length round some other stem, in the same manner as that adopted by
the Hop, but in the reverse direction, i.e. to the left. EUROPE, N. AFRICA, N. ASIA, TEMPERATE AMERICA, AUSTRALASIA.
235
236
HUTCHINSON'S POPULAR BOTANY
pterodactylus, of plesiosaurus and ichy thesaurus ; but the Vegetable AVorld
has its giants now. Think of the Wellingtonias (Sequoia) of California, in
their sheltered valleys five thousand feet above the level of the sea, with
stems three hundred feet and more in height, and ninety, one hundred, or
even a hundred and twenty feet in circumference. Think of the mighty
Eucalyptus-trees of
Western Australia,
rising from the glens of
the Warren Biver and
the deep recesses of the
Dandenong, and pierc-
ing the sky four and
five hundred feet up —
trees that might look
down upon the spire of
Strasburg Cathedral, or
cast their shadows over
the Great Pyramid ! *
Think of the great
Banyan - tree of the
Nerbuddah, with its
three hundred and
twenty main trunks and
three thousand smaller
ones, covering an area
of two thousand feet —
a giant which shelters
beneath its umbrageous
arms a host of Custard-
apple and other fruit
trees. Think, too. of
the Silk-cotton-trees
(Bombax ceiba) of Yuca-
tan, with stems so large
that in some cases fifteen
men, with arms ex-
tended, can scarce
embrace a single trunk ;
and of the lofty Moras of Guiana, of which, as we have seen, Waterton
has left so vivid a picture. " Heedless and bankrupt in all curiosity must
he be " — again we quote from the hero of the Wanderings — " who can
journey through the forests of Guiana without stopping to take a view
* A Eucalyptus-tree measured by Froude, the historian, was forty-five feet round at the
height of his shoulder (Oceani, p. 127).
Photo by] [E. Step.
FIG. 292. — GREATER STITCHWORT (Stellaria holostea).
It climb? the hedge by sticking out its stiff leaves at right angles with the weak
stem. EUROPE, w. ASIA.
NATURE'S WOODCRAFT: A CHAPTER ON STEMS
237
Photo by]
FIG. 293. — BLACK BRYONY (Tamus communis).
IE. Step.
Like the Convolvulus, the Black Bryony climbs by twining always to the left. It is the only British representative
of the Yam family. The specimen photographed is a young plant ; in older individuals the red berries are produced
in bunches. EUROPE, N. AFRICA. W. ARIA.
of the towering Mora. Its topmost branch, when naked with age, or
dried by accident, is the favourite resort of the toucan. Many a time has
this singular bird felt the shot faintly strike him from the gun of the fowler
beneath, and owed his life to the distance betwixt them." Would that
some of our English song-birds, growing scarcer amongst us every year,
had trees as high to nest in !
The " Monster Cactus " which reached Kew Gardens in 1846 measured
nine and a half feet in circumference and weighed a ton. Eight strong
mules were required to draw it over the mountains of Mexico, and ten
men to place it in the scales at the Royal Gardens (see fig. 96). Con-
sidering that Cactuses are only succulent plants, these statistics are indeed
astonishing.
The length attained by the fleshy stems of many Seaweeds may be
referred to in this connection. One species of Sea-wrack, Macrocystis
pyrifera, which abounds in the southern oceans between Tierra del Fuego
and New Zealand, though its stalk is not thicker than a pen-holder,
sometimes measures upwards of nine hundred feet in length ; and Lessonia,
238
HUTCHINSON'S POPULAR BOTANY
another plant of the same interesting family (Laminariacege), attains to
tree-like dimensions and has a stem as thick as a man's thigh. Probably
the extraordinary length of some of these ocean Thallophytes is the
originating cause of most fables about the sea-serpent.
To return for a moment to plants with woody stems. There is a
Chestnut-tree (Castanea vesca) on Mount Etna, which measures a hundred
and eighty feet in circumference ; a Plane-tree (Platanus orientalis} near
Constantinople with a
TV* ^-S^r^t.^:/ -I Diameter of nearly fifty
feet ; and Lime - trees
(Tili(L) in Lithuania with
a girth of eighty-seven
feet ; though none of
these offers anything
remarkable in regard to
height. They are
dwarfs, indeed, beside
the Eucalyptus-trees of
Australia and the Wel-
lingtonias of California.
There are other vener-
able old Limes besides
those of Lithuania. At
Chalouse, in Switzerland,
there stood one of these
trees in Evelyn's time,
" under which was a
bower composed of its
branches, capable of con-
taining three hundred
persons sitting at ease.
It had a fountain set
about with many tables
formed only of the
boughs, to which the
ascent was by steps, all
kept so accurately and so very thick, that the sun never looked into
it." Another famous member of the same family existed — perhaps still
exists — at Neustadt, in Wurtemberg, whose huge limbs were supported by
numerous stone columns.
But it is not size alone which makes a tree noteworthy, else would the
tropical Tumboas or Welwitschias — well called mirabilis or " wonderful " —
find no place of mention here (fig. 297). The Welwitschias are not, indeed,
giants of the Vegetable World, but their stems are, none the less, curiosities.
[E. Step.
FIG. 294. — BRAMBLE AND HONEYSUCKLE.
The Bramble (Riibus fruticosus) largely climbs by means of stout spines.
The Honeysuckle does so by twining. See fig. 295.
239
240
HUTCHINSON'S POPULAR BOTANY
The first European discovery of the plant was made by Mr. C. J. Atkinson,
who forwarded specimens to the Botanical Museum at Cape Town, but
was otherwise rather reticent concerning the discovery. There was no
occasion for reticence. }Velwitschia mirabilis is an unique plant — a mono-
typic genus, indeed— totally unlike every other member of the Vegetable
Kingdom, both in appearance and mode of growth, and therefore a plant
to be taken account of. Fortunately, within a few years of its discovery,
the celebrated botanical traveller, Dr. Welwitsch, rediscovered it. While
exploring the waste and arid deserts of South- West Tropical Africa, not
far from Cape Negro, the doctor came upon a hard rough-looking disc,
elevated some ten or twelve inches from the ground, and having a diameter
of from three to four feet. It was the
stem of a Tumboa. From deep grooves
in the circumference of the stem, two
opposite leaves — tough, brown, and torn
into innumerable thongs — hung down and
trailed, curling, along the sand to a distance
of five or six feet in both directions. These
were the true leaves.* It has since been
discovered that only two such leaves are
developed on every plant, and that they
persist during the long life of the indi-
vidual. The flowers which resemble the
cones of the Larch, spring up annually in
crimson clusters round the edge of the
disc, though the wood is of a stony
hardness. The concentric layers which
compose the stem show that growth in
thickness takes place as in dicotyledons :
but upward growth is arrested at an early
period.
The age of many forest-trees is
enormous. The great Chestnut of Tort-
worth is believed to have been a flourishing young sapling in the time
of Egbert; an Oak in Normandy— the chene chapelle — which was con-
verted into a chapel some two centuries ago, was probably at that time
seven hundred years old ; while the famous Salcey Oak is probably much
older than either, and the Winfarthing Oak (see fig. 244) on the Earl
of Albemarle's estate near Diss, in Norfolk, is perhaps more patriarchal
still. But the Methuselah of the race, according to Mr. W. Senior, is the
famous Greendale Oak at Welbeck, which is believed to have weathered
the storms of fifteen centuries. About a hundred and sixty years ago this
* Not the cotyledons, as was at first supposed. Two cotyledons are, indeed, produced,
but they fall away while the plant is still quite young.
FIG. 296. — Ceropegia sunder soni.
The flower of a climber whose growing tip makes
circular movements in search of a support.
NATURE'S WOODCRAFT: A CHAPTER ON STEMS
241
tree "was deprived of its heart by the eccentric desire of the then owner
to make a tunnel through the trunk. This novel piece of engineering was
effected without any apparent injury to the tree. An opening was made
through which a Duke of Portland drove a carriage and six horses, and
three horsemen could ride abreast. The arch is 10 ft. 3 in. high, and 6 ft.
3 in. wide." The Greendale Oak has no longer the Cowthorpe Oak at
"Wetherby, in Yorkshire, as a competitor. This tree was reported to be in
possession of " a few green leaves " so late as the year 1880, and was then
thought to be about eighteen centuries old, but it is now a ruin. In 1776
its circumference
three feet from the
ground was forty-
eight feet, though
Jesse, sixty years
ago. gave its
measurement at the
base as seventy-
eight feet. The
"Winfarthing Oak,
mentioned above,
measured seventy
feet in circumference
at the base of its
trunk in 1820, and,
in the opinion of
some judges, is quite
as ancient as its
Welbeck rival. It
is said that it was
an old tree at the
time of the Norman
Conquest, FIG. 297.— TCJMBOA (Welwitschia mirabilis).
Other large Oaks A remarkable plant of tropical Africa, consisting of a hard disc from which is given
, • -, -, T off on opposite sides a pair of leaves torn into leathery thongs which are six feet in
mentioned. Dy JeSSe length. A flower-cone is shown below.
include the Salcey
Forest Oak, Northamptonshire, as being forty-six feet in circumference,
presumably at the base of the trunk ; the Flitton Oak in Devonshire, thirty-
three feet at one foot above the ground ; the Hempstead Oak in Essex,
fifty-three feet ; and the Merton Oak in Norfolk, sixty-three feet. He also
mentions the remains, at Ellerslie in Renfrewshire, of the Wallace Oak,
in which it is said William Wallace and three hundred of his followers
hid themselves from the English.
Nor are Oaks and Chestnuts the only trees famous for longevity. An
Ivy (Hedera helix) near Montpellier is nearly four hundred and sixty
19
242
HUTCHINSON'S POPULAR BOTANY
years old, and a Rose-tree at Hildesheim, in Germany, can be traced back
to the time of Charlemagne. There are Cedars (Cedrus libani) on Mount
Lebanon from six hundred to eight hundred years old ; and Lime-trees
(Tilia vulyaris) near Friburg that have existed for one thousand two
hundred and thirty years. The Yew-trees (Taxus baccata) of Fountains
Abbey are believed to have been in a nourishing condition twelve centuries
ago ; " the Olives (Olea oleaster') in the Garden of Gethsemane were full-
grown when the Saracens were expelled from Jerusalem ; and a Cypress
(Cupressus sempervirens)
at Somma, in Lom-
bardy, is said to have
been a tree in the time
of Julius Caesar. Yet
the sacred Bo-tree (Ficus
religiosa) [at Anaraja-
poora] is older than the
oldest of these by a
century, and would
almost seem to verify
the prophecy pro-
nounced when it was
planted, that it would
' flourish and be green
for ever.'" It was
under a Bo-tree that
Gautama reclined when
he passed through the
crisis of his ministry ;
and Buddhist super-
stition sees in that
event the origin of the
quivering of the Bo-
tree's heart-shaped
FIG. 293. — THE GREENDALE OAK, WELBECK.
Believed to be over fifteen hundred years old. A former owner had a passige
cut through the bole to allow his carriige to pass through.
leaves. Even the patri-
archal giant of Anaraja-
poora is not so ancient
as the older' Wellingtonias, however, some of which were lusty millenarians
when that veteran was a baby !
Here let us pause, though not for want of matter to carry us farther.
The topic, indeed, is inexhaustible. Even in a subject so apparently tame
and dry as the stems of plants, how much there is to interest and inform !
How infinite in variety, how wealthy in resource, how wonderful, is Nature
— whichever way we turn, on whatever class of objects we fix the eye !
How many curious facts— morphological and biological — have been before
Photo fry] [E. Step.
FIG. 299. — ACORNS AND LEAVES OF PEDUNCULATE OAK (Quercus pedunculata).
This form of the Common Oak (Quercus robur) is by some authors considered a distinct species. Its distinguishing characters
are — the leaves are nearly or quite -without stalks, and the flowers and acorns are on long stalks. The Oak is native from
the Atlas range and Syria in the south almost up to the Arctic circle.
243
244
HUTCHINSON'S POPULAR BOTANY
us since we began!
Glance back for a
moment and consider a
few of them. Recall
a leading fact here and
there. Think of the
structure of a plant with
reference only to leaf.
root, and stem (for the
flower as yet we have
not reached) ; think of
the millions of cells and
vessels which compose
it : of the provision for
the upward and down-
ward flow of sap ; of its
life-sustaining and life-
destroying secretions ; of
the means by which its
growth is effected. What
lessons in patience and
prudence, in thrift and
economy, the plants
could teach us ! How
sentient and wise they
appear to be — how
steady and methodical—
how provident for the future plant ! Think of the endless variety of
external forms in root and stem ; of the habits, metamorphoses, and
motions of those organs ; of their latent vegetative possibilities, their
vigorous growth, their longevity. Poets would even persuade us that
they have passions like ourselves — envies and jealousies, loves and anti-
pathies ; and one almost wonders at times if the thought is only fanciful.
But we are treading on forbidden ground.
FIG. 300. — THE W INEARTHING OAK, NEAR Diss.
A tree of great age. whose trunk is over seventy feet in circumference at its base.
CHAPTER VIII
LEAF-BEGINNINGS AND LEAF-FORMS
"Only leaves? Yet where would any of vis be to-day but for the silent offices of leaves?"—
Finger-post Essays.
HAVING- treated at some length in a previous chapter of the internal
structure and functions of the leaves of the plants, we may now
devote a few pages to their external forms — a subject by no means
easy to treat in a popular manner. Nevertheless, we think that it has
recommendations of its own and will not be found unfruitful of interest.
The beginning of the leaf is the bud. The foliage buds which we see
expanding in the spring are formed the autumn before ; and the busy
Photo by-]
FIG. 301. — HORSE-CHESTNUT (dSsculus hippocastanum).
[E. Step.
On the right is a leaf with a normal leaf-stalk; on the left one with broad furry stalk ; and in the centre a bud-scale.
The intermediate character of the left-hand leaf shows that the bud-scale is a modified leaf.
245
246
HUTCHINSON'S POPULAR BOTANY
protoplasts, as though aware that the nipping frosts of winter will have
to be faced by these nurslings of the Vegetable World, provide them
with jackets which effectually keep oat the cold, and which may be
thrown off with the milder spring's return. These jackets are botanically
known as scale-leaves or bud-scales (fig. 302).
In some plants — as the Horse-chestnut (/Escidus hippocastanum) — the
scales are covered with a gluey substance, resulting from the conversion
into mucilage of a layer of epidermal cells beneath the cuticle, which
increases their efficiency as bud protectors ; while in many speoies of
Willow (Salix) and not a few other plants the scales are provided with
a coating of soft hair or down. When bud-scales are not developed,
the leaf-like appendages— stipules — at the bases of the }'oung leaves
frequently serve as protectors ; or the leaves
themselves may be covered with wool. In the
majority of cases — the Indiarubber-plant (Ficus
elastica) may be cited as an example — these pro-
tective coverings drop off when the leaf is strong
enough to bear exposure to sun and weather
(fig. 304) ; but in others they persist throughout
W' the life of the plant. The membranous stipules
£^\ of the Tulip-tree ( Liriodendron tulipifera) close
^E» over tne voung leaf like the shells of a walnut;
and on pulling them apart the folded leaf may
'.I be seen curled up, and looking as snug as a kitten
{\ in a basket (fig. 307). These stipules shrivel and
% fall off directly their work is done.
Another and more familiar form of protective
bud-scales is the brown, drjr, chaffy -looking growth
which covers the tender green fronds of many
Ferns, and which may be well studied in the
Common Scale-fern (Asplenium ceterach), one of
the prettiest of our mural species. The closely packed overlapping scales,
which are of a rust-coloured brown, completely cover the under surface
of the fronds ; and in this case are persistent, for the plant grows in exposed
situations and cannot afford to dispense with its chaffy undervest as it grows
older. "When dry winds prevail or the sun is in his fiercer moods, the fronds
roll up, and thus make the most of their protective scales. The leaves of
evergreen plants, which, though they have to brave the rigours of winter,
lose their scales at an early period, are provided with a specially tough and
water-tight epidermis, and their smooth glossy surfaces are admirably
adapted to prevent the accumulation of snow upon them. Good examples
are offered by the Common Holly (Ilex aquifolium) and the Sweet Bay-tree
(Laurus nobilis).
Buds are usually formed either at the ends of branches, when they are
FIG. 302. — CHRISTMAS ROSE
(Helleborus niger).
The sm 1'er figure shows a leaf-bud
before opening ; in the larger figure it
has emerged from the bud-scale.
Photo by~\ [E. Step.
FIG. 303. — HORSE-CHESTNUT (ASaculus hippocastanum).
A new shoot. Below, the first leaves of a new branch ; above them, the gummy bud-scales from which the limp
upper leaves and stem ending in the flower-buds have emerged.
247
248 HUTCHINSON'S POPULAR BOTANY
called terminal, or in the axils of leaves, when they are said to be axillary •
and they are frequently found in both positions on the same plant. Those
which fall under neither of these categories are described as adventitious.
Adventitious buds apparently give rise to most of the leafy shoots on
old tree-trunks ; * and not infrequently they are developed on roots.
Injury to the aerial parts of certain plants will induce the formation of
root-buds. The felling of a tree, for example, may be the occasion for a
whole crop of underground buds ; for the protoplasts in the root may —
and often do — recover from the shock, and being diverted from their
regular work, they busy themselves in the formation of buds, from
which, in due course, arise new leaf-shoots, containing all the promise
and potency of future trunks.
Occasionally adventitious buds are borne on
leaves, and to such the name epiphyllous has
been applied. If a leaf of one of the large-leaved
species of Begonia or of Gloxinia be planted in a
suitable soil, it will put out roots from its stalk,
and buds from various parts of the blade — a fact
of which horticulturists take every advantage.
When it is desired to multiply any of these plants,
the nurseryman collects a number of the older
leaves, and having made incisions with a sharp
knife across the principal nerves on the under
side, he spreads the leaves on sand or coconut
fibre, and shades them carefully from the sun. As
a result of this treatment, bulbils presently appear
at the lower ends of the nerves, and when these
have attained to a certain size, they are removed
and placed in separate pots. Each bulbil is now
a distinct plant.
Epiphyllous buds are sometimes met with on
Liliaceous and Orchideous plants, as well as on
the Lady's-smock or Cuckoo-flower (Cardamine
pratensis) and the Celandine (Chelidonium majus) ;
but the plant which is most celebrated for its bud-
bearing leaves is probably Bryophyllum calycinum,
an Indian evergreen shrub of the House-leek
family, common enough nowadays in English
stovehouses, where it is grown as a curiosity.
The thick fleshy leaves of this plant (fig. 309)
need no artificial incisions to stimulate their
FIG. 304.— INDIARTJBBER productiveness. Nature has already notched the
* Possibly, however, such buds are more often axillary
Young leaf expanding and throwing . •" '
off scale. buds which nave lam dormant.
LEAF-BEGINNINGS AND LEAF-FORMS
249
IE. Step.
FIG. 305. — SCALY SPLEENWOKT (Asplenium ceterach).
ck of the frond is covered with golden-brown chaffy scales, which protect it before expansion and when it rolls up
as though dead in dry weather. EUROPE, N. AFRICA, w. ASIA, HIMALAYA.
leaves at the margin, and every full-sized leaf, even when growing on the
parent plant, exhibits at each of the notches a group of cells — the embryo
bud — which to the naked eye appears like a speck. When one of these
leaves is removed and placed in a moist situation, the buds develop and
leafy shoots appear ; while the old leaf soon falls to decay, and the young
plants become independent and self-supporting.
A New Zealand Fern, Asplenium bulbiferum, is likewise noted for its
budding propensities. The buds are borne on the, divisions (pinnules) of
the older fronds, which are so proliferous that a single plant may be the
parent of many hundreds of new individuals. Other Ferns — as Aspleniutn
edgetvorthii, Ceratopteris thalictroides, Gleichenia cryptocarpa, G. flabellata,
and G. cunninghami — display the same vital energy : -indeed, there is reason
for believing that a fern-frond is simply a cladode or flattened branch, and
that the buds are normally produced like the flower-buds of the cladodes
of the Butcher's Broom. A graceful North American species of Hart's-
tongue Fern known as the Jumping-leaf (Scolopendrium rhizophyllum)
usually produces buds at the ends of its narrow lanced-shaped fronds. The
fronds bend over until their slender tips touch the ground, when roots form
250
HUTCHINSON'S POPULAR BOTANY
FIG. 306. — ORIENTAI
PLANE-TREE (Platanus
orientMs.)
A leaf-bud with its protecting
cap removed.
' -" on the under surface at the points of contact, and
m from the upper surface new fronds arise (fig. 308).
/I It may be well to remark here that the plant
^^. J9 known as the Butcher's Broom Helwingia (H. rusci-
d^ f mm flora), the flower-buds of which are seated on the
JWllr m[A foliage-leaf, is not to be classed with plants like
/J^^ »L Bryophyllum, and for this reason : the flower-buds of
^y WtF Helwingia are not true epiphyllous buds. They do not
j^J spring from the tissues of the leaves on which they
are seated, but from the axes of the leaves, and with
these axes they are connected by strands, which are
simply disguised flower-stalks. In short, the buds
are not the result of protoplasmic activity in the
leaf-tissue, but spring from the rudimentary flower-
stalks, which differ from ordinary flower-stalks by being fused with the
midrib of the leaf. Another plant which somewhat resembles Helwingia
in this respect is Pfiyllonoma ruscifolium, a Mexican shrub ; but the leaf
in this case is surmounted by a long acumen below the base of which the
flowers appear.
The manner in which the young rudimentary
leaves are arranged in the leaf-buds — in scientific
parlance, their vernation or prefoliation — forms an
interesting study. Each species of plant has its
own particular method of folding its unexpanded
leaves, and a definitive term is applied to each.
In the Ferns (Filices) the fronds are coiled from
tip to base (drcinate) ; in the Grasses (Graminece)
from one side to the other (convolute) ; in the
Violet ( Viola) the lateral margins are simultaneously
rolled inwards towards the midrib (involute) ; in the
Cowslip (Primula) and Dock (Rumex) a similar roll-
ing is seen, but outwards (revolute) : in the Currant
(Ribes) and Beech (Fagus) the leaf is plaited with
several folds lengthwise (plicate) ; and in the Cherry
and Plum (Prunus) it is folded flat from the midrib
with the edges in contact (conduplicate). These
distinguishing names being descriptive are easily
acquired ; but we do not lay stress upon them just
now. The fact that we would emphasize (and it is
very remarkable) is this— that the tissues forming
the leaves are manufactured folded up I We can
understand a loom weaving a material, and then
folding it ; but here is the material folded up, and
unfolding only when it is all woven !
FIG. 307. — TULIP-TREE
(Liriodendron tulipifera).
Young leaf lying be
stipules, on
•if which
removed .
bee
is
11
251
252
HUTCHINSON'S POPULAR BOTANY
The arrangement of the mature and developed leaves on the stem is
also worthy of attention. To regard the mass of foliage on a tree as an
orderly arranged series of organs might seem to be a far-fetched thought ;
yet order reigns in nature where the unpractised eye sees only disorder.
It was long ago remarked by Charles Bonnet, an eminent Swiss naturalist
of the eighteenth century, that leaves and their modifications have normally
a spiral arrangement on the stem. The fact (for the truth of the obser-
vation is beyond question) is more easily understood of the foliar than of
the floral leaves, and may be better seen in some plants than in others.
It is spoken of as phyliotaxy.
The leaves of a Cherry-tree (Cerasus) will
furnish a suitable illustration. Here (fig. 313)
is a piece of a branch with all the leaves be-
longing to it. We will number them in their
order of growth, 1, 2, 3, 4, 5, and 6. Now for
our spiral. Commencing at number 1, draw a
chalk line from the base of the leaf to the
base of number 2, and from thence to the
same point in leaf 3, and so on, to the base
of each leaf in succession till number 6 is
reached. See now what has happened ! The
chalk line has traversed in a spiral manner
exactly twice round the branch, and the be-
ginning of the line at number 1 is exactly
under the end of the line at number 6; or, in
other words, the first leaf corresponds verti-
cally with the sixth. Had the fragment of
branch been longer, and contained eleven
leaves instead of six, we should have found
on continuing the line in the same manner —
that is, from base to base of the additional
leaves — that the point of the chalk would
have travelled, as before, twice round the
branch in order to reach number 11. More-
over, and as a consequence, the leaf specified
would have been found to be in the same vertical line as 1 and 6. As to
the other leaves, number 7 would have been found to be over number 2,
8 over 3, 9 over 4, and 10 over 5 — in fact, the interesting discovery would
have been reached that the leaves are disposed on the branches in cycles
of five ; and the way would have been cleared for the statement that the
laws which regulate the foliar arrangement of all plants, and the floral no
less than the foliar, may be reduced to the same mathematical precision
(fig. 313).
Not, of course, that the leaves of all plants fall under the same arrange-
G. 309. — Bryophyllum
calycinum.
formation of buds at the edges of a leaf.
LEAF-BEGINNINGS AND LEAF-FORMS
253
ment as the Cherry. In monocotyledons — particularly the Grasses— the
arrangement is often two-ranked (distichous) ; that is to say, the third leaf is
over the first, the fifth over the third, etc. ; while on the opposite side of the
stem the fourth leaf is over the second, the sixth over the fourth, and so on.
A three-ranked
(tristichous) arrange-
ment is, however,
by far the most
common among mo-
nocotyledons. The
cycles in such in-
stances are three-
leaved, numbers 4,
7, 10, 13, etc., each
commencing a new
cycle. An eight-
ranked (octastichous)
arrangement (eight
leaves in a cycle) is
found in the Holly
(Ilex), Aconite, and
many other plants.
The above are, per-
haps, the most com-
mon varieties of
phyllotaxis, but the
list is very far from
exhausted when
these have been
enumerated. A Fir-
cone is simply a col-
lection of modified
leaves, arranged in
a highly character-
istic spiral manner.
All plants, we
must remember, do
not possess leaves.
The Broomrapes and
Dodders, for example — those thriftless parasites which feed upon the
juices elaborated by the host plants to which they attach themselves — have
no need of leaves. The Cacti and many tropical Euphorbias are also deficient
in these organs, though their spines are really metamorphosed leaves or
branches, affording them (as we saw on a former occasion) protection from
Photo by] [E. Step.
FIG. 310. — LADY'S SMOCK (Cardamines pratensis).
ailed Cuckoo-flower. A familiar sprii
Dmetimes <
pinnate leaves often bear buds in their axils
.? flower in moist meadows. The
fhich develop into new plants.
254
HUTCHINSON'S POPULAR BOTANY
herbivorous wild animals. Leafless plants, however, are exceptional among
Phanerogams, and it is only when we descend the scale of Vegetable Life,
and place ourselves among the Cryptogams, or Flowerless Plants, that a
general absence of leaves becomes apparent. The Ferns have them, it is true,
their green fronds being among the chief beauties of Nature. The Mosses have
them also, but their minute and delicate leaves are destitute both of woody
vessels and stomata, and can scarcely be ranked with the busy sap-elaborating
organs of Flowering Plants. The Fungi are provided with nothing analogous
to leaves ; nor is any provision necessary, as the food on which they thrive is
derived from a host (plant or animal) or from decomposed organic matter
which does not need to be elaborated by exposure to light and air. They
are known, therefore, as saprophytes,
or feeders upon rotten substances.
A systematic description of the
various forms of leaves would, we
fear, be very wearisome. The names
themselves are as numerous as the
names of the English sovereigns from
Egbert to George V., and by no means
as easy to remember. Not only has
every part of a typical leaf its Latin
appellation, but every sort of margin,
base, and apex has a qualifying cog-
nomen. In a Grass-leaf, for example
(fig. 321), the flattened upper part of
the leaf is called the blade ; the portion
enfolding the stem is the sheath ; and
the scale-like formation between the
sheath and blade is the ligule. More-
over, the leaf is parallel-veined — i.e.
the fibrous bundles which form the
skeleton run side by side without
interlacing — a characteristic feature of almost all monocotyledons ; * its
margin is entire — i e. it is even and smooth all round— and its shape is
linear, that is, narrow and straight and several times longer than its width.
The parts of a dicotyledonous leaf have an even greater number of
distinguishing names. Take, for instance, the comjpoimcHeaf of the Dog-rose
(Rosa canina), the Ash (Fraxlnus excelsior}. Sainfoin (Onobrychis viciaifolia},
Silver-weed (Poientilla anserina\ or Kidney Vetch (Anthyllis vulneraria).
The leaf as a whole is called compound because its stalk bears numerous
leaflets, it is pinnate (Lat. pinnatus, feathered) because leaflets grow
featherwise along the sides of the stalk, and it is unequally or impari-
* There are three or four British monocotyledons— notably the Black Bryony (Tamus
communis) and the Cuckoo-pint (Arum maculatum} — which have net-veined leaves.
FIG. 311.— SWEET VIOLET (Viola odjratz).
An example of Involute vernation.
Photo by]
FIG. 312. — FERN FRONDS UNROLLING.
This photograph of the Lady Fern is a good example of Circulate vernatian, fie bud appearing as though the frond
had been rolled up from the tip to its base.
255
256
HUTCHINSON'S POPULAR BOTANY
pinnate because there is an odd lobe at the extremity. * The leaflets
themselves are net-veined, the large central vein in each being known as the
midrib ; their shapes are broadly elliptical, and their sharp, saw-like margins
are serrate (Lat. serratus, saw-like). The portion of the leaf-stalk at the base
of the leaf is the petiole (Lat. petiolus, a little foot) ; but beyond the first pair
of leaflets it is called the
rachis (Greek rachis, the
spine). The two small
leaf-like organs at the base
of the petiole are stipules
(Lat. stipula, a blade).
Now, all this is very be-
wildering ; nevertheless,
a few walks in the country,
if the neighbourhood be
at all favourable for botan-
izing, will soon familiarize
one with the principal
leaf-forms, and more will
probably be learnt in a
single hour thus spent
(with text-book in hand
for reference) than in five
or six hours of wearying
desk-work. There is a
spot which we could men-
tion, not twenty miles from
London, which is peculiar-
ly adapted for this purpose.
It is a charming piece of
Surrey landscape, in his
lifetime a favourite spot
with that prince of Nature-
interpreters, Richard
Jefferies ; so we will trans-
port ourselves thither in
imagination, and saunter
together down the shady lane, not yet disfigured by lamp-post or flaming
FIG. 313. — FIVE-RANKED (PENTASTICHOUS) ARRANGE-
MENT or LEAVES OF THE CHERRY.
* Compound leaves which have no such terminal lobe, but all the leaflets of which
run in pairs (fig. 315), are described as pari-pinnate (Lat. par, paris, equal, and pinnatm).
We get this form in the Vetches ( Vicid). In many of the Acacias each of the pinnae of the
pinnate leaves is itself pinnate, so that the form is doubly or li-pinnate ; while in the Lesser
Meadow-rue (Thalictrum minus) the division is carried a step further, and we have a tri-
pinnate form.
WAl.KKR'S CATTLEYA (Cattleya Walkeriatia).
C.attleyas are a favourite genus of evergreen Orchids, producing some of the finest of flowers. Walker's Cattleya
LEAF-BEGINNINGS AND LEAF-FORMS
257
FIG. 314. — WILD CHERRY (Primus avium).
The flowers are produced before the leaves are fully expanded. At this stage they will be seen to have the
two halves of the leif-blade folded with their upper surfaces in contact.
pillar letter-box, and beside a narrow stream which separates the parson's
few acres from the neighbouring farm, and so on to the schoolmaster's
cottage, gathering our leaves by the way. Lane, stream, meadow, corn-
field, cottage garden — these will supply all, and more than all, the forms
required, and future rambles will help to fix in the memory the facts
elicited.
Behold, then, the lane ! — winding, odorous, leafy ; a spot for poesy,
such as might rouse the happy muse in a Clare or Cowper, or move to
loving activity the pencil of a Birket Foster. It is a bright June day,
and the song of birds, the hum of innumerable flying insects, and the
click of the grasshopper make music the whole way^ong. Noble Horse-
chestnut-trees (sEsculus hippocadanum) rise out of the lane-side hedges
at every few paces, and their branches meet over us, their spreading
digitate leaves affording welcome shade (fig. 303). An ivy-clad Oak (Quercus
robur) is also passed, easily to be recognized by its knotty, widespread
branches and wealth of sinuate leaves (fig. 317). Shakespeare, whose
quick eye let nothing escape him, called this tree " the unwedgeable and
20
258
HUTCHINSON'S POPULAR BOTANY
gnarled Oak," and no description could be more appropriate. Notice
the Ivy (Hedera hdix), a familiar object everywhere. The beauty
of its light-veined leaves has often been celebrated by poets. Observe
particularly the direction of the principal veins in one of these leaves.
They radiate outwards from the base of the leaf, like the outspread
fingers of the hand :
The leaves on the
climbing stems of
the Ivy are always
lobed, and the de-
pressions or sinuses
between the lobes
are usually shallow ;
but in other leaves
— as the Common
E a g w o r t (Setucio
jacobcea) — they are
deep and pinnate
(fig. 318). That
bushy-looking weed,
whose pale green
purple-edged flowers
must be sought for
earlier in the year,
is the Stinking
Hellebore (Helle-
borus fcetidus} ; and
we are fortunate in
meeting with a
specimen here, as
the plant is rarely
found growing wild.
Its palmately veined
leaves are deeply
divided, on which
account they are
called palmati-partite (fig. 316) ; while the downward-turned lobes at the
base of each define their place as among pedate leaves. Palmati-partite
leaves should be carefully distinguished, on the one hand, from palmately
lobed (palmatifid) leaves, the divisions of which do not extend so far as
those of the former ; and, on the other hand, from palmately cleft (pal-
matisect) leaves, in which the divisions extend very nearly to the base. The
Photo ly] [E. Step.
FIG. 315. — TUFTED VETCH (Vicia cracca).
The finest of our Vetches, the bright blue flowers being gathered into a dense raceme
which makes them very conspicuous. The plant climbs by means of tendrils, which
are a continuation of the rachis.
Photo by-]
[E. Step.
FIG. 316. — STINKING HELLEBORE (Helleborus fostidus).
The foliage offers good examples of the pedate leaf. The sepals constitute the conspicuous part of the flower, and are
. pale yellow-green rimmed with red-purple. The petals have been converted into nectaries, and are hidden below the
stamens. It is a native of Western Europe only, and a rare plant in the South and Bast of England.
259
260
HUTCHINSON'S POPULAR BOTANY
branch of Ivy which
we were just examining
offers examples of pal-
matifid leaves, and the
well-known Monkshood
(Aconitum napellus), of
which the school-
master's garden will
furnish specimens, bears
leaves of the deeply cut
palmatisect form (fig.
819).
As we are now down
among the grass, we
may pause a moment
to admire the splendid
white blossoms and
pretty leaves of the
little Trefoil, creeping
in and out between the
cool blades. It is a
species of Clover or
Trefoil (Trifoliutn sub-
terraneum, fig. 319).
Notice that the tiny
leaflets all spring from
the top of the petiole
or leaf-stalk, just as in
the case of the Horse-chestnut-leaf gathered at the beginning of our
walk ; and as these leaflets are always three in number in the Trefoil,
its leaves are said to be 3-foliate or ternate. We say " always three in
number," but now and again a sprig with only two leaflets will turn up,
and if the happy finder of this rarum folium be an East-country maiden,
she will probably treasure it as a charm.
A Clover, a Clover of two,
Put it on your right shoe ;
The first young man you meet,
In meadow, lane, or street,
You'll have him, or one of his name.
So runs the rhyme ; while the finding of a 4-foliate Clover-leaf is said to
be a hardly less auspicious event :
If you find an even Ash-leaf or a four-leaved Clover,
Look to meet your true love ere the day be over.
Photo by]
FIG. 317. — THE OAK (Quercus robur).
[J. Holma
Showing a normal trunk with its principal limbs, thrown in the open. In woods
the limbs and brunches are less spreading.
LEAF-BEGINNINGS AND LEAF-FORMS
261
But two- and four-leaved Clovers must be regarded as abnormal occur-
rences, the 3-foliate form being sufficiently common to be characteristic ;
and hence the Latin name of the genus — Trifolium — is quite appropriate.
Horse-chestnut-leaves, on the other hand, regularly vary as to the number
of their leaflets, and you will often find on the same tree 5-foliate or
quinate forms, 7-foliate or septenate. and so on. "When a ternate leaf is
further subdivided, it becomes either biternate or triternate, as in the
Master wort (Peucedanum ostruthium] and Baneberry (Actcea spicatci) respec-
tively. The Herb-paris (Paris quadrifolia),. which should be looked for in
moist and shady woods, has, as its Latin name implies, 4-foliate (quadrate)
leaves.
Let us linger
among these
meadow Grasses a
moment longer
while we examine a
single blade of one
of them, with Ruskin
for our guide and
teacher. " Nothing
there, as it seems,
of notable goodness
and beauty," he says
to us.
A very
little strength and
a very little tallness,
and a few delicate
long lines meeting in
a point— not a per-
fect point, either, but
blunt and unfinished,
by no means a credit-
able or apparently
much-cared-for ex-
ample of Nature's
workmanship, made
only to be trodden
on to-day, and to-
morrow to be cast
into the oven — and
a little pale and
hollow stalk, feeble
and flaccid, leading
down to the dull
IE. step.
FIG. 318. — RAGWORT (Senecio jacobcea).
The leaves are deeply cut into lobes in a pinnatifid manner The bright yellow
flower-heads are grouped in dense corymbs.
262
HUTCHINSON'S POPULAR BOTANY
brown fibres of roots. And yet, think of it well, and judge whether, of
all the gorgeous flowers that beam in summer, and of all strong and
goodly trees, pleasant to the eyes, or good for food — stately Palm and
Pine, strong Ash and Oak, scented Citron, burdened Vine — there be any
by man so deeply loved, by God so highly graced, as that narrow point
of feeble green." The specimen we have gathered is the Sweet-scented
Vernal-grass (Anthoxanthum odora-
twni), a grass to which our summer
hayfields owe much of their frag-
rance. The scent is a volatile oil
contained in minute glands in the
husk-like valves or glumes of the
flowers (fig. 321).
But we are now at the end of
the lane, and fields, farm, and stream
are all in view. On pushing open
the crazy swing-gate, the first weed
to greet our gaze is the rare Yellow
Star-thistle (Gentaurea solstitialis),
whose flower-head, surrounded by a
collar of needle-like spines, is just
preparing to open. Mark the ab-
sence of petioles on its leaves,
which are therefore called sessile.
In another week the yellow florets
will be open, and you will find
in their delicate structures much
that will repay attention. Yonder,
not five paces off', is a cluster of the
Common Buttercup (Ranunculus),
with its golden cup — the " winking
Mary-buds " of Shakespeare. Here,
instead of the absence of leaf-stalks,
you have petioles of an unusual
length. Observe how they clasp
the stems with their expanded bases.
We name such leaves amplexicaul, or
stem-clasping. Other familiar plants which may be cited as furnishing
examples of amplexicaul leaves are the Groundsel (Senecio vulgaris} and the
Shepherd's Purse (Capsella bursa-pastoris), in each of which the base of the
leaf clasps the stem ; and almost any species of the great Umbelliferous
family, in which the clasping is done by the swollen base of the leaf-stalk.
Now step a little nearer to the stream that skirts the meadow, and
regard carefully the tall plant which lifts its purple crest by the water's
FIG. 319. — MONKSHOOD AND TREFOIL.
The Monkshood (upper) is a good example of the palmatifid
leaf. Below it is the Subterranean Clover with ternate
leaves or trefoils.
Photo by] [W. Rossiter.
FIG. 320. — COTTON THISTLE (Onopordon bracteatum).
The spiral arrangement of the spiny leaves on the stem is very clearly marked in the illustration.
263
264
HUTCHINSON'S POPULAR BOTANY
FIG. 321.—
VERNAL- GRASS.
edge. Ifc is a Marsh Plume-thistle (Cnicus palustris). Its
brown-tinged thorny leaves recall old Chaucer's lines :
For thistles sharp of many maners,
Netlis, thornes, and crooked briers ;
For moche they distroubled me,
For sore I dredid to harmed be.
Notice that the lower part of the leaf is united for a certain
length with the stem, which is on that account called winged.
The leaf is decurrent (fig. 322).
As we are now so close to the hedge, peep through the
gap into the cornfield beyond, and observe that singular
plant with small greenish yellow flowers, whose stem, branched
at the top, passes almost through the centre of the oval
leaves (fig. 323). It is the Common Hare's-ear (Buplea-
rum rotundifolium). Our Saxon forefathers called it Thorow-
wax. from the circumstance of the stalk going through (A.S.
thorow) the leaf ; wcix being the old word for " grow." Our
Latin-loving botanists of to-day call such leaves perfoliate.
Ah ! you have smelt the Honeysuckle. Had you waited
another week you would have been too late, for this is the
rare Perfoliate Honeysuckle ( Lonicera capri/olium), which
seldom flowers after June, and which is almost confined to
Oxfordshire and Cambridgeshire. There it is, twining in and
out among the Privet bushes. Observe its sessile upper
leaves (fig. 323). which look as if they have grown together
at their bases. Leaves which offer this singular appearance
are described as connate. More familiar examples may be
found in the Yellow AVort (Chlora perfoiiata) and the Teasel
(Dipsacus sylvesfris1 fig. 324).
Before moving away you should notice the lance-shaped
(lanceolate) leaves of the bush which supports the Honey-
suckle— viz. the Privet (Ligustrum, fig. 328) — and also the egg-
shaped (ovate) leaves of the Crab-tree (Pyrus mains] which
over-shadows them. With these last may be contrasted
the smooth pale green leaves of the Water-pimpernel
(Samolus valerandi), growing on the margins of the stream
below. They are broadest and roundest at the apex, and
taper towards the base — in other words, are inversely egg-
shaped or obovate.
How various is Nature ! The lane, the meadow, the corn-
field, the hedgerow, the brookside, even the tiny stream
itself, have something fresh to show at every step. Here
are Violets (Viola} with their pretty heart-shaped (cordate)
LEAF-BEGINXINGS AND LEAF-FOEMS
265
leaves, though it is vain to seek for flowers on them now. The capri-
cious days of April are the days when the nodding Violet blows. And here
is Wood-sorrel (OxaHa), which children delight in, though for esculent
rather than aesthetic reasons. The form of the bright green leaflets which
compose its ternate
leaves is just the reverse
of the leaf-form of the
Violet ; for the rounded
lobes are at the apex
of each. Here the
shape is called obcordate.
You will notice also that
there is a notch at the
blunt apex of each leaf-
let, as though a piece
had been cut out. All
apices which have this
peculiarity are emargin-
aie.
Do not mistake that
pretty yellow-flowered
creeper, with quinate
leaves and inversely
egg-shaped leaflets, for
a species of Buttercup.
It is the Creeping
Cinquefoil (Potentilla
reptans, fig. 326). You
will meet with it on
almost every wayside
bank, and often, as
here, winding its devi-
ous way among the
linear leaves of the
meadow Grasses. That
other creeper, with
fragrant kidney-shaped
(reniforni) leaves, is a
frequent companion of
the Cinquefoil, delighting, like its quinate friend, in sunny banks and meadows.
Its stalked and downy leaves, whose crenate margins should be noted well
(figs. 327. 331), were in great request for tea in olden times, when the plant
was sold by the " herbe-women of Chepeside " under the names of Gill-by-the-
ground, Hay-maid, Cat's-foot, etc. It is the familiar Ground Ivy (Xepeta
Photo by} [E. Step.
FIG. 322. — MARSH-PLUME-THISTLE (Cnicus palustris).
The leaves are decurrent, that is, continued as wings far down the stem.
266
HUTCHINSON'S POPULAR BOTANY
gleckoma). The small yellow flowers which, peep through the tall grass in
the corner of the meadow belong to a species of Medicago—the Spotted
Clover of Cornish nomenclature, the Medicago maeulata or Spotted Medick
of botanists. The little purple spot in the centre of each of its cuneate
or wedge-shaped leaflets explains the origin of its specific name. Keep
a sharp eye on the hedges for a taller, purple-flowered species of this genus,
the Lucerne (M. sativa), whose serrated leaflets offer good examples of the
oblong form. The flattened
apices of the leaflets
sometimes have a sharp
point about the middle, and
then they are called mucron-
ate.
Daisies (Bellis perennis)
are everywhere — the com-
monest of all flowers, yet
the flower that is never
common! Who of us that
loves Nature has not felt
something of Chaucer's de-
light in what a later poet
has called the " wee, modest,
crimson-tippet flower" —
" the little dazy that at even-
ing closes " ? gladly con-
fessing with him that this
is of all floures the floure,
Fulfilled of all vertue and hon-
oure ;
And evir like faire and fresh of
hewe,
As well in winter as in summer
newe.
FIG. 323.-PERFOLIATE HONEYSUCKLE (Lonicera capri- But ifc is the brOad round
folium), WITH CONNATE LEAVES ; AND PERFORATE leaves, whose margins taper
LEAVES OF HARE'S-EAB (Bupleurum rotundifolium). down to the base, rather
than the pretty pink-tipped
florets, that we have to notice (fig. 332). They are called spathulate ;
though you would probably find on examining other specimens that the
leaves more generally incline to the inversely ovate form, like those of
the Water-pimpernel. The London Pride (Saxifraga umbrosa) offers a
more fixed type of spathulate leaf ; but there is [small chance of finding it
growing wild in these parts (fig. 330).
Before we cross the narrow footbridge and leave the stream at our back,
Photo l>y\ IE. Step.
FIG. 324. — TEASEL (Dipsacus sylvestris).
The leaves are united round the stem, and the lower pairs form capacious basins in which dew and rain collect,
imposing an impassable barrier to the ascent of creeping insects.
267
HUTCHINSON'S POPULAR BOTANY
FIG. 325. — RENIFORM LEAF
OF A SPECIES OF ARISTOLO-
CHIA.
pluck a leaf of that handsome water-plant with
the white three-petalled flowers. It is the Common
Arrowhead (Sagittaria sagittifolia). Sagitta is the
Latin word for " arrow," and you have only to
glance at the leaf in order to appreciate the fit-
ness of its name (fig. 329). All arrow-shaped
leaves are termed sagittate ; and those who have
been much in the country parts of Norfolk and
Suffolk will have noticed this attractive form in
the leaves of the Tower Mustard (Turritis glabra),
which grows rather plentifully on the drier banks.
The pink-flowered Sheep's-sorrel (Rumex acetosa),
which may be met with on dry heaths and downs,
has somewhat similar leaves, though the two
lobes at the base of the leaf turn
outwards, whence they are classed
with halbert-shaped or hastate
leaves. Those aquatic plants
with white flowers and three-lobed
floating leaves, growing beyond
the long sivord-shaped leaves of the
Yellow Flag (Iris pseudacorus), are
Water-crowfoots (Ranunculus aqua-
tilis). On pulling one of them up,
it will be found that its submerged
leaves are quite different from the
floating leaves, being divided into
hair-like segments. Such leaves are
called til ifornij while plants which
produce
two or more different kinds of leaf on the same
stem are said to be heterophyllous. We shall have
more to say about submerged and floating leaves
on a future occasion.
Beauty is everywhere. Nature's brightest
colours meet the eye at every step, for June is em-
phatically the month of flowers. How they glint
and glow among the Barley !— though the farmer
who owns the field has little praise to bestow upon
them — be sure of that!
FIG. 326. — CINQUEFOIL (Potentilla reptans),
\Vith Cjiiinate or five-parted leaves, and an epicalyx to the
FIG. 327. — GROUND IVY
(Nepeta glechoma),
Showing reniform leaves in pairs,
There are velvet Campions, whits and red,
And Poppies, like morning glories spread,
That flash and glance with their scarlet sheen
The stalks of the bearded grain between
LEAF-BEGINNINGS AND LEAF-FORMS
269
— not to mention the numerous representatives of the White Mustard
< Sinapis alba), Corn-spurrey (Spergula arvensis), Hare's-ear (Bupleurum),
Corn-cockle (Agroatemma gilhago), Succory (Cichorium intybus), etc. But
the Poppies (Papaver rhceas) are pre-eminent. They "fill every interstice
between the Barley-stalks, their scarlet petals turned back in very languor
of exuberant colour, as the awns, drooping over, caress them" (Jefferies).
Observe the irregular leaves of these frail beauties, with their divi-
sions extending very nearly to the midrib. We call a leaf of this
kind pinnatisect. If you
compare with these a
leaf of the White Mus-
tard (Sinapis alba), that
tallish plant with yellow
four-petalled flowers,
you will find that it is
not so deeply divided,
though the divisions, as
in the Poppy, follow
the direction of the
principal veins. It is
pinnatijid. Leaves of
this plant may also
be described as lyrate,
from their general re-
semblance to a lyre,
their terminal lobes be-
ing much the largest,
and the other lobes de-
creasing gradually to-
wards the base.
Ere quitting the field,
secure a specimen of the
Corn-spurrey (Spergula
arvensis). This plant is
a friend of farmers when
found on meadow-land,
but a troublesome obnoxious weed here among the corn. Its small white
rlowers are very sensitive to atmospheric changes. Qne writer affirms that
he has seen a whole field, which was whitened with its blossoms, entirely
changed in appearance by the petals closing when a black cloud passed
over and discharged a few drops of rain. The plant may always be
recognized by its slender cylindrical leaves, arranged in whorls round
the stem. Leaves which thus grow in whorls are said to be
verticillate.
Photo by\ • IE. Step.
FIG. 328. — PEIVET (Ligustrum vulgare).
Showing the lance-shaped, opposite leaves and black berries.
270
HUTCHINSON'S POPULAR BOTANY
Yonder dainty little plant, with bright scarlet flowers, is the Scarlet
Pimpernel or Poor Man's Weather-glass (Anagallis arvensis], which is no
less sensitive to the weather than the Corn-spurrey. Gerard e tells us that
the closing of the flowers " betokeneth rain and foul weather ; contrarywise,
if they be spread abroad, fair weather." But as they have definite hours
for opening and closing despite the weather, absolute confidence must not
be placed in them as weather prophets. You will notice that the sea-
green sessile leaves are placed in pairs on opposite sides of the stem ;
hence they are described as opposite, to distinguish them from alternate
leaves, which issue singly from their nodes, and which, as they succeed each
other, are placed alternately on different
sides of the stem. Notice further in the
Pimpernel that each pair of leaves crosses
the pair immediately below it at right
angles, for which reason they are said to
be decussate. The Lilac (Syringavulgaris),
Privet (Ligwstrum vulgare), and Sycamore
(Acer pseudo-platanus) are other familiar
examples of decussate leaves.
Here is the stile, and we may as well
step over it, and cross the dusty road to
the schoolmaster's cottage. Observe as
you do so the plant with prostrate stem
and pale greyish lilac flowers. It is the
Dwarf Mallow (Malva rotundifolia], a lover
of farmyards, field borders, and dry way-
'fjf^ i "^^^L sides. The specific name of the plant is
^P • JH derived from its sub-rotund or orbicular
leaves — a form which we have not hitherto
met with (fig. 333). Among Orientals
these leaves have long been in use for
culinary purposes ; indeed, it has been
supposed that this is the plant referred
to by Job, when he bitterly complains of the derision of men younger
than himself, " whose fathers he would have disdained to have set with
the dogs of his flock," and whose employment was once no better than
to " cut up mallows by the bushes."
At last we are at the cottage. The little Pearlworts (Sagina procumbens),
straggling over the garden path, show that the neatly fenced garden has
been allowed to run somewhat wild of late. They are among the smallest
of our wild-flowers, and their awl-shaped (subulate} leaves are scarcely
thicker than a pack-thread. The Dandelions (Taraxacum officinale) witness
of the same neglect, and are disputing every inch of space with their
tinier neighbours. Observe the runcinate leaves of this weed, the pointed
FIG. 329. — LEAF OF ARROW-HEAD.
A typical example of the aerial leaves of this
aquatic plant. For other forms see fig. 335.
Photo by] [E. Step.
FIG. 330. — LONDON PKIDE (Saxifraga umbrosa).
• The foliage offers a good type of the spathulate leaf, and the edges are crenately toothed. The plant is wild in th e
West and South-west of Ireland : also in Spain, Portugal, and Corsica.
271
272
HUTCHINSON'S POPULAR BOTANY
lobes of which turn downwards, whence their name, from runcina, a saw.
They are also called radical leaves, but the term is founded on error,
for though they appear to spring from the root, they really arise from the
much-shortened stem, and this is the case with most — if not all — so-called
radical leaves. Where, as in the Pearlwort, it is evident on a superficial
examination that the leaves proceed from the stem, they are termed
cauline.
How gay the Tropaeolums look, with their bright orange and yellow
flowers, and handsome peltate leaves ! Peltate (Lat. pelta, a shield) is a
good name, for the leaves are held aloft by the plant like true shields,
the peculiar insertion of the stalk or petiole on the under side of the blade
giving them that appearance. The peltate leaves of the Sacred Lotus
(Nelumbium speciosurii), one of the beautiful aquatic plants to be seen in
the Victoria Regia House at Kew, sometimes measure as much as two feet
in diameter (fig. 337). Those hardy Begonias in the centre bed rival the
Tropaeolums in brilliancy of colour. Notice well their unequal-sided or
oblique leaves (fig. 336), which are characteristic of the large family of
succulent herbs to which these plants belong.
Ah, you have pricked your hand against the hedge ! There was need
to warn you of the Holly's spiny leaves; but doubtless the offender will
be forgiven on account of its associations, and the pleasure which its green
FIG. 331. — GROUND IVY (Nepeta glechoma).
A familiar hedgerow plant, with opposite, kidney-shaped leaves and blue-purple labiate flowers.
[E. Step.
LEAF-BEGINNINGS AND LEAF-FOEMS
273
FIG. 332. — DAISY (Bellis perennis).
The leaves are of the spathulate shape, and form a rosette from which arise the composite
IE. Step.
vers on scapes.
and glossy leaves afford when other trees are stripped and brown. Southey
says :
When all the summer trees are seen
So bright and green,
The Holly-leaves their fadeless hues display
Less bright than they ;
But when the bare and wintry woods
we see,
What then so cheerful as the Holly-
tree ?
The Holly (Ilex) is, in short, an evergreen, the leaves of one year re-
maining on the plant through the winter, until those of the next spring
have formed ; in which respect it resembles the Ivy and Laurel. Many
of the Conifers (Pines, Yews, Junipers, etc.) have needle-shaped (adcular)
leaves, which persist for many years (fig. 339). The great majority of
plants, however, shed their leaves in the autumn — they are deciduous.
A far more dangerous fellow than our red-berried Christmas friend is
the plant whose straggling woody stem finds support against the Holly's
tougher boughs. Its drooping clusters of lurid purple flowers, with yellow
anthers united into a cone, at once proclaim it to be the Woody Night-
shade, or Bittersweet (Solanum dulcamara). Notice its upper leaves, the
small basal lobes of which form two little wings, or ears. Such leaves
21
274
HUTCHINSON'S POPULAR BOTANY
FIG. 333. — DWARF MAIXOW.
Orbicular or sub-rotund leaf.
are called auriculate. This plant is not the
Deadly Nightshade, but persons are said to
have been poisoned by eating its roots.
There, within a finger's length of the
nearer of the Tropseolums, is a Saxifrage ;
but not the one which we were wanting just
now. It is the kidney-shaped species (Saxi-
fraga geum), and the sharply toothed or dentate
margins of its leaves should receive attention,
as they are the first < instances of such a
margin that have come before us. You will
perceive that the teeth point outwards, and not, like the teeth in a serrated
margin, towards the apex of the leaf.
It is fortunate that the garden contains a specimen of the Tulip-tree
(Liriodendron tulipifera}. Notice the curiously abrupt or truncated ter-
mination of the leaves, which gives them the appearance of having their
upper extremities cut off. No plant furnishes better examples of a trun-
cate leaf than this. We would press the importance of always noting
the forms of leaf apices when preparing schedules of plants. Trivial
points of this kind are often of assistance in determining species and
varieties. In addition to the forms already
described — namely, the mucronate, emarginate,
and truncate — four others may be briefly al-
luded to. Two of these — the acute and obtuse
(i.e. blunted) — are extremely common, and
hardly need to be described ; the third is the
retuse, which differs from the obtuse in having
a broad, shallow notch in the middle, as may
be seen in the leaves of the Red Whortleberry
( Vaccinium vitis-idcea} ; and lastly the acumin-
ate, in which the apex narrows suddenly and
lengthens into a point or acumen. A some-
what extreme example of the latter form is
furnished by the Mexican shrub Phyllonoma
ruscifolium, which, however (as we saw earlier),
is chiefly interesting because of the peculiar
growth of its flowers, which are produced in
little bunches on the upper surface of the
midrib, just below the base of the acumen.
If, as some have suggested, the lower part of
the leaf is really a cladode, then the acumen
alone is the true leaf, and should be described
as lance-shaped rather than acuminate. How-
ever, it is quite unnecessary to go so far afield
FIG. 334. — PIMPERNEL.
With opposite and decussate leaves, each
pair crossing those above and_below it.
275
276
HUTCHLNSOK'S POPULAR BOTANY
FIG. 33fi.— BEGONIA.
forgotten that
a sound knowledge of plants presup-
poses a thorough acquaintance with the
forms of leaves), we would recommend
the practice of keeping a scrap-book,
in which the leaves collected may
be mounted
and arranged.
Let one page
be devoted to
uet-veined
1 eaves ;
another to
for specimens of leaves with acuminate apices.
Two of our British Willows — the Osier and White
Willow (Salix viminaiis and S. alba)— offer ex-
cellent examples, particularly the former ; and
although we have passed neither of these on the
way, the White Willow is so common throughout
the country that there need be no difficulty in
obtaining specimens.
So ends our excursion. All the principal leaf-
forms have now been touched upon, and we have
really travelled over most of the ground covered
by the text-books. We trust that what the present
plan has lost in method it has gained in interest.
To those who would pursue the subject further (and
let it not be
FIG. 337. — LEAF OF SACRED LOTUS.
ander
FIG. 338. — DANDELION.
A runcinate leaf.
The leaf-stalk beins attached to the centre of the
side, the leaf is said to be peltate.
parallel-
veined ; a third and a fourth to compound and single
leaves respectively; a fifth to the different kinds
of margin ; a sixth to the different kinds of apex ;
nnd so on, till every variety of shape is represented
and classified. In this way one is brought face to
face with many curious and instructive facts, of
which even the fullest treatises say nothing, and
the foundation of a trustworthy knowledge of
botany is laid that will be found increasingly valu-
able the further such investigations are pushed.
Thus, too, will one's acquaintance with Nature
herself become more and more extended, and the
facts which we have been accumulating by steady
patience and reverent study will yield in the
near future an abundant harvest of joy.
Photo by] [E. Step.
FIG. 333. — JUNIPER (Juniperua communis).
This evergreen shrub has spine-tipped, needle-shaped leaves. The berry-like cones are coated with a waxy " bloom."
and are known as baccate cones. It is native in Europe, N. Airk-a, Asia, and N. America.
277
CHAPTER IX
THE LEAF IN RELATION TO ITS ENVIRONMENT
A change in the surroundings of any plant can so react upon it as to cause it to change. By the
attempt, conscious or unconscious, to adjust itself to the new conditions, a true physiological change
is gradually wrought within the organism. — PROFESSOR DEUMMOND.
A LTHOUGrH the previous chapter was devoted chiefly to the
-E±- consideration of the forms of leaves, we must now briefly
resume the subject in order to refer to a few forms not hitherto
noticed — curious and exceptional forms, of which, in most cases, our
British plants afford no examples. This will pave the way to the subject
more especially before us — namely, the adaptation of foliage leaves to
their environment.
The subject of environment, in so far as the sustaining of vegetable
life and vigour is concerned, has been already dealt with in preceding
chapters, where we have seen that, while in the plant itself resides the
principle of Life, in the environment are found the conditions of Life ;
and that without the fulfilment of those conditions — in other words,
without the regular supply of heat, air, water, inorganic substances,
and so forth, to the living
tissues — the plant would
languish and die. This part
of the ground — the most
important part without
doubt — we do not propose
to retrace. What will be
before us in the pages im-
mediately succeeding is the
effect of environment in
modifying the structure
rather than in sustaining
the life of the plant — the
effect, indeed, which is evi-
dent in what is called Vari-
ation. This may appear to
FIG. 340. — LEAF OF A Laportea. be anticipating, but many
With a cup-like enlargement of the extremity of the mid-rib. of the morphological facts
278
THE LEAF IN RELATION TO ITS ENVIRONMENT 279
which have been
grouped together for
preliminary mention are
intimately connected
with the phenomena of
Variation.
Of the multifarious
leaf forms which the
Vegetable World pre-
sents, few, perhaps, are
so singular as those of
the Sarracenias and
Nepenthes. These have
already been treated at
considerable length in
Chapter IV., when the
insectivorous habits of
plants were before us ;
and we may therefore
dismiss them here in
few words. In both
genera the insect-catch-
ing pitchers are them-
selves the leaves, but
they have this differ-
ence : in Sarracenia the
tall trumpet-shaped por-
tion of the leaf is looked
upon as an expansion
of the petiole or leaf-
stalk, and the lid as the lamina or blade ; while in Nepenthes the pitcher is
regarded as a modification of the lamina, the lid being a special pro-
longation of the apex. In the Australian Pitcher-plant (Cephalotus folli-
cularis) the parts of the singular tankard-shaped leaves correspond rather
with those of Sarracenia than of Nepenthes. Leaves of the pitcher class
are called ascidiform, from the Greek askidion, a little bottle.
Recently, at Kew, one of the attendants pointed out to us a species of
Laportea, lately arrived from New Guinea, each of the leaves of which was
finished off at the apex as a little cup (fig. 340) ; but we were unable to
ascertain what purpose these ascidiform appendages fulfill in the economy
of the plant. They can hardly be insect-traps like the pitchers of Nepenthes,
as the downward curve of the leaf gives the cups an inverted position.
One would like to know whether, in their natural habitat, a vertical position
is ever assumed by the leaf.
Photo by]
FIG. 341. — LIME (Tilia platyphyllos),
Showing the heart-shaped
[E. Step.
and globose fruits with the long bracts
attached.
280
HUTCHINSON'S POPULAR BOTANY
If, as is generally agreed, the trumpet-shaped portion of the leaves of
Sarracenia is really an expansion of the petiole, it would be botanically
described as a phyllode, and thus would answer to the leafy expansion of the
petiole of certain Australian species of Acacia — as, for instance, Acacia
melanoxylon, which, when young, possesses bipinnate leaves with flattened
petioles, but which are succeeded by others more phyllode-like as the plant
grows older, until at last the leaflets (pinnce) entirely disappear, and phyl-
lodes only are produced. The phyllodes have the appearance, and per-
form all the functions, of normally developed foliage-leaves.
There is a tendency among the Acacias, as well ,as some closely allied
plants, to develop different forms
of leaf on the same individual with
a capriciousness that is extra-
ordinary. Not only will you find
pinnate, bipinnate, and tripinnate
leaves en the one plant, but .in-
stances are not uncommon in
which a single leaf inclines to all
these forms at once. The leaf of
the Honey-locust-tree (Gleditschia
triacantkos) is a case in point (fig.
342). The tree is a native of
North America, where its long
thorny branches wage incessant
war with the unarmed Maple-
trees, in close proximity to which
it is usually found growing.
Surely if plants, like animals, are
liable to be affected by changes of
the moon, the Honey-locust-tree
has fallen under the baneful in-
fluence ! It reminds one of those
old Lime-trees (Tilia platyphyllos)
mentioned by Dr. Burnett, .which, instead of developing the cordate or
obliquely cordate leaves of this species, regularly put forth leaves of a
hooded (cucullate) form. These trees were growing in the churchyard of
Seidlitz, in Bohemia, seventy years ago— possibly they are still growing
there. In Burnett's time the peasants affirmed that the production of
the hooded leaves was due to the fact that some monks from a neigh-
bouring convent had been hanged on the trees !
Those who have what Americans would call " a big swallow " may be
satisfied with this explanation, but the diversity of form in the normally
heterophyllous leaves of Gleditschia triacant.hos. Acacia heterophylla, etc., has
no such convenient story to account for it, nor are we in a position to suggest
FIG. 342. — HETEROPHYLLOUS LEAF or HONEY-
LOCUST-TREE.
Some of the leaflets are entire, others broken up in various
degrees into smaller leaflets.
THE LEAF IN RELATION TO ITS ENVIRONMENT
281
FIG. 343. — CABOMBA.
A submerged leaf.
a probable explanation — indeed, it is only
when we turn to aquatic plants that the special
usefulness of heterophyllous leaves becomes
apparent. Mention has been made of the
Water-crowfoot (Ranunculus aquatilis}, whose
submerged leaves are so different from the
floating ones, the former consisting merely of
narrow thread-like segments, while the latter
are three-lobed with dentate margins. This
difference may be partly accounted for by the
fact that the submerged leaves, being less
favourably situated for light than the others, make the most of the rays
that visit them by assuming the shredded form. It has been further
remarked that aquatic plants which develop filiform leaves are usually, if
not always, found in running water ; and how well are they adapted for
such environment! — yielding readily to the current, and participating in
its movements without injury. These observations apply equally to the
Potamogetons (P. heterophyllus, rufescens, and spathulatus), to the Water-
caltrops (Trapa natans), and to the Cabomba (Cabomba aquatica, figs. 343,
344). The latter may be studied to advantage in the Victoria Regia
House at Kew.
I'he buoyancy of floating leaves is, in not a few cases, secured by special
air-channels, which may be situated either in the blade or the leaf-stalk —
more frequently the latter. In the Brazilian Pickerel-weed (Pontederia
crassipes^ the swollen and hollow leaf-stalks act as floats to the whole plant,
which, as it does not root itself to the irmd, is carried hither and thither by
wind and current like a rudderless ship. In Desmanthus natans, an aquatic
plant of the Leguminous order, the stem takes the form of " a large-celled,
spongy, air-containing mantle," which subserves the same purpose as
the leaf-stalks of the Pickerel-weed, and is, in
fact, a veritable swimming apparatus.
As a consequence of their situation, aquatic
plants imbibe much more water than land
plants, and the transpiration is proportionately
greater. One sees in this fact the advantage
of their broad, flat, floating leaves, which, ly-
ing side by side on the surface of the water,
present so large a field for the sun's opera-
tions ; for it will be remembered that transpira-
tion takes place through the stomata, and that
these organs, in aquatic plants, are placed on
the upper surface of the leaves. AVhen it is
stated that a single Water-lily-leaf of very pIG 344 CABOMBA.
ordinary size may contain as many as eleven An aerial leaf and flower.
282
HUTCHINSON'S POPULAR BOTANY
and a half million stomata, one may realise what liberal provision is made
for the removal of superfluous moisture.
Still further to assist this end, the under sides of many floating leaves
are coloured violet or crimson by a pigment known as anthocyanin (some-
times called cyanophyll], which has the remarkable propert}^ of changing
light into heat and thus of giving increased warmth to the parts where
transpiration is going
on. This foliage paint-
ing is seen to perfection
in the magnificent leaves
of the Victoria regia.
Our drawing (see fig.
346), which was made
from one of the speci-
mens at Kew, fails to
do justice to the tropi-
cal queen, which, in-
deed, must be seen in
its native habitat to be
properly appreciated.
The plant was first dis-
covered by Sir Eobert
Schomburgk during his
explorations in South
America on behalf of
the Royal Geographical
Society ; and the dis-
tinguished traveller thus
records the event : " It
was on January 1st,
1837, while contending
with the difficulties
which Nature interposed
in different forms to
stem our progress up
the River Berbice (lat.
4° 30' N., long. 52° W.),
that we arrived at a part where the river expanded and formed a current-
less basin. Some object on the southern extremity of this basin attracted
my attention, and I was unable to form an idea what it could be: but
animating the crew to increase the rate of their paddling, we soon came
opposite the object which had raised my curiosity, and behold, a vegetable
wonder ! All calamities were forgotten ; I was a botanist, and felt myself
rewarded ! There were gigantic leaves, five to six feet across, flat, with a
FIG. 345. — Godwinia gigas.
A Centra American Arum, whose leaves are fourteen feet in length.
283
281
IIUTCHINSON'S POPULAR, BOTANY
broad rim, light green above and vivid crimson below, floating upon the
water; while in character with the wonderful foliage I saw luxuriant
flowers, each consisting of numerous petals, passing in alternate tints
from pure white to rose and pink. The smooth water was covered with
the blossoms, and as I rowed from one to the other I always found some-
thing new to admire. . . . Ascending the river, we found this plant
frequently, and the higher we advanced the
more gigantic did the specimen become ; one
leaf we measured was 6ft. 5 in. in diameter,
the rim five and a half inches high, and the
flowers a foot and a quarter across."
The under surfaces of these leaves — as,
indeed, of nearly all floating leaves — afford
resting-places for numberless aquatic insects
and snails ; while certain birds which prey
on fish use the leaves as rafts. The French
traveller Marcoy, who saw large numbers of
the Victoria Lilies on the Nufia Lake, Peru,
likens the collective effect of the leaves to a
splendid carpet, on which, to quote his own ex-
pression, " quite a multitude of stilt-plovers,
ibises, jacanas, anhunas, savacas, Brazilian
ostriches, and spoonbills disported themselves."
The jacanas mentioned by Marcoy are the
Parrce of naturalists — wading birds, somewhat
analogous both in structure and habits to
the European water-hen, and their light bodies
and long toes enable them to walk on the float-
ing leaves with as much facility as if they
were on land.
Large as are the leaves of the Victoria Lily,
they are by no means the largest known. The
Gochuinia (or Dracontium) gigas (fig. 345), a
species of Arum discovered in Central America
by Dr. Seeman so recently as 1869, produces
a leaf no less than fourteen feet long. Its stalk,
which is beautifully mottled with purple and
yellow, has been compared to a huge snake
standing erect at the bidding of an Eastern charmer. But there are greater
leaves even than this. At Kew, not long since, one of the Sago Palms bore
fronds * which were upwards of forty feet in length ; and we believe that
* In speaking of Palm-leaves as "fronds," we uss popular language. In botanical
terminology a frond is the leaf of a Fern or other Cryptogam, though in recent years
the tendency has been to spsak of fern-leaves, not fronds.
FIG. 347. — LATTICE-LEAF.
In this Madagascar plant the perforations
of the leaf are so numerous that it re-
sembles a skeleton leaf.
THE LEAF IN RELATION TO ITS ENVIRONMENT
285
FIG. 348. — Monslera deliciosa.
The remarkable perforated leaf of this tropical Aroid.
even larger ones have
been met with. Never-
theless, the Victoria
Lily is the largest of
floating leaves, and well
deserves all the praise
that has been lavished
upon it.
Forty years ago the
G in i n e 11 1 G- e r in. a 11
botanist Hildebraiid
gave an a c count of
some interesting obser-
vations on the physi-
ology of the floating
leaves of Mar 8 He a
quadrifolia. in the Bo-
tanize he Zeitung. He
found that when a
plant of this species is
sunk beneath the sur-
face of the water, so
that all the leaves are more or less deeply covered, those leaves which are
fully developed at the time of immersion remain unchanged, Avhile those
which are not so far advanced undergo a remarkable change, the petioles
gradually lengthening in succession according to their position on the stem,
and soon over-topping those which were already formed. At first the four
leaflets do. not increase, but presently they begin to enlarge, and by the
time the surface of the water is reached they exceed in size the ordinary
leaves, forming a four-rayed star on the surface. "While the petioles of the
ordinary leaves are stiff, so that they stand erect out of the water, these
floating leaves are weak and flexible, like those of water-lilies, allowing the
leaf to maintain its position on the surface with the rise and fall of the
water. Their upper surface is shining and coated with wax, so that
the water flows off them. If immersed in deeper water, the petioles will
lengthen still further even to the extent of three feet.
Before passing from water-plants, we must call attention to that delicate
Madagascar aquatic, the Lattice-leaf-plant (Ouvirandra fenestralis), which
is remarkable from the fact that the network of its leaves, instead of being-
filled up with tissue (parenchyma) in the ordinary way, is left open, the
chlorophyll in each leaf being contained in a thin layer of cells which covers
the strands (fig. 347). The plant is entirely submerged, and when viewed
from above has the appearance of a large oval piece of green net spread
out upon the mud in which its roots are fixed. This appearance is due. to
286
HUTCHINSON'S POPULAR BOTANY
the procumbent position of the lace-like leaves, which form a rosette round
the short mud-embedded stem. They remind one, as Kerner aptly says, of
autumn leaves which have fallen into water and lost all their parenchyma
through maceration, the skeletons alone remaining. It may be added that
a few of the Seaweeds (e.g. Agarum gmelini and Thallasiophyllum clathrus)
offer the same peculi-
arity as Ouvirandra,
their fronds being per-
forated in a very beauti-
ful manner.
The existence of
leaf-holes in certain
land-plants is also to be
noted. Such perfora-
tions are confined to the
large upper leaves of
tropical plants like the
Aroids (Monstera deli-
ciosa, etc., fig. 348),
which, but for this pro-
vision, would entirely
exclude the sun from
the lower leaves, and
thus impair the activity
of the green tissues. The
deep incisions and clefts
which give such beauty
of outline to palmati-
sect and pinnatisect
leaves evidently sub-
serve a similar purpose ;
while the disposition of
the leaves on the stem,
and of the leaflets on the
petiole, has definite rela-
tion to the same impor-
tant end.
It is highly probable,
also, that the laciniated (fringed) forms of specially large leaves bear the
same relation to the wind that the thread-like forms of submerged leaves
do to water— that is, they present no large unbroken surfaces to the
varying currents of air, and thus escape rupture during heavy storms. In
many cases tearing is prevented by a strengthening of the epidermal cells,
particularly at the edges of the leaves, where of course the strain is
\_K. Step.
FIG. 349. — REEDMACE (Typha latifolia).
Commonly confused with the r.ulrush ($cir/iitx /«r«.<7m).
of all the long strap-shaped leaves, so that the whol<
Rented to the wind.
Note the spiral twist
surface is never pre-
[E. Step.
FIG. 350. — PURPLE CROCUS (Crocus oflicinali.i).
The narrow linear leaves have a white channel down the centre, and the undersHe is white. The margins are
rolled back towards the midrib. The beautiful purple flowers with their darker streaks are spring favourites in every
garden. It is a native of Middle and Southera Europe.
287
HUTCHINSON'S POPULAR BOTANY
greatest. This is well illustrated in the leathery leaves of the Holly
(Ilex) and the Indiarubber-plant (Fiats elasiica).
Leaves which assume a vertical position are specially exposed to the
violence of the wind. The currents of air usually take a course which is
parallel to the earth and therefore strike against such leaves at right angles,
so that special adaptations are needed to enable the latter to retain their
upright position. In many of the Grasses — the
Common Reed (Phragmites communis) may serve as
an example — the leaf-blades turn on the haulms
(which is the stalk of a grass of any kind)
like weathercocks. In the Reedmace (Ty-pha lati-
folia, fig. 349) the leaf is spirally twisted, so that a
whole surface is never presented to the wind — an
arrangement the advantage of which is sufficiently
obvious In other plants, protection from the wind
is secured by the leaf being hollow. It is well
known that a tube resists flexion more effectually
than a solid body; and tubular or fistular leaves will
maintain their erect position even in the roughest
weather. Examples of the fistular leaf are pre-
sented by the Common Onion (Allium cepa) and
other bulbous plants. In the Purple Crocus (C.
oflicinalix) the edges of the leaf roll over towards
the white central stripe so as to form a sort of
double tube ; and thus this little harbinger of spring
is able " to take the winds of March with beauty "
(fig. 351).
When speaking of buds, we showed that the
chief purpose of the woolly growth which often
covers them is to protect the young leaves from the
cold winds and nipping frosts of winter. It must not
be imagined, however, that this is also the chief pur-
pose of the wool and hairs which cover more or less
thickly the surfaces of many adult leaves. Heat,
rather than cold, is the danger to which the mature
leaf is exposed, and the purpose of its covering
hairs is not so much to promote warmth as to pre-
vent excessive exhalation. Just as the succulent stems of the Cactuses and
many tropical Euphorbias are provided with a leathery membrane to retard
evaporation, so, and for the same reason, a great number of leaves are
provided with hair-like structures, which, by shielding the epidermis from
the direct rays of the sun, reduce transpiration and save the leaves from
untimely desiccation.
END OF VOL. I
FIG. 351. — CROCUS.
A two-barrelled fistular leaf.
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