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Full text of "Popular botany; the living plant from seed to fruit"

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. . 13 n 
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 . . . . 2 67 


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 


Cot . . . .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 vegetation r 
and burn it. You will find that all there is left is a thin layer of fine ash r 
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 e3 7 e-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 T Vth 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 *P edeS 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 (i H 10 0,-,. 
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 i n f 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 P knt 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 p rot i st a. 








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 (C 6 H 10 5 ), 
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] 



Ste P- 



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 

Ba C k onifer a ^docarp^ takeS P laCG whe11 the tree is twent J- ( 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 p art ~ 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). 




Phto 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 (C 6 H 10 5 ), 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 (C 6 H 10 6 ), 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 (C0 2 ) 
from the atmosphere or water (the latter in the case 
of submerged plants), and this gaseous compound 
reacts with water (H 2 0) in the chlorophyll corpuscles 
under the action of light. The first organic product 
as a result of this process is, in most plants, glucose 
(C 6 H 12 6 ), 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 G y is brou S ht into P la ^- 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 (C 6 H 10 5 ), 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 f rom 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 C 12 H 22 U , of the latter C 6 Hi 2 9 ; 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. ^. j n the j u i ce o f 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 W T ILLOW (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 Cycads r 
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 ordinarj 7 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 (C0 2 ) ; 
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 (H 2 0) 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 (NH 3 ), 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. 




t A. 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 P arfc 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 (16281705) 
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- 
fts gia?d%dLf. leS 3ia^ified h 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. * Q r ^ ra ther, stomata-pores. They are really pores in the outer- 

Section through part of stem mogt j r of t i ssues /f or t j ie 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^ S^), 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 
(C 6 Hi 2 G ), possibly canose (C 12 H 22 O n ) 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. 

Y T ou 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 H 2 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 (C H 10 5 ), is converted, by 
means of a ferment called diastase, into 
the soluble substance sugar* (C 6 H 12 6 ), 
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, 1889 r 

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 I n plain prose, the plant secretes a fragrant essential 
(Schistostega osmundacea). Q ^ ^ n g rea t abundance : and in warm weather this 
The so-caiied luminosity is a false exudes anc i 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 n ly 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 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 r ip e 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 P oet mi S ht 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 2 i 7 _TH E 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 

. . arlrk fV, OT . c^nf rv 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-shapedare 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 alwaj T s 
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 is r 
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 showi eaed Se nodes 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 Kerner r 

* 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 2 85. 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 Ph oto 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 voun g l ea f 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, drj r , 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 sylvesfris 1 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 Medicagothe 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 p IG 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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