Animals and grass—Travellers in the elephant grass—Enemies in Britain—Cactus versus rats and wild asses—Angora kids v. acacia—The Wait-a-bit thorn—Palm roots and snails—Wild yam v. pig—Larch v. goat—Portuguese and English gorse—Hawthorn v. rabbits—Briers, brambles, and barberry—The bramble loop and sick children or ailing cows—Briers of the wilderness—Theophrastus and Phrygian goats—Carline near the Pyramids—Calthrops—Tragacanth—Hollies and their ingenious contrivances—How thorns and spines are formed—Tastes of animals.

BY far the greater number of wild animals live by eating vegetables. If one thinks of the elephant's trunk, the teeth of a hippopotamus, or even of the jaws and lips of mice, rats, and voles, the thoroughly practical character and efficiency of their weapons become the more astonishing the more one reflects upon them.

Yet the defences adopted by plants are just as wonderful, and are often most ingenious.

It seems at first remarkable that the most usual food of animals, grass, should be apparently unprotected. It is upon grass that the great herds of bison, of buffalo, of antelope, and guanaco, are or were supported. Yet grass is so wonderfully reproductive, produces such enormous quantities of buds and foliage, and grows in such luxuriance, that there is no fear of its being killed out.

There are many places in the world where vegetation defies the attacks of the animal world. Neither man nor elephant can live comfortably in the thick jungles of West Africa and the great forests of Brazil. Nor can either man or elephant utilize great tracts of country in Central Africa which are covered by the Elephant Grass.

For, perhaps, four or five hours the weary caravan plods on through a sort of burrow, two feet wide, made in this gigantic grass. The stems are ten feet or more in height, and nearly meet overhead. There is nothing whatever to be seen except the narrow path. The atmosphere is stifling and hot. To cut a new road a few hundred yards long through it involves hours of labour. It is only when there has been a long drought that it is possible to set fire to the Elephant Grass, and then for a very short time the young growing shoots can be grazed. But no cattle can break through when it is fully grown.

The very exuberance of vegetation in such cases prevents any harm.

Perhaps it is best to show how, even in Great Britain, all plants have many dangerous foes. The roots of trees are nibbled by mice, voles, and sometimes by swine. The bark is injured by cattle, roedeer, reddeer, fallowdeer, who tear the bark with their horns, and especially by rabbits and hares. The leaves are eaten by the same animals and also by horses, goats, sheep, etc. The young buds are attacked by squirrels, who also break off the leading shoots of certain firs when they happen to be in a playful mood.

But it is in cultivated lands and in open, rather dry and arid country that one finds the most interesting weapons in the fights between plant and animal. It is in such places that some of the most beautiful and useful creatures have their home. The horse, ass, camel, goat, and sheep probably belong to those wonderful lands which border the great deserts of Africa and Asia. These animals have been obliged to travel far and fast, and to perfect their bodily strength in order to pick up a living.

They have been taught (perhaps we should say learnt) by the thorns and briers of the wilderness.

The Cactus, Prickly Pears, or other succulent plants which belong to true deserts, are covered over with most curious and interesting spines. A row of little projections runs down each edge of the round fleshy stem. On each projection there is a rosette of spines. Sometimes these are long, slender, and diverging; in other cases they are short, stout, and curving over.

Now imagine a guanaco in South America, or even a rat or mouse, which is perishing of thirst in the arid desert where such things are found. It will be seen that it is by no means easy for it to taste the water in the juicy stem, for even the thin muzzle of a rat could scarcely get between the thorns.

Kerner describes how the wild asses in South America root up or try to split the Cacti with their hoofs to get at the juicy tissue of the unarmed lower parts. Yet they often receive dangerous wounds in doing so from the frightful spines of Melocactus[80] and others.

It is very interesting to see a flock of Angora goats in South Africa attacking an Acacia. The kid is a pretty, white, fluffy little creature, with the most meek, mild, and innocent expression. Yet it is a quarrelsome little brute. In a few minutes an Acacia will be despoiled, broken, and robbed of its foliage by a flock of them, although it bristles all over with long spines, of which there are a pair at the base of each leaf. Even the Kameeldorn, Camelthorn Acacia, or the Wait-a-bit in South Africa cannot defend itself.

The Wait-a-bit (Wacht een beetje) is so called from the ingenious nature of its spines. There are two together, of which one is straight and the other curved round like a hook. Both are very sharp and strong, so that an incautious traveller is sure to injure himself and his clothes. The straight one runs into his tender flesh, whilst the curved one fixes itself in his clothes.

It is by thorns, spines, and prickles that plants often protect themselves against the attacks of grazing animals. But it must be remembered that these are by no means the only safeguard. Plants produce poisonous, bitter, or strong-smelling substances which keep off their enemies, and these indeed often afford a more efficient protection (see Chap. III.). These thorns, etc., can be produced in the most unexpected places. There is one rule, however, namely that they are invariably found in the exact spot where they can be most useful.

Thus there are certain palms which possess green, juicy leaves, much relished by snails. These are protected by a sort of spine entanglement formed upon certain roots, which grow at the base of the leaves. Nor is this the only case in which spines are found on roots. There are certain South African bulbs (MorÆa) which are protected from the wild pigs by a dense mass of spiny roots.[81] On my march to Uganda from Mombasa, I was very much astonished to see an extraordinary Wild Yam. It had a huge underground tuberous part full of starchy matter, but it was quite impossible for any marauding wild boar to get at it, for it was entirely enclosed in a sort of arbour of long, arching roots densely covered by stout spines, which made a perfect protection.[82]

It is more usual to find thorns developed on the branches or stems. Generally these are formed on the outside towards the end of the branches. In the Alps, larches have to suffer from the attacks of goats which nibble off the ends of the young shoots. The part behind the scar dries up, but fresh twigs are put out from further back along the branch, until the tree becomes a closely branched, twiggy, bristling mass which looks like the clipped yews in old gardens. But so soon as it has grown tall enough to be above the reach of the goats, an ordinary larch stem develops and may grow into quite a respectable tree. This fact is given by Kerner von Marilaun (l.c., p. 445), and is very instructive, as explaining why it is that so often the ends of the branches become hard thorns: the green leaves and twigs are hidden and protected.

One of the neatest examples of this is the Portuguese Gorse or Whin, which resembles a little cushion with every branch ending in strong thorns and every leaf terminated by a stout spine.

The common Whin, Furze, or Gorse, is very nearly as perfect an example of thorniness and spininess. The Southdown sheep do not seem to injure it on those beautiful Sussex downs so famous for succulent mutton, yet in the early spring, or in a very wet season, one often finds in the grass at the foot of the bush (or even in the bush itself) small shoots which would be taken at first sight as belonging to some other plant. These little shoots are grey with hairs and have soft trefoil leaves which are quite unprotected, for their spines are quite soft. They are probably seldom eaten, for most of them are in the shelter of the old spiny bushes. Yet even the old bushes can be used as fodder for sheep if they are crushed and ground up so as to break the thorns and spines. The Gorse is a very hardy plant, and is said to be only out of flower "when kissing is out of fashion" (see p. 100).

There is still some uncertainty as to the exact way in which animals set to work when they are eating thorny or spiny bushes. This makes the arrangement of the thorns sometimes a little difficult to follow. Moreover it is often not so much the leaves as the juicy bark in winter and early spring that is required. Sometimes everything above ground is eaten down.

Rabbits, for instance, do not as a rule touch the Hawthorn, yet Mr. Hamilton says, "The second winter after planting was very severe and this hedge was eaten down to the very ground by rabbits. For about 600 yards I do not think that a single plant was missed."[83] In frost and snow almost every plant is attacked by rabbits, and indeed by any grazing animal.

Remembering that it is very often the young juicy shoots that are sought after, it is quite easy to see why the young Rose suckers and shoots from the base of the stem fairly bristle with long and short prickles. These latter are generally straight, not curved like those of the long arching branches which are supposed to hook themselves on the branches of the surrounding trees. The young light-coloured branches of the cultivated Gooseberry are flexible, and hang over in such a way as to make it difficult for an animal to reach the bark: a cow or sheep, if it wished to eat these branches, would begin at the hanging tip and make a sort of upward tearing jerk while its tongue gathered the branch into its mouth. If one copies this with the hand it is easy to see how the length and arrangement of the prickles and the flexible nature of the spray would make such a proceeding on the cow's part most uncomfortable.

So also in the Barberry, the young juicy upright shoots which spring from the older branches have stout three to seven-branched prongs pointing downwards, of the most efficient character. Each is really a modified leaf and is found below each bud. Even the mere idea of an animal's tender lips or tongue tearing at these shoots from below gives one a momentary shudder. In the younger, wavy branches of the Barberry the spines are straighter or more diverging. The young leaves of the short bud above alluded to are also most efficiently protected by their spines. The Hawthorn has a curious arrangement of very long stout thorns, behind which the leaves are sheltered. The younger flexible branches have smaller spines, which become efficient in winter and tend to prevent animals from eating the bark. The Cockspur thorns are 4 to 5-1/2 inches long, and extremely like the spur of a gamecock.

Bramble prickles are generally curved back in order to hook or cling to the branches of other trees, but any one who has tried to force his way through a clump of brambles knows the difficulty of doing so. The loops made by the branches fixing themselves in the ground (see p. 93) were at one time given credit for healing various diseases. Children in Gloucestershire used to be dragged backwards and forwards under these loops; in Cornwall also people afflicted with boils were made to crawl under them. Even cows when suffering from paralysis (supposed to be due to a shrew-mouse walking over them) were dragged through the Bramble-loop, in which case Professor Buckman remarks, "If the creature could wait the time of finding a loop large enough and suffer the dragging process at the end, we should say the case would not be so hopeless as that of our friend's fat pig, who, when she was ailing, had a mind to kill her to make sure on her."[84] The brambles and briers of Gilead and Ezekiel were probably brambles of which Rubus discolor is common in Palestine,[85] and the Butcher's Broom (Ruscus aculeatus). This last plant is really of the Lily family, and its flat leaf-like branches end in a sharp spine. The rabbit does not eat it.[86]

Amongst foreign thorny and spiny plants it is very difficult to make a selection.

Theophrastus (one of the very earliest botanists—see p. 37) describes a class of shrub very common in Phrygia, in which the leaves are produced at the base of the young shoots, which latter end at the top in branch thorns. These thorns, therefore, entirely cover the foliage and keep off that vegetable demon the goat. Some of the Crucifers, Roses, Composites, Labiates, etc., take on this habit in goat-infested countries.[87]

In Egypt, near the Pyramids, one often finds Carlina acaulis, a little thistle which has no stem, but is merely a flower seated in the middle of a rosette of leaves which lie flat on the sand. In the centre there is a circle of sharp spines, each of which is from one to two inches in length. The nostril of a hungry camel or donkey is sure to be pierced if it tries to eat the leaves. The spines of this thistle, like those of our Carline and the Centaurea calcitrapa (thistle of the Bible), spring from the bracts surrounding the flower. The ancient "calthrops" or "crawtaes" (first used by the Romans) were designed from the spines of the last-named plant[88] (calx, heel, and trappa, snare.) It had four iron spines, so that, however it was thrown down on the ground or in a ford, a spine was sure to stick up and to lame man or horse.

1. Old Roman Calthrops, left on roads, fords, etc., to lame horses.
2, 3. Fruits of Tribulus, showing efficient spines. Animals' feet, in passing, must catch them. They are more efficient than Calthrops.