By Grant Allen

Reaching my hand into the hedgerow to pick a long, lithe, blossoming spray of black byrony—here it is, with its graceful climbing stem, its glossy, heart-shaped leaves and its pretty greenish lily flowers—I have stung myself rather badly against the nettles that grow rank and tall from the rich mud in the ditch below. Nothing soothes a nettle sting like philosophy and dock-leaf; so I shall rub a little of the leaf on my hand and then sit awhile on the Hole Farm gate here to philosophize about nettles and things generally, as is my humble wont. There is a great deal more in nettles, I believe, than most people are apt to imagine; indeed, the nettle-philosophy at present current with the larger part of the world seems to me lamentably one-sided. As a rule, the sting is the only point in the whole organization of the family over which we ever waste a single thought. This is our ordinary human narrowness; in each plant or animal we interest ourselves about that one part alone which has special reference to our own relations with it, for good or for evil. In a strawberry, we think only of the fruit; in a hawthorn, or the flowers; in a deadly nightshade, of the poisonous berry; and in a nettle, of the sting. Now, I frankly admit at the present moment that the nettle sting has an obtrusive and unnecessarily pungent way of forcing itself upon the human attention; but it does not sum up the whole life-history of the plant in its own one peculiarity for all that. The nettle exists for its own sake, we may be sure, and not merely for the sake of occasionally inflicting a passing smart upon the meddlesome human fingers.

However, the sting itself, viewed philosophically, is not without decided interest of its own. It is one, and perhaps the most highly developed, among the devices by which plants guard themselves against the attacks of animals. Weeds and shrubs with juicy, tender leaves are very apt to be eaten down by rabbits, cows, donkeys and other herbivores. But if any individuals among such species happen to show any tendency to the development of any unpleasant habit, which prevents the herbivores from eating them, then those particular individuals will of course be spared when their neighbors are eaten, and will establish a new and specially protected variety in the course of successive generations. It does not matter what the peculiarity may be, provided only it in any way deters animals from eating the plant. In the arum, a violently acrid juice is secreted in the leaves, so as to burn the mouth of the aggressor. In the dandelion and wild lettuces, the juice is merely bitter. In houndstongue and catmint it has a nauseous taste. Then again, in the hawthorn and the blackthorn, some of the shorter branches have developed into stout, sharp spines, which tear the skin of would-be assailants. In the brambles, the hairs on the stem have thickened into pointed prickles, which answer the same purpose as the spines of their neighbors. In the thistles, the gorse and the holly, once more, it is the angles of the leaves themselves, which have grown into needle-like points so as to deter animals from browsing upon them. But the nettle probably carries the same tendency to the furthest possible limit. Not content with mere defense, it is to some extent actively aggressive. The hairs which clothe it have become filled with a poisonous, irritating juice, and when any herbivore thrusts his tender nose into the midst of a clump, the sharp points pierce his naked skin, the liquid gets into his veins in the very neighborhood of the most sensitive nerves, and the poor creature receives at once a lifelong warning against attacking nettles in future.

The way in which so curious a device has grown up is not, it seems to me, very difficult to guess. Many plants are armed with small sharp hairs which act as a protection to them against the incursions of ants and other destructive insects. These hairs are often enough more or less glandular in structure, and therefore liable to contain various waste products of the plant. Suppose one of these waste products in the ancestors of the nettle to be at first slightly pungent, by accident, as it were, then it would exercise a slightly deterrent effect upon nettle-eating animals. The more stinging it grew, the more effectual would the protection be; and as in each generation the least protected plants would get eaten down, while the more protected were spared, the tendency would be for the juice to grow more and more stinging till at last it reached the present high point of development. It is noticeable, too, that in our warrens and wild places, most of the plants are thus more or less protected in one way or another from the attacks of animals. These neglected spots are overgrown with gorse, brambles, nettles, blackthorn, and mullein, as well as with the bitter spurges, and the stringy inedible bracken. So, too, while in our meadows we purposely propagate tender fodder plants, like grasses and clovers, we find on the margins of our pastures and by our roadsides only protected species; such as thistles, houndstongue, cuckoo-pint, charlock, nettles (once more), and thorn bushes. The cattle or the rabbits eat down at once all juicy and succulent plants, leaving only these nauseous or prickly kinds, together with such stringy and innutritious weeds as chervil, plantain, and burdock. Here we see the mechanism of natural selection at work under our very eyes.

But the sting certainly does not exhaust the whole philosophy of the nettle. Look, for example, at the stem and leaves. The nettle has found its chance in life, its one fitting vacancy, among the ditches and waste-places by roadsides or near cottages; and it has laid itself out for the circumstances in which it lives. Its near relative, the hop, is a twisting climber; its southern cousins, the fig and the mulberry, are tall and spreading trees. But the nettle has made itself a niche in nature along the bare patches which diversify human cultivation; and it has adapted its stem and leaves to the station in life where it has pleased Providence to place it. Plants like the dock, the burdock, and the rhubarb, which lift their leaves straight above the ground, from large subterranean reservoirs of material, have usually big, broad, undivided leaves, that overshadow all beneath them, and push boldly out on every side to drink in the air and the sunlight. On the other hand, regular hedgerow plants, like cleavers, chervil, herb Robert, milfoil, and most ferns, which grow in the tangled shady undermath of the bank and thickets, have usually slender, bladelike, much-divided leaves, all split up into little long narrow pushing segments, because they cannot get sunlight and air enough to build up a single large respectable rounded leaf.

The nettle is just halfway between these two extremes. It does not grow out broad and solitary like the burdock, nor does it creep under the hedges like the little much-divided wayside weeds; but it springs up erect in tall, thick, luxuriant clumps, growing close together, each stem fringed with a considerable number of moderate-sized, heart-shaped, toothed and pointed leaves. Such leaves have just room enough to expand and to extract from the air all the carbon they need for their growth, without encroaching upon one another’s food supply (for it must always be borne in mind that leaves grow out of the air, not, as most people fancy, out of the ground), and so without the consequent necessity for dividing up into little separate narrow segments. Accordingly, this type of leaf is very common among all those plants which spring up beside the hedgerows in the same erect shrubby manner as the nettles.

Then, again, there is the flower of the nettle, which in most plants is so much the most conspicuous part of all. Yet in this particular plant it is so unobtrusive that most people never notice its existence in any way. That is because the nettle is wind-fertilized, and so does not need bright and attractive petals. Here are the flowering branches, a lot of little forked antler-like spikes, sticking out at right angles from the stem, and half concealed by the leaves of the row above them. Like many other wind-fertilized flowers, the stamens and pistils are collected on different plants—a plan which absolutely insures cross-fertilization, without the aid of the insects. I pick one of the stamen-bearing clusters, and can see that it is made up of small separate green blossoms, each with four tiny leaf-like petals, and with four stamens doubled up in the center. I touch the flowers with the tip of my pocket knife, and in a second the four stamens jump out elastically as if alive, and dust the white pollen all over my fingers. Why should they act like this? Such tricks are not uncommon in bee-fertilized flowers, because they insure the pollen being shed only when a bee thrusts his head into the blossom; but what use can this device be to the wind-fertilized nettle? I think the object is somewhat after this fashion. If the pollen were shed during perfectly calm weather, it would simply fall upon the ground, without reaching the pistils of neighboring plants at all. But by having the stamens thus doubled up, with elastic stalks, it happens that even when ripe they do not open and shed the pollen unless upon the occurrence of some slight concussion. This concussion is given when the stems are waved about by the wind; and then the pollen is shaken out under circumstances which give it the best chance of reaching the pistil.

Finally, there is the question of fruit. In the fig and mulberry the fruit is succulent, and depends for its dispersion upon birds and animals. In the nettle it takes the form of a tiny, seed-like, flattened nut. Why is this, again? One might as well ask, why are we not all Lord Chancellors or Presidents of the Royal Academy. Each plant and each animal makes the best of such talents as it has got, and gets on by their aid; but all have not the same talents. One survives by dint of its prickles; another by dint of its attractive flowers; a third by its sweet fruit; a fourth by its hard nut-shell. As regards stings, the nettle is one of the best protected plants; as regards flower and fruit, it is merely one of the ruck. Every plant can only take advantage of any stray chances it happens to possess; and the same advantageous tendencies do not show themselves in all alike. It is said that once a certain American, hearing of the sums which Canova got for his handicraft, took his son to the great man’s studio, and inquired how much he would ask to make the boy a sculptor. But there is no evidence to show that that aspiring youth ever produced an Aphrodite or a Discobolus.