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The Vegetable In The Witness Box
By Islip Collyer, 1922



It was through observing the law of reversion to type that I first conceived the idea of writing on the subject of Evolution. I was led to the conviction that throughout the vegetable kingdom at all events, there is a universal law of conformity to the original type, and plants which have been altered by artificial selection and cultivation will rapidly revert to their natural conditions when the work of cultivation is relaxed. It is like stretching a piece of elastic. Within certain limits it is not difficult to alter the shape, but when the force which has affected the change ceases to act, the original form is resumed.

It always seems to me that this law of reversion implied a natural, created condition for all plants and that it was out of harmony with the theory of Evolution, and now, after a careful perusal of Darwin's principal works, I am of the same opinion. If all plants and animals have evolved from very simple


types, all the innumerable stages in the long line of descent would be equally natural. Why, then, should there be any innate tendency to revert to a previous condition?

There is little doubt that as a general rule the wild plants are more hardy than the cultivated, and therefore are better fitted for a wild condition, but reversion to type is not by natural selection preserving the hardiest. It is a mysterious disposition innate in the plant, which sometimes bridges the distance between the highly cultivated plant, and the wild type In a very short time.

In Darwin's book, The Origin of Species, the following passage occurs, page 80, "Unless favourable variations be inherited by at least some of the offspring, nothing can be effected by natural selections. The tendency to reversion may often check or prevent the work; but as this tendency has not prevented man from forming by selection numerous domestic states, why should it prevent against natural selection?

Page 121, "There may truly be said to be a constant struggle going on between, on the one hand, the tendency to reversion to a less perfect state, as well as an innate tendency to new variations, and on the other hand the power of steady selection to keep the breed true."

Here then is the crux of the whole questions so far as the law of reversion is concerned. There is "a constant struggle, between the tendency to reversion" and the power of selection, but if man has succeeded


in overcoming the tendency to revert, why should not Nature?

Several weighty answers can be given to this question. In the first place selection by man is much, more vigorous and rapid than natural selection could possibly be. In the second place, selection by man is in the direction of improving organs which exist, not to produce new ones. it is claimed that under Nature all the wonderful capacities of animals and plants are the results of this natural selection of chance variations, and the chances of variations in the direction of producing an entirely new organ are assuredly very different from the chances of an increase in size or a change of colour. Thirdly, natural selection cannot take place unless there is a struggle for existence, and this struggle, as Darwin admitted, is not incessant (Origin of Species, p. 61). Fourthly, man takes pains to prevent inter-crossing between different varieties. This is not prevented under Nature, and inter-crossing is the surest means of bringing the law of reversion into activity. And lastly, we may say that when the work of artificial selection and cultivation ceases, reversion is actually seen to occur very rapidly, and a work which would require hundreds of years of natural selection, even granting all the powers claimed for it, is undone in a few generations.

A good many years ago a farm in which the writer was interested was purchased for the purpose of fruit growing. From sixty to seventy acres were appor


tioned for fruits and vegetables and the ground was cleared and prepared ready for planting. A number of fruit trees of various kinds were planted while other parts were devoted to the culture of vegetables and small fruits. Two mistakes were made in the initial stages. The ground was not sufficiently cleared of the roots of weeds, and many of the fruit trees were planted too close together. Those who have had experience in this direction will understand what occurred. We were completely mastered by the weeds. The effort to keep the ground clear between the closely-planted fruit trees had to be abandoned, and in a few years, as it almost invariably happens in such cases, a rough kind of grass obtained the upper band and almost covered the ground. This did not very much interfere with the fruit trees, and as it could be mown to prevent it growing too long it was allowed practically undisputed possession, other weeds only growing in places where the grass was thin and scarce. Meanwhile other parts of the estate were better tended and a considerable degree of attention was given to the cultivation of strawberries. One Summer day when I had occasion to go among the thickly planted fruit trees I was astonished to find the ground studded with wild strawberry plants. They had seized on parts where the grass was not very thick and flourished with the vitality of weeds. There were dozens of them probably some hundreds, and they had ripened their tiny fruit quite perfectly Now I was aware that very many of our cultivated


strawberries had been dropped there, for I had frequently seen birds fly in the direction of these trees when driven off the strawberry beds and I could often see that they carried strawberries in their beaks. Undoubtedly many of them would be dropped in such positions, but I could not see at first how this could account for the growth of these wild plants. It was not simply the size I judged by, but the whole character of the fruit was unlike our cultivated. varieties, and proved clearly that they were either really wild strawberries from a wild stock or else it was a case of reversion. I had sometimes found odd seedlings in various parts of the estate which were evidently from the cultivated beds. They had grown through being dropped in particularly favourable positions and although they were in a measure degraded, they still bore the clearest evidence of their domesticated origin. I attributed the degradation principles at all events, to the direct effects of their struggle for existence. The fact is, our cultivated strawberries are not as a rule good fighters, and so we cannot expect the seeds liberally scattered about by the feathered marauders, to take root unless they happen to fall on favourable ground. These partially degraded plants I speak of were few in number, whereas the wild strawberries between the fruit trees were very numerous.

The discovery of these plants greatly puzzled me, for although I fully believed in the principle of reversion to type, I had always imagined that it


would take a succession of generations of neglect to step the distance back to the old form, whereas this appeared to be a case of reversion in a single generat1on. I mentioned the matter to one of the gardeners, and he was of the same opinion. He had no doubt that they would revert, if left uncultivated for a long time, but be did not believe that these plants could be the offspring of the varieties we were cultivating. He expressed the opinion that they must be from original wild stock. The more this theory was examined, however, the less likely it seemed to be. Wild strawberries were not plentiful in the neighbourhood before our beds were planted, indeed I have no reason to believe that they were ever found at all, and since in the indiscriminate scattering of the seeds by birds, a large percentage must inevitably be wasted, it seemed incredible that these hundreds of plants suddenly appearing in a small patch of ground could be from wild stock. I was driven to the conclusion that they furnished an instance of reversion, and at first I was disposed to believe they were the proceeds of the few partially degraded seedlings I have already mentioned. It was not until I read Darwin's Origin of Species, that the case became clear. In argument with regard to another matter, Darwin incidentally brings out -- a case of reversion which throws a great light on the circumstances I have narrated and suggests an idea which may prove to be of great importance.

In supporting the contention that all existing


varieties of pigeons are descended from the wild rock pigeon, Darwin recounts an experiment he made.

Origin of Species, pp. 18, 19: -- " I crossed some white fantails, which breed very true, with some black barbs, and so it happens that blue varieties of barbs are so rare that I never heard of an instance in England; and the mongrels were black, brown and mottled. I also crossed a barb with a spot, which is a white bird with a red tail and a red spot on the forehead, and which notoriously breeds very true; the mongrels were dusky and mottled. I then crossed one of the mongrel barb fantails with a mongrel barb-spot, and they produced a bird with as beautiful blue colour, with the white loins, double black wing bar and barred and white-edged tail feathers as any wild rock pigeon! We can understand these facts on the well-known principle of reversion to ancestral characters if all the domestic birds are descended from the rock pigeon."

Now here it appears to me that in the effort to establish the fact that the rock pigeon is the progenitor of all our domestic birds the real significance of the experiment is overlooked. It simply means that through interbreeding between different varieties two generations sufficed to destroy the work of untold years of artificial selection by man. What is to prevent this intercrossing in a state of Nature? When I read this passage from The Origin of Species, a solution of the difficulty regarding the strawberries at once occurred to me. We were cultivating a great


number of varieties and this would consequently be a great deal of cross-fertilization.

Darwin's experiments confirm the view that this cross-fertilization will quickly bring the law of reversion into play. What is to prevent it in a state of Nature? With plants it would always take place. Thus in the war between the tendency to vary and the tendency to revert, there would be a constant presence of the conditions which encourage reversion. Two generations of this indiscriminate fertilization are sufficient to turn the most highly cultivated of pigeons into the primitive type; a single generation will undo all the work of the cultivation of strawberries. How many thousands of generations of natural selection would have sufficed to equal this work of man?