“I do not say that this would always happen—I should be sorry for any theory which depended upon the intelligence of a sheep—but it was a very striking object-lesson to my two companions; and any one who looks around during this summer with an inquiring mind will find plenty of evidence that grazing, browsing, and nibbling animals avoid flowers, and stick to greenstuff when they can get it.
“I do not say that all animals avoid the same flowers. Horses, for instance, may dislike large flowers like roses and conspicuous yellow flowers like buttercups, but they will bite off flat clusters of minute white or pale yellow flowers, such as yarrow or wild parsnip. These distinctions made by certain kinds of beasts will probably in the future be found to afford valuable evidence as to the regions of origin of our flowers and animals. Such plants as the yarrow and the wild parsnip, for instance, probably did not originate in the home of the wild horse, because they are not protected against it.
“As a general rule, however, there is abundance of evidence that plants with conspicuous flowers gain a large advantage in the struggle for existence, because grazing and browsing animals avoid them; while there is no real evidence at all that conspicuous flowers attract insects.”
Kay Robinson extends this explanation to the shape, the scent, and the nectar of flowers. He admits that many flowers are adapted to the visits of insects, but this is, he asserts, but a secondary result. The “real, primary meaning” of the shapes of flowers of curious configuration is, he insists, “a deterrent to grazing or browsing animals.”
According to him plants, like the snap-dragon, which have “blossoms in the semblance of a mouth,” are avoided by grazing animals, because they mistake such flowers for mouths, and have no wish to be bitten! Orchids, he asserts, “are strongly deterrent to grazing and browsing animals, which are looking for greenstuff, and regard these gaudy, spidery, winged blossoms as live creatures.” “If this is not the truth,” he asks, “will any adherent of the theory that we owe the shapes of flowers to insects explain why some of our common British orchids are so like bees, spiders, etc.? Some which have no particular resemblance to any insect still exhibit weird shapes, suggestive to the human mind of living things, such as lizards, etc. The reason why they look like bees, spiders, lizards, and various unclassed creatures is quite simple. Grazing animals are looking for greenstuff, and do not wish to eat living creatures which may bite or sting or taste nasty. Thus the orchids have acquired the power of looking like creatures.
“Every one,” he continues, “who is familiar with the blossom of the wild carrot—a flat head of minute, dull-white blossoms—must have noticed how very often the centre blossom in each head is purplish or reddish-black. This makes it very conspicuous in the middle of the flat white flower head. Now what conceivable use can this barren little blackish blossom—scarcely bigger than a pin’s head—be to the wild carrot plant if we regard the flat head of white flowers as an attraction to the sight of insects? If, on the other hand, we rightly regard the flat head of white blossoms as an advertisement to grazing animals that it is not wholesome greenstuff, but innutritious blossoms liable to be infested with ants and other stinging insects, we see at once the great use of this small blackish flower in the middle. It looks like an insect, and possibly in the home of the wild carrot there is some minute blackish insect with a peculiarly villainous smell or taste—or perhaps a potent sting—which grazing animals carefully avoid whenever they can see it. Thus the wild carrot flourishes; though here in Britain—where the wild carrot has established itself now—we may fail at first to see the exact meaning of the trick. I think, however, that, when we understand it, it fits admirably into the theory that the shapes and colours of flowers are primarily useful as deterrents to grazing and browsing animals and not as attractions to insects.
“Thus we see,” he concludes, “that the queer shapes of these orchids, which are a great stumbling-block in the way of those who preach that we owe the shapes of flowers to the tastes of insects, become a strong confirmation of my theory that we owe the shapes of flowers to grazing and browsing animals.”
Of the nectar of flowers, Kay Robinson writes: “Since this is eagerly sought for by hosts of insects, whose visits are in most cases useful to the flowers, it seems only natural to suppose that we see cause and effect in this connection.
“Here, however, I will outline my theory of the origin of nectar and of flowers in general.
“I think there is no doubt whatever that all the parts of a flower are modified leaves. The original type of flowering plant—I think we may safely assume—had a single stem and produced its seed at the summit, as the crown of its year’s endeavour. The flower, before it became what we would recognise as a flower, was a cluster of protecting leaves round the seed-making parts of the plant. To the production of the seed the whole energies of the plant were devoted, and into the cluster of leaves at the top of the stem all the essences of the plant were concentrated. If during the coming spring you handle and examine the leaves at the end of the strong shoots of thorns or fruit bushes, you will find that the surface of the young leaves is quite sticky. If you observe browsing animals also, you will discover that—contrary to expectation—they do not like strong-growing, juicy shoots, evidently preferring mature leaves lower down the branch. This shows, I think, that plants have the power of protecting their new shoots by crowding into them the volatile oils and essences which they produce as a protection against animals. Now nectar appears always to be distasteful to grazing and browsing animals; and they also dislike scented flowers. I think, therefore, that it is reasonable to suppose that the nectar and scents which now distinguish so many flowers were first produced as an exudation of concentrated sap upon the surfaces of the protecting leaves round the seed-making parts of the original flowers. As these leaves became more efficiently protective by assuming colours, shapes, and markings which warned animals of their character, so their apparatus for producing scent and honey became specialised; and at this point the insect appeared upon the scene as a factor in the life’s success of the plant.”