Until a few decades ago, it was the universal belief that flowers had been specially created for man’s exclusive delight. This was such an easy way, you know, to overcome the difficulty of explaining the immense variety of forms and colours in the floral world; and it was, above all, so flattering to man’s egregious vanity. But one fine morning in May a German naturalist, Conrad Sprengel, published a remarkable book in which he pointed out that flowers owe their peculiar shape, colour, and fragrance to the visits of insects. Not that the insects visit the flowers in order to shape and paint and perfume them. On the contrary, they visit them for the unÆsthetic purpose of eating their pollen and their honey; while the flowers’ scent and colour exist solely for the purpose of indicating to winged insects at a distance where they can find a savoury lunch.

But why should flowers take such pains to attract insects by serving them with a breakfast of honey, and by hanging out big petals to serve as coloured and perfumed signal-flags? Nature is economical in the expenditure of energy; and as the production of honey and large flowers costs the plant some of its vital energies, we may be sure that this expenditure secures the plant some superior advantage. Sprengel noticed that the insects, while pillaging flowers of their honey, unwittingly brushed off with their wings and feet some of the fertilising dust or pollen, and carried it to the pistil or female part of a flower. But it remained for Darwin to point out what advantage this transference of the pollen secured to the flower. Darwin, says Sir John Lubbock, “was the first clearly to perceive that the essential service which insects perform to flowers consists not only in transferring the pollen from the stamens to the pistil, but in transferring it from the stamens of one flower to the pistil of another. Sprengel had indeed observed in more than one instance that this was the case, but he did not altogether appreciate the importance of the fact. Mr. Darwin however, has not only made it clear from theoretical considerations, but has also proved it, in a variety of cases, by actual experiment. More recently Fritz MÜller has even shown that in some cases pollen, if placed on the stigma of the same flower, has no more effect than so much inorganic dust; while, and this is perhaps even more extraordinary, in others, the pollen placed on the stigma of the same flower acted on it like poison”—a curious analogy to the current belief that close intermarriage is injurious to mankind.

What Darwin and others have proved by their experiments is that cross-fertilised flowers are more vigorous than those fertilised with their own pollen, and have a more healthy and numerous offspring. With this fact before us we need only apply the usual evolutionary formula to account for the beauty of flowers. It is well known that Nature rarely, if ever, produces two leaves or plants that are exactly alike. There is also a natural tendency in all parts of a plant except the leaves to develop other colours besides green. Now any plant which, owing to chemical causes, favourable position, etc., developed an unusually brilliant colour, would be likely to attract the attention of a winged insect in search of pollen-food. The insect, by alighting on a second flower soon after, would fertilise it with the pollen of the first flower that adhered to its limbs, thus securing to the plant the advantages of cross-fertilisation. Thanks to the laws of heredity, this advantage would be transmitted to the young plants, among which again those most favoured would gain an advantage and a more numerous offspring. And thus the gradual development not only of coloured petals, but of scents and honey, can be accounted for.

What makes this argument irresistible is the additional fact, first pointed out by Darwin, that plants which are not visited by insects, but are fertilised by the agency of the wind, are neither adorned with beautifully-coloured flowers, nor provided with honey or fragrance. And another most important fact: Darwin found that flowers which depend on the wind for their fertilisation follow the natural tendency of objects to a symmetrical form; whereas the irregular flowers are always those fertilised by insects or birds. This points to the conclusion that insects and birds are responsible not only for the colours and fragrance of flowers, but also for the shape of those that are most unique and fantastic. And this a priori inference is borne out by thousands of curious and most fascinating observations described in the works of Darwin, Lubbock, MÜller, and many others. The briefest and clearest presentation of the subject is in Lubbock’s Flowers, Fruits, and Leaves, which no one interested in natural Æsthetics should fail to read. There is indeed no more interesting study in biology than the mutual adaptation of flowers, bees, butterflies, humming-birds, etc.; for just as these animals have modified the forms of flowers, so the flowers have altered the shape of these animals.

Many of the changes in the shapes of flowers are made not only with a view to facilitate the visits of winged insects, but also for keeping out creeping intruders, such as ants, which are very fond of honey, but which, as they do not fly, would not aid the cause of cross-fertilisation. Of these contrivances, “the most frequent are the interposition of chevaux de frise, which ants cannot penetrate, glutinous surfaces which they cannot traverse, slippery slopes which they cannot climb, or barriers which close the way.”

How obtuse are those who, with Ruskin and Emerson, accuse science of destroying the poetry of nature! What poetry is there in the thought that flowers were made for unÆsthetic man, when not one man in a thousand ever takes the trouble to examine one, while for every single flower on which a human eye ever rests, a million are born to blush unseen?

But if we abandon the narrow anthropocentric point of view, and admit that insects too have a right to live, how the scope of Nature’s poetry widens! How easy it then becomes to share not only Wordsworth’s belief that “every flower enjoys the air it breathes,” but to endow it with a thousand thoughts and emotions like our own—delight in a gaily-coloured floral envelope; hope that yonder gaudy butterfly will be attracted by it; anxiety lest that “horrid” ant may steal some of its honey; determination to breathe the sweetest perfume on this darling honey bee, so as to induce it to speedily call again.

Love dramas, too, tragic and comic, are enacted in this world of flowers and insects. Thus the Arum plant resorts to the following stratagem to secure a messenger of love for carrying its pollen to a distant female flower:—

“The stigmas come to maturity first, and have lost the possibility of fertilisation before the pollen is ripe. The pollen must therefore be brought by insects, and this is effected by small flies, which enter the leaf, either for the sake of honey or of shelter, and which, moreover, when they have once entered the tube, are imprisoned by the fringe of hairs. When the anthers ripen, the pollen falls on to the flies, which, in their efforts to escape, get thoroughly dusted with it. Then the fringe of hairs withers, and the flies, thus set free, soon come out, and ere long carry the pollen to another plant” (Lubbock).

Then there are male flowers which go a-courting like any amorous swain of a Sunday night. One of these belongs to the Valisneria plant, concerning which the same writer observes that “the female flowers are borne on long stalks, which reach to the surface of the water, on which the flowers float. The male flowers, on the contrary, have short, straight stalks, from which, when mature, the pollen detaches itself, rises to the surface, and, floating freely on it, is wafted about, so that it comes in contact with the female flowers.”

But alas for the poor flowers! Few of them are thus privileged to roam about and seek their own bride. Most flowers have no more free choice in the selection of their spouse than an Oriental or a French girl. There is no previous acquaintance, no courtship before marriage, hence no Romantic Love, even if the undifferentiated germs of nervous protoplasm in the plant were capable of feeling such an emotion.

Poor flowers! Their honeymoon is without pleasure, unconscious. The wind may woo, the butterfly caress them—but the wind has no thought of the flower, and the insect’s attachment is mere “cupboard love.” The beauty of one flower cannot exist for another which has no eyes to see it; its honey and its fragrance are not for a floral lover’s delight, but for a gastronomic insect’s epicurean use. No modest coyness, no harmless flirtation, no gallant devotion and self-sacrifice, enter into the flower’s sexual life; not even the bitter-sweet pangs of jealousy, for, as Heine has ascertained, “the butterfly stops not to ask the flower, ‘Has any one kissed thee before?’ nor does the flower ask, ‘Hast thou already flitted about another?’”

Thus “flower-love,” with all its poetic analogies, has none of the elements of Romantic Love. Even attraction fails, for plants are commonly sessile, and cannot go forth to seek a mate.

Two important lessons of this chapter should, however, be carefully borne in mind; for though our search for Love has so far yielded only negative results, some light has been thrown on the general laws of Beauty in Nature. The lessons are:—

(1) That there is in flowers a natural tendency towards Symmetry of Form, all normal irregularities being due to the agency of insects and birds.

(2) That the superior Beauty of one flower over another is due to its superior vitality or Health, which, again, is promoted by cross-fertilisation or intermarriage—the choosing of a mate not in the same but in another flower-bed.

Regarding the beauty of flowers a further detail may be added. Some of the coloured lines on flowers are so placed as to guide the visiting bees to the nectar or honey. More complicated colour-patterns probably owe their existence to the advantage of having an easy means of recognition at a distance. It is well known that bees on any single expedition visit the flowers of one species only. Now it has been experimentally proved by Lubbock that bees can distinguish different colours; and, if we may judge by analogy with the human eye, they can distinguish colours at a greater distance than forms. Hence the advantage to each flower of having its own colours in its flag.