by Grant Allen
Still, if you so throw yourself into the scene, you cannot avoid carrying your own individuality with you into the beetle’s body. You fancy him admiring that fairy landscape as you would admire it were you in his place, provided always you felt yourself quite secure from the murderous jaws and hooked feet of some gigantic insect tiger lurking in the bristly thicket behind your back. But, as a matter of fact, I greatly doubt whether the beetle has much feeling for beauty of scenery. For a good many years past I have devoted a fair share of my time to studying, from such meagre hints as we possess, the psychology of insects: and on the whole I am inclined to think that, though their æsthetic tastes are comparatively high and well-developed, they are, as a rule, decidedly restricted in range. Beetles and butterflies only seem to admire two classes of visible objects — their own mates, and the flowers in which they find their food. They never show much sign of deliberate love for scenery generally or beautiful things in the abstract outside the limits of their own practical life. If this seems a narrow æsthetic platform for an intelligent butterfly, one must remember that our own country bumpkin has perhaps a still narrower one; for the only matter in which he seems to indulge in any distinct æsthetic preference, to exercise any active taste for beauty, is in the choice of his sweetheart, and even there he is not always conspicuous for the refinement of his judgment. But there is a way in which one can really to some extent throw oneself into the mental attitude of a human being reduced in size so as to look at the moss-forest with the eye of a beetle, while retaining all the distinctive psychological traits of his advanced humanity: and that is by making himself a microscopic eye with the aid of a little pocket-lens. Even for those who do not want to use one scientifically, it opens a whole universe of new and delightful scenery in every tuft of grass and every tussock of wayside weeds; and by its aid I hope to show you this morning how far the eyes and æsthetic tastes of insects help us to account for the pedigree of our familiar childish friend, the daisy. No fairy tale was ever more marvellous, and yet certainly no fairy tale was ever half so true.
I propose then, to-day, to dissect one of these daisies with my little knife and glass, and unravel, if I can, the tangled skein of causes which have given it its present shape, and size, and colour, and arrangement. If you choose, you can each pick a daisy for yourselves, and pull it to pieces as I go along, to check off what I tell you; but if you are too lazy, or can’t find one within reach, it doesn’t much matter; for you can at least carry the picture of so common a flower well enough in your mind’s eye to follow what I have to say without one: and that is all that is at all necessary for my present purpose.
The question as to how the daisy came to be what it is, is comparatively a new one. Until a short time ago everybody took it for granted that daisies had always been daisies, cowslips always cowslips, and primroses always primroses. But those new and truer views of nature which we owe to Mr. Darwin and Mr. Herbert Spencer have lately taught us that every plant and every animal has a long history of its own, and that this history leads us on through a wonderful series of continuous metamorphoses compared with which Daphne’s or Arethusa’s were mere single episodes. The new biology shows us that every living thing has been slowly moulded into its existing shape by surrounding circumstances, and that it bears upon its very face a thousand traces of its earlier stages. It thus invests the veriest weed or the tiniest insect with a fresh and endless interest: it elevates them at once into complex puzzles for our ingenuity — problems quite as amusing and ten times as instructive as those for whose solution the weekly papers offer such attractive and unattainable prizes. What is the meaning of this little spur? How did it get that queer little point? Why has it developed those fluffy little hairs? These are the questions which now crop up about every part of its form or structure. And just as surely as in surveying England we can set down Stonehenge and Avebury to its prehistoric inhabitants, Watling Street and the Roman Wall to its southern conquerors, Salisbury and Warwick to mediæval priests and soldiers, Liverpool and Manchester to modern coal and cotton — just so surely in surveying a flower or an insect can we set down each particular point to some special epoch in its ancestral development. This new view of nature invests every part of it with a charm and hidden meaning which very few among us have ever suspected before.
Pull your daisy to pieces carefully, and you will see that, instead of being a single flower, as we generally suppose at a rough glance, it is in reality a whole head of closely packed and very tiny flowers seated together upon a soft fleshy disk. Of these there are two kinds. The outer florets consist each of a single, long, white, pink-tipped ray, looking very much like a solitary petal: the inner ones consist each of a small, golden, bell-shaped blossom, with stamens and pistil in the centre, surrounded by a yellow corolla much like that of a Canterbury bell in shape, though differing greatly from it in size and colour. The daisy, in fact, is one of the great family of Composites, all of which have their flowers clustered into similar dense heads simulating a single blossom, and of which the sunflower forms perhaps the best example, because its florets are quite large enough to be separately observed even by the most careless eye.
Fig. 2. — Ray floret of Daisy.
Fig. 3. — Central floret of Daisy.
Now, if you look closely at one of the central yellow florets in the daisy, you will see that its edge is vandyked into four or five separate pointed teeth exactly like those of the Canterbury bell. These teeth clearly point back to a time when the ancestors of the daisy had five separate petals on each flower, as a dog-rose or a May-blossom still has. Again, before the flowers of the daisy had these five separate petals, they must have passed through a still earlier stage when they had no coloured petals at all. And as it is always simpler and easier to recount history in its natural order, from the first stages to the last, rather than to trace it backward from the last to the first, I shall make no apology for beginning the history of the daisy at the beginning, and pointing out as we go along the marks which each stage has left upon its present shape or its existing arrangement and colour.
Fig. 4. — Longitudinal section of Common Buttercup.
The very earliest ancestor of the daisy, then, with which we need deal to-day, was an extremely simple and ancient flower, hardly recognisable as such to any save a botanical eye. And here I must begin, I fear, with a single paragraph of rather dull and technical matter, lest you should miss the meaning of some things I shall have to tell you in the sequel. If you look into the middle of a buttercup or a lily you know that you will see certain little yellow spikes and knobs within the petals, which form a sort of central rosette, and look as if they were put there merely to give finish and completeness to the whole blossom. But in reality these seemingly unimportant spikes and knobs are the most important parts, and the only indispensable parts, of the entire flower. The bright petals, which alone are what we generally have in our minds when we think of flowers, are comparatively useless and inessential organs: a vast number of flowers have not got them at all, and, in those which have got them, their purpose is merely subsidiary and supplementary to that of the little central spikes and knobs. For the small yellow rosette consists of the stamens and pistils — the ‘essential floral organs,’ as botanists call them. A flower may be complete with only a single stamen or a single pistil, apart from any petals or other bright and conspicuous surroundings; and some of the simplest flowers do actually consist of such separate parts alone: but without stamens and pistils there can be no flower at all. The object of the flower, indeed, is to produce fruit and seed, and the pistil is the seed-vessel in its earliest form; while the stamen manufactures the pollen without which the seeds cannot possibly be matured within the capsules. In some species the stamens and pistils occur in separate flowers, or even on separate plants; in others, the stamens and pistils occur on the same plant or in the same flower, and this last is the case in almost all the blossoms with which we are most familiar. But the fundamental fact to bear in mind is
this — that the stamens and pistils are the real and essential parts of the flower, and that all the rest is leather and prunella — mere outer decoration of these invariable and necessary organs. The petals and other coloured adjuncts are, as I hope to show you, nothing more than the ornamental clothing of the true floral parts; the stamens and pistils are the living things which they clothe and adorn. Now probably you know all this already, exactly as the readers of the weekly reviews know by this time all about the personage whom we must not describe as Charlemagne, or the beings whom it is a mortal sin to designate as Anglo-Saxons. But then, just as there are possibly people in the worst part of the East End who still go hopelessly wrong about Karl and the Holy Roman Empire, and just as there are possibly people in remote country parishes who are still the miserable victims of the great Anglo-Saxon heresy, so, doubtless, there may yet be persons — say in the western parts of Cornwall or the Isle of Skye — who do not know the real nature of flowers; and these persons must not be wholly contemned because they happen not to be so wise as we ourselves and the Saturday Review. An eminent statistician calculates that Mr. Freeman has demolished the truculent Anglo-Saxon in 970 several passages, and yet there are even now persons who go on firmly believing in that mythical being’s historical existence. And the moral of that is this, as the Duchess would say, that you should never blame any one for telling you something that you knew before; for it is better that ninety-nine wise men should be bored with a twice-told tale, than that one innocent person should be left in mortal error for lack of a short and not wholly unnecessary elementary explanation.
Fig. 5. — Frond and flower of Duckweed.
The simplest and earliest blossoms, then — to return from this didactic digression — were very small and inconspicuous flowers, consisting, probably, of a single stamen and a single pistil each. Of these simplest and earliest forms a few still luckily survive at the present day; for it is one of the rare happy chances in this queerly ordered universe of ours that evolution has almost always left all its footmarks behind it, visibly imprinted upon the earth through all its ages. When any one form develops slowly into another, it does not generally happen that the parent form dies out altogether: on the contrary, it usually lingers on somewhere, in some obscure and unnoticed corner, till science at last comes upon it unawares, and fits it into its proper place in the scale of development. We have still several fish in the very act of changing into amphibians left in a few muddy tropical streams; and several oviparous creatures in the very act of changing into mammals left in the isolated continent of Australia; and so we have also many low, primitive, or simple forms of plants and animals left in many stray situations in every country. Amongst them are some of these earliest ancestral flowers. On almost every wayside pond you will find all the year round a green film of slimy duckweed. This duckweed is, as it were, the Platonic idea of a flowering plant — the generic type common to them all reduced to its simplest elements. It has no roots, no stem, no branches, no visible blossom, no apparent seed; it consists merely of solitary, roundish, floating leaves, budding out at the edge into other leaves, and so spreading till it covers the whole pond. But if you look closely into the slimy mass in summer time, you may be lucky enough to catch the weed in flower — though not unless you have a quick eye and a good pocket-lens. The flowers consist of one, and sometimes two, stamens and a pistil, growing naked out of the edge of the leaf. No one but a botanist could ever recognise their nature at all, for they all look like mere yellowish specks on the slender side of the green frond; but the pistil contains true seeds, and the stamens produce true pollen, and from the botanical standpoint that settles the question of their floral nature at once. They are, in fact, representatives of the simplest original form of flower, preserved to our own day on small stagnant ponds, where the competition of other plants does not press them hard as it has pressed their congeners on dry land or in open lakes and rivers. From some such simple form as this we may be pretty sure that all existing flowering plants are ultimately descended.
a, Carpels or ovaries; b, stamens; c, petals; d, calyx.
Fig. 6. — Diagram of primitive dicotyledonous flower.
In most modern flowers, however, each blossom contains several stamens and several carpels (or pistil-divisions), and the way in which such a change as this might come about can be easily imagined; for even in many existing plants, where the separate flowers have only a single stamen or a single pistil each, they are nevertheless so closely packed together that they almost form a single compound flower, as in the case of the bur-reed and the various catkins, not to mention the arum and the spurge, where only a trained eye can make out the organic separateness. I shall not trouble you much, however, with these earlier stages in the development of the daisy, both because I shall describe them elsewhere in part, à propos of other subjects, and because the later stages are at once more interesting and more really instructive. It must suffice to say that at some very ancient period the ancestors of the daisy, and of one half the other modern flowers, had acquired an arrangement of stamens and pistils in groups of five, so that each compound flower had as a rule a pistil of five or ten carpels, surrounded by a row of five or ten stamens. And almost all their existing descendants still bear obvious traces of this original arrangement in rows of fives. On the other hand, the ancestors of our lilies, and of the other half of our modern flowers, had about the same period acquired an arrangement in rows of three. And of this other ternary arrangement all their existing descendants still bear similar traces. In fact, most flowers at the present day show clear signs of being derived either from the original five-stamened or the original three-stamened blossom. I don’t mean to say that this is the only mark of distinction between the two great groups: on the contrary, it is only a very minor one; but it is for our present purpose the one of capital importance.
a, Carpels or ovaries; b, stamens, inner row; c, stamens, outer row; d, petals; e, calyx.
Fig. 7. — Diagram of primitive monocotyledonous flower.
The very primitive five-parted common ancestor of the daisy, the rose, the buttercup, and our other quinary flowers, was still an extremely simple and inconspicuous blossom. It had merely green leaves and plain flower-stems, surmounted by a row of five or ten stamens, inclosing five or ten carpels. Perhaps beneath them there may have been a little row of cup-shaped green bracts, the predecessors of the calyx which supports all modern flowers; but of this we cannot be at all sure. At any rate, it had no bright-coloured petals. The origin of these petals is due to the eyes and selective tastes of insects; and we must look aside for a moment at the way in which they have been produced, in order rightly to understand the ancestry of the daisy.
No pistil ever grows into a perfect fruit or sets ripe and good seeds until it is fertilised by a grain of pollen from a stamen of its own kind. In some plants the pollen is simply allowed to fall from the stamens on to the pistil of the same flower; but plants thus self-fertilised are not so strong or so hearty as those which are cross-fertilised by the pollen of another. The first system resembles in its bad effect the habit of ‘breeding in and in’ among animals, or of too close intermarriages among human beings; while the second system produces the same beneficial results as those of cross-breeding, or the introduction of ‘fresh blood’ in the animate world. Hence, any early plants which happened to be so constituted as to allow of easy cross-fertilisation would be certain to secure stronger and better seedlings than their self-fertilised neighbours; and wherever any peculiar form or habit has tended to encourage this mode of setting seeds, the plants have always prospered and thriven exceedingly in the struggle for existence with their less fortunate congeners. A large number of flowers have thus become specially adapted for fertilisation by the wind, as we see in the case of catkins and grasses, where the stamens hang out in long pendulous clusters, and the pollen is easily wafted by the breeze from their waving filaments to the pistils of surrounding flowers. In such cases as these, the stamens are general
ly very long and mobile, so that the slightest breath shakes them readily; while the sensitive surface of the pistil is branched and feathery, so as readily to catch any stray passing grain of wind-borne pollen.
But there are other flowers which have adopted a different method of getting the pollen conveyed from one blossom to another, and this is upon the heads and legs of honey-eating insects. From the very first, insects must have been fond of visiting flowers for the sake of the pollen, which they used to eat up without performing any service to the plant in return, as they still feloniously do in the case of several wind-fertilised species; and to counteract this bad habit on the part of their unbidden guests, the flowers seem to have developed a little store of honey (which the insects prefer to pollen), and thus to have turned their visitors from plundering enemies into useful allies and friends. For even the early pollen-eaters must often unintentionally have benefited the plant, by carrying pollen on their heads and legs from one flower to another; but when once the plant took to producing honey, the insects largely gave up their habit of plundering the pollen, and went from blossom to blossom in search of the sweet nectar instead. As they did so, they brushed the grains of pollen from the stamens of one blossom against the pistil of the next, and so enabled the flowers to set their seed more economically than before.