Page:Popular Science Monthly Volume 33.djvu/327

Rh. And this is how the gourd and cucumber have solved that great crux of plant organization:

The male flowers are larger than the female, and consist simply of a funnel-shaped corolla, inclosing a column of yellow stamens. They have no fruit or ovary in the center, nor even the abortive rudiment of such an organ. The female flowers, on the other hand, have no stamens, but the corolla caps a small round berry, the parent or embryo of the future fruit. Its center gives rise to a slender style, forked and feathered at the tip, which is the sensitive surface of the unswollen ovary. Now, when the bee or other fertilizing insect visits a male flower, he dusts himself all over (unconsciously, of course) with the fertilizing pollen. If, on flying away, he next visits another male blossom on the same plant, he only collects still more pollen. But if he happens to flit off to a female flower, he brushes off some of the pollen, as he passes, on to the feathery, sensitive surface protruded by the plant right in his path, on purpose to meet him. In this way, each female blossom makes perfectly certain of due fertilization from a separate organism; and such cross-fertilization, as Darwin has shown, produces in the long run the most fertile seeds, and the strongest, heartiest, and most vigorous seedlings.

Originally, there can be little doubt, the flowers of the gourd family were all hermaphrodite, as those of many among their less developed relations still remain to the present day. But, once upon a time, certain progressive gourds happened accidentally to acquire the habit of producing more or less abortive stamens on certain blossoms; and as these gourds would therefore almost necessarily insure cross-fertilization, and so produce in the long run the finest seedlings, the habit once accidentally set up would be carefully fostered by natural selection, till it grew at last into a confirmed practice of the entire race. All through nature, indeed, we find that the scrubbiest, weediest, and shabbiest species still retain the primitive habit of self-fertilization or in-and-in breeding; but that all the chief places in the hierarchy of life are filled by species which have acquired in one way or another the salutary practice of cross-fertilization, and which thus encourage to the utmost of their power the frequent introduction of fresh blood. The gourds, as a very dominant race, have naturally conformed to the general practice of higher types in this respect; and gardeners find, when they exclude insects from their hot-houses and cucumber-frames, that they have to come to the aid of Nature by artificial means, and to fertilize the blossoms with a camel's hair pencil.

The flowers of the melon, the cucumber, and the vegetable marrow are bright yellow and almost, if not quite, scentless. Those of the true gourd, on the other hand, with which we are