Origin of Species Variorum

the sake of mere variety, like toys in a shop. ↑ With plants having separated sexes, and with those in which, though hermaphrodites, the pollen does not spontaneously fall on the stigma, some aid is necessary for their fertilisation. With several kinds this is effected by the light and incoherent pollen-grains being blown by the wind through mere chance on to the stigma; and this is the simplest plan which can well be conceived. An almost equally simple, though very different, plan occurs in many cases, in which a symmetrical flower secretes a few drops of nectar, and is consequently visited by insects; and these carry the pollen from the anthers to the stigma.

From this simple stage we may pass through an in-exhaustible number of contrivances, all for the same purpose and effected in essentially the same manner, but entailing changes in every part of the flower; with the nectar stored in variously shaped receptacles, with the stamens and pistils modified in many ways, sometimes forming trap-like contrivances, and sometimes capable of neatly adapted movements through irritability or elasticity. From such structures we may advance till we come to such an acme of perfect adaptation, as has lately been described by Dr. Crüger in the case of Coryanthes. This orchid has its labellum or lower lip hollowed out into a great bucket, into which drops of almost pure water, not nectar, continually fall from two secreting horns which stand above it; and when the bucket is half full, the water overflows by a spout on one side. The basal part of the labellum curves over the bucket, and is itself hollowed out into a sort of chamber with two lateral entrances, within which and outside there are some curious fleshy ridges.