Page:On the Various Contrivances by Which British and Foreign Orchids are Fertilised by Insects, and on the Good Effects of Intercrossing.djvu/46



I will begin with the genus Cattleya, of which I have seen several species, and which I fertilised in a very simple manner, different from that in any British Orchid. The rostellum (r, Fig. A, B) is a broad, tongue-shaped projection, which arches slightly over the stigma: the upper surface is formed of smooth membrane; the lower surface and the central portions (originally a mass of cells) consist of a very thick layer of viscid matter. This viscid mass is hardly separated from the viscid matter thickly coating the stigmatic surface which lies close beneath the rostellum. The generally projecting upper lip of the anther rests on, and opens close over, the base of the upper membranous surface of the tongue-shaped rostellum. The anther is kept closed by a sort of spring at the back, at its point of attachment to the top of the column. The pollinia consist of four (or eight in Cattleya crispa) waxy masses, each furnished (see Fig. C and D) with a ribbon-like tail, formed of a bundle of highly elastic threads, with numerous pollen-grains adhering to them. Hence the pollen is of two kinds, waxy masses and separate grains (each, as usual, consisting of four granules) united by elastic threads: this latter kind of pollen is identical with that of Epipactis and other Neotteæ.

These tails, though consisting of good pollen, act also as caudicles, and are thus designated, for they serve as the means for removal of the large waxy masses from the anther-cells. The tips of the caudicles are generally reflexed, and in the mature flower protrude a little way out of the anther-case (see Fig. A), and lie on the base of the upper membranous lip of the rostellum. The labellum enfolds the column, making the flower tubular,