Page:On the Various Contrivances by Which British and Foreign Orchids are Fertilised by Insects, and on the Good Effects of Intercrossing.djvu/74

 regions, where the Vanilla flourishes, either do not visit the flowers, though they secrete an abundance of nectar, or do not visit them in the proper method. We have now arrived at Lindley's last and seventh Tribe, including only one genus, Cypripedium, which differs from all other Orchids far more than any other two do from each other. An enormous amount of extinction must have swept away a multitude of intermediate forms, and left this single genus, now widely disseminated, as a record of a former and more simple state of the great Orchidean Order. Cypripedium possesses no rostellum; all three stigmas being fully developed, but confluent. That anther, which is present in all other Orchids, is here rudimentary, and is represented by a singular shield-like projecting body, deeply notched or hollowed out on its lower margin. There are two fertile anthers which belong to an inner whorl, represented in ordinary Orchids by various rudiments. The pollen-grains do not consist of three or four united granules, as in all other genera, excepting the degraded Cephalanthera. The grains are not united into waxy masses, nor tied together by elastic threads, nor furnished with a caudicle. The labellum is of large size, and as in all other Orchids is a compounded organ.

The following remarks apply to the four species which I have seen, namely, C. barbatum, purpuratum, insigne, and venustum. The manner of fertilisation is here widely different from that in all the many before-given cases. The labellum is folded round the short column, so that its edges nearly meet along the dorsal surface; and its broad extremity is folded over and backwards in a peculiar manner, so as to for a sort of shoe, which closes up at the end of the flower. Hence arises the English name of Ladies'-slipper. In the position in which the flower grows, and as it is here represented, the dorsal surface, with the edges of the labellum almost meeting, is uppermost. The stigmatic surface is slightly protuberant, and is not viscid; it fronts the basal surface of the labellum. The margin of the upper and dorsal surface of the stigma can be barely distinguished between the edges of the labellum and through the notch in the rudimentary, shield-like anther (a'); but in the drawing (s, Fig. A) this margin is brought outside the edges of the labellum by their depression; the toe also of the labellum is a little bent down, so that the flower is represented as rather more open than it really is. The edges of the pollen-masses of the two lateral anthers (a) can be seen lying down