MB. G. BENTIIAH ON OI101IIDE.E. 359 



as a distinct tribe only. Their habit is that of several Orehidese 

 (Apostasia often closely resembles Corymbis) ; they are all ter- 

 restrial, with erect simple leafy stems arising from a short or 

 creeping rhizome, without tubers or pseudobulbs, their inflores- 

 cence terminal, simple, or slightly branched. Their perianth is 

 various, but always within the limits of true Orchidea?. The 

 column is short, bearing two perfect anthers, one on each side of 

 the rostellum or style ; the dorsal anther, the only one in other 

 Orchidea;, is here usually reduced to a variously shaped barren 

 staminodium ; it is, however, perfect, as well as the lateral ones, iu 

 one genus, and totally deficient in one species of another genus. 

 The rostellum or style is more or less prominent or elongated 

 between the lateral anthers, and dilated at the end into a more or 

 less oblique stigma. Their geographical distribution is northern 

 i or tropical ; they are unknown in Africa, extratropical South 

 America, or extratropical Australia. 



The typical genus is Cypripedium, Linn., so well known for its 

 slipper-shaped labellum, and agreeing with the other tribes of 

 Orchideae in its one-celled ovary and capsule with parietal pla- 

 . centas. Its cultivation for the beauty of its flowers has of late 

 been so much the fashion, that horticulturists, by diligent re- 

 search in its native localities and by careful hybridizing, have 

 succeeded in carrying the number of its published species to 

 above forty, several, however, to be hereafter reduced as varieties. 

 In their wild state they are dispersed over Europe, temperate 

 and tropical Asia, and North America, including Mexico. Their 

 structure is far too uniform to admit of their being divided into 

 sections, and can only be distributed into three series from minor 

 deferences in their foliage and the number of flowers, which, 

 w uen more than one, are in a simple raceme, and very rarely above 

 two or three in the raceme. 



Selenipedium, Eeichb. f, about ten species, replaces Cypripe- 

 dium in the mountains of tropical America. The species have 

 generally the slipper-shaped labellum of Cypripedium, under which 

 g«mus most of them were first published ; but a slight difference 

 in habit and inflorescence (the flowers several in a simple or 

 branched raceme), and the important character of the perfectly 

 three-celled ovary and axile placentation, justifies their being 

 maintained as a distinct genus, connecting Cypripedium with 

 Apostasia. Two small-flowered species, S. palmifolium, Eeichb. f, 

 and another, have quite the habit of Apostasia. One species with 



LINN. JOUEN. — UOTANT, VOL. XVIII 2 D 



