Orchidaceae % \ 



Tribe i. Cypripedileae. Flozvers zygomorphic. 

 Column curved towards the slipper-shaped label lum. 



Only British genus : Cypripedium. 



Subfamily 2. MonaJtdrae. Anterior stavien of 

 outer whorl fertile. Lateral stigmas receptive, odd one 

 rudimentary or developed as rostellum. 



a. Basitonae. Anther confluent with column. Pol- 

 linia with appendages at base which are in connection 

 with glands in rostellum. 



Tribe 2. Ophrydeae. The only tribe. Terrestrial 

 orchids with root tubers. 



Subtribe Serapiadinae. Column short with labellum 

 at base. Anthers erect. Stigma disc-like. Glands of 

 polli?tia enclosed in rostellar pouch. 



Spur long : both glands in a single pouch. Orchis. 



Spur absent : both glands in one pouch. Aceras. 



Spur absent : glands in two distinct pouches. 



Ophrys. 



Subtribe Gymnadeniinae. As above, but pollen masses 

 naked or surrounded by processes of the anthers. 



Without spur. Herminium. 



With spur. Habenaria. 



b. Acrotonae. Anther deciduous. Pollen masses 

 without appendages. ^ 



(a) Acranthae: Inflorescences terminal on branches 

 whose basal portions make up a sympodial shoot. 

 [(^) Pleuranthae {main axis sympodial hut flozvers borne 

 on special lateral axes) : not represented in Britain.] 



I. Convolutae. Leaves convolute in bud. Sheath 

 and blade not distinct from one another. Pollen granular. 

 Anther withering without falling. 



