j8 NATIVE BRITISH ORCHIDACE^ 



One European species, E. Muelkri Godf.,^ has no rostellum, and is probably the 

 most ancient form of Epipactis. It is entirely self-fertihsing. The stigma curves back- 

 wards to such an extent that it roofs over the chnandrium, its upper edge bemg 

 pushed well beneath the base oj the anther, which projects so far above it that it deposits 

 the two poUinia nearly on the middle of its upper surface, where they stand erect on 

 their bases. This unique plant was published as a new genus {Farapactis epipactoides) 

 by Zimmerman,^- but it appears to be rather a phase of development in Epipactis 

 than a distinct genus. There are two British species (E. leptochila G. and E. dimensis G.) 

 which are intemiediate between E. Muelkri and the other species of Epipactis, m 

 which the rostellum is present in bud and sometimes in the flower when it first opens, 

 but disappears after a few hours, the upper part of the pollinia sliding over the edge 

 of the stigma on to its viscous surface. The antiquity of the genus Epipactis is mdi- 

 cated by its wide geographic range. E. palustris extends through Europe and Asia 

 to Japan, and southwards to N. Africa. E. gigantea inliabits N.E. Asia and N. America, 

 where E. latijolia also occurs, but was introduced into Canada, perhaps also into the 

 States. Unless therefore it is assumed that the genus Epipactis was evolved inde- 

 pendently in the old and new worlds (which is improbable, there being only one 

 species indigenous in America), it must have existed as a genus when plant migration 

 was possible between the two hemispheres. 



KEY TO THE GENUS EPIPACTIS 

 Section I Arthrochilium Irmisch 



Hypochile with an ear on each side; epichile separated by a deep incision, only 

 attached by an elastic hinge. 



1. Rootstock creeping. Flowers white, streaked with violet-rose within, often 



brownish outside; epichile rounded, with a yellow plate at base. Marsh 

 plant. E- palustris 



Section II Eu-EPiPACTis Irmisch 



Hypochile without ears; epichile only separated by a fold, rigid, without basal plate. 



A. Rostellum nearly globular, conspicuous. 



2. Roots in a tassel. Leaves large, soft, elliptical to ovate-lanceolate with tapering 



point; bracts long. Ovary not hairy; sepals green; petals and lip pale rose 

 (rarely all violet-red). Borders of woods. E- latifoha 



^ mLBad. ilndesv. Natkd. Freiburg, N.F. i, 232 (1922), and Fedde, Repertorium, xviii, 283 

 (1922). 



