Adenochilus
Introduction '''''Adenochilus''''', commonly known as '''gnome orchids''' is a genus of two species of flowering plants in the orchid family Orchidaceae, one endemic to New Zealand and the other to Australia. Both species have a long, horizontal, underground rhizome with a single leaf on the flowering stem and a single resupinate flower with its dorsal sepal forming a hood over the labellum and column.
Description Orchids in the genus ''Adenochilus'' are terrestrial, perennial, deciduous, sympodial herbs with a long, thin, horizontal underground rhizome and a single leaf either on a long stalk or attached to the flowering stem. When present, there is a single resupinate flower on the end of the flowering stem. The dorsal sepal is free and forms a hood over the labellum and column. The lateral sepals and petals are free from each other, longer and narrower than the dorsal sepal, and spread widely apart. The labellum is also free, attached at the base of the column by a short stalk or "claw". The labellum is curved and has a narrow central band of yellow calli.
Taxonomy and naming The genus ''Adenochilus'' was first formally described in 1853 by Joseph Dalton Hooker and the description was published in ''Flora Novae-Zelandiae''. Hooker described ''A. gracilis'' in the same publication, making it the type species. The name ''Adenochilus'' is derived from the Ancient Greek words ''aden'' meaning "gland" and ''cheilos'' meaning "lip", referring to the labellum calli of these two species.
Distribution and habitat ''Adenochilus gracilis'' Hook.f. is widespread in New Zealand where it often grows in deep leaf litter under beech trees and sometimes near wetlands. It is found on both the North and South Islands and on Stewart and Chatham Islands. ''Adenochilus nortonii'' Fitzg. has a restricted distribution in New South Wales, growing at altitudes of  in the Blue Mountains, Barrington Tops and Point Lookout areas, often growing under Antarctic beech trees.
See also * List of Orchidaceae genera
References