Herbs buff to reddish brown, lacking chlorophyll. Rhizome subterranean, coralloid, sometimes branching, covered with tightly tubular sheaths, of few to many internodes of equal length. Stem without leaves but with tubular amplexicaul sheaths. Inflorescence glabrous to pubescent; peduncle with one to few scattered sheathing bracts; floral bracts glabrous to pubescent, equal in length to pedicel plus ovary. Flowers non-resupinate, campanulate, the outer surfaces of the sepals glabrous to pubescent. Lateral sepals free, similar to dorsal sepal, usually enclosing the base of the lip, spreading or connivent with labellum. Petals oblong to ligulate-lanceolate, upper margin adnate to dorsal sepal but often free from it, membranous. Labellum hypochile shallowly concave to semi-globose, containing a small entire fleshy appendage on each side; mesochile elongate, semi-tubular to tubular, exterior of each side usually with a lamellate, entire or dentate flange; epichile bilobed. Column short, stout, semi-terete, slightly dilated toward apex; anther ovoid, biloculate; clinandrium shallow; rostellum narrowly deltoid, thin, remnant entire to shortbifid; stigma lobes weakly to well separated, often confluent, small to relatively large, placed at apex of column under rostellum; column wings two, on the lower apical margins of column, forwardpointing, rounded at apex or dentiform. Ovary cylindric-fusiform, glabrous to pubescent. Capsule not seen. (PO, PC).
A genus of about five species ranging from India to China and Japan. (PO, PC).
Little is known about the ecology of these plants except that they grow underground in humus on forest floors from 1500 to 2600 m. Chamaegastrodia shikokiana probably grows at lower elevations in Japan, but precise data are not available. (PO, PC).
None recorded. (PO, PC).
None of the species is in cultivation and not likely to be because of the mycotrophic nature of the plants. (PO, PC).
Nothing is known of pollinationin the genus, but flowers of herbarium specimens have swollen ovaries before anthesis, possibly indicating autogamy. (PO, PC).
Chamaegastrodia is closely related to Odontochilus Blume, sharing features such as lip shape and structure and a column with frontal stigma lobes. However, Chamaegastrodia differs in having non-resupinate flowers and a simpler column with column wings at the lower apical margin of the column. Taxa of Odontochilus with apparently non-resupinate flowers, such as forms of O. eiwesii Clarke ex Hook.f., have erect flowers like certain species of Zeuxine Lindl. (e.g. Z. violascens Ridl.). Furthermore, the column wings of Odontochilus are always ventral, intramarginal, and under or behind the stigma lobes rather than at their sides.
Kuhlhasseltia J.J.Sm. is also similar to Chamaegastrodia, but the former can be distinguished by its resupinate flowers with a column that has connate rather than separate to confluent stigma lobes and lacks column wings. Evrardianthe Rauschert and its nomenclatural synonyms, previously considered congeneric with Chamaegastrodia, have been included under Odontochilus, with which it agrees completely except for the aphyllous habit. (PO, PC)