Description from Flora of China
Herbs, mycotrophic, erect, or scrambling vines, often with rather stout, tuberous rhizomes. Stem yellowish brown or reddish brown, often stout, slightly fleshy, with scales at nodes. Raceme or panicle terminal and lateral, with many slightly fleshy flowers; rachis pubescent; floral bracts persistent. Flowers usually yellow or tinged with reddish brown, medium-sized. Sepals free, abaxially often hairy. Petals slightly smaller than sepals, glabrous; lip unlobed, usually concave, cup-shaped or saccate, ± embracing column, conspicuously larger than sepals, spurless, with longitudinal ridge or callus adaxially. Column often short and stout, dilated at apex, curved, without column foot, subterminal; pollinia 2, cleft, granular-farinaceous, without caudicle or viscidium; stigma large, deeply concave; rostellum short, wide, above stigma. Fruit a dry capsule, rather long, dehiscent. Seeds with stout testa, with broad surrounding wing.
About ten species: mainly in tropical Asia, extending to S China, Japan, New Guinea, and Madagascar; four species (one endemic) in China.
(Authors: Chen Xinqi (陈心启 Chen Sing-chi); Phillip J. Cribb)