Description from Flora of China
Herbs, epiphytic. Stems pseudobulbous or caulescent, former 1-3-leaved, latter with up to 12 leaves, very short or elongate. Leaves distichous or arranged in a fan, erect to spreading, terminal, sometimes fleshy, jointed on equitant sheaths, articulate. Inflorescences lateral or arising from base of pseudobulb, racemose, laxly to densely many flowered. Flowers resupinate, pale green or white, minute, opening widely or not, often self-pollinating. Sepals similar, free, sometimes connivent; lateral sepals often ± adnate to column foot forming a mentum. Petals often smaller than sepals; lip often with a basal claw attached to end of column foot, base concave or ± saccate, margin entire or obscurely 3-lobed. Column short, with a conspicuous foot; anther terminal, obtuse at apex; pollinia 8, in 2 groups of 4, waxy, attached by a narrow caudicle to a small viscidium.
About 190 species: from Sri Lanka and mainland Asia, through SE Asia, to Australia, New Guinea, and the Pacific islands, most species occurring in Indonesia and New Guinea; four species (two endemic) in China.
(Authors: Chen Xinqi (陈心启 Chen Sing-chi); Jeffrey J. Wood)