Epiphytic herbs. Stem obscure. Roots numerous, elongate, flattened, dull green or grayish green with brown tip. Leaves absent or present only in young plants. Inflorescence racemose, with many flowers; peduncle slender, often densely pubescent. Flowers small; sepals subequal, lateral ones adnate to lower side of column foot; petals adnate to upper part of column foot, often truncate at apex; lip mobile, articulated with foot of column, saccate or concave at base, with 2 large erect lateral lobes and a small midlobe, disc with various forms of pubescent calli or ridges; column short, foot nearly twice as long; anther terminal, operculate, each side with a filiform appendage fitted in furrow of column; pollinia of 2 globose bodies, each divided into 2 unequal parts, attached by stipe to small visidium; viscidium broader than stipe; clinandrium shallow. Capsules elongate cylindrical.
About 15 species, in southern China, the Himalaya, India, through Indochina to Indonesia. One species in Taiwan.