Epiphytic herbs. Rhizomes prostrate, densely rooting, bearing a series of aerial stems. Stems tufted, erect or pendulous, frequently branching; branches with several nodes, narrowed at base, slightly dilated upward, terminal or uppermost internode dilated and forming pseudobulb. Pseudobulbs often lustrous, flattened, clavate or fusiform, producing new shoots from its base. Leaves solitary, on apex of pseudobulb, nearly sessile, usually oblong or ovate-oblong, coriaceous. Racemes with few flowers, terminating pseudobulb, subtended by a series of many bracts; bracts scarious. Flowers fugacious, lasting less than half a day; sepals similar, lateral ones often oblique at base and adnate to foot of column forming a saccate mentum; petals similar to dorsal sepal or narrower; lip 3-lobed or rarely unlobed, lateral lobes erect, midlobe varying in shape, often with crisped or fimbriate margins, disc usually keeled; column short and stout, base producing into a distinct foot; anther terminal, operculate, 2-celled; pollinia waxy, 4, in 2 aggregated groups, without caudicle or viscidium. Capsules fusiform.
About 70 species, mainly in Southeast Asia, southward to Pacific islands and Australia. Two species in Taiwan.