Epiphytic herbs with 2 forms of vegetative structure; pseudobulbous plants with few leaves at top of pseudobulbs; non-pseudobulbous plants with long or short compressed stem bearing many distichous leaves with equitant sheaths. Leaves oblong or linear, articulate with sheaths. Peduncle arising from base of pseudobulb, or lateral on stem; raceme or spike with many small flowers. Flowers not opening widely; dorsal sepal free; lateral sepals attached to column foot, cohering at base forming mentum; petals smaller; lip adnate to foot of column, usually unlobed, with borad limb and narrow base, sometimes concave or saccate at base; column stout, with distinct foot; anther terminal, operculate, mainly 2celled, each divided into 4 partitions; pollinia 8, waxy, connected in 2 groups by long slender caudicle to an elongate viscidium; stigma entire; rostellum bifid.
About 150 species, from the Himalaya, northern India, southern China, through the Philippines and Malaysia to Papua New Guinea and the Pacific islands. Four species in Taiwan.