Infl. of various forms, in small plants fls solitary or in simple racemes, us. arising at base of a pseudobulb; floral bracts often small. Per. large to very small; labellum sts apparently uppermost; dorsal sepal free, often short; lateral sepals adnate to column-foot (forming a mentum), free or ± connate; petals us. < sepals. Labellum scarcely lobed, hinged to end of column-foot, us. mobile. Column short, us. with ± horned wings, its foot long; anther narrowly joined to column just below its apex, caducous, pollinia 4, ± waxy, without caudicles; stigma concave, just below anther. Plants epiphytic or rupestral; rhizome creeping or hanging, each segment ending in a swollen internode or pseudobulb carrying a lf on top; sympodial growth continued by rhizome from base of pseudobulb. Lvs various. Genus of > 1,000 spp., mostly in the tropics of America, Africa and Asia, extending north to Japan and south to Australia and represented in N.Z. by 2 spp., at least one of them endemic.