Herbs, epiphytic or lithophytic, sympodial. Roots velamentous, glabrous. Stems rhizomatous, covered by scarious sheaths; pseudobulbs often angled, ovoid, stout. Leaves conduplicate, articulate, thin to leathery. Inflorescences lateral from base of pseudobulb, spikes [racemes], erect to pendent, pedunculate, rachis swollen, fleshy. Flowers resupinate, sessile; dorsal sepal distinct and free; lateral sepals adnate to column foot forming mentum; petals distinct and free, smaller than sepals; lip fleshy; column erect with aristate terminal teeth or wings; anther terminal, incumbent, operculate; pollinia 2 or 4, hard, waxy; stigma entire; ovary sessile [pedicellate]. Fruits capsules, beakless. x = 19, 20.
Pantropical, mostly Asia and Africa.
Species 1000–1200 (1 in the flora).