Herbs, terrestrial, rarely epiphytic, glabrous except for minute hairs on bracts. Rhizome creeping, scales tubular, soon caducous, rarely persistent; roots filiform, not branching, villous. Pseudobulbs alternating, 1-6 with a leaf and 1 with an inflorescence, articulate at junction with petiole or scape, scales 1 per pseudobulb, tubular, generally soon caducous. Leaf 1 per pseudobulb, convolute, petiolate. Inflorescence an erect raceme, unbranched, both scape and rachis elongating during anthesis. Flowers resupinate, turned to all sides, opening widely. Lateral sepals inserted on column foot. Lip immovable, narrowly attached to column foot, usually 3-lobed, without spur (but column foot with a spur); hypochile basal portion clawlike with parallel margins, front part usually with lateral lobes, lateral keels 2, from base elevating into an entire lobe or into an oblique structure hollow in front, from there continuing to front, median keel absent or present, simple; epichile recurved. Column suborbicular in section, with a seam in front laterally on either side, foot with a spur; anther 2-locular; pollinia 2, hard, waxy, without appendages, obliquely conic with an obtuse top and a hollow base. Capsule fusiform, column and back wall of column foot persistent when mature, with an irregular row of unicellular hairs inside along margins. Seeds fusiform.