Epiphytic herbs. Stem ascending or sometimes pendent, enclosed in leaf-sheaths. Leaves few to several, distichous, conduplicate, apex acute, acuminate or unequally bilobed, coriaceous, articulate to a sheathing base. Inflorescence axillary, racemose, arching to pendent, flowers borne simultaneously along whole inflorescence in one season, facing all directions; rachis alate and sulcate. Flowers resupinate, not ephemeral, sometimes strongly scented. Dorsal sepal and petals free. Lateral sepals usually larger, base adnate to column foot. Petals often smaller than sepals, sometimes erose-serrulate. Labellum rigidly attached to column foot, conical to saccate, laterally compressed, trilobed, ecallose inside, sometimes hirsute, the anterior wall much thickened toward apex, side lobes entire or bilobulate, ascending, midlobe reduced, spreading forward; spur conical or saccate, often spreading horizontally, almost continuing the line of column foot, laterally compressed, narrowed toward apex. Column with an obliquely decurrent foot; pollinia two, waxy, subglobose to ovoid, entire, solid, stipe rudimentary, viscidium distinct; rostellum bifid, with a median tooth, the two teeth sometimes strongly retrorse and fitting into two cavities on viscidium.