Usually pendent, epiphytic herbs. Stem to about 10 cm long, obscured by leaf-sheaths, leafy. Leaves narrow, strap-shaped, apex unequally bilobed, coriaceous. Inflorescences often clustered, racemose, as long as the leaves, c. 7–25-flowered; rachis terete or laterally compressed, sometimes slightly keeled or winged, the keels or wings tapering upward and mutually continuous at their base, leaving a concavity where the flower has fallen; floral bracts scale-like, obtuse or acute. Flowers showy, long-lasting, opening simultaneously, sometimes sweetly scented, white or yellow, marked with red, lilac-pink or orange-brown. Dorsal sepal free. Lateral sepals and petals adnate to column foot. Labellum articulate to column foot and bent upward at an angle, motile, distinctly clawed, trilobed, carinate, side lobes linear or tooth-like, midlobe triangular, acute, sometimes reduced to a low fleshy keel, sometimes with a pair of raised linear appendages in front of side lobes; spur distinct, about 1 cm long, saccate, ecallose. Column slightly broadened at truncate apex, with small apical stelidia, column foot long; rostellar projection terminal, about as long as the column, filiform, closely appressed to inner surface of column; anther cap ovate, cucullate, apex often triangular, acute, pollinia two, globose, sulcate, stipe to 5 mm long, viscidium obovate or oblong.