Climbing, epiphytic herbs. Stem simple or branching, up to 1 m long, internodes to about 2 cm long, bearing many support roots at intervals. Leaves linear, to 17 × 2 cm, usually much less. Inflorescence lateral, leaf-opposed, bending through a right angle so the rachis points either straight up or straight down, racemose, to c. 15 cm long, few- to many-flowered. Flowers usually non-resupinate, fleshy, usually yellow with purple markings, or pink. Sepals oblong or obovate, obtuse, often reflexed, lateral sepals connate for a short distance at base. Petals linearobovate or oblong, obtuse, often reflexed. Labellum porrect, saccate, spurred, apex trilobed, midlobe much smaller than sac or spur; spur saccate, with a back wall callus, longitudinal septum, and usually a bilobed callus on front wall. Column variable, usually extended into a proboscis-like structure; pollinia four, as two unequal masses, stipe linear, viscidium ovate.