Epiphytic herbs. Stems pendent or erect, simple or branching, up to 1 m in length. Leaves oblong, ligulate or terete, unequally bilobed or acute. Inflorescence supra-axillary, racemose. Flowers resupinate, pinkish white, various shades of blue, deep magenta or dark purple. Sepals and petals spreading. Labellum firmly adnate to column, urceolate, trilobed above; spur cylindrical, gently curving, interior containing either an upward-pointing, central protuberance on the back wall or a decurved shelf-like back wall callus; front wall callus flap-like; median septum absent. Column erect, cylindrical, foot decurrent on the back wall of labellum as a thickened cushion, or free; pollinia four, appearing as two, each completely divided into free halves, stipe long, linear, viscidium subquadrate; stigma oval, vertical; rostellum distinct, porrect or stiffly erect, bilobed, lobes broad.