Breda, Kuhl & Hasselt, Gen. Sp. Orchid. Asclep.: t. 15 (1827)
Rambling (up to 5 m long), epiphytic, occasionally lithophytic herbs. Stem pendent or ascending, sometimes clambering, simple, with a few to many nodes covered by leaf-sheaths. Leaves distichous, linear to oblong, sometimes falcate, usually unequally bilobed or retuse, flat, coriaceous, articulate to a sheathing base. Inflorescences lateral, penetrating the leaf-sheaths, racemose or paniculate, with the flowers clustered in the distal portion of each racemose branch, erect or pendent, many-flowered; peduncle shorter or longer than rachis (or the terminal rachis branch in panicles), glabrous, minutely papillose or distinctly pubescent; rachis with flowers opening from base of inflorescence; floral bracts persistent, triangular, acute to acuminate, erose. Flowers resupinate or not, usually widely opening, rarely scented. Sepals and petals free, similar, spreading. Labellum firmly attached to column, trilobed, shortly spurred, side lobes erect, deltoid or triangular, the back edge of each lobe usually producing a right angle to the front edge, midlobe fleshy, often recurved, usually suborbicular or ovate-triangular; spur bucket-shaped, front wall thicker than back wall, back wall with a projecting erect, rectangular, bifid to subtruncate, ligulate appendage reaching or exserted beyond the entrance to spur. Column erect or slightly recurved, column foot absent; anther cap shortly beaked, pollinia four, arranged as two unequal pairs, waxy, semi-globular, solid, with a long common stipe and a single, usually concave viscidium; rostellum hammer-shaped, bifid after removal of the pollinarium, shorter than diameter of column.