Epiphytic or lithophytic herbs. Stems erect, elongate, with many leaves. Leaves distichous with sheathing bases, coriaceous, conduplicate, unequally bilobed, sessile, articulate to sheath. Inflorescence axillary, racemose or paniculate, lateral, many-flowered. Flowers resupinate. Sepals similar, free, spreading. Petals smaller and narrower than sepals, spreading. Labellum adnate at base to column, trilobed, side lobes erect, midlobe recurved, adaxial surface usually conspicuously wrinkled, base with two calli at spur entrance; spur cylindrical. Column without foot; anther cap rostrate; pollinia four, waxy, globose, almost equal in size, separate from each other, attached by a caudicle to a linear-spatulate stipe at an angle, viscidium subglobose; stigma suborbicular; rostellum arcuate acute or bilobed.