Scrambling terrestrial or epiphytic herbs. Stem climbing or pendent, terete, elongate, branching or not. Leaves distichous, fleshy, terete, channelled adaxially, articulate to a sheathing base; sheaths coriaceous, tightly enclosing stem, persistent. Inflorescence lateral, 1- to several-flowered. Flowers resupinate. Sepals and petals free, subsimilar, spreading, petals usually larger. Labellum broadly adnate to column foot, non-articulate, spurred, variously trilobed, side lobes erect, either parallel to or embracing column, midlobe often dilated and bi- or trilobed; spur funnel-shaped, conical to long horn-shaped, without interior callosities. Column subterete, foot prominent; pollinia two, shortly cleft, waxy, attached by a broadly triangular or subquadrate stipe to a large viscidium; rostellum beaked.