Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1: 994 (1913)
(Plate 80; Fig. 657.1) Epiphytic herbs. Roots terete, not or sparsely branching, glabrous, smooth. Stem patent, rooting in the basal part. Leaves conduplicate, articulate, distichous, linear-oblong to elliptic-ovate, often twisted at base so as to lie in one plane with stem, usually fleshy, surface rugulose; margins smooth or more frequently denticulate to serrulate; apex obtuse to emarginate, minutely bidentate or mucronate; leaf-sheaths smooth or papillose-rugose, margins entire or fimbriate. Inflorescence lateral, solitary or sometimes in sparse fascicles, patent or pendent, racemose; rachis almost umbellate, rarely elongating over time and producing flowers over a long period. Flowers usually opening simultaneously, quaquaversal, thin-textured, usually translucent white or greenish with a green labellum. Sepals free, usually relatively broad and obtuse, sometimes narrower and acute, margins denticulate to serrulate. Petals similar to sepals. Labellum not motile, spurred, concave, entire, margins entire or denticulate to serrulate; spur up to as long as sepals. Column semi-terete, often dilated apically, lacking a column foot; anther cucullate, pollinia two, subglobose, with a small pore, stipe often tapering toward apex, longer than pollinia, viscidium elliptic to rectangular; rostellum bidentate. Ovary glabrous or rarely pubescent. Capsule terete, sometimes angular.