Herbs, perennial, epiphytic, epipetric, or terrestrial, rhizomatous. Stems simple or branched. Leaves few, spread along stem, rarely crowded near apex, opposite, unequal or subequal, rarely equal in a pair; leaf blade glabrous to pubescent or strigose, base cuneate to subcordate. Inflorescences lax, often dichotomously branched, axillary, 1- to many-flowered cymes; bracts 2, opposite. Calyx actinomorphic, 5-sect from base or near base; segments equal. Corolla white, yellowish, purple, or pinkish, often spotted within, zygomorphic, inside glabrous to subglabrous; tube broadly tubular, gibbous abaxially, 2-4 X longer than limb, 1-2 cm in diam.; limb 2-lipped; adaxial lip 2-lobed; at least slightly shorter than abaxial lip; abaxial lip 3-lobed, lobes equal or central lobe longer, apex rounded to obtuse. Stamens 4, adnate to corolla tube near base or near middle, included; anthers basifixed, coherent in pairs at apex, thecae subparallel, confluent or not at apex, dehiscing longitudinally; connective not projecting; staminode 1 or absent, adnate to adaxial side of corolla tube. Disc ringlike. Ovary oblong to linear, 1-loculed; placentas 2, parietal, projecting inward, 2-cleft. Stigmas 2, equal, oblong to suborbicular, undivided. Capsule straight in relation to pedicel, narrowly oblong to linear, much longer than calyx, dehiscing loculicidally to base; valves 2, straight, not twisted. Seeds (when known) with 1 hairlike appendage at each end.

Seven species: Bhutan, China, India, Myanmar, Nepal, Sikkim, N Vietnam; all seven species in China.