Shrubs or climbers, epiphytic or epipetric, not rhizomatous. Stems often pendent, branched or unbranched. Leaves usually many, along stem, opposite, sometimes whorled, equal to subequal in a pair; leaf blade glabrous, rarely puberulent or pubescent, base cuneate to rounded or attenuate. Inflorescences umbel-like, lax or sometimes dense, axillary or pseudoterminal, 1-10-flowered cymes; bracts 2, opposite. Calyx actinomorphic, 5-sect from base to 5-lobed; segments equal, rarely unequal. Corolla red to orange, seldom greenish, yellow, or white, zygomorphic, inside sparsely puberulent, sparsely glandular puberulent, glabrous, or with a hair ring; tube narrowly tubular to funnelform-tubular, often curved, not swollen, much longer than limb, 0.4-1.5 cm in diam.; limb indistinctly or distinctly 2-lipped; adaxial lip 2-lobed; usually equalling, occasionally to 1/2 X length of abaxial lip; abaxial lip 3-lobed, lobes equal or subequal, apex rounded to acute. Stamens 4, adnate to corolla tube near or above middle, usually exserted; anthers basifixed, usually coherent in pairs at apex, thecae parallel, not confluent, dehiscing longitudinally; connective not projecting; staminode 1 or absent, adnate to adaxial side of corolla tube. Disc ringlike. Ovary linear, 1-loculed; placentas 2, parietal, projecting inward, 2-cleft. Stigma 1, terminal, capitate to depressed-globose, undivided. Capsule straight in relation to pedicel, linear, much longer than calyx, dehiscing loculicidally to base; valves 2 or 4, straight, not twisted. Seeds with 1(or 2-50) hairlike appendages, opposite end with 1 hairlike appendage, seldom 1 linear appendage at each end.