Description from Flora of China
Herbs, perennial, terrestrial, rhizomatous. Stems simple. Leaves few, along stem, opposite, those near apex sometimes alternate, often unequal in a pair; leaf blade puberulent to scabrous, base attenuate to rounded. Inflorescences compound racemose, lax, pseudoterminal, few to many flowered; bract 1, subtending each flower, alternate. Flowers zygomorphic, sometimes replaced by propagules in upper part of inflorescence. Calyx actinomorphic, 5-sect from base; segments equal. Corolla yellow, zygomorphic, inside glabrous; tube subtubular to funnelform-tubular, not swollen, longer than limb, 0.9-1.6 cm in diam.; limb 2-lipped; adaxial lip 2-lobed, slightly shorter than abaxial lip; abaxial lip 3-lobed, lobes subequal to unequal, apex rounded. Stamens 4, adnate to corolla tube near base, included; anthers basifixed, coherent in pairs, thecae parallel, not confluent, dehiscing longitudinally; connective not projecting; staminode 1, adnate to adaxial side of corolla tube. Disc ringlike. Ovary ovoid, 1-loculed; placentas 2, parietal, projecting inward, 2-cleft. Stigmas 2, strongly unequal; adaxial 1 small, deltoid to suborbicular, undivided; abaxial 1 narrowly obtriangular to ligulate, 2-lobed to emarginate. Capsule straight in relation to pedicel, ovoid, nearly as long as calyx, dehiscing loculicidally to base; valves 4, straight, not twisted. Seeds with scalelike membranous appendages at each end.
One species: China, Japan.