Description from Flora of China
Herbs, perennial, seldom annual, epipetric or terrestrial, rhizomatous or not rhizomatous, stemmed or stemless. Leaves many, along stem and opposite, or basal, equal to subequal in a pair; leaf blade adaxially puberulent, adaxially densely woolly to pannose, hairs branched, base subcordate to cuneate. Inflorescences monochasial or pseudo-paniculate, lax or rarely dense, axillary and terminal, few- to many-flowered cymes; bracts 2, opposite. Calyx zygomorphic, 2-lipped; adaxial lip 3-lobed; abaxial lip 2-sect from base. Corolla white, pink, or purplish, zygomorphic, inside glabrous; tube oblique, campanulate, not swollen, longer than limb, 3.5-6 mm in diam.; limb slightly 2-lipped; adaxial lip 2-lobed, slightly shorter than abaxial lip; abaxial lip 3-lobed, lobes subequal, apex rounded. Stamens 2, adnate to abaxial side of corolla tube near base, included; anthers dorsifixed, coherent, thecae divaricate, confluent at apex, dehiscing transversely; connective not projecting; staminode 1, adnate to adaxial side of corolla tube. Disc ringlike. Ovary oblong, 1-loculed; placentas 2, parietal, projecting inward, 2-cleft. Stigma 1, terminal, lingulate, undivided. Capsule straight in relation to pedicel, narrowly oblong to narrowly ovoid, ca. 2 X longer than calyx, dehiscing loculicidally to base; valves 4, spirally twisted. Seeds unappendaged.
About 13 species: China, Malaysia, Myanmar, Thailand; one species in China.