Description from Flora of China
Shrubs or perennial herbs. Stems with stellate hairs. Leaves petiolate; leaf blade margin serrate, adaxially stellate puberulent/hirsute, abaxially densely stellate lanate. Inflorescences axillary, sometimes basal, rarely terminal, cymes pedunculate or sessile, sometimes in spikes or panicles; bracts subcircular to linear-lanceolate. Calyx campanulate to tubular, 10-veined, 5-toothed, teeth equal or subequal. Corolla purple-red or yellow to white, 2-lipped, straight or curved, long exserted; tube abruptly or gradually dilated at throat, not hairy annulate inside; upper lip straight, slightly galeate, entire or emarginate, sometimes mucronulate; lower lip spreading, 3-lobed, middle lobe longest. Stamens 4, underlying upper lip, anterior 2 longest; filaments complanate, hairy on two sides or glabrous; anthers close together in pairs, cells parallel, transverse. Style included, apically subequally 2-cleft. Nutlets 1-4 maturing per flower, obovoid to ovoid, rarely globose, rugulose, glabrous or hirsute, drupelike, areole oblique.
About 36 species: China, India, Indonesia, Malaysia, Myanmar, Philippines, Thailand, Vietnam; 15 species in China.
Gomphostemma is one of few tropical rain forest genera in the Lamiaceae.