Herbs, perennial. Rhizomes short, thick. Stems and twigs 4-angled, distinctly winged along edges. Leaves opposite, small, simple to deeply 3-lobed and almost palmate, usually early deciduous. Inflorescences axillary, simple cymes or reduced to 1 flower. Flowers usually of 2 kinds, open or cleistogamous. Calyx deeply 4- or 5-lobed, slightly enlarged in fruit, conspicuously 8-10-veined; lobes linear-lanceolate, equal or subequal. Stamens 4, didynamous. Ovary 4-locular; ovules 1 per locule. Stigma slightly 2-cleft. Open flowers with corolla longer than calyx, tube slender, 2-lipped, lower lip 3-lobed, upper lip erect and 2-lobed; stamens exserted; style longer than stamens. Cleistogamous flowers with corolla shorter than calyx; stamens and style shorter than corolla. Nutlets 4, obovate, puberulent, basally obscurely reticulate.

Two species: endemic to China.

The genus is sometimes included in Lamiaceae. There are collections that are somewhat intermediate between the two species.