Description from Flora of China
Shrubs erect or ascending. Stems and branches terete. Leaves petiolate, with simple or stellate hairs, margin serrate or crenate. Inflorescences pedunculate to subsessile; verticillasters few flowered, in spikes or capitula; bracteoles minute, linear. Pedicel short to obsolete. Calyx tubular-campanulate, 10-veined, glabrous at throat; teeth 5, subequal. Corolla yellow to purple, sometimes spotted, 2-lipped; tube exserted, curved, dilated at throat, not hairy annulate inside; upper lip straight; lower lip ± patent, slightly unequally 3-lobed, middle lobe sometimes emarginate. Stamens 4, reaching upper lip of corolla, anterior 2 longer; filaments slightly hairy; anthers ellipsoid, cells 2, divaricate, apex confluent. Ovary glabrous. Style apex unequally 2-cleft. Nutlets oblong to oblanceolate, flattened dorsiventrally, swollen on 1 side, apex membranous winged.
About six species: Bhutan, China, India, Laos, Myanmar, Nepal, Thailand, Vietnam; five species in China.