Description from Flora of China
Herbs diffuse or ascending, perennial. Leaves circular to cordate, palmately lobed or divided. Verticillasters axillary; bracteoles needlelike. Flowers small. Calyx tubular to tubular-campanulate, 5-10-veined; teeth 5, unequal, 2 slightly larger, conspicuous, spreading especially in fruit. Corolla white, yellow to brown-purple, 2-lipped; tube not hairy annulate; upper lip straight, entire or emarginate; lower lip 3-lobed, spreading, middle lobe widest and cordate. Stamens 4, small, anterior 2 longer, included; filaments short; anther cells 2, divergent. Style included, apex 2-cleft. Nutlets triquetrous, ovoid, smooth, scaly to finely netted.
Four species: mainly in N Asia, three species in China.