Description from Flora of China
Herbs, subshrubs, or shrubs. Leaves simple or pinnately compound. Verticillasters 2- to many flowered, in racemes, panicles, or spikes, rarely solitary, axillary; bracteoles minute. Calyx tubular to campanulate, hairy or glabrous on throat inside, 2-lipped; upper lip entire, 2-toothed, or 3-mucronate; lower lip 2-toothed. Corolla 2-lipped; tube straight, horizontal, curved upward or adaxially dilated, with or without hairy annulus inside; upper lip folded, straight or falcate, apex entire or emarginate; lower lip spreading, 3-lobed; middle lobe widest, margin entire, apex emarginate, fringed, or 2-lobulate; lateral lobes oblong or circular, spreading or reflexed. Stamens 2; filaments short, horizontal or erect; connectives prolonged, linear, T-shaped; upper arms with fertile elliptic or linear anther cells; lower arms robust or slender, with fertile or sterile anther cells, separated or connected to each other; staminodes 2, small or absent. Style 2-cleft, lobes subulate, linear or circular, equal, anterior lobe larger or posterior lobe indistinct. Disc slightly swollen in front or ringlike. Nutlets triquetrous, ovoid or oblong, glabrous, smooth.
About 900(-1100) species: tropical and temperate zones of the Old and New World, 84 species in China.
There are many taxonomic problems in the flora area, especially in Sichuan and Yunnan provinces; collation with the situation in the Himalaya is much needed.