Description from Flora of China
Herbs erect. Leaf blade margin dentate. Cymes dichotomous, axillary and/or in terminal panicles; bracts and bracteoles linear, early deciduous. Calyx campanulate, 10-veined; teeth 5, triangular to linear, subequal or posterior teeth much longer; fruiting calyx dilated or saccate-dilated, base rounded. Corolla yellow, rarely white, marked with purple-red or brown on upper lip; tube exserted, straight, base narrow, dilated above middle, annulus absent inside; upper lip straight, galeate, base obliquely cuneate or sometimes short clawed; lower lip spreading, 3-lobed, middle lobe ligulate to ovate, lateral lobes ovate or circular. Stamens 4, subequal, included in upper lip or slightly exserted; filaments complanate, usually glabrous; anther cells 2, apically divaricate, becoming confluent. Style as long as stamens, anterior lobe subulate, posterior lobe short to inconspicuous. Nutlets ovoid, glabrous, adaxially veined, abaxially rounded, constricted at base, areole small.
About 24 species: Asia, 20 species in China.