Perennial, stoloniferous herb. Lvs simple, ± crenately toothed. Fls in dense axillary whorls; bracts resembling lvs. Calyx tubular-campanulate, 10-veined, not gibbous at base; teeth 5, almost equal, subulate. Corolla bilabiate, yellow; upper lip helmet-shaped, laterally compressed; lower lip with 3 almost equal lobes, the middle lobe ± triangular; tube > calyx, dilated in upper part, with ring of hairs inside. Stamens lying below upper lip; anther cells divergent, glabrous. Style gynobasic, its arms subequal. Nutlets trigonous, smooth.

Annual or perennial herbs, often diffuse or decumbent; stems sometimes rhizomatous and creeping, but not stoloniferous. Lvs simple, crenate to dentate. Verticels crowded in dense axillary or, less commonly, terminal whorls. Bracts mostly similar to lvs. Calyx tubular or campanulate, 5-nerved, not gibbous at base, with 5 equal or subequal teeth. Corolla white to pink or purple, 2-lipped; upper lip hooded, densely hairy outside; lower lip with the main central lobe obcordate or obovate, with or without small lateral lobes. Stamens lying below upper lip; anther cells divergent. Style gynobasic. Nutlets ± trigonous, truncate at apex.