Herbs or subshrubs. Leaves entire or dentate. Verticillasters few to many flowered, widely spaced, uniform or reduced in size at end of branches. Calyx tubular to obconical, rarely dilated, 10-veined, straight or curved, truncate or oblique at throat, projected on posterior side; teeth 8-10, usually equal in size. Corolla usually white, rarely yellow, purple, brownish, or scarlet, 2-lipped, tube included; upper lip straight, galeate, densely villous outside; lower lip longer, 3-lobed, middle lobe largest. Stamens ascending beneath upper lip of corolla, close together in pairs; anther cells 2, ovoid, divaricate, apex confluent, often orange. Style unequally 2-cleft at apex, posterior lobe short or obsolete. Nutlets ovoid, triquetrous, subtruncate at apex.

About 100 species: Africa, Asia, Australia, Pacific Islands, two naturalized in South America; eight species in China.