Description from Flora of China
Subshrubs or perennial or annual herbs, usually aromatic, occasionally gynomonoecious or gynodioecious. Verticillasters in spikes or opposite cymes in racemes or panicles; floral leaves bractlike; bracts narrow, shorter than to longer than flowers. Calyx (13-)15(-17)-veined, tubular or campanulate, slightly curved or straight, throat oblique or regular; limb 2-lipped or not; teeth 5, equal or unequal, subulate or narrowly lanceolate to oblong-triangular, apex acuminate to spiny-acuminate. Corolla 2-lipped; tube basally narrow, ± abruptly dilated into an ample throat; upper lip ± flat or concave, 2-lobed or emarginate; lower lip large, 3-lobed, with middle lobe larger, concave or ± flat, margin undulate or dentate; lateral lobes small, straight or reflexed, ovate to semicircular. Stamens 4, nearly parallel, glabrous, ascending under upper lip of corolla, posterior 2 longer than anterior, included or exserted, fertile; stamens of pistillate flowers rudimentary, included; anther cells 2, ellipsoid, divaricate, apex not confluent. Style exserted, apex subequally 2-cleft. Nutlets oblong-ovoid, ellipsoid, ovoid, or obovoid, adaxially slightly ribbed, smooth or warty.
About 250 species: temperate Asia, N Africa, and Europe, most abundant in the Mediterranean region and SW and C Asia; 42 species in China.