Description from Flora of China
Herbs or subshrubs. Leaves succulent, petiolate or subsessile, margin dentate. Verticillasters dense, overlapping, in ovoid-oblong or cylindric terminal spikes. Calyx ovoid, nearly straight, lower half dilated in fruit, mouth oblique; teeth small or obscure, posterior tooth large, margin entire, reflexed or incurved and closing mouth in fruit. Corolla 2-lipped; tube slender, exserted, recurved at middle, dilated at throat; upper lip obtuse, 3- or 4-lobed; lower lip entire, elongated, incurved. Stamens 4, anterior 2 longer, declinate; filaments free, edentate; anthers ovoid, cells 2. Style longer than stamens, apex subequally 2-cleft, lobes subulate. Nutlets flattened, ovoid, smooth, glandular.
About 20 species: Africa, Asia; one native and another cultivated in China.