Shrubs or herbs with opposite or verticillate exstipulate leaves. Flowers corymbose, spicate or capitate, rarely solitary. Calyx tubular, persistent, inferior. Corolla deciduous, irregular, often 2-lipped. Stamens 4 and didynamous, or only 2. Style terminating the ovary. Fruit 2- or 4-celled, nucamentaceous or drupaceous; cells 1-seeded. There are between 40 and 50 genera and about 600 species, common in the tropics, but rare in temperate regions.