Herbs or small shrubs, sometimes branched. Leaves opposite or verticillate, sessile or subsessile, 1-5-veined. Inflorescences axillary and/or terminal, dichasial panicles. Flowers (4-)5-merous, sometimes heterostylous; calyx deeply (4-)5-lobed, lobes imbricate, often weakly winged, inside at base some very small glands; corolla tubular or salver-shaped, regularly (4-)5-lobed; stamens (4-)5, inserted on various levels in corolla tube, filaments short, anthers sagittate, ellipsoid or oblongoid, dorsifixed or sometimes basifixed, connective sometimes broadened; pollen in monads; stigma capitate or 2-lobed. Fruit a capsule with persistent calyx, ovoid-ellipsoid; seeds globose to irregular angular.