Perennial herbs, undershrubs or shrubs, succulent, usually with erect stem. Leaves opposite, decussate, or verticillate, simple and unlobed or lobed to pinnatifid or sometimes pinnately compound, usually petiolate, rarely sessile, flat or sometimes terete, crenate, succulent. Inflorescence terminal or axillary, usually corymb-like, loose to dense, few to many-flowered, rarely panicle-like. Flowers pedicellate, 4-merous, usually pendulous, bisexual, large brightly coloured. Calyx tubular, lobes 4, rarely free, usually connate below. Corolla tubular, distinctly 4-angled, lobes ovate, triangular, ovate-lancoelate sometimes constricted. Stamens 8, in two whorls, adnate to the corolla-tube, exserted. Carpels 4, free or connate at the base, attenuated into the long styles, styles longer than the ovaries, usually exserted. Nectar scales semicircular, quadrate or linear. Follicles 4, many seeded. Seeds oblong or obovoid with rugulose tegument.