Annual or perennial succulent herbs, subshrubs or shrubs with succulent leaves. Leaves opposite, usually decussate, the lowest usually rosulate, free or ± connate in a sheath, usually simple, undivided and entire. Flowers usually 5-merous, usually small, not showy, in cymes which are arranged in axillary clusters, thyrses, corymb-like inflorescences or with 1(-2) flowers in the leaf axils. Sepals free or connate at base. Corolla usually white, sometimes turning brown when dry; petals connate at base into a tube. Stamens as many as petals. Carpels free or connate at base.