Succulent perennials with stems of varied shape and bristles arising from complex axillary structures (areoles). Flowers solitary on areoles, sessile (except in Pereskia), bisexual, usually actinomorphic; perianth segments ? (5–13 in species of F.Z. area), imbricate in bud, with gradual transition between sepals and petals, fused below to form a tube (hypanthium). Stamens ?, inserted at base of perianth; anthers 2-thecous, splitting longitudinally. Carpels 3–?, syncarpous; ovary inferior, unilocular with 3–? parietal placentas; ovules ?; style single with 3–? stigmatic lobes. Fruit a berry. Seeds ?.