Herbs [shrubs], annual or perennial, succulent, usually papillate. Roots fibrous. Stems prostrate to erect, forming mats; rooting at nodes in some species. Leaves cauline, opposite, those of each pair equal; stipules absent; petiole bases clasping to ± connate, ± widened, margins usually scarious; blade usually flat, linear to spatulate or ovate, tapered, margins entire. Inflorescences axillary, flowers solitary or in cymes, sessile or pedicellate; bracts absent or 2. Flowers: hypanthium obconic; calyx lobes 5, reddish adaxially, usually hooded near tip; petals and petaloid staminodia absent; stamens [1-]5-30, often connate proximally; pistil 2-5-carpellate; ovary half inferior, 2-5-loculed; placentation axile; ovules to 60; styles 2-5, papillate; stigmas 2-5. Fruits capsules, ovoid to obconic, dehiscence circumscissile. Seeds to 60, black to brown, arillate, usually reniform, shiny or dull, smooth or rugose. Sesuvium crithmoides Welwitsch, a west African perennial with linear leaves and sessile flowers, has been reported from waste places along wharves in Georgia (J. K. Small 1933); it apparently is not naturalized in the flora.