Herbs, annual or perennial, subshrubs, or shrubs, succulent. Stems erect or prostrate. Leaves simple, rarely pinnate, mostly opposite, sometimes alternate, in many species fleshy, margin entire, rarely with teeth; true stipules absent, sometimes a stipule-like sheath present at base of petiole. Inflorescences terminal or seemingly axillary cymes, or solitary flowers. Flowers bisexual, rarely unisexual, actinomorphic, perigynous or epigynous. Nectaries separate or in a ring around ovary. Tepals (4 or)5(–8), connate below into a tube. Petals absent or present. Stamens 3 to many, free or connate at base, outermost often as filamentous staminodes; anthers dehiscing by longitudinal slits. Ovary inferior, syncarpous; carpels 2 to many; ovules 1 to many, on long funicles, mostly campylotropous; placentation axile or parietal, sometimes basal-parietal. Stigmas as many as carpels. Fruit a hygroscopic or circumscissile capsule, more rarely a berry or nut. Seeds with slender embryo curved around perisperm, rarely with an aril; endosperm scanty or absent.

The family is divided into five subfamilies, of which two, Sesuvioideae and Tetragonioideae, are represented by native species in China.

Many members of the subfamilies Mesembryanthemoideae and Ruschioideae are ornamentals and are in cultivation worldwide. Until the early 20th century, these were nearly all included in the genus Mesembryanthemum. Since then, the majority of the members of that genus has been placed in a great number of smaller genera. Five species have been recorded as cultivated in China: Aptenia cordifolia (Linnaeus f.) Schwantes, Carpobrotus edulis (Linnaeus) L. Bolus, Glottiphyllum longum (Haworth) N. E. Brown, Lampranthus spectabilis (Haworth) N. E. Brown, and Mesembryanthemum crystallinum Linnaeus. Further species are likely to be introduced into China.

Tetragonia, together with the genus Tetragonocarpus, is sometimes treated as an independent family, the Tetragoniaceae. Sesuvium and Trianthema, together with Cypselea Turpin and Zaleya N. L. Burman, are sometimes treated as a separate family, the Sesuviaceae.

About 135 genera and 1800 species: mainly in arid, subtropical regions, most species in S Africa, some in Australia and W parts of the Americas, some pantropical; three genera and three species in China.

(Authors: Lu Dequan (鲁德全) ; Heidrun E. K. Hartmann)