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.

Source: [
• 1
• 4
]. 

Herbs, shrubs, or subshrubs, annual or perennial, often succulent, papillate, glabrous, hairy, or scaly. Roots usually fibrous, sometimes tuberous. Stems underground, or prostrate and mat-forming to erect. Leaves cauline or basal, alternate or opposite, sessile or petiolate; stipules usually absent, or free from or adnate to petiole; blade flat, terete, or triquetrous (3-angled), occasionally scalelike. Inflorescences axillary or terminal, flowers solitary or in cymes; bracts present or absent; bracteoles usually absent (present in Trianthema, Cypselea); pedicel present or absent. Flowers bisexual (sometimes unisexual in Tetragonia), inconspicuous to showy, tubular or campanulate; hypanthium present; calyx lobes (3-)4-5(-8), sometimes colored and petaloid, occasionally hooded and/or appendaged, equal or unequal; nectary absent, a ring, or separate glands; petals (including petaloid staminodia) 0-250[-300], distinct or connate proximally, often 2-4-seriate, linear; stamens 1-500(-700), distinct or connate in groups; pistil 1, 1-25-carpellate; ovary superior, inferior, or half-inferior, 1-25-loculed; placentation usually parietal, infrequently axile, apical, free-central, or basal; styles absent or 1-25, distinct or partly connate; stigmas 2-25. Fruits usually capsules, dehiscence loculicidal or septicidal, usually with multiple valves, with or without membranes covering seeds, or dehiscence circumscissile, or indehiscent berries, or nutlike. Seeds 1-500(-1000), often arillate, usually papillose; embryo coiled around perisperm.

Source: [
• 5
]. 

Fruit capsular, loculicidal or circumscissile

Source: [
• 2
]. 

Seeds usually subreniform, not strophiolate; embryo usually curved

Source: [
• 2
]. 

Stamens 5–?, hypogynous, sometimes in pairs or in fascicles, when definite alternate with the perianth segments

Source: [
• 2
]. 

Ovary superior, of 1–5 united carpels; loculi as many as carpels; ovules 1–? per loculus; placentation parietal, axile or apical

Source: [
• 2
]. 

Perianth segments 5, united below into a tube or almost free, ± herbaceous, imbricate or valvate, persistent

Source: [
• 2
]. 

Annual or perennial herbs or subshrubs, mostly succulent or subsucculent, glabrous or pubescent

Source: [
• 2
]. 

Leaves simple, opposite, alternate or sometimes crowded, exstipulate, sometimes with small stipuliform lobes at base

Source: [
• 2
]. 

Inflorescences solitary or in groups, axillary

Source: [
• 2
]. 

Flower hermaphrodite, regular

Source: [
• 2
]. 

Succulent or subsucculent annual or perennial herbs or subshrubs, less often shrubs

Source: [
• 3
]. 

Leaves simple, alternate, opposite or verticillate, sometimes crowded, often with an expanded membranous base, exstipulate or with membranous stipules

Source: [
• 3
]. 

Inflorescences cymose, loosely dichasial to umbelliform or glomerulate (flowers sometimes solitary), axillary or terminal

Source: [
• 3
]. 

Flowers regular, hermaphrodite, rarely unisexual

Source: [
• 3
]. 

Calyx of 5, less often 4 or 3, members, polysepalous or gamosepalous, usually herbaceous and persistent

Source: [
• 3
]. 

Petals absent

Source: [
• 3
]. 

Staminodes sometimes present, then often petaloid

Source: [
• 3
]. 

Stamens 5-many, hypogynous or episepalous, sometimes fascicled, when definite alternate with the calyx-lobes

Source: [
• 3
]. 

Ovary superior or inferior, of 2–5-many united (rarely free) carpels, or of 1 carpel; loculi as many as carpels; ovules one, few, or many per loculus; placentation basal, axile, apical or parietal but not free-central

Source: [
• 3
]. 

Fruits usually capsular, loculicidal or circumscissile, sometimes indehiscent, rarely mericarpic

Source: [
• 3
]. 

Seeds usually subreniform, rarely strophiolate; embryo usually curved

Source: [
• 3
]. 

SELECTED REFERENCES

Adamson, R. S. and H. M. L. Bolus. 1950. Aizoaceae. In: R. S. Adamson and T. M. Salter. 1950. Flora of the Cape Peninsula. Cape Town. Pp. 363-365. Boetsch, J. R. 2002. The Aizoaceae and Molluginaceae of the southeastern United States. Castanea 67: 42-53. Brown, N. E., A. Tischer, and M. C. Karsten. 1931. Mesembryanthema. Ashford. Herre, H. 1971. The Genera of the Mesembryanthemaceae. Cape Town. Jacobsen, H. 1976. A Handbook of Succulent Plants.... 3 vols. Poole. Vol. 3. Jacobsen, H. 1977. Lexicon of Succulent Plants..., ed. 2. Poole. Pp. 395-583. Pax, F. A. and K. Hoffmann. 1934. Aizoaceae. In: H. G. A. Engler et al., eds. 1924+. Die natürlichen Pflanzenfamilien..., ed. 2. 26+ vols. Leipzig and Berlin. Vol. 16c, pp. 179-233, 587. Schwantes, G. 1957. Flowering Stones and Mid-day Flowers. London. Smith, G. F. et al. 1998. Mesembs of the World. Pretoria.

Source: [
• 5
].