Description:

• Annual to perennial (in the large species) fleshy herbs, prostrate, decumbent or erect; stems herbaceous, terete, angled or winged; with fibrous roots
• Leaves decussate throughout or becoming alternate in inflorescences or alternate throughout, flat and tapering to a pseudopetiole, or terete, club-shaped or almost globular, shortly fused towards bases, margins occasionally undulate, epidermal bladder cells large to much flattened
• Flowers in dichasia, rarely solitary, 10-60 mm in diameter; open in daylight hours
• Sepals 5, 2 often foliaceous
• Petals united at base into a short tube or sometimes free towards base; pink, yellow or white
• Stamens arising within corolla tube; staminodes 0 or present
• Nectary consisting of 5 shallow or deep grooves
• Ovary semi-inferior; placentas axile; stigmas (4)5, filiform, erect
• Fruit a 5-locular capsule, of Mesembryanthemum type; expanding keels extending to centre of fruit; covering membranes 0; valve wings present, either inflexed over valves or reflexed and fused in pairs
• Seeds D-shaped or triangular, 0.5-1 mm long, black, brown, ochre or whitish, surface rough or ± smooth
• x = 9 (polyploidy)

• Flowering mainly in spring and summer

• Distinguishing characters:
  • Stems herbaceous, surfaces conspicuously covered with bladder cells

Nomenclature:

• Mesembryanthemum L. emend. L.Bolus
  • Linnaeus: 480 (1753)
  • Bolus: 164-168 (1939)
  • Friedrich: 81 (1970)
  • Herre: 204 (1971)
  • Smith et al.: 38 (1998)
  • Gerbaulet: ### (in press)~(Page number missing - No access to the publication?)
• Callistigma Dinter & Schwantes
  • Dinter & Schwantes: 644 (1928)
• Cryophytum N.E.Br
  • Brown: 412 (1925)
• Derenbergiella Schwantes
  • Schwantes: 599 (1928)
• Eurystigma L.Bolus
  • Bolus: 179 (1930)
  • Herre: 154 (1971)
• Halenbergia Dinter
  • Dinter: 158, 200 (1937)
  • Herre: 166 (1971)
• Hydrodea N.E.Br.
  • Brown: 412 (1925)
  • Herre: 174 (1971)
• Opophytum N.E.Br.
  • Brown: 412 (1925)
  • Herre: 240 (1971)

Distribution & Notes:

• Southern Africa: Species 16; Southern Angola, Namibia, western and central South Africa with the distribution extending eastwards to the Eastern Cape. Species of Mesembryanthemum occur in North Africa, the Mediterranean region, California, along the western coast of South America and in Australia, but are likely to have been introduced to these areas