Description:

• Annual or perennial herbs, shrubs or trees, usually with milky, usually caustic latex, often fleshy (succulent) and sometimes spinescent; monoecious, or less often dioecious
• Leaves alternate or opposite, often much reduced in succulent species; with or without stipules, sometimes stipules spinescent in succulent species
• Inflorescences axillary or terminal with flowers in cyathia: distinct, cup-shaped structures with (2-)4 or 5(-8) nectariferous glands around the rim alternating with (2-)4 or 5(-8) involucral lobes; inside involucre numerous very reduced male flowers and 1 female flower, or in separate involucres; sepals and petals 0 or rudimentary; cyathia solitary or 2-many in cymes, umbels, panicles, or clusters
• Male flowers reduced to individual stamens which are usually arranged in groups opposite involucral lobes, often interspersed with bracteoles; pedicel articulated with filament; anthers 2-thecous, longitudinally dehiscent
• Female flowers solitary within involucre surrounded by male flowers, sessile or on short pedicel, usually elongating after fertilisation, with or without much reduced calyx; ovary (2)3(4-7)-locular, with 1 pendulous ovule in each locule; styles usually 3, free or ± connate, entire or bifid
• Fruit a capsule with carpels bivalved, sometimes fleshy but becoming woody at maturity, separating from persistent, central axis and opening along inner face
• Seeds with smooth or sculptured surface; with or without caruncle
• x = 6, 7, 9, 10, 11 (5, 8, 13, 19) (high polyploidy, B-chromosomes)

Nomenclature:

• Euphorbia L.
  • Linnaeus: 450 (1753)
  • Brown: 222 (1915)
  • White, Dyer & Sloane: 59 (1941)
  • Meyer: 1 (1967)
  • Carter: 409 (1988)
  • Webster: 128 (1994)
  • LaFon & Schwartz (general editors of Euphorbia Journal) (1983-1994)
• Chamaesyce S.F.Gray
  • Gray: 260 (1821)
  • Koutnik: 262 (1984)
  • Carter: 415 (1988) treated as subgenus
  • Webster: 129 (1994) artificial but usable group, although the recognition of Chamaesyce as a separate genus makes Euphorbia a paraphyletic group
• Poinsettia Graham
  • Graham: 412 (1836)

Distribution & Notes:

• Global: Species ± 1600, or over 2000 with some segregate genera like Chamaesyce included, worldwide
• Southern Africa: Species over 300, widespread, predominantly succulent in drier areas