Description :

• Annual or perennial herbs, with stinging and nonstinging hairs on same plant; stems simple or branched, erect, ascending or sprawling; plants monoecious or dioecious
• Leaves opposite, simple, dentate or serrate, (3-)5-7-nerved, petiolate, with dot-like or ± elongate cystoliths; stipules lateral, usually free, rarely connate
• Inflorescences axillary, in racemose or paniculate clusters; bracts narrowly triangular to lanceolate, lacking hooked hairs
• Flowers bisexual or functionally unisexual, minute, often ebracteate
• Male flowers : tepals 4, equal, free, with stinging hairs; stamens 4; ovary rudimentary, cup-shaped, translucent
• Female flowers : tepals 4, unequal, inner 2 equal to achene, outer 2 smaller; staminodes 0; ovary straight, ovoid; style usually 0 or sometimes short; stigma penicillate-capitate, deciduous or persistent
• Achene sessile, laterally compressed, ovate or oblong in outline, loosely enclosed in enlarged, membranous, rarely fleshy, persisting inner tepals
• x = 10, 11, 12, 13 (polyploidy)

Nomenclature:

• Urtica L.
  • Linnaeus: 983 (1753)
  • Linnaeus: 423 (1754)
  • Jussieu: 403 (1789)
  • Endlicher: 283 (1837)
  • Weddell: 55 (1856)
  • Weddell: 39 (1869)
  • Bentham: 381 (1880)
  • Engler: 104 (1888)
  • Rendle: 242 (1917)
  • Brown: 542 (1925)
  • Ball: 67 (1964)
  • Friis: 3 (1989)
  • Friis: 620 (1993)
  • Chew: 70 (1989)

Distribution & Notes:

• Global : Species ± 50, subcosmopolitan but mostly in northern temperate regions, with a few in the tropics and southern temperate regions
• Southern Africa : Species 3, 1 indigenous, 2 introduced weeds, fairly widespread, Gauteng, Free State, KwaZulu-Natal, Lesotho, Northern, Western and Eastern Cape