Description:

• Annual, biennial or perennial herbs, usually less than 0.3 m tall, often tufted or cushion-like
• Leaves small, variable in shape, with cauline ones opposite, petiolate or sessile; stipules 0
• Inflorescence often a panicle or cyme, terminal or rarely axillary, sometimes flowers solitary; bracts herbaceous
• Flowers bisexual, subperigynous
• Sepals 5, very rarely 4, free
• Petals 5, white, cream or pink, entire or emarginate, rarely 0
• Stamens 5 or 10, arising on a glandular perigynous disc
• Ovary 1-locular; ovules many on a free-central placenta; styles (2)3(-5), episepalous
• Fruit a capsule, subglobose, oblong or pyriform, dehiscent, mostly by twice the number of teeth as styles present, by 2 or 3(-5) bifid valves
• Seeds many, compressed, smooth or tuberculate
• x = 10, 11 (7, 8, 9, 12, 13) (high polyploidy)

Nomenclature:

• *Arenaria L.
  • Linnaeus: 423 (1753)
  • Linnaeus: 193 (1754)
  • Jussieu: 301 (1789)
  • Candolle: 400 (1824)
  • Pax: 84 (1889)
  • Williams: 326 (1898)
  • Pax & Hoffmann: 315 (1934)
  • McNeill: 102 (1962)
  • McNeill: 245 (1963)
  • Chater & Halliday: 116 (1964)
  • Meikle: 261 (1977)
  • Bittrich: 225 (1993)

Distribution & Notes:

• Global: Species ± 150, mainly in northern temperate regions, also in the arctic, some species on the mountains of South America and Northeast Africa
• Southern Africa: Species 2 introduced, infrequent