Swainsona is a genus of about 85 species of flowering plants in the family Fabaceae, and is endemic to Australia. Plants in this genus are herbs or subshrubs with imparipinnate leaves and usually purple flowers similar to others in the family.

Swainsona
Swainsona villosa
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Tribe: Galegeae
Subtribe: Astragalinae
Genus: Swainsona
Salisb.[1]
Species

See text.

Synonyms[1][2]

Description edit

Plants in the genus Swainsona are prostrate to erect annuals or perennial herbs or subshrubs, often with many stems at the base. The leaves are usually imparipinnate (pinnate, with a terminal leaflet) with a few to many leaflets, with stipules at the base of the petiole. A few to many flowers are borne in a raceme in leaf axils on an erect peduncle with bracts at the base, and small bracteoles at the base of the sepals. The sepals are joined at the base to form a bell-shaped tube with 5 equal lobes, or the upper 2 lobes shorter. The petals are mostly purple, sometimes white, pink, yellow orange or red. The standard petal is kidney-shaped to more or less round, usually longer than the wings and often longer than the keel. There are ten stamens, nine of which are joined with each other and the tenth free and facing the standard petal.[3][4][5][6]

Taxonomy edit

The genus Swainsona was first formally described in 1806 by Richard Anthony Salisbury in Paradisus Londinensis and the first species he described (the type species) was Swainsona coronillifolia, (now accepted as a synonym of Swainsona galegifolia.[7][8][9]

A member of the family Fabaceae (legumes), this species is most closely related to the New Zealand genera Montigena (scree pea), Clianthus (kakabeak), and Carmichaelia (New Zealand broom).[10] The genus name (Swainsona) honours the English botanist Isaac Swainson.[11]

A few species are known to produce swainsonine, a phytotoxin harmful to livestock (see Locoweed). In Australia, animals intoxicated with swainsonine are said to be pea struck.[12]

Species list edit

The following is a list of species of Swainsona accepted by Plants of the World Online as of 10 September 2023:[2]

Distribution edit

Species of Swainsona are found in all six Australian states and in the Northern Territory and Australian Capital Territory.[7]

References edit

  1. ^ a b "Swainsona". Australian Plant Census. Retrieved 10 September 2023.
  2. ^ a b "Swainsona Salisb." Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 10 September 2023.
  3. ^ Thompson, Joy; James, Teresa A. "Swainsona". Royal Botanic Garden Sydney. Retrieved 10 September 2023.
  4. ^ "Swainsona". State Herbrium of South Australia. Retrieved 10 September 2023.
  5. ^ Jeanes, Jeff A.; Stajsic, Val. "Swainsona". Royal Botanic Gardens Victoria. Retrieved 10 September 2023.
  6. ^ "Swainsona". FloraBase. Western Australian Government Department of Biodiversity, Conservation and Attractions.
  7. ^ a b "Swainsona". Australian Plant Name Index. Retrieved 10 September 2023.
  8. ^ Salisbury, Richard A. (1806). Paradisus Londinensis. London: William Hooker. p. 28. Retrieved 10 September 2023.
  9. ^ "Swainsona coronillifolia". Plants of the World Online. Retrieved 10 September 2023.
  10. ^ Wagstaff, Steven J.; Peter B. Heenan; Michael J. Sanderson (1999). "Classification, origins, and patterns of diversification in New Zealand Carmichaelia (Fabaceae)". American Journal of Botany. 86 (9). American Journal of Botany, Vol. 86, No. 9: 1346–1356. doi:10.2307/2656781. JSTOR 2656781. PMID 10487821.
  11. ^ Sharr, Francis Aubi; George, Alex (2019). Western Australian Plant Names and Their Meanings (3rd ed.). Kardinya, WA: Four Gables Press. p. 116. ISBN 9780958034180.
  12. ^ "THE DARLING PEA". The Sydney Morning Herald. National Library of Australia. 14 May 1897. p. 5. Retrieved 16 May 2014.