Swainsona gracilis is a species of flowering plant in the family Fabaceae and is endemic to the south-west of Western Australia. It is a prostrate or ascending perennial herb with imparipinnate leaves with up to 15 wedge-shaped or narrowly oblong leaflets, and racemes of up to 4 purple or blue flowers.
| Swainsona gracilis | |
|---|---|
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Fabales |
| Family: | Fabaceae |
| Subfamily: | Faboideae |
| Genus: | Swainsona |
| Species: | S. gracilis
|
| Binomial name | |
| Swainsona gracilis | |
Description
editSwainsona gracilis is a prostrate or ascending perennial herb that typically grows to a height 30–40 cm (12–16 in) and has several stems 1–2 mm (0.039–0.079 in) wide, arising from a taproot. Its leaves are imparipinnate 15–70 mm (0.59–2.76 in) long with up to 15 wedge-shaped or narrowly oblong leaflets 1–8 mm (0.039–0.315 in) long and 1–3 mm (0.039–0.118 in) wide on a very long petiole. There is a stipule often 3–4 mm (0.12–0.16 in) long at the base of the petiole. The flowers are arranged in racemes 60–120 mm (2.4–4.7 in) of up to 4 on a peduncle 0.5–1 mm (0.020–0.039 in) long, each flower mostly 5–7 mm (0.20–0.28 in) long in the top 10–20 mm (0.39–0.79 in) of the peduncle. The sepals are joined at the base, forming a tube about 2 mm (0.079 in) long, the sepal lobes shorter than the tube. The petals are purple or blue, the standard petal 7.0–8.5 mm (0.28–0.33 in) long, the wings 6.5–6.7 mm (0.26–0.26 in) long, and the keel 7.0–7.5 mm (0.28–0.30 in) long. Flowering occurs in August and September, and the fruit is a glabrous pod 7–10 mm (0.28–0.39 in) long and 6–7 mm (0.24–0.28 in) wide with the remains of the twisted style about 4 mm (0.16 in) long.[2][3][4]
Taxonomy and naming
editSwainsona gracilis was first formally described in 1864 by George Bentham in his Flora Australiensis, from specimens collected near the Murchison River by Augustus Oldfield.[4][5] The specific epithet (gracilis) means "thin" or "slender".[6]
Distribution and habitat
editThis species of pea grows in a variety of soils in moist places in the Avon Wheatbelt, Carnarvon, Coolgardie, Gascoyne, Geraldton Sandplains, Murchison and Yalgoo bioregions of Western Australia.[2][3]
Conservation status
editSwainsona gracilis is listed as "not threatened" by the Western Australian Government Department of Biodiversity, Conservation and Attractions.[3]
References
edit- ^ "Swainsona gracilis". Australian Plant Census. Retrieved 24 January 2024.
- ^ a b Thompson, Joy (1993). "A revision of the genus Swainsona (Fabaceae)". Telopea. 5 (3): 475–476. Retrieved 11 December 2023.
- ^ a b c "Swainsona gracilis". FloraBase. Western Australian Government Department of Biodiversity, Conservation and Attractions.
- ^ a b Bentham, George (1864). Flora Australiansis. London: Lovell Reeve & Co. p. 220. Retrieved 25 January 2024.
- ^ "Swainsona gracilis". Australian Plant Name Index. Retrieved 11 December 2023.
- ^ Sharr, Francis Aubi; George, Alex (2019). Western Australian Plant Names and Their Meanings (3rd ed.). Kardinya, WA: Four Gables Press. p. 209. ISBN 9780958034180.