Swainsona extrajacens
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Faboideae
Genus: Swainsona
Species:
S. extrajacens
Binomial name
Swainsona extrajacens

Swainsona extrajacens is a species of flowering plant in the family Fabaceae and is endemic to central Australia. It is an erect, annual plant with imparipinnate leaves with 9 to 21 linear, egg-shaped leaflets, and racemes of purple flowers in racemes of 5 to 10.

Description

Swainsona extrajacens is an erect, apparently annual, with one to several stems mostly 2–4 mm (0.079–0.157 in) wide, that typically grows to 30 cm (12 in) high. The leaves are imparipinnate, 30–150 mm (1.2–5.9 in) long with 9 to 25 linear, egg-shaped leaflets mostly 10–15 mm (0.39–0.59 in) long and 2–5 mm (0.079–0.197 in) wide with narrowly lance-shaped stipules about 5 mm (0.20 in) long at the base of the petioles. The flowers are purple, arranged in racemes of 5 to about 10 on a peduncle 1–2 mm (0.039–0.079 in) wide with broadly lance-shaped bracts about 2 mm (0.079 in) long at the base. The sepals are joined at the base, forming a tube about 2.0 mm (0.079 in) long with lobes shorter than the tube. The standard petal is 8–9 mm (0.31–0.35 in) long and 9–10 mm (0.35–0.39 in) wide, the wings 7–8 mm (0.28–0.31 in) long and the keel 6–8 mm (0.24–0.31 in) long and about 2.5 mm (0.098 in) deep.[2][3]

Taxonomy and naming

Swainsona extrajacens was first formally described in 1990 by Joy Thompson in the journal Telopea, from specimens collected on the far north-western plains of New South Wales in 1974.[4][5] The specific epithet (extrajacens) means "remote from populated areas.[2]

Distribution

This species of pea grows in clay-loam floodplain in the north-western Corner of New South Wales and the north-eastern corner of South Australia.[2]

References

  1. ↑ "Swainsona extrajacens". Australian Plant Census. Retrieved 30 December 2022.
  2. 1 2 3 Thompson, Joy (1993). "A revision of the genus Swainsona (Fabaceae)". Telopea. 5 (3): 507–508. Retrieved 30 December 2023.
  3. ↑ Thompson, Joy; James, Teresa A. "Swainsona extrajacens". Royal Botanic Gardens, Sydney. Retrieved 30 December 2023.
  4. ↑ Thompson, Joy (1990). "New species and new contributions in the genus Swainsona (Fabaceae) in New South Wales". Telopea. 4 (1): 3–4. Retrieved 30 December 2023.
  5. ↑ "Swainsona eremaea". Australian Plant Name Index. Retrieved 27 December 2023.
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