Common Name

Rudall River Myall

Family

Fabaceae

Distribution

Restricted to a small area in Rudall R. Natl Park, northern W.A.

Description

Tree to c. 3 m high; crown dense and silvery green. Bark fissured, grey. Branchlets slightly ribbed, appressed-puberulous towards extremities, glabrescent. Phyllodes erect, straight to slightly curved, terete to subterete, 8–12 cm long, 1–1.5 mm diam., innocuous to coarsely pungent, coriaceous, appressed-puberulous, typically glabrescent, striate by numerous closely parallel fine nerves. Inflorescences 1–4-headed racemes; raceme axes 0.5–6 mm long; peduncles 4–8 mm long, white or pale yellow appressed-puberulous; heads globular, 4.5–5 mm diam., 35–40-flowered. Flowers 5-merous; sepals free, together with petals and bracteoles golden appressed-puberulous. Pods (old valves) constricted between and somewhat raised over seeds, straight, ±6.5 cm long, 5–5.5 mm wide, chartaceous, appressed-puberulous. Seeds not seen.

Habitat

Grows in quartz gravel on hillsides and gullies in spinifex communities.

Specimens

W.A.: upper Rudall R. area, B.R.Maslin 2101 (BRI, DNA, NSW, PERTH).

Notes

Nearest A. sibilans which has wider and seemingly much longer pods, fewer-flowered heads, white or very pale yellow, appressed-puberulous petals, more slender and commonly longer and more sinuous phyllodes as well as being geographically disjunct. The inadequacy of collections (especially fruiting material) makes it difficult to accurately assess the taxonomic status of A. auripila.

B.R.Maslin, in J.P.Jessop (ed.), Fl. Central Australia 130 (1981), treated this species as ‘A. aff. rigens’. Acacia rigens is readily distinguished by its yellow-ribbed branchlets, non-racemose inflorescences, glabrous corolla, much narrower pods and a geographic range considerably further south.

FOA Reference

Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia

Author

R.S.Cowan