Family

Fabaceae

Distribution

Occurs in the Mukinbudin–Bonnie Rock (c. 45 km due NNE of Mukinbudin) area and near Maynard Hills (c. 100 km due SE of Sandstone), W.A. A variant from Shark Bay is discussed below.

Description

Shrub to 2.5 m high. Branchlets glabrous. Phyllodes subsessile, erect, usually rhombic in section, ±straight to shallowly incurved, 8–15 cm long, usually 0.9–1.5 mm wide, with an indurate dark brown ±straight and erect mucro, smooth, subrigid, green to subglaucous, glabrous, 4-nerved but the adaxial nerve bifurcating near lowermost gland; nerves yellow; glands 3–17 mm above the much-reduced pulvinus, and an obscure gland also at base of mucro. Inflorescences mostly 2–4-headed racemes; raceme axes (1–) 2–10 (–15) mm long, glabrous; peduncles 1–2 (–5) cm long, glabrous; heads globular, 15–30-flowered, golden. Flowers 5‑merous; sepals free, linear-spathulate. Pods narrowly oblong, raised over seeds, 6–11 cm long, 7–10 mm wide, chartaceous, light brown, glabrous. Seeds longitudinal to longitudinally oblique, ovate, sometimes oblong or elliptic, 5.5–7 mm long, shallowly depressed at centre, slightly shiny, black, exarillate.

Habitat

Grows in yellow sand in Acacia coolgardiensis tall shrubland.

Specimens

W.A.: 99.5 km SE of Sandstone on the road to Menzies, B.R.Maslin 5032 (PERTH); 1.5 km NE of Walyahmoning Rock, c. 60 km NW of Bullfinch, K.Newbey 9552 (PERTH).

Notes

A member of the ‘A. murrayana group’, nearest A. pachyacra which has shorter peduncles, transverse to oblique seeds and less rigid phyllodes with different apices and a basal gland.

A variant occurring in red-brown sandy loam in the Shark Bay area (S of Carnarvon) is not included in the above description (e.g. c. 6 km W of Overlander-Denham road towards Tamala, B.R.Maslin 3682, CANB, K, MEL, PERTH). This variant has the phrase name, Acacia sp. Shark Bay (B.R. Maslin 3682), and among other things differs from typical A. subrigida in its ±flat phyllodes which are 2 mm wide: see B.R.Maslin, Nuytsia 10: 198 (1995), for discussion.

FOA Reference

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

Author

Minor edits by B.R.Maslin & J.Rogers

B.R.Maslin