Acacias of Australia

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Acacia petraea Pedley

Common Name





Occurs in south-western Qld on the Grey Ra. and its outliers, on lateritic scarps and ridge-tops; recorded in N.S.W. near the Qld border ESE of Hungerford and in the Louth–Bourke area.


Shrub or tree to 10 m high. Bark longitudinally stringy, grey-brown. Branchlets angular towards apices, yellow-brown to purplish brown, appressed-pubescent, later glabrous. Phyllodes linear, ±straight to curved, 13–26 cm long, 2–6 (–8) mm wide, acuminate, coriaceous, inconspicuously multistriate; midnerve the most prominent; minor nerves 8–10 per mm, not anastomosing; gland 1, basal, to 2 mm above pulvinus. Inflorescences racemose; raceme axes 1–6 mm long. Spikes 2–4.5 cm long, bright yellow. Flowers 5-merous; calyx 0.7–1.2 mm long, dissected to 1/4–1/3; corolla 1.7–2.1 mm long, dissected to 1/2; ovary ±pubescent. Pods linear, slightly constricted between and slightly raised over seeds, to 11 cm long, 3–4 mm wide, chartaceous, glabrous. Seeds longitudinal, elliptic-oblong, 3–4.5 mm long, dark brown to brownish black; areole short, surrounded by a U-shaped pleurogram with a pale halo.


Flowers mid-May–Sept.


Qld: near Eulo, Sept. 1981, Casben (NSW); 16.1 km from Thargomindah P.O., N.Hall H78/44 (NSW); 18 miles [28 km] S of Toompine on Quilpie–Thargomindah road, I.V.Newman 922 (BRI, NSW); Quilpie, L.Pedley 2823 (BRI, NSW). N.S.W.: 11 km N of Brindingabba HS, near Hungerford, Qld, W.E.Mulham 1513 (NSW).


This species is allied to A. doratoxylon which does not occur in Qld and has smaller flowers, often shorter phyllodes, a better developed rudimentary axis bearing the spikes and seeds with a longer, narrow areole without a pale halo.

FOA Reference

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


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

Dr M.D.Tindale and Dr P.G.Kodela with the assistance of M.Bedward, S.J.Davies, C.Herscovitch, D.A.Keith and/or D.A.Morrison