Acacias of Australia

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Acacia orthotricha Pedley




Occurs between Mt Elizabeth Stn, Tableland Stn and Kununurra, W.A., and on Inverway Stn, N.T.


Shrub less than 1 m high. Branchlets pubescent; hairs long, spreading to reflexed or ±erect. Stipules 0.7–1.5 mm long. Phyllodes in whorls of 7–11, slightly incurved, recurved at apex, slightly flattened and deeply grooved above, 4–7.5 mm long, shortly mucronate, pubescent with ±erect hairs. Peduncles 5–10 mm long, pubescent. Heads 25–35-flowered. Flowers 5-merous; calyx 0.9–1.6 mm long, finely but distinctly ribbed; calyx lobes broadly triangular, obtuse, acuminate or laciniate, with some long hairs on margins; corolla lobes striate, hairy towards apex. Pods linear, to 60 mm long, 9–13 mm wide, glabrous but ±viscid. Seeds transverse or slightly oblique, c. 5 mm long, not seen mature.


Grows on plains in lateritic soil, in open shrubland.


W.A.: Kununurra, June 1966, A.Douglas (PERTH); Mt Elizabeth Stn, J.Petheram 425 (PERTH); 7 km NE of Tableland Stn on Marion Downs track, T.Willing 502 (PERTH). N.T.: 33 km W of Inverway Stn, G.M.Chippendale NT5943 (BRI, DNA).


A very distinct species with indumentum and calyx similar to A. chippendalei, but it has markedly larger flowers and heads and transverse seeds. The arrangement of the seeds suggests some affinity with A. adoxa which, however, has shorter hairs on the branchlets and phyllodes and a calyx with linear, not broadly triangular, lobes.

FOA Reference

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