Acacias of Australia

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Acacia pycnocephala Maslin




Occurs from Narrogin to near Rocky Gully and E to Beaufort Inlet, and near Lake King, south-western W.A. Locally abundant.


Erect or spreading shrub 0.3–0.6 m high. Branches orange to (reddish) brown. Branchlets puberulous with patent to slightly retrorse hairs. Stipules setaceous to narrowly triangular, 2–4 mm long. Phyllodes often crowded, patent to slightly reflexed, narrowly semi-trullate with a prominent gland-angle on adaxial margin near base, 6–11 mm long, 1.5–4 mm wide, acuminate, pungent with a 1.5–2.5 mm long cusp, rigid, olive green, glabrous, sometimes sparsely puberulous; midrib prominent, central; lateral nerves absent. Inflorescences simple, 1 per axil; peduncles 1–3 mm long, puberulous; heads globular, 4-flowered, golden. Flowers 4-merous; sepals 2/3–2/5-united, with lobes broadly triangular. Pods terete, ±abruptly narrowed at both ends, curved, to 4.5 cm long, 3–4 mm diam., red-brown, striate, minutely puberulous. Seeds longitudinal, shape and size variable, oblong to elliptic, 3.5–4.5 mm long; aril terminal, conical.


Grows in often lateritic sand or loam, in a variety of vegetation, but commonly mallee shrubland or Wandoo (Eucalyptus wandoo) woodland.


W.A.: Narrogin, C.A.Gardner 1496 (PERTH); 54.7 km S of Kojonup on road to Rocky Gully, B.R.Maslin 637 (CANB, PERTH); 6 km N of Mt Madden towards Lake King, B.R.Maslin 4063 (PERTH).


Distinguished from other members of the ‘A. horridula group’ by golden flower-heads and rugose to verruculose seeds (seeds smooth in other members of the group). Closest to A. horridula which has much longer peduncles and less hairy pods.

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