Acacias of Australia

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Acacia dilatata Benth.




Scattered in south-western W.A. from near Mingenew S to Mogumber, c. 30 km W of Wongan Hills and near Darkin Swamp, c. 35 km SW of York.


Sprawling or compact multistemmed shrub to 0.7 m high. Branchlets usually puberulous. Stipules 2–4 mm long, rigid, commonly ±spinose. Phyllodes dimidiate, with adaxial margin conspicuously rounded with its proximal edge frequently ±parallel to branchlet, normally 10–20 mm long, (5-) 7–10 (-15) mm wide, slightly undulate, short- or long-acuminate, pungent, coriaceous, dark green or yellow-green, usually puberulous; midrib very close to abaxial margin; secondary nerves running into adaxial margin. Inflorescences simple; 1 per axil; peduncles 5–10 mm long, usually puberulous; heads globular to obloid, subdensely 15–25-flowered, golden. Flowers 5-merous; sepals shortly united, with lobes linear-triangular; petals striate. Pods curved, terete, to c. 5.5 cm long, 4–5.5 mm diam., crustaceous, dark red-brown, longitudinally striate, usually finely puberulous. Seeds longitudinal, oblong, 4.8–5.5 mm long, brown; aril terminal, conical.


Flowers during summer.


Grows in often lateritic or rocky sand, in heath or low shrubland with scattered Eucalyptus and Banksia.


W.A.: c. 5.5 km W of Mogumber siding, A.S.George 8643 (CANB, K, PERTH); c. 6.4 km S of Marchagee, B.R.Maslin 1444 (PERTH); northern edge of Mortlake Ck, Wongan Hills, K.F.Kenneally 5399 (PERTH); near Darkin Swamp, 23 Jan. 1924, O.H.Sargent s.n. (PERTH).


Similar to A. phaeocalyx, especially in phyllode, petal and pod morphology. Acacia flabellifolia, which occurs within the range of A. dilatata, has similar phyllodes but is readily distinguished by its spinose branchlets, non-striate petals and coiled pods.

Glabrous variants are uncommon and occur between Eneabba and Mogumber (e.g. A.S.George 8643).

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 J.Rogers