Acacias of Australia

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Acacia effusa Maslin

Common Name

Punurunha Minni Ritchi




Restricted to north-western W.A., collected only from within the Hamersley Ra. Natl Park, locally abundant.


Dense, wide-spreading, multi-stemmed, domed or flat-topped, somewhat viscid shrub 0.3–1.2 m tall. Bark ‘Minni Ritchi’, grey or greyish red. Branchlets terete, puberulous, becoming glabrous with age. Stipules sub-persistent, 1–2 mm long, dark brown. Phyllodes obliquely oblong to elliptic or oblong-obovate, (0.6–) 0.9–1.5 (–2) cm long, (2–) 3–7 mm wide, with indumentum as on branchlets, dull green (mature phyllodes) but mealy white over the nerves; rounded at apex with a laterally positioned, sub-pungent, straight, brown point; with a central longitudinal nerve and a less prominent nerve parallel to it close to (and ultimately merging with) the upper margin, minor nerves sparingly anastomosing; gland 1, obscure, basal, 2–4.5 mm above pulvinus. Spikes 10–18 mm long, to 25 mm in fruit, bright golden; peduncles 7–10 mm long, hairy. Flowers 5-merous, rarely some 4-merous; calyx dissected to 1/2–2/3, glabrous. Pods flat but slightly raised over seeds, curved to once-coiled, to 8.5 cm long, 6–8 mm wide, coriaceous, glabrous. Seeds oblique, rotund to very broadly elliptic, 3–5 mm long, dark tan; areole small, closed, surrounded by pale halo.


Flowers May–Sept.


Grows in rocky red loam, on lower slopes particularly along creeks where the watercourses leave the hills.


W.A.: 4.5 km along Mt Bruce road from Marandoo road, B.G.Briggs 8765 & L.A.S.Johnson (BRI, NSW, PERTH); 3 km W of Mt Bruce, C.G.Dawe 212 (PERTH); 6 km N of Marandoo on road to Tom Price, B.R.Maslin 5278 (NSW, PERTH); NE footslope of Mt Bruce, Pilbara region, R.Pullen 10.940 (NSW, PERTH).


Regenerates from the base of main stem following fire and after clearing.

Related to A. trachycarpa which has narrowly linear, longer phyllodes and A. monticola which has larger phyllodes and globular to obloid heads. Acacia daweana may have originated as a hybrid between A. effusa and A. hamersleyensis.

FOA Reference

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


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

Edited by B.R.Maslin