Acacias of Australia

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Acacia orbifolia Maiden & Blakely




Extending from near Watheroo SE to Muntadgin and near Bulyee with one outlying collection from near Northampton, c. 250 km NNW of Watheroo, south-western W.A.


Dense domed shrub 0.5–1.8 m high, to 3 m diam. Branchlets white-waxy, ±pilose or appressed-pilose. Phyllodes obliquely orbicular to obliquely obdeltate, with upper margin conspicuously rounded and distally sinuate to sinuate-dentate, commonly 8–20 mm long, 6–15 mm wide, mucronulate, appressed-puberulous marginally at least when young, with 2 fine divergent longitudinal nerves per face; lateral nerves few or absent. Inflorescences simple or sometimes short racemes and sometimes growing out at anthesis; raceme axes to 4 mm long; peduncles 10–26 mm long, ±puberulous to pilose; heads globular, 5.5–7.5 mm diam., 20–32-flowered, usually white to cream. Flowers 5-merous; sepals united. Pods (immature) constricted between the longitudinal seeds and raised over them, 1–2-coiled, often twisted, to 2 cm long (unexpanded), 3–4 mm wide.


Grows in rocky or lateritic clay or loam in Eucalyptus woodland.


W.A.: 29.1 km S of Wongan Hills Police Stn, R.Coveny 7787 & B.R.Maslin (NSW, PERTH); 22.1 km S of Northampton to Nanson turnoff 1 km SE of North West Coastal Hwy, R.J.Cranfield 2725 (PERTH); Piawaning, B.R.Maslin 3813 (K, NY, PERTH); c. 16 km N of Bulyee, K.Newbey 3423 (PERTH, RH).


Phyllode indumentum is usually ±appressed and restricted to the margin and it is frequently absent on mature phyllodes; only on specimens from near Wyalkatchem, Piawaning and Northampton has the indumentum been seen to cover the entire surface of the lamina. The disjunct Northampton plants (e.g. R.J.Cranfield 2725) have the smallest phyllodes and shortest peduncles. Plants from near Watheroo and Piawanning are unusual in having golden flower-heads (e.g. B.R.Maslin 6225, CANB, PERTH).

Related to A. bidentata with which it forms putative hybrids near Watheroo.

FOA Reference

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