Acacias of Australia

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Acacia hilliana Maiden x Acacia stellaticeps Kodela, Tindale & D.Keith




Scattered in north-western W.A. from the NW edge of the Pilbara region N to Anna Plains Stn, adjacent to Eighty Mile Beach.


Spreading, multistemmed, resinous, glabrous shrub 0.3–0.4 m high and 1–2 m across, ±flat-topped or low-domed, not noticeably aromatic. Bark grey. Branchlets obscurely tuberculate, obscurely ribbed. Phyllodes solitary or occasionally 2 or 3 in clusters, mostly linear to narrowly oblong, acute with innocuous to coarsely pungent points, 15–30 (–35) mm long, (1–) 1.5–2.5 (–3) mm wide, flat, rather wide spreading, mostly straight or shallowly recurved, often finely longitudinally wrinkled when dry, dull green to sub-glaucous; longitudinal nerves 3 to numerous, very obscure; gland obscure, 0.5–2 mm above pulvinus. Inflorescences simple, erect; peduncles 10–25 (–30) mm long; spikes obloid to short cylindrical, 10–15 mm long, golden. Flowers 5-merous, buds subacute; calyx very shortly dissected. Pod (few seen) erect, narrowed at both ends, flat, 40 mm long, 5 mm wide, straight, woody, opening elastically from apex, longitudinally nerved, red-brown; margins thick, pale coloured. Seeds longitudinal, seated pronounced depressions, oblong, c. 6 mm long, brown; funicle-aril straight and narrowly conical.


Flowers May.–July.


Grows in deep red, sometimes gravelly sand or less frequently on low rocky hills, in Pindan country with spinifex ground cover. It is not common in the places where it occurs.


W.A.: c. 25 km E of De Gray R. crossing (between Port Hedland and Broome) on Great Northern Hwy, B.R.Maslin 8743 (NSW, PERTH); 31.1 km W of turnoff to Eighty Mile Beach camping ground (near Wallal Downs) on Great Northern Hwy, L.Thomson LXT1172A (PERTH).


Field observations and plant morphology suggest that this taxon is a hybrid between A. hilliana and A. stellaticeps. Most collections record the two putative parents as growing with or near the putative hybrid. See B.R.Maslin et al., Wattles of the Pilbara CD-ROM (2010), for further discussion.

Plants from between Port Hedland and Anna Plains, W.A., that were referred to by NSW, Fl. Australia 11B: 228 (2001), under Acacia sp. E are referable to this putative hybrid. Acacia sp. E is described here as Acacia sp. Barklys (J.L.Egan 124) and although superficially very similar to the putative hybrid it has a more northerly distribution, its spikes are often longer and its phyllodes are often broader, more commonly shallowly incurved and have the (very small) gland further removed from the pulvinus.

FOA Reference

Flora of Australia Project