Acacia pachyacra Maiden & Blakely, J. Roy. Soc. W. Australia 13: 21, pl. 14, figs 1–7 (1928)
Shrub or tree 1–5 m high, often bushy with a casuarina-like appearance. Branches frequently red-brown. Branchlets slender, sometimes faintly (rarely markedly) pruinose, glabrous. Phyllodes ascending to erect, filiform, straight to shallowly curved, quadrangular to terete, rarely flat, 8–20 cm long, 0.5–1 mm wide, with a curved mucro with a gland at its base, not rigid, slightly longitudinally wrinkled or grooved when dry, light green to grey-green, glabrous, 4-nerved; gland basal, also at base of mucro. Inflorescences racemose; raceme axes 1–3 cm long, slender, glabrous; peduncles 4–7 mm long, slender, glabrous; heads globular, 20–30-flowered, light golden to mid-golden. Flowers 5-merous; sepals free, linear-spathulate. Pods narrowly oblong, prominently rounded over seeds, to 8 cm long, 7–11 mm wide, chartaceous, light brown, glabrous. Seeds transverse to oblique, oblong to widely ovate-elliptic or orbicular, 4.5–5.5 mm long, shallowly depressed at centre, dull, black, exarillate.
Occurs in the western part of the Arid Zone from Mt Farquhar, W.A., to the Docker R. area, N.T., and the Birksgate and Musgrave Ra., S.A. Grows in sand in spinifex country.
A member of the ‘ A. murrayana group’ with phyllodes very similar to those of A. subrigida . Perhaps A. pachyacra would be better regarded as a subspecies of A. murrayana from which it is (rather arbitrarily) distinguished by its narrower phyllodes which are normally quadrangular to terete. A few specimens from far north western S.A. and adjacent N.T. with flat phyllodes 1–1.5 mm wide seem intermediate between the two species, e.g. 51.5 km E of Docker R. Settlement, C.Dunlop 1968 (PERTH). Typical representatives of both species also occur within this region.
The seed is eaten by Aborigines, fide P.Latz, Bushfires & Bushtucker 112 (1995).
Type of accepted name
Victoria Desert Camp 40, near Barrow Ra., W.A., 3 Sept. 1891, R.Helms 10 ; holo: NSW; iso: AD, K, PERTH (Fragment of holo).
Illustrations
J.H.Maiden & W.F.Blakely, loc. cit .; B.R.Maslin, in J.P.Jessop (ed.), Fl. Central Australia 119, fig. 158N (1981); D.J.E.Whibley & D.E.Symon, Acacias S. Australia 2nd edn, 127 (1992).
Representative collections
W.A.: near Mt Farquhar, J.V.Blockley 437 (PERTH); Gibson Desert, 110 km by road S of Warburton towards Rawlinna, B.R.Maslin 5682 (MO, PERTH). N.T.: 51 km E of Docker R., N.Henry 301 (PERTH). S.A.: 11 km S of Mt Davies camp, Tomkinson Ranges, J.R.Maconochie 817 (AD, K, PERTH).
(BRM)
The information presented here originally appeared on the WATTLE CD-ROM which was jointly published by the Australian Biological Resources Study, Canberra, and the Department of Parks and Wildlife, Perth; it was produced by CSIRO Publishing from where it is available for purchase. The WATTLE custodians are thanked for allowing us to post this information here.
