Acacia alcockii Maslin & Whibley, Nuytsia 6: 19; 20, fig. 1 (1987)
Bushy shrub to c .3 m high, often suckering. Branchlets dark reddish, glabrous. Phyllodes on short stem-projections, narrowly elliptic to oblanceolate, straight to shallowly recurved, mostly 6–9 cm long and 8–21 mm wide, narrowed at base, acute to acuminate and subuncinate, infrequently obtuse, thin, glabrous, 1-nerved per face, obscurely penninerved; gland normally 8–12 mm above pulvinus; pulvinus 2–6 mm long. Inflorescences mostly 5–11-headed racemes; raceme axes normally 2–4 cm long, glabrous; peduncles 4–5 mm long, 8–10 mm long when peduncles not in racemes (rare); heads globular, 25–40-flowered, pale yellow. Flowers 5-merous; sepals c. 5/6-united. Pods oblong to narrowly oblong, straight-edged to constricted between seeds, flat, to c. 9 cm long but often shorter, 8–17 mm wide, coriaceous to crustaceous, occasionally subwoody, glabrous. Seeds transverse, oblong-elliptic, 5–6 mm long, dull, black; funicle encircling seed in a double fold, light red-brown; aril clavate.
Occurs in several areas at the southern extremity of Eyre Penin., S.A., namely, along the SW coast between Mt Drummond and Mt Dutton and from the SE coast between Billy Light Point (near Port Lincoln) to West Point in the Lincoln Natl Park. Normally grows in sand over limestone in Mallee communities, sometimes with Melaleuca spp.
Plants from Port Lincoln and the northern part of the Lincoln Natl Park (i.e. Stamford Hill and Cape Donnington Penin.) have normally shallowly recurved phyllodes 8–11 mm wide and thin to moderately coriaceous pods to 7–9 cm long and 8–12 mm wide. In the southern part of the Park (i.e. West Point, Memory Cove and Jussieu Bay) the phyllodes are normally straight and 12–21 mm wide, and the pods to 3.5–5 cm long, 12–17 mm wide and moderately coriaceous to crustaceous or subwoody. The northern populations may represent a stabilised hybrid involving probably A. anceps and A. leiophylla while the southern populations may represent a spontaneous hybrid between these putative parents, fide B.R.Maslin & D.J.E.Whibley, Nutysia 6: 22- 23 (1987).
Acacia alcockii is a member of the ‘ Acacia microbotrya group’ distinguished from A. anceps and A. leiophylla by a combination of its racemose inflorescences and transverse seeds. It is similar to A. notabilis which has thicker, grey-green to glaucous phyllodes and bright golden flower-heads.
Type of accepted name
Eyre Peninsula district, Lincoln Natl Park, 2.6 km N of Port Lincoln- Cape Donnington road towards Stamford Beach, Stamford Hill, S.A., 18 Sept. 1983, J.D.Briggs 1211 ; holo: PERTH; iso: AD, BRI, CANB, MEL, PERTH.
B.R.Maslin & D.J.E.Whibley, loc. cit .; D.J.E.Whibley & D.E.Symon, Acacias S. Australia 2nd edn, 157 (1992).
S.A.: ‘Pillie Lakes’, c. 15 km S of Port Lincoln, C.R.Alcock 1256 (AD, NSW, PERTH); Stanford Hill, roadside through Lincoln Natl Park, C.R.Alcock 3279 (CANB n.v ., NSW, PERTH); Near Billy Light Point, Port Lincoln, D.E.Symon 6693 (AD).