Acacia aemula Maslin, Nuytsia 10: 169 (1995)
Openly branched, rush-like subshrub 0.2–0.4 m high, commonly ±prostrate. Branchlets terete, striate by prominent ribs, smooth or muricate, glabrous. Stipules 2–3 mm long. Phyllodes distant, resembling branchlets, occasionally a few terminal ones reduced to horizontally flattened scales, pentagonal-terete to ±flat and linear, 1–11 cm long, 1–2 mm wide, mucronate, smooth or muricate, glabrous, 5-nerved in all, 1-nerved on each face and upper margin nerve-like when phyllodes ±flat; gland not prominent, 1–3 mm above base; pulvinus indistinct. Inflorescences simple, 1 or 2 per axil, rarely more; peduncles 5–15 mm long, often reflexed, glabrous or appressed-puberulous; heads globular, loosely 6–11-flowered, cream or golden; buds ovate to elliptic, acute. Flowers 4-merous; sepals 2/3–3/4-united, small; petals flabellate-striate, glabrous. Pods stipitate, 3–6 cm long, 4–5 mm wide, acuminate, curved, ±thinly coriaceous-crustaceous, reddish brown, glabrous, acutely quadrangular by winged margins c. 2 mm wide. Seeds longitudinal, oblong, 4–5 mm long; aril terminal, conical.
Occurs from Stirling Ra. (Stirling Ra. is E of Cranbrook) E to Cape Arid (c. 110 km due E of Esperance), south-western W.A.
Related to A. tetragonocarpa and A. cummingiana which are readily distinguished by the absence of phyllodes. Also related to A. volubilis . It seems likely that G.Bentham, Fl. Austral . 2: 336 (1864), included elements of both A. tetragonocarpa and A. aemula in his account of A. tetragonocarpa .
Two subspecies are recognised.
Branchlets and phyllodes smooth
Branchlets and phyllodes muricate
Acacia aemula Maslin subsp. aemula
Stems and phyllodes smooth and slender. Flower-heads golden.
Scattered from Stirling Ra. E to Cape Arid. Grows in sand and sandy clay flats, also on rocky outcrops, in scrub and Mallee shrubland.
Type of accepted name
Rawlinson Rd, Munglinup area E of Ravensthorpe, W.A., 1 June 1979, B.R.Maslin 4483 ; holo: PERTH; iso: MEL.
W.A.: base of Mondurup, Stirling Ra., R.J.Cumming 998 (PERTH); Condingup, T.C.Daniell 11 (PERTH); Cape Arid Point, G.J.Keighery 7831 (PERTH).
Acacia aemula subsp. muricata Maslin, Nuytsia 10: 171 (1995)
Stems thicker and more prominently ribbed than on the typical subspecies, muricate, excrescences sparse on plants E of Jerramungup. Phyllodes muricate, subrigid. Flower-heads cream.
Disjunct, occurring from Stirling Ra. E to Jerramungup - Ravensthorpe area, with one collection from Scadden (c. 50 km due N of Esperance), W.A. Grows in sand in Mallee shrubland.
Type of accepted name
25.7 km S of Jerramungup towards Albany, W.A., 2 Oct. 1970, B.R.Maslin 1017 ; holo: PERTH; iso: MEL.
Acacia tetragonocarpa var. scabra Benth., Fl. Austral . 2: 336 (1864); A. tetragonocarpa f. scabra (Benth.) E.Pritz., Bot. Jahrb. Syst . 35: 292 (1904). Type: without locality, A.Oldfield s.n .; iso: PERTH (Fragment, presumably ex K).
W.A.: Scadden, H.E.Knox 1 (PERTH); Stirling Ra., Chester Pass, B.R.Maslin 4015 (PERTH).