Acacia biflora R.Br., in W.T.Aiton, Hortus Kew . 2nd edn, 5: 463 (1813)
Shrub 0.3–0.6 m high. Branchlets sparsely to densely puberulous to shortly pilose. Phyllodes inequilateral, obtriangular to obdeltate with a prominent gland-bearing angle on adaxial margin, with adaxial proximal margin contiguous with branchlet, 3–7 mm long and 3–8 mm wide, may reach 15 mm long and wide on old stems, pungent, glabrous or hairy; midrib near abaxial margin, a minor nerve extending from base towards the gland. Inflorescences simple, 1 per axil; peduncles 3–8 mm long, glabrous to sparsely hairy; heads globular, 2-flowered, white to cream; buds abruptly acute. Flowers 4-merous; sepals c. 3/4-united, with broadly triangular lobes; petals glabrous, obscurely 3–7-nerved at apices. Pods narrowly oblong, curved, to 5.5 cm long, 4–5 mm wide, coriaceous-crustaceous, glabrous; margins thick. Seeds longitudinal, oblong, 3–3.5 mm long, glossy, greyish brown; aril terminal.
Occurs from the Stirling Ra. Natl Park- Albany area E to near Jerramungup and Bremer Bay with disjunct occurrences in the Scaddan area and at Lucky Bay, south-western W.A. Usually grows in sand in woodland, low Mallee scrub or shrubland.
Acacia biflora , together with A. chrysocephala , A. divergens , A. incrassata , A. mooreana , A. phlebopetala and A. robinae comprise the ‘A. biflora group’, fide B.R. Maslin, Nuytsia 2: 270 (1978). These species are similar vegetatively but readily distinguished by inflorescence and flower characters. Acacia biflora is recognised by a combination of the following features: heads white to cream and 2-flowered, peduncles 3–8 mm long, petals 2–3.5 mm long and 3–7-nerved at apices. The species with which A. biflora is most likely to be confused are A. chrysocephala and A. robinae . Specimens from the Fitzgerald R. Natl Park combine phyllodes of A. biflora with flowers of A. robinae .
Type of accepted name
Bay 1 [Lucky Bay, E of Esperance], W.A., Jan. 1802, R.Brown ; lecto: BM, [Britten no.] 4309, fide B.R.Maslin, Nuytsia 2: 288 (1978), superfluous relectotypified in B.R.Maslin & R.S.Cowan, Nuytsia 10: 113 (1995); isolecto: BM, E, K.
Mimosa biflora (R.Br.) Poir., Encycl. Meth. (Bot.) Suppl. 5: 530 (1817), nom. inval . (combination not actually made). Type: as for accepted name.
Acacia triangularis Benth., in S.F.L.Endlicher et al ., Enum. Pl . 42 (1837). Type: Australia, F.A.Bauer , ex herb. Vind. 1837; holo: K; iso: W.
B.R.Maslin, Nuytsia 2: 290, fig. 9 (1978).
W.A.: Swan R., J.Drummond (?4:) 2 (BM, G, G-DC, K, MEL, OXF, P, PERTH, W); 19.5 km S of Grass Patch towards Esperance, B.R.Maslin 2507 (PERTH); 16 km S of Jerramungup towards Albany, B.R.Maslin 2589 (CANB, K, PERTH); 2 km W of L. Carabundup, A.E.Orchard 4391 (PERTH).