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Acacia bidentata

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Acacia bidentata Benth., London J. Bot . 1: 333 (1842)

Prostrate or domed shrub to 0.5 (–1) m high. Branchlets scurfy white, pubescent, hirsutellous, appressed-puberulous or subglabrous, not spinose. Stipules caducous or inconspicuous and less than 1 mm long. Phyllodes inequilaterally obovate to obtriangular-obdeltate, with upper margin forming a prominent, rounded angle towards the apex and lower margin straight to shallowly convex and ending in a distinct, short, acute point, concave between the angle and point, usually 4–7 mm long and 2.5–5 mm wide, slightly thickened, green, glabrous or hairy on margins; main nerve obscure and near lower margin, sometimes with second nerve from pulvinus. Inflorescences 1–3-headed racemes with axes to 2 mm long; peduncles 3–10 mm long, glabrous or hairy; basal bracts persistent; heads globular to obloid, loosely 10–16-flowered, creamy white or pale yellow. Flowers 5-merous; sepals united; bracteoles not exserted in bud. Pods strongly curved to 1–1 1/2-coiled, to 15 mm long (unexpanded), 3–4 mm wide, thinly crustaceous, glabrous. Seeds longitudinal, oblong-ovate, 3–3.5 mm long; aril oblique.

Occurs predominantly from near Winchester S to the Stirling Ra. Natl Park and E to near Grass Patch and Coolinup (c. 50 km E of Esperance); also found in the Kalbarri area, c. 250 km N of Winchester, south-western W.A. Grows in clay, sand, sandy loam, gravelly loam and loam, in mallee woodland and heath.

Similar to A. orbifolia which has larger, sinuate-dentate phyllodes, longer peduncles and larger heads with more flowers per head. The few specimens of A. bidentata (including Drummond 38 and 148 ) with larger than normal phyllodes, i.e. to 10 mm long and 7 mm wide, can be distinguished by the other character states separating the species. The two species appear to hybridise near Watheroo (cf. R.J.Cumming 2122 , MELU, PERTH). Specimens of A. ericksoniae and A. improcera were formerly confounded with this species, and broad phyllode forms of A. acanthoclada are superficially similar; all three species are distinguished from A. bidentata by their spinose branchlets and golden flower-heads. Also similar to A. aristulata .

Type of accepted name

Swan R., W.A., J.Drummond s.n .; holo: K.


Acacia bidentata var. pubescens Meisn., in J.G.C.Lehmann, Pl. Preiss . 1: 10 (1844). Type: 9 miles [14.5 km] from York, W.A., 10 Sept. 1839, L.Preiss 958 ; lecto: LD, fide B.R.Maslin & R.S.Cowan, Nuytsia 9: 403 (1994); isolecto: C, CGE (sphalm. ‘445’), FI, K, M, MEL, MO, P, PERTH, TCD (sphalm. ‘445’); near Dom Barker’s property [between York and Toodyay], W.A., 11 Apr. 1840, L.Preiss 969 ; paralecto: LD, NY.

Acacia bidentata f. typica E.Pritz., Bot. Jahrb. Syst. 35: 298 (1904), nom. inval .

Doubtful name

Acacia bidentata f. australis E.Pritz.: see Doubtful Names.


M.Simmons, Acacias Australia 57 (1981), the accompanying text on p. 56 includes elements of other species formerly confounded with A. bidentata .

Representative collections

W.A.: c. 3 km N of Winchester, 28 Aug. 1972, C.Chapman s.n . (PERTH); 24.1 km from Kalbarri Coast road (Grey St) on road towards Ajana, R.S. & R.A.Cowan A-814 (CANB, K, MEL, NSW, NY, PERTH, US); Swan R., J.Drummond 38 (K, MEL, PERTH) and 148 (BM, K, LD, MEL, NSW, OXF, P, PERTH); c. 8 km NE of Ravensthorpe, B.R.Maslin 3927 (K, PERTH); Mt Madden, P.G.Wilson 6764 (CANB, MEL, NSW, NY, PERTH).


WATTLE Acacias of Australia CD-ROM graphic

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.

Page last updated: Thursday 22 June 2023