Acacia amblygona A.Cunn. ex Benth., London J. Bot. 1: 332 (1842)
Sprawling shrub to c. 1 m high, sometimes prostrate. Branchlets sparsely to densely hirsutellous, sometimes glabrous. Stipules persistent or caducous. Phyllodes sessile, patent, inequilateral, normally lanceolate to lanceolate-elliptic and acuminate, 4–20 mm long, 1.5–4 mm wide, l:w usually 2–5, pungent, rigid, glabrous to hirsutellous, with midrib situated towards lower margin, with 1–3 normally sparingly branched minor nerves subparallel to midrib on its adaxial side; gland 0.5–1.5 mm above base. Inflorescences 1-headed rudimentary racemes with axes c. 0.5 mm long; peduncles 5–13 mm long, glabrous; basal bracts persistent; heads globular to shortly obloid, 10–16-flowered, golden; bracteoles subsessile, concave, obtuse, brown. Flowers 5-merous; sepals 1/2–3/4-united. Pods strongly arcuate to openly coiled, to 7 cm long, 3–5 mm wide, firmly chartaceous to thinly coriaceous, glabrous. Seeds longitudinal, oblong, c. 3 mm long; aril c. 1/2 length of seed.
Extends from Temora, N.S.W., N to the Expedition Ra. and Peak Downs, Qld, seemingly also occurring just S of Ravensthorpe, W.A. Grows in Eucalyptus forest or mallee communities, in stony skeletal soils, in undulating ridge country or on the footslopes of mountain ranges.
The inflorescence characters and phyllode venation of the W.A. specimens suggest their inclusion in A. amblygona , but pods are required to confirm this determination. The phyllode shape and prominently raised midrib which is close to the lower margin resembles some forms of A. gunnii which differs in having cream to pale yellow, 20–30-flowered heads (and straight pods enclosing mottled, exarillate seeds).
A variant from Chinchilla, Qld, recognised by its sparsely hairy branchlets (hairs minute, c. 0.1 mm long) is noted by L.Pedley, Austrobaileya 1: 225 (1978). A prostrate variant with horticultural potential is noted in W.R.Elliot & D.L.Jones, Encycl. Austral. Pl. 2: 14 (1982); these plants have phyllodes which are usually more elongate than normal (l:w to 14).
A member of the ‘ A. pravifolia group’ and sometimes confused with A. pravifolia itself, which has frequently obtriangular to obdeltate, shorter phyllodes, slightly shorter peduncles and glabrous or hirsutellous to short-pilose, tightly coiled and irregularly twisted pods; it also is characterised by a longer, frequently denser branchlet indumentum. Also closely related to A. lanceolata from W.A. Phyllodes sometimes superficially similar to A. hubbardiana .
Type of accepted name
Native of the high land W of the Macquarie R., N.S.W., C.Fraser ; lecto: K, fide L.Pedley, Austrobaileya 1: 224 (1978); Wellington Valley, N.S.W., A.Cunningham s.n. ; paralecto: K; Brisbane R., Qld, A.Cunningham s.n. ; paralecto: K.
Racosperma amblygonum (A.Cunn. ex Benth.) Pedley, Austrobaileya 2: 344 (1987). Type: as for accepted name.
Acacia nernstii F.Muell., Fragm . 4: 3 (1863). Type: Mountains between the Suttor R. and Peak Ra., Qld, 1856, F.Mueller s.n .; syn: MEL118321; Ipswich, Qld, J.Nernst ; syn: K, MEL118319, 118320 & 118322; ‘in collibus prope urbem Brisbane, C. St.’; n.v. , synonymy following G.Bentham, Fl. Austral. 2: 378 (1864).
[ Acacia pravifolia auct. non F.Muell.: B.A.Lebler, Wildfl. SE Queensland 2: 65 (1981), as to flowering illustrations and Flagstone Ck population].
B.A.Lebler, op. cit. 64; G.M.Cunningham e t al. , Pl. W New South Wales 352 (1981); M.Simmons, Acacias Australia 2: 53 (1988); T.Tame, Acacias SE Australia 80, fig. 67, pl. 67 (1992).
Qld: 24 km N of Munduberra, I.B.Armitage 816 (BRI, NSW, PERTH); on Nathan Gorge road, 40 km from Cracow, P.I.Forster 7200 (BRI, MEL, PERTH). N.S.W.: Wallaby Scrub Rd, 3 km E of Singleton- Windsor road, B.R.Maslin 5932 (AD, MEXU, NSW, PERTH). W.A.: 12 km SW of Ravensthorpe, K.Newbey 9460 (MELU, PERTH).