Acacia rigida Maslin, Nuytsia 12: 390 (1999)
Shrub either compact and intricate or sprawling and diffuse, to 1.5 m high and 3.5 m across. Branches reddish orange. Branchlets densely retrorsely hirsutellous-pubescent. Stipules setaceous, 2.5–3.5 mm long. Phyllodes patent, inequilaterally lanceolate to narrowly lanceolate, sometimes narrowly linear, usually 9–14 mm long and 1.2–2 mm wide, pungent, rigid, green, normally glabrous, 5-nerved, the 2-nerved adaxial margin usually convex, thick and nerve-like; midrib prominent, near the non-thickened abaxial margin. Inflorescences simple, normally 1 per axil; peduncles usually 5–9 mm long, glabrous or hirsutellous; heads globular, rather loosely 8–12-flowered, golden. Flowers 4-merous; sepals 1/2–2/3-united; petals puberulous, nerveless. Pods shallowly curved, terete, to 6 cm long and 4.5 mm diam., coriaceous, red-brown, obscurely striate, puberulous. Seeds longitudinal, oblong, 5.5 mm long; aril terminal, conical.
Occurs from near Kellerberrin to Kondinin with the western margin ranging from Meckering (c. 70 km due W of Kellerberrin) and Darling Ra. (E of Mundaring) to Cuballing (c. 12 km due N of Narrogin), south-western W.A. Grows in shrubland or woodland, in deep sand or gravelly loam or clay.
Specimens from along the western margin of the range differ in their short peduncles (3–4 mm long) and narrowly linear phyllodes to 20 mm long and 0.7 mm wide (e.g. P.G.Wilson 6376 and A.Selkirk s.n .).
Resembles A. costata in phyllode morphology which is most readily distinguished by its more numerous-flowered heads, 5-merous flowers and striate petals. Also resembles members of the ‘ A. horridula group’ in inflorescence and carpological features but is readily distinguished by its phyllodes having a thick, nerve-like adaxial margin.
Type of accepted name
7.5 km E of Corrigin towards Bendering, W.A., 13 June 1976, B.R.Maslin 4174 ; holo: PERTH; iso: CANB, K, MEL, NY.
Representative collections
W.A.: c. 14 km N of Kellerberrin, L.Atkins HLA62 (PERTH); 7.5 km E of Corrigin towards Bendering, B.R.Maslin 4371 (PERTH); E of Mundaring on West Talbot Rd, 6 Dec. 1976, A.Selkirk s.n . (PERTH); 1 km E of Meckering, P.G.Wilson 6376 (CANB, G, K, MEL, MO, NSW, PERTH).
(BRM)
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.
