Family

Fabaceae

Distribution

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.

Description

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, with 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, 3–4.5 mm diam., coriaceous, red-brown, obscurely striate, puberulous. Seeds longitudinal, oblong, 5.5 mm long; aril terminal, conical.

Habitat

Grows in shrubland or woodland, in deep sand or gravelly loam or clay.

Specimens

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).

Notes

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.

The name A. rigida Heer was described for a fossil-species from Switzerland, fide I.M.Turner (l.c.). 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.).

FOA Reference

Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia

Author

B.R.Maslin

Minor edits by J.Rogers