Family

Fabaceae

Distribution

Occurs in a belt from the Murchison R. (E of Kalbarri) to the Newdegate area (which is c. 50 km due E of Lake Grace), W.A.

Description

Shrub 0.5–2 m high. Branchlets terete or weakly angled, glabrous, occasionally tomentulose or ±sericeous. Phyllodes inclined to erect, slender, straight to curved, terete, 1–3.5 cm long, (0.5–) 0.7–0.9 (–1.2) mm diam., rounded-obtuse, mucronate, glaucous when young, ageing pale green, glabrous, striate by 14–18 slightly raised nerves. Inflorescences simple, 2 per axil; peduncles (0–) 2–4 (–7) mm long, slender, glabrous; basal bracts persistent, cucullate; heads globular, 2.5–3.5 mm diam., loosely 8–17-flowered, golden. Flowers 5-merous; sepals 1/3–2/3-united, rarely free; petals 1/2–3/4-united. Pods breaking readily into 1-seeded, fusiform articles at the narrow constrictions between the seeds, to 3 cm long, 1.2–1.8 mm wide, thin, sparingly appressed-puberulous. Seeds longitudinal, narrowly oblong-elliptic, 2.5–3 mm long, slightly glossy, tan, mottled, exarillate.

Habitat

Grows in sandy, loamy and lateritic soils, in open scrub and shrubland.

Specimens

W.A.: c. 4 km W of Newdegate on road to Lake Grace, E.M.Canning WA/68 7407B (PERTH); Mt Madden, J.Goodwin 224 (PERTH); 9 km NNE of Bruce Rock on road to Merredin, B.R.Maslin 6473 (CANB, PERTH, Z); Murchison R., c. 15 km E of North West Coastal Hwy, M.Whiting & J.Coxon (PERTH00684031).

Notes

There is considerable variation in some of the characters, especially in the vestiture of the branchlets and degree of union of the perianth parts, fide R.S.Cowan & B.R.Maslin, Nuytsia 10: 250 (1995).

Acacia dielsii together with A. nivea and A. obesa constitute the ‘A. dielsii group’, fide R.S.Cowan & B.R.Maslin, Nuytsia 10: 249 (1995). The pods of A. dielsii are very distinctive and with their exarillate seeds, form the most important characters separating the species from the other members of the group.

FOA Reference

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

Author

R.S.Cowan

Minor edits by B.R.Maslin & J.Reid