Acacia dielsii E.Pritz., Bot. Jahrb. Syst. 35: 294 (1904)
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, 0.7–1.2 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 mostly 2–4 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.
Occurs in a belt from the Murchison R. (E of Kalbarri) to the Newdegate area (which is is c. 50 km due E of Lake Grace), W.A., Grows in sandy, loamy and lateritic soils, in open scrub and shrubland.
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 its exarillate seeds, form the most important characters separating the species from the other members of the group.
Type of accepted name
In Avon district, 5 km S of Tammin, W.A., 21 May 1901, L.Diels 2859 ; iso: PERTH (Fragment ex B).
Synonymy
Acacia ewartiana W.Fitzg. ex Jean White, in A.J.Ewart et al ., Proc. Roy. Soc. Victoria n. ser. 23: 287; pl. 50, figs 5–7 (1911). Type: Cowcowing, W.A., Aug. 1904, M.Koch 998 ; syn: MEL n.v. ; Cowcowing, W.A., Sept. 1904, M.Koch 998 ; syn: MEL n.v . See B.R.Maslin & R.S.Cowan, Nuytsia 9: 395 (1994), for discussion of types.
Acacia ewartiana W.Fitzg., J. Bot . 50: 19 (1912). Type: Cowcowing, W.A., Aug. 1904, M.Koch 998 ; lecto: BM, fide B.R.Maslin & R.S.Cowan, Nuytsia 9: 395 (1994); isolecto: K, MEL n.v. , NSW, PERTH; Cowcowing, W.A., Sept. 1904, M.Koch 998 ; paralecto: NSW, MEL n.v ., PERTH.
Illustration
A.J.Ewart et al ., loc. cit. , as A. ewartiana.
Representative collections
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).
(RSC)
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.
