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Acacia dissona

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Acacia dissona R.S.Cowan & Maslin, Nuytsia 10: 209 (1995)

Shrub 0.5–2 m high; branches often contorted. Branchlets ridged, appressed-puberulous. Phyllodes inclined to erect, straight, subterete or terete, 2–4 cm long, 1–1.5 mm wide, rather abruptly narrowed to a sharply pungent or mucronate to mucronulate tip, rigid, glabrous or pulvinus often puberulous adaxially, with numerous closely parallel, raised nerves that are sometimes paler than internerve spaces; stomata evident in internerve spaces; gland small; pulvinus normally slightly expanded at base. Inflorescences simple, 2 per axil; peduncles mostly 2–4 mm long, glabrous; heads globular, 5–6 mm diam. (fresh), 3–4 mm diam. (dry), 15–20-flowered, golden. Flowers 5-merous; sepals free. Pods linear, raised over and constricted between seeds, moderately curved, to 6 cm long and 2.5 mm wide, thin-crustaceous or thin-coriaceous, appressed-puberulous. Seeds longitudinal, oblong-elliptic, 2.5–4.5 mm long, 1.5 mm wide, glossy, dark brown; aril terminal, conical or broadly rounded and crested, pale yellow.

Scattered and discontinuous in an area bounded by Coorow, Ongerup, Southern Cross and Norseman, inland south-western W.A.

A member of the ‘ A. densiflora group’. Morphologically similar to A. mackeyana which commonly has recurved phyllodes and subterete, thick-walled, crustaceous pods. Also resembles A. kalgoorliensis which has longer phyllodes with protracted, long-spinose tips.

Comprises two closely related varieties.

Phyllodes sharply pungent, with nerves and internerve spaces often uniform in colour; pods distinctly constricted between seeds; seeds 4.5 mm long, the aril obconic

var. dissona

Phyllodes pungent, with nerves paler than internerve spaces; pods scarcely constricted; seeds 2.5- 3.5 mm long, the aril galeiform

var. indoloria

 

Acacia dissona R.S.Cowan & Maslin var. dissona

Phyllodes subterete, 2–4 cm long, contracted to sharply pungent apex; nerves and internerve spaces often uniform in colour; stomata sometimes tuberculate. Pods distinctly constricted between the seeds, sparingly appressed-puberulous. Seeds 4.5 mm long; aril long-conical.

Disjunct, occurring from Merredin- Southern Cross S to near Ongerup with outliers in the Coorow-Wanarra area (c. 250 km due NW of Merredin) and the Norseman area (c. 350 km due NE of Ongerup). Grows in a variety of soils, often clay, in eucalypt woodland and mallee.

Type of accepted name

14 km N of Lake Grace, W.A., 5 Oct. 1975, B.R.Maslin 3843 ; holo: PERTH; iso: CANB, G, K, MEL, NSW, NY.

Representative collections

W.A.: 21.6 km ENE of Merredin, R.Coveny 8340 & B.Habersley (NSW, PERTH); 5 km SE of Coorow, A.Doley 4 (PERTH); Norseman, J.Goodwin 271 (PERTH); c. 4 km S of Karlgarin on Pederah Rd, B.R.Maslin 6738 (PERTH).

 

Acacia dissona var. indoloria R.S.Cowan & Maslin, Nuytsia 10: 211 (1995)

Phyllodes terete, mucronate to mucronulate, innocuous to coarsely pungent; nerves paler than internerve spaces in mature phyllodes. Pods scarcely constricted between seeds, sparsely appressed-puberulous, at least between seeds. Seeds 2.5–3.5 mm long, with a broadly obtuse, crested aril.

Disjunct, occurring at Ballidu- Mollerin (c. 75- 145 km due E of Moora), Bruce Rock- Muntadgin (Muntadgin is c. 45 km due NE of Bruce Rock) and Frank Hann Natl Park (located 30- 110 km ENE of Lake King). Grows in sand, sandy loam and loam, mostly in open mallee.

The differences separating the two varieties comprising this species are indicated in the key. They are obviously closely related, with most of the differences in the pods and seeds.

Type of accepted name

12 km E of Kulja towards Mollerin, W.A., 9 Jan. 1979, B.R.Maslin 4448 ; holo: PERTH; iso: CANB, K, NY.

Representative collections

W.A.: 4.8 km NW of Muntadgin, J.Goodwin 67 (PERTH); 25 km ESE of Tadpole Lake, Frank Hann Natl Park, K.Newbey 5538 (PERTH).

(RSC)

WATTLE Acacias of Australia CD-ROM graphic

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.

Page last updated: Tuesday 11 September 2018