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Acacia oswaldii

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Acacia oswaldii F.Muell. (as ‘Oswaldi’), Fragm . 4: 5 (1863)

Umbrella Wattle , Umbrella Bush , Miljee , Nelia , Middia , Curly Yarran , Whyacka , and others

Shrub or tree 2–8 m high. Branchlets terete, glabrous, appressed-puberulous or tomentulose, typically with many red, resinous micro-hairs. Phyllodes spreading to erect, linear, narrowly elliptic or narrowly oblong-elliptic, straight to recurved, terete to flat, (1–) 2.5–10.5 cm long, (1–) 3–15 mm wide, acute to acuminate, or obtuse and mucronate, coarsely to sharply pungent or innocuous, coriaceous to rigid, occasionally glaucous, glabrous, with 3–6 distant, raised main nerves and with nearly as prominent secondary nerves occasionally anastomosing. Inflorescences simple, 2 per axil; peduncles normally 0–0.8 mm long; heads depressed globular, 4.5–5 mm diam., 4–15-flowered, pale yellow. Flowers 5-merous; sepals 1/4–2/3-united. Pods linear, openly coiled or twisted, to 31 cm long, 6–12 mm wide, coriaceous to woody, minutely appressed-puberulous and (when young) with many clumps of red micro-hairs. Seeds longitudinal, oblong-elliptic, 6–8 mm long, glossy, dark brown; aril broad and fleshy, yellow-orange.

Widespread and scattered in arid, semi-arid and subtropical areas in all mainland states S of 19 Lat. S; mainly in calcareous sands or loam.

A transcontinental species with many variations but none of sufficient importance and discontinuity to recognise infraspecific categories (see R.S.Cowan & B.R.Maslin, Nuytsia 12: 426–428 (1999) for full discussions of variation and of synonomy). The phyllodes are especially variable in form, from flat to terete and elliptic to linear or oblong, with the apex often pungent, but sometimes only acute, or obtuse and innocuous (e.g. B.R.Maslin 5378 , PERTH and P.K.Latz 5718 , BRI, DNA, PERTH). Some specimens have golden or silvery-sericeous new shoots that lack the reddish resin hairs that normally characterise the species. A dwarf variant c. 2 m tall with short phyllodes (1–2.5 cm long) occurs near Lake Moore, W.A.

The relatives of A. oswaldii are problematic, but it is possibly closest to A. lanigera which is a small shrub with woolly branchlets, more numerously-flowered heads, smaller pods and smaller seeds lacking the large, colourful aril of A. oswaldii . The relationship of the species is surely not very close to the microneurous group of species within which G.Bentham, Fl. Austral. 2: 384 (1864), included it.

Type of accepted name

Morundee on Murray R., S.A., Feb. 1851, F.Mueller s.n. ; lecto: MEL, upper branchlet, fide R.S.Cowan & B.R.Maslin, Nuytsia 12: 426 (1999); ?isolecto: K.


Racosperma oswaldii (F.Muell.) Pedley, Austrobaileya 2: 353 (1987). Type: as for accepted name.

Acacia oswaldii F.Muell., Linnaea 26: 609 (1855), nom. nud ., pro syn. sub A. lanigera .

Acacia oswaldii F.Muell., Pl. Victoria 2: 27 (1863), nom. inval. (not effectively published, see A.B.Court et al ., Nuytsia 9: 315- 318 (1994), for discussion).

? Acacia oswaldii var. abbreviata Benth. (as ‘Oswaldi’), Fl. Austral. 2: 384 (1864). Type: S. Coast, R.Brown ; n.v. In the absence of seeing the type this name is provisionally treated in synonymy here.

Acacia sessiliceps F.Muell., Chem. & Druggist Australas . Suppl. 5 (51): 26 (1882). Type: near Finke R., N.T., 1880, H.Kempe ; holo: MEL, lower half of sheet excluding fruiting material at top; iso: PERTH, fragment ex MEL.

Acacia amaliae Domin, Biblioth. Bot . 89: 249 (1926). Type: Qld, A.Dietrich ; holo: PR.

Acacia amaliae var. orthophylla Domin, loc. cit. Type: Dividing Range near Jericho, Qld, Mar. 1910, K.Domin ‘5402’ and ‘5404’ ; syn: PR.


F. von Mueller, Iconogr. Austral. Acacia dec. 2 [pl. 5] (1887), as A. sessiliceps , & dec. 6 [pl. 10] (1887), as A. osswaldi ; J.H.Maiden, Forest Fl. New South Wales 7: 89, pl. 238, figs A–K (1920); L.F.Costermans, Native Trees & Shrubs SE Australia 322 (1981); G.M.Cunningham et al. , Pl. W New South Wales 368 (1981); B.R.Maslin, in J.P.Jessop (ed.), Fl. Central Australia 123, fig. 160B (1981); T.Tame, Acacias SE Australia 73, fig. 57, pl. 57 (1992); D.J.E.Whibley & D.E.Symon, Acacias S. Australia 2nd edn, 223 (1992).

Representative collections

W.A.: 3.2 km N of Cundeelee Mission, N of Zanthus, A.S.George 6000 (CANB, PERTH). N.T.: 6.4 km S of Alice Springs, D.J.Nelson 2251 (PERTH). S.A.: on Mt Hopeless Rd, R.H.Kuchel 2605 (PERTH). Qld: 14 km from Springsure on road to Arcturus Downs, B.O’Keeffe 862 (BRI, PERTH). N.S.W.: 6.3 km NNE of Coolamon Post Office on Temora Rd, R.Coveny 11996 & P.Hind (NSW, PERTH). Vic.: c. 2 km SE of Mt Crozier, M.G.Corrick 6645, P.S.Short & B.A.Fuhrer (MEL, PERTH).


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: Thursday 22 June 2023