Acacia ophiolithica R.S.Cowan & Maslin, Nuytsia 10: 246 (1995)
Bushy, rounded shrub 0.3–2 m high. Branchlets glabrous, scarred by raised stem-projections where phyllodes have fallen. Phyllodes congested, ascending to erect, becoming patent, very slender, straight, terete, 1.5–4.5 cm long, 0.7–1 mm diam., abruptly and obliquely narrowed to a short but distinct, excentric mucro, glabrous, seemingly 4- or 8-nerved but nerves very indistinct or more commonly not visible; pulvinus slender, terete, 1.5–2 mm long, orange. Inflorescences simple, 2 per axil; peduncles filiform, 5–13 mm long, glabrous; heads globular, 3–3.5 mm diam., 10–15-flowered, bright light golden. Flowers predominantly 5-merous; sepals free. Pods linear, slightly raised over seeds on alternating sides, not constricted between seeds, straight or slightly curved, 3–4 cm long, 2–3 mm wide, thinly coriaceous, reddish brown, glabrous; margins thickened, yellow. Seeds (slightly immature) longitudinal, oblong to obovate, c. 2 mm long, slightly shiny, dark brown; aril subterminal.
Restricted to and locally common in the Jerdacuttup R. area E of Ravensthorpe township in south-western W.A. Grows in brown to pale yellow-brown clay or clay loam derived from serpentine, sometimes rocky, on river banks and beneath mallee eucalypts, often forming dense stands.
A member of the ‘ A. fragilis group’, differing in its habitat from its presumed closest relative, A. uncinella , which also differs in having discernibly 8-nerved phyllodes and shorter peduncles bearing heads with more flowers. It is sufficiently similar to A. uncinella that G.Bentham, Fl. Austral . 2: 341 (1864: 341), cited a G.Maxwell collection of A. ophiolithica from the Oldfield R. area as A. uncinella . It is sympatric with and superficially resembles A. binata which is most readily distinguished by its fleshy, obtuse phyllodes, larger flower-heads in short, 2-headed racemes and its curved to openly coiled pods.
Type of accepted name
Adjacent to Jerdacuttup R. on North Jerdacuttup Road, 10.5 km E of Ravensthorpe- Hopetoun road, W.A., 31 Aug. 1980, B.R.Maslin 4789 ; holo: PERTH; iso: AD, BRI, CANB, K, MEL, NSW, NY.
Synonymy
[ Acacia uncinella auct. non Benth.: G.Bentham, Fl. Austral. 2: 341 (1864), as to the Maxwell specimen cited (MEL, NSW, PERTH)]
Representative collections
W.A.: c. 13 km E of Ravensthorpe, 20 Aug. 1979, E.M.Bennett s.n. (AD, K, MEL, NY, PERTH); Jerdacuttup R. elbow, C.A.Gardner 14083 (PERTH); 22.5 km E of Ravensthorpe on Hwy No. 1 to Esperance, B.R.Maslin 5461 (BM, CANB, G, MO, PERTH, Z).
(RSC & BRM)
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.
