Acacia didyma A.R.Chapm. & Maslin, Nuytsia 8: 264; 261, fig. 4A (1992)
Dense, rounded shrub or tree 1.5–4 m high. Branchlets pruinose, glabrous. Phyllodes orbicular to widely elliptic, 2–5 cm long, 1.5–4 cm wide, obtuse, subfleshy with age, glaucous, lightly pruinose, glabrous, 2-nerved, imperfectly 3–4-nerved on broadest phyllodes; lateral nerves not prominent, anastomoses few, sometimes obscured by wrinkling; glands 2, lowermost 1–8 mm above pulvinus, uppermost at base of mucro. Inflorescences normally 4–12-headed racemes; raceme axes 2–4 cm long; peduncles twinned, 5–10 mm long, rather stout, glabrous; heads globular, subdense, c. 20-flowered, golden. Flowers 5-merous; sepals united into a truncate calyx. Pods strongly curved to openly once-coiled, to 10 cm long, 12–15 mm wide, coriaceous-crustaceous, lightly pruinose, glabrous, outer margin shallowly undulate. Seeds longitudinal, widely oblong-elliptic, 4.5 mm long, shiny, dark brown to black; aril large, yellow-brown (dry).
Scattered in the Shark Bay area where it occurs on Dirk Hartog Is. and Carrarang and Tamala Stns, also on East Wallabi Is. in the Houtman Abrolhos Group, W.A. Grows in sand on limestone ridges and consolidated dunes in scrub and shrubland.
A member of the ‘ A. bivenosa group’ distinguished from the more northerly A. bivenosa and A. startii , and the more southerly A. telmica and A. xanthina , by racemes with twinned peduncles, large, strongly-curved to openly once-coiled, flat pods and orbicular to widely elliptic phyllodes (l:w = 1- 2).
Type of accepted name
3.6 km W of Tamala HS road, on Useless Loop Rd., Shark Bay, W.A., 31 Aug. 1988, A.R.Chapman 601 ; holo: PERTH; iso: CANB, G, K, MEL, NY.
Synonymy
Acacia elliptica A.Cunn. ex Benth., London J. Bot. 1: 347 (1842) p.p. , not as to lectotype, as to A.Cunningham [330] , Dirk Hartog Is., fide A.R.Chapman & B.R.Maslin, op. cit. 256.
[ Acacia bivenosa auct. non DC.: G.Bentham, Fl. Austral. 2: 381 (1864) p.p. , as to A.Cunningham [330], Dirk Hartog Is.]
[ Acacia xanthina auct. non Benth.: B.R.Maslin & L.Pedley, Res. Notes W. Austral. Herb. 6: 126 (1982), as to grid cell 201]
Illustration
A.R.Chapman & B.R.Maslin, op. cit. 261 .
Representative collections
W.A.: 1.6 km W of causeway, near Carrarang Stn, T.E.H.Aplin 3432 (PERTH); Tamala Stn, B.R.Maslin 3699 (CANB, K, PERTH); East Wallabi Is., 8 Sept. 1959, G.M.Storr (PERTH).
(ARC & 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.
