Acacia megalantha F.Muell., J. Proc. Linn. Soc., Bot. 3: 143 (1859)
Resinous shrub to 4 m high. Bark smooth, grey. Branchlets flattened towards apices, orange-brown, squamulose. Phyllodes narrowly elliptic or elliptic, often oblique, 5–11 cm long, 14–28 mm wide, coriaceous, rigid, mostly with 3 prominent longitudinal nerves, the minor nerves 4–6 per mm, longitudinal, usually non-anastomosing except at apex and base; gland 1, basal, inconspicuous. Spikes 1.4–3.5 cm long, golden. Flowers 5-merous; calyx 1.1–1.5 mm long, dissected to 1/4–1/3, sometimes squamulose or slightly hairy; corolla 2.9–4 mm long, dissected to 7/12–4/5, glabrous; ovary tomentose. Pods straight-sided, straight to curved, flat, 3–10 cm long, 7.5–10 mm wide, woody, glabrous; margins pale, thick. Seeds longitudinal, orbicular to broadly elliptic, 4.8–6.2 mm long, light brown, minutely pitted; pleurogram prominent; areole closed, light-to mid-brown.
Occurs near Mount Isa, Qld, and in the Arnhem Land ranges (and Victoria River region), N.T., S to the east Kimberley region, W.A. Grows on sandstone, in shallow soil on rocky hillsides and plateaux in eucalypt-spinifex woodland. Flowers Apr.–Sept.
The large individual flowers on interrupted spikes are distinctive; also the faint transparent longitudinal nerves in the corolla. The specimen ‘Keep R., N.T., A.S.Mitchell 326 (DNA)’ has large phyllodes (to 13.5 cm long) and spikes (to 5 cm long, 12 mm wide).
Type of accepted name
Sturts [Sturt] Creek, [W.A./N.T.], F.Mueller 98 ; holo: MEL; iso: K, NSW.
Racosperma megalanthum (F.Muell.) Pedley, Austrobaileya 2: 352 (1987). Type: as for accepted name.
J.Brock, Top End Native Pl. 67 (1988).
W.A.: Helicopter Spring, South Turkey, I.Cowie 1880 (CANB, DNA, PERTH). N.T.: 25 km WNW of Twin Falls, Kakadu Natl Park, L.A.Craven 6230 (CANB, NSW); Koolpin Gorge, C.Dunlop 3600 (NSW, NT); Keep River Natl Park, C.Dunlop 5822 (DNA, NSW); range E of UDP Falls, C.H.Gittins 2614 (NSW). Qld: 27.2 km from Mount Isa on Camooweal road, C.H.Gittins 750 (NSW); L. Moondarra, Mount Isa, R.G.Coveny 477 (NSW).