Acacia leptostachya Benth., Fl. Austral . 2: 406 (1864)
Small shrub to tree, 0.5–6 m high. Branchlets usually appressed-puberulous except on ribs. Young shoots resinous, not viscid. Phyllodes narrowly elliptic to lanceolate, sometimes almost linear, straight or shallowly curved, mostly 4–9 cm long and 2–12 mm wide, usually subglabrous to pubescent with silvery appressed hairs, with numerous, fine, rather close (4–7 per mm), nonanastomosing veins, with 2 or 3 more prominent. Inflorescences 2-headed racemes, 1–5 (–10) mm long; peduncles 1–3 mm long, normally appressed puberulous; receptables glabrous; spikes 2–4 cm long, subdense to interrupted, golden. Flowers 5-merous; sepals united, golden puberulous to glabrous; ovary densely hairy. Pods linear, raised over seeds, to 6 cm long, 2–9 mm wide, firmly chartaceous to thinly coriaceous, glabrous. Seeds longitudinal or (when pods broad) transverse, oblong, 2.7–4 mm long, shiny, brown; aril small.
Occurs from the E central part of Cape York Penin. near Coen through coastal and inland districts as far S as Maryborough and Boatman Stn, S of Charleville, Qld. It also occurs near Riversleigh Stn (c. 200 km NW of Mt Isa). Grows in deep sand and skeletal soil on sandstone or granite in eucalypt woodland, open eucalypt forest or Triodia hummock grassland.
A variable species and further study is required to elucidate the complex variation patterns. The variation is especially marked in the species’ habit, phyllode dimensions, indumentum of calyx, and pod width, fide L.Pedley, Austrobaileya 1: 144 (1978). Following L.Pedley, op. cit . 143, A. capillosa is treated as conspecific with A. leptostachya . However, specimens agreeing with the type of A. capillosa are very distinctive in having densely pubescent to villous (almost velvety) branchlets, phyllodes and peduncles The hairs of the indumentum are not closely appressed as in typical A. leptostachya (young plants of typical A. leptostachya have pubescent branchlets and phyllodes). In general appearance A. leptostachya resembles A. scopulorum and its phyllodes can be similar to those of A. burdekensis .
Type of accepted name
Newcastle Ra., Qld, F.Mueller s.n .; syn: K; Port Denison, Qld, J.Dallachy ; syn: K; isosyn: ?MEL1606751; Port Denison, Qld, E.F.A.Fitzalan ; syn: K; isosyn: MEL, NSW; Broadsound, Qld, Bowman, herb. Mueller ; syn MEL. See L.Pedley, Austrobaileya 1: 143 (1978) re typification.
Racosperma leptostachyum (Benth.) Pedley, Austrobaileya 2: 351 (1987). Type: as for accepted name.
Acacia argentea Maiden, Proc. Roy. Soc. Queensland 30: 41, t. 4, figs 8A–14 (1918). Type: Alma-den, Qld, 20 Aug. 1913, R.H.Cambage 3893 ; holo: NSW; iso: BRI.
Acacia capillosa Pedley, Proc. Roy. Soc. Queensland 75: 29 (1964). Type: Upper Emu Ck, S of Irvinebank, Qld, 2 June 1962, F.W.Whitehouse ; holo: BRI; iso: BRI.
[ Acacia conspera auct. non F.Muell.: K.Domin, Biblioth. Bot . 89: 268 (1926), fide L.Pedley, Austrobaileya 1: 143 (1978)]
F.Mueller, Iconogr. Austral. Acacia dec. 10 [pl. 3] (1888), as to flowering material only; J.H.Maiden, Proc. Roy. Soc. Queensland 30: 41, t. 4, figs 1–5 and (as A. argentea ) figs 8A–14 (1918); M.Simmons, Acacias Australia 265 (1981); W.R.Elliot & D.L.Jones, Encycl. Austral. Pl . 2: 76 (1982).
Qld: 11 km SW of beach at Yeppoon towards Rockhampton, R.Cumming 3219 (PERTH); Boatman [Stn], S.L.Everist 5624 (BRI n.v. ); 36 km S of Riversleigh Stn, A.J.Gray & D.M.Gordon 3340 (BRI); Blackdown Tableland, W.G.Trapnell 39 & K.A.Williams (BRI).