Acacia leptocarpa A.Cunn. ex Benth., London J. Bot . 1: 376 (1842)
Tree to 15 m high, rarely a shrub to 4 m. Bark ‘ironbark’ type, dark grey to almost black. Branchlets angular towards apices, lenticellate, glabrous. Phyllodes narrowly elliptic, attentuated towards both ends, markedly falcate, 9–26.5 cm long, (6–) 10–35 mm wide, thinly coriaceous, glabrous, with 3 prominent main nerves (the lower 2 often confluent towards base and the uppermost sometimes confluent with upper margin before reaching apex), the minor nerves 1–3 per mm, longitudinal, occasionally anastomosing; gland usually 1, basal, conspicuous. Spikes 3.5–9.5 cm long, yellow to golden. Flowers 5-merous; calyx 0.4–0.9 mm long, sinuate or dissected to 1/4, with fimbriate margins, glabrous; corolla 1.3–2 mm long, dissected to 1/2, glabrous; ovary densely pubescent. Pods slightly or variably constricted between and raised over seeds, curved, curled or twisted, 8–15 cm long, usually 2–3.5 mm wide, thinly coriaceous to chartaceous, glabrous. Seeds longitudinal, oblong-elliptic, 3–4 mm long, dark brown; pleurogram U-shaped; funicle-aril massive, longer than seed, yellow-orange.
Occurs in tropical Australia from Carlton Hill Stn in northern W.A. eastwards to Arnhem Land and the Gulf of Carpentaria, including offshore islands of N.T. (N of c. 17S), to Cape York southwards along the eastern coast to c. 26S, Qld. Grows in open eucalypt and/or Melaleuca woodlands, in sandy or rocky soils, sometimes on laterite. Also recorded from southern New Guinea, fide L.Pedley, Contrib. Queensland Herb. 18: 19 (1975).
Similar to A. cowleana and A. elachantha but distinguished by a combination of its glabrous branchlets, glabrous and thinner phyllodes, commonly longer flower-spikes which occur in groups of 2–5 within the phyllode axils and its generally longer, more curved or twisted pods. Perhaps also with affinities to A. tropica and it may possibly intergrade with A. cretata . The coiled pods resemble those of A. gardneri .
Details of ecology, utilisation, etc. of A. leptocarpa are given in J.W.Turnbull (ed.), Multipurpose Austral. Trees & Shrubs 152 (1986).
Type of accepted name
Cape Flinders, [Qld], Aug. 1820, A.Cunningham 118 ; lecto: K, fide L.Pedley, Contr. Queensland Herb. 18: 19 (1975); isolecto: BM n.v.
Racosperma leptocarpum (A.Cunn. ex Benth.) Pedley, Austrobaileya 2: 351 (1987). Type: as for accepted name.
Acacia polystachya A.Cunn. ex Benth., London J. Bot. 1: 376 (1842), p.p. , not as to lectotype, as to paralectotype: Port Essington, [N.T.], Armstrong .
J.H.Maiden, Proc. Roy. Soc. Queensland 30: pl. 5, figs 1–9 (1918); J.Brock, Top End Native Pl. 65 (1988); C.R.Dunlop, G.J.Leach & I.D.Cowie, Fl. Darwin Region 2: 12, fig. 5 (1995); B.R.Maslin & M.W.McDonald, A key to useful Australian acacias for the seasonally dry tropics , CSIRO, 40 & 41 (1996).
W.A.: Carlton Hill Stn, M.W.McDonald 1919 (BRI, CANB, PERTH). N.T.: Croker Is., Cape Croker, C.R.Dunlop 6946 (BRI, DNA, MEL, NSW); 25 km W of Borroloola, M.O.Parker 966 (DNA, K, NSW, NT). Qld: 56.8 km by road NW of ‘Lakeland Downs’, R.G.Coveny 7011 & P.Hind (BRI, CANB, K, MEL, NSW, QRS, US); c. 14 km SW of Agnes Water, L.W.Jessup 347 & G.P.Guymer (BRI, CANB, ILL, K, MEL, MO, NSW, PERTH).