Acacia arida Benth., London J. Bot . 1: 370 (1842)
Erect shrub to 3 m high, branching from base. Bark smooth, grey or grey-brown. Branchlets soon terete, light to dark brown, with conspicuous lenticels, glabrous, often with a thin waxy, finely cracked resinous coating; ridges inconspicuous. Phyllodes linear to narrowly oblong or linear-oblanceolate, flat, straight, 2.5–9.8 cm long, 1–5.5 mm wide, coriaceous, subglaucous, glabrous, resinous, the midvein conspicuous, sometimes with 2 other obscure, longitudinal veins, rarely with numerous, parallel minor veins; stomata commonly conspicuous; gland 1, inconspicuous, basal, 0.2–2 mm above pulvinus. Spikes 1–2.4 cm long, golden. Flowers 5-merous; calyx 0.5–0.8 mm long, dissected to 1/4–5/6, the apex minutely hoary; corolla 0.3–1.3 mm long, dissected for 1/3–1/2, glabrous; ovary glabrous. Pods erect, linear-oblanceolate, terete to quadrangular, 3.4–7 cm long, striate, resinous, opening elastically from apex; margins inconspicuous; seed-partitions thick. Seeds oblique, narrowly oblong-elliptic, 4.5–7 mm long, brownish black; pleurogram elongate, U-shaped, yellowish; areole depressed; funicle-aril conical.
Occurs in tropical W.A., in the Kimberleys and adjacent coast to the north and in the Roebourne–Exmouth Gulf–Mt Newman–Paterson Ra. Area. Grows in red sandy loam or coarse, gravelly, skeletal sand on laterite or sandstone, in low, open eucalypt forest. Flowers May–Oct.
Acacia arida is closely related to A. orthocarpa which is somewhat arbitrarily distinguished by its terete to sub-teete phyllodes; the relationship between these two species requires further study. A specimen collected by M.Lazarides 6392 (CANB, NSW), 19.2 km NNW of Elgie Cliffs Stn, Kimberleys, is intermediate between these species. Also related to A. arrecta . A possible hybrid between A. arida and A. stellaticeps has been collected in the Roebourne/Wickham area of W.A. ( K.Glennon 196 , PERTH).
Type of accepted name
Parched desert shores of Cambridge Gulf, [W.A.], Sept. 1819, A.Cunningham 481 ; holo: K; iso: NSW.
Acacia trachycarpa E.Pritz., Bot. Jahrb. Syst . 35: 308 (1904), p.p. , not as to lectotype, as to paralectotype: near Roebourne, W.A., 18 Apr. 1901, E.Pritzel 279 (B, DBN, E, K, L, M, P, PR), fide B.R.Maslin, Nuytsia 4: 99 (1982).
Acacia subrotata Domin, Biblioth. Bot . 89: 265 (1926). Type: between the Ashburton and Yule Rivers, W.A., E.Clement ; holo: PR n.v .; iso: K.
J.R.Wheeler, in J.R.Wheeler (ed.) et al ., Fl. Kimberley Region 318, fig. 92A (1992).
W.A.: Wittenoom Gorge, B.Maloney 19/69 (NSW); 3.5 km W of Whim Ck on NW Coastal Hwy to Roebourne, B.R.Maslin 5797 (NSW, PERTH); Cape Ra. Natl Park, R.Pullen 10953 (CANB, NSW); 65 miles [104 km] S of Kalumburu Mission, North Kimberleys, N.H.Speck 4972 (CANB, NSW).