Acacias of Australia

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Acacia unifissilis Court




Occurs from Kellerberrin S to Fitzgerald R. Natl Park and near Peak Charles Natl Park, south-western W.A.


Compact shrub 0.15–0.7 m high. Branchlets rigid, puberulous, pruinose between the yellowish ribs. Stipules 1.5–4 mm long. Phyllodes continuous with branchlets and commonly shortly decurrent with them, linear to subulate or narrowly triangular, commonly ±recurved, ±pentagonal when very narrow, 1–3 cm long, 1–3 mm wide, pungent, rigid, green, glabrous, 5-nerved, with the 2-nerved adaxial margin thick and nerve-like; midrib prominent; adaxial nerves sometimes submarginal so phyllodes appear 2-nerved per face. Inflorescences simple; heads sessile, globular or obloid, 8–20-flowered, light golden; bracteoles scarious, brown, fimbriolate, conspicuous in buds. Sepals united, deeply cleft adaxially, scarious, brown, fimbriolate; petals 5. Pods constricted between seeds, tightly coiled or twisted, 1–1.5 cm long (unexpanded), crustaceous, dark brown, glabrous. Seeds oblong-elliptic, 3–4 mm long, ridged peripherally; aril oblique.


Grows in sand in heath, shrubland or mallee communities.


W.A.: near Collgar, c. 10 km SSE of Merredin, A.M.Ashby 1803 (PERTH); 5 km N of Dunn Swamp, c. 80 km NE of Ravensthorpe, J.Taylor 737 et al. (PERTH); 0.8 km E of Newdegate towards Lake King, M.D.Tindale 3761 (A, AD, CANB, K, NSW, PERTH, US).


The sessile heads, very unusual calyx and tightly coiled or twisted pods readily distinguish the species from taxa with similarly 5-nerved, pungent phyllodes such as A. baxteri.

FOA Reference

Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia