Acacia semitrullata Maslin, Nuytsia 2: 282; 284, fig. 7 & 326, fig. 20 (1978)
Erect shrub 0.3–0.5 m high, sometimes taller. Branches orange-brown. Branchlets antrorsely puberulous, the hairs often appressed. Stipules narrowly triangular, sometimes setaceous, 1–2 mm long, spreading, often incurved. Phyllodes patent, sometimes reflexed, narrowly semi-trullate with a slight gland-angle on adaxial margin near base, sometimes triangular-lanceolate without gland-angle, 5–10 mm long, 1.3–2 mm wide, pungent with a slender, 0.5–1.5 mm long cusp, rigid, green, glabrous or subglabrous; midrib prominent; lateral nerves absent. Inflorescences simple, 1 per axil; peduncles 3–8 mm long, densely puberulous with straight, patent hairs; heads globular, 5–8-flowered, cream to white. Flowers 4-merous; sepals c. 1/2-united, with lobes triangular; petals puberulous, 1-nerved. Pods terete, narrowed at both ends, to 7.5 cm long, 2–3 mm diam., red-brown, striate, finely appressed-puberulous. Seeds oblong, 4 mm long; aril terminal, conical.
Occurs from Yarloop S to Collie and the Whicher Ra., south-western W.A. Grows in sand in open heath frequently fringing seasonally dry swamps, and in sand over laterite in shallow depressions in open Jarrah forest.
A member of the ‘ A. horridula group’ most closely related to A. uliginosa which has sparser branchlet hairs restricted to the ribs, erect stipules, 8–15-flowered heads, and glabrous, nerveless petals.
Type of accepted name
Between Harvey and Myalup, W.A., 20 Aug. 1976, B.R.Maslin 4193 ; holo: PERTH; iso: CANB, K, MEL.
[ Acacia horridula auct. non Meisn. G.Bentham, Fl. Austral. 2: 350 (1864) p.p. , as to Swan R., Drummond s.n. and Harvey R., Oldfield s.n. ]
B.R.Maslin, Nuytsia 2: 284, fig. 7 (1978).
W.A.: W of Yarloop, R.J.Cranfield 121 (NSW, PERTH); Whicher Ra., A.S.George 6212 (NSW, NY, PERTH); 3.2 km SW of Donnybrook towards Capel, B.R.Maslin 448 (NSW, NY, PERTH).