Acacias of Australia

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Acacia trinalis R.S.Cowan & Maslin




A poorly collected species, restricted to the area near Marchagee (c. 65 km N of Moora) SE to the Mortlock R. (near Goomalling) where several collections have been made.


Shrub or bushy tree 1.5–4 m high, dense, rounded, multistemmed, glabrous. New growth resinous, glabrous. Branchlets ±angular, resin-ribbed at extremities. Stipules caducous, triangular, minute. Phyllodes patent to ascending, linear, straight to slightly incurved, 4.5–9 cm long, 2–3 mm wide, short-acuminate with recurved to subuncinate tip, thinly coriaceous, glabrous, with 3 raised ±resinous nerves of which the central nerve most prominent and more regularly resinous; gland inconspicuous, 1–2 mm above pulvinus. Inflorescences simple, 2 per axil; peduncles mostly 4–6 mm long; heads globular, 4–4.5 mm diam., 22–28-flowered, golden; bracteoles fusiform, elliptic or oblanceolate, acute, ciliate. Flowers 5-merous; sepals narrowly oblong to linear-spathulate, free to 1/4–1/2-united, glabrous except ciliolate at apex; petals free. Pods and seeds not seen.


Grows in or near areas with saline conditions in more or less swampy areas in brown sand and clay loam.


W.A.: 10 km S of Goomalling on Mortlock R. along W side of Toodyay Rd, R.S.Cowan A734 & B.R.Maslin (CANB, K, MEL, NSW, PERTH); near 25 km SE of Coorow, A.Doley 1 (PERTH); Swan R., J.Drummond 2: 139 (BM, CGE, G, K, LUND, NSW, OXF, P, PERTH, W) and s.n. (K); 3.5 km W of Miling on Miling West Rd, B.R.Maslin 6211 (BRI, NSW, PERTH).


At both K and BM, the numbered Drummond collection cited above is mounted on the same sheet with syntype material of A. benthamii.

May be mistaken for the more southern A. heteroclita which differs most obviously in its normally golden-sericeous new shoots and non resin-ribbed branchlet apices.

FOA Reference

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