Acacias of Australia

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Acacia triptycha F.Muell. ex Benth.




Occurs sporadically from Mt Frankland E to near Ponier Rock and Cape Arid Natl Park in south-western W.A.


Bushy shrub to small tree 1–4 m high. Branchlets glabrous. New growth golden appressed-puberulous. Phyllodes ascending to erect, linear, straight or more often shallowly curved, flat to subterete, (3–) 7–10 (–13) cm long, 1–2 mm wide, arcuately long-acuminate with point appressed-puberulous ageing glabrous, glabrous (except tip), 8-nerved in all, 3-nerved per face when flat; gland 1–11 (–15) mm above pulvinus. Inflorescences simple, 2 per axil; peduncles 4–10 mm long, glabrous to sparsely appressed-puberulous; heads globular, 4–6 mm diam., mostly 26–40-flowered, ±golden. Flowers 5-merous; sepals free, spathulate; petals partly united. Pods linear, slightly raised over seeds, straight, to 6 cm long, 3–4 mm wide, thinly crustaceous, glabrous to sparsely appressed-puberulous. Seeds longitudinal, elliptic to oblong-elliptic, 2.8–3.3 mm long, glossy, mottled shades of brown, nigrescent; aril subapical.


Grows usually in association with granite or quartzite in granitic sand or reddish-brown clay-sand over quartz, in open scrub or heath on hills, hence the sporadic distribution.


W.A.: Mt Ragged, T.E.H.Aplin 4331 (AD, BRI, CANB, K, PERTH); Jacup Ck, Fitzgerald R., 12 Oct. 1935, C.A.Gardner s.n. (BM, PERTH); c. 10 km from Ravensthorpe towards Lake King, B.R.Maslin 3873 (CANB, G, K, MEL, NSW, NY, PERTH); 31 km W of Ponier Rock, K.Newbey 7626 (PERTH).


The J.Drummond 4: 132 and 5: 5 collections cited by G.Bentham, Fl. Austral. 2: 337 (1864), under this name are A. subflexuosa.

The closest relative is A. heteroclita which has broader phyllodes. Also related to A. trinalis and to the ‘A. fragilis group’, particularly A. assimilis, which has slender, more nearly terete phyllodes with more numerous, less conspicuous main nerves.

FOA Reference

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