Acacia densiflora Morrison
Acacia densiflora Morrison
Occurs from near Wyalkatchem and Chiddarcooping (c. 80 km due NNE of Merredin) S to Ongerup and Frank Hann Natl Park (30–110 km ENE of Lake King), with outliers to the E near Coolgardie, inland southern W.A.
Rounded shrub mostly 0.5–1.2 m high. Branchlets tomentulose. Phyllodes inclined to ascending, straight, terete to compressed or flat and linear, 2–5 (-6) cm long, 1–2 mm wide, coarsely to sharply pungent, rigid, glabrous except pulvinus and base of phyllodes tomentulose, with ±16 plane to slightly raised closely parallel yellowish nerves; stomata evident in darker coloured internerve spaces; glands 1 or occasionally 2, small. Inflorescences simple, 2 per axil; peduncles 0.5–1.5 mm long, crisped-tomentulose; basal bract caducous, rostriform, 1.5–3 mm long; heads globular, 4–5 mm diam., mostly 15–18-flowered, rarely 11–25-flowered, golden. Flowers 5-merous; sepals 1/2–3/4-united. Pods linear, raised over and slightly constricted between seeds, slightly curved, to 4.5 cm long, 2.5 mm wide, thin-crustaceous, tomentulose. Seeds longitudinal, elliptic, ±3 mm long, glossy, black; aril apical.
Grows mostly in sand and loam in mallee communities.
W.A.: 30 km W of 90 Mile Tank, Frank Hann Natl Park, T.E.H.Aplin & M.E.Trudgen 5918 (K, MO, NY, PERTH); 29 km W of Pederah on road to Kulin, B.R.Maslin 532 (K, MEL, PERTH); 8 km due W of Merredin, B.R.Maslin 2352 (CANB, K, NY, PERTH); 15 km SSW of Queen Victoria Rocks, K.Newbey 5681 (PERTH).
Collections from near Coolgardie (e.g. K.Newbey 5681) and Frank Hann Natl Park (e.g. T.E.H.Aplin & M.E.Trudgen 5918) have phyllodes with coarser, tuberculate nerves. The gradual progression in phyllode shape in cross-section from completely terete (as in the type) to subterete to flat makes recognition of infraspecific taxa impractical, at least on this basis, even though the extremes look superficially different.
Acacia densiflora together with A. dissona, A. eremophila, A. graciliformis, A. hadrophylla, A. kalgoorliensis, A. mackeyana, A. papulosa and A. undosa constitute the ‘A. densiflora group’, fide R.S.Cowan & B.R.Maslin, Nuytsia 10: 206 (1995) and B.R.Maslin & C.Buscumb, Nuytsia 17: 257 (2007). Acacia densiflora is nearest to A. eremophila, and also close to A. kalgoorliensis and A. mackeyana. Narrow phyllode specimens of A. undosa sometimes resemble A. densiflora.
Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia
Minor edits by J.Reid
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