Acacia coolgardiensis Maiden
Acacia coolgardiensis Maiden
Widely distributed from Nerren Nerren Stn (c. 80 km NE of Kalbarri) and Northampton, SE to near Holt Rock (c. 100 km NE of Lake Grace) and Menangina Stn (c. 80 km E of Menzies), W.A. Collections previously noted by R.S.Cowan, Fl. Australia 11B: 329 (2001) from Carey Downs, Byro and Curbur stns, W.A. are now provisionally referred to A. incognita.
Multi-stemmed shrub or tree 2–5 (–7) m high, stems with few to many, shallow to deeply longitudinal flutings. Bark smooth except finely fissured at extreme base of stems on oldest plants. New shoots resin-encrusted, with sparse, reddish, glandular hairlets on young phyllodes. Branchlets resin-ribbed, appressed-puberulous between ribs. Phyllodes filiform, terete, rarely subterete, innocuous to coarsely pungent, sub-straight to shallowly incurved, (4–) 6–11 (–15) cm long, 0.6–0.8 (–1) mm diam., not rigid, grey-green or dull green; longitudinal nerves fine, numerous and close together, sometimes resinous. Inflorescences simple, mostly 2 per axil; peduncles 0.5–2 (–3) mm long (obscured by stamens at anthesis so heads appear sessile), stout, silvery-white appressed puberulous and with normally sparse, red-brown glandular hairlets; heads obloid to short-cylindrical, rarely globular, 5–9 (–12) mm long, (4–) 5–6 mm diam., golden. Flowers 5-merous; sepals free to 1/2-united. Pods straight to slightly curved, terete, (2–) 4–8 (–10) cm long, 1–2 mm wide, thinly coriaceous-crustaceous, ±obscurely longitudinally nerved. Seeds longitudinal, oblong, 2.2–4 mm long, shiny, normally tan; arils creamy white.
Grows in a wide variety of soils including granitic or lateritic gravel, sand, sandy loam or loam, often on sandplains, but also on low hills and granite outcrops in shrubland and spinifex.
W.A.: c. 25 km N of Murchison R. on North West Coastal Hwy, A.M.Ashby 4630 (AD n.v., PERTH); Coolgardie, C.A.Gardner 1293 (PERTH); 0.4 km W of Boorabbin Siding, B.R.Maslin 1858 (AD, DNA, PERTH); near Modesty Downs Station, c. 21.5 km N of Holt Rock, B.R.Maslin 3938 (PERTH); 97.5 km NNE of Kalgoorlie on road to Edjudina Stn, B.R.Maslin 4849 (PERTH).
Until recently a wide-ranging species comprising three subspecies but now considered more appropriate that the subspecies be treated as distinct species, A. coolgardiensis, A. effusifolia (syn. A. coolgardiensis subsp. effusa) and A. latior (syn. A. coolgardiensis subsp. latior). See B.R.Maslin & C.Buscumb, Nuytsia 18: 107–125 (2008) for discussion.
Acacia coolgardiensis along with A. effusifolia, A. incognita, A. latior and A. sulcaticaulis comprise the ‘A. coolgardiensis group’, fide B.R.Maslin & C.Buscumb, loc. cit. Sympatric with group members A. effusifolia and A. latior in the Mullewa area.
Most closely related to A. effusifolia which differs in its flat, broader phyllodes and often longer peduncles and spikes. Furthermore, A. effusifolia has a generally more inland distribution; however, intermediates between the species occur where their distributions overlap. Also related to A. incognita. Superficially similar to A. resinosa but is distinguished by its ±sessile heads, terete pods and non-mottled seeds.
Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia
Revised by B.R.Maslin & J.Reid
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