Acacia cowleana Tate
WATTLE
Acacias of Australia
Common Name
Halls Creek Wattle
Family
Fabaceae
Distribution
Acacia cowleana has a discontinuous distribution in the northern arid zone between latitudes 20°–25°S. Its main area of occurrence extends from the W.A.–N.T. border to central Qld and S into central-northern N.S.W. in the Enngonia–New Angledool area. In W.A. it occurs mainly in the Pilbara region.
Description
Openly branched and sometimes rather spindly shrub 1.5–3 (–4) m tall, sometimes a tree to 8 m. Branchlets prominently angled at extremities but soon terete, minutely sericeous, rarely glabrous. New shoots at initiation encrusted with dark brown resin that obscures the underlying appressed indumentum, rarely glabrous. Phyllodes shallowly to moderately falcate, rarely dimidiate, (7–) 12–20 (–22) cm long, 14–36 mm wide, coriaceous, wide-spreading, minutely sericeous, silvery green or grey-green to sub-glaucous, rarely glabrous; longitudinal nerves numerous and ±widely spaced, 2 or 3 per mm, with 3 more evident than the rest and the lowermost 2 running together at base of phyllode; minor nerves with few anastomoses; apical point knob-like or ±oblong; gland absent from apex of phyllode. Inflorescences 1 or 2 per axil, simple or vestigial binate racemes with axes to 2 mm long; peduncles (1–) 3–10 mm long, sericeous, rarely glabrous; spikes 3–5 cm long, bright golden, flowers subdensely arranged; bracteoles spathulate, 0.7 mm long. Flowers 5-merous; sepals united; petals glabrous. Pods linear, straight to shallowly curved, 3.5–5 mm wide, chartaceous to coriaceous, very sparsely minutely hairy or glabrous. Seeds longitudinal, ±oblong, 3.5–5 mm long, glossy, dark brown to black; aril yellow.
Phenology
Flowers late May–Aug.
Habitat
Grows mainly along the banks of seasonal creeks.
Specimens
W.A.: Fortescue, Marra Mamba, Hamersley Ra., J.V.Blockley 319 (PERTH). N.T.: Old Tennant Creek telegraph stn, c. 13 km N of Tennant Creek township, B.R.Maslin 7461, M.McDonald & G.Leach (PERTH, DNA). Qld: Gilruth Plains (N Brandy) c. 50 km ESE of Cunnamulla, M.G.Brooker B220,221 (NSW). N.S.W.: ‘Beulah’, Enngonia, 27 Sept. 1983, G.Cunningham s.n. (NSW).
Notes
Closely related to and previously confused with the tetraploid species A. elachantha, see M.W.McDonald & B.R.Maslin, Austral. Syst. Bot. 10: 303–320 (1997) for discussion. For example, in L.Pedley, Austrobaileya 1: 95–96, 98–99 (1978), the A. cowleana description represents A. elachantha while the A. oligophleba description represents typical A. cowleana. These two species sometimes putatively hybridize in the Mitchell district, Qld. Hybrids between A. cowleana and A. holosericea have been collected from Coorajah Ck, Budgerygah Stn, Qld, fide M.W.McDonald & B.R.Maslin, loc. cit. Acacia cowleana also putatively hybridizes with A. hammondii near Musselbrook, Qld. The distinguishing characteristics of A. cowleana and its closest allies, A. colei, A. elachantha, A. leptocarpa, A. longispicata and A. thomsonii, are given by M.W.McDonald & B.R.Maslin, Austral. Syst. Bot. 10: 306, 307 & 311 (1997). Also related to A. holosericea and its allies. An apparently rare glabrous variant of A. cowleana occurs in the Laglan–Jericho region, Qld.
Acacia cowleana has the ability to regenerate from basal coppice, however, it more commonly regenerates from seed (especially following disturbance). It is a fast growing, short-lived species often used in seed-mixes for mine site rehabilitation. It has been rarely cultivated compared to its close relative A. elachantha. The information given under A. cowleana in J.C.Doran & J.W.Turnbull (eds), Austral. Trees & Shrubs: species for land rehabilitation and Australian Trees & Shrubs: Species for Land Rehabilitation & Farm Planting in the Tropics 134–135 (1997) and P.Latz, Bushfires & Bushtucker 94 (1995) is mainly attributable to A. elachantha.
FOA Reference
Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia
Author
P.G.Kodela, M.W.Mcdonald
Edited by B.R.Maslin
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