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Photographer: M.W. McDonald
Photographer: E. McCrum
Photographer: M.W. McDonald
, Karratha, BRM 28 March 1984, ORIGINAL SCAN, ADJUSTED RICHARD WOODMAN.jpg)
Photographer: B.R. Maslin
Photographer: E. McCrum
Photographer: B.R. Maslin
Photographer: B.R. Maslin
Photographer: J. Maslin
, BRM 8626, lab photo by Fiona McCallum ADJUSTED.jpg)
Seed from one herbarium voucher. Scale in mm. Photographer: F. McCallum.
Numerous flowered variant. Photographer: B.R. Maslin
Numerous flowered variant. Photographer: B.R. Maslin
Botanical name
Acacia stellaticeps Kodela, Tindale & D. Keith, Nuytsia 13: 483, fig. 1 (2001)
Common name
Northern Star Wattle (preferred common name), Poverty Bush and Glistening Wattle
Aboriginal name
Pirrnyur, Pirrinyurru, Pitinyurru or Panmangu (Nyangumarta) and Panmangu (Ngarla)
Description
Dense, spreading, rounded or flat-topped, glabrous, somewhat resinous shrubs 0.3-1.5 (-2) m tall and up to about 3 m across, with a number of slender main stems diverging from ground level. Bark grey, smooth or finely fissured. Branchlets resin-ribbed at their apices. New shoots light green and resinous (but not sticky). Phyllodes asymmetrically elliptic-obovate to narrowly so or sometimes almost rounded, often slightly sigmoid, (5-) 8-20 (-25) mm long, (3-) 4-12 (-15) mm wide, slightly thickened and therefore very finely longitudinally wrinkled when dry, dull green to greyish green or sub-glaucous; superficially nerveless or with 1-3 very indistinct longitudinal nerves slightly more evident than the rest; apex terminated by a small but distinct, erect, knob-like or conical, thickened point. Inflorescences simple, single within axil of phyllodes; peduncles (5-) 10-30 (-40) mm long, erect; heads prolific and showy, globular, rather large (10-14 mm in diameter when fresh), golden, 7-25 (-45)-flowered. Flowers 5-merous, the buds normally large, wide-spreading and ±narrowed at apex (i.e. sub-acute); calyx shortly dissected; petals finely striate. Pods ±linear to narrowly oblanceolate or narrowly elliptic, broadest at apex and tapered towards the base, flat but slightly raised over the seeds, mostly straight-sided, mostly 2.5-10 cm long, 4-10 mm wide, held erect, crustaceous to sub-woody, splitting first along edge opposite seed attachment then opening elastically (and explosively) from apex with the valves strongly recurved following dehiscence (often many dehisced valves are found on ground under the plants), obliquely nerved, shiny and resinous (but not sticky) when young; margins thickened. Seeds obliquely longitudinal in pods, seated in shallow but distinct chambers separated by narrow partitions, obloid to narrowly obloid-ellipsoid, 4-6 mm long, light brown (sometimes tinged greenish) to dark brown; pleurogram obscure but bordered by a narrow, pale yellow band of tissue; funicle-aril turbinate, straight, creamy white except tinged green near attachment to seed.
Characteristic features
Commonly low shrubs. New shoots light green and resinous. Phyllodes small, short and broad (mostly 8-20 x 4-12 mm), asymmetric, nerves superficially absent or scarcely evident, terminated by a small conical, callose point. Heads globular; peduncles long (mostly 10-30 mm) and erect; flower buds large, wide-spreading and sub-acute. Pods held erect, sub-woody, flat with thickened margins, obliquely nerved, opening elastically from apex, the valves strongly recurved following dehiscence; funicle-aril straight and narrowly conical.
Distribution and ecology
Occurs in north western and northern Western Australia from Exmouth Gulf to near Broome and eastwards through the Great Sandy Desert and the extreme southern Kimberley region to the Tanami area in Northern Territory. Acacia stellaticeps is common in the Pilbara, especially in northern coastal and near-coastal areas; it does not occur south of the Fortescue River except in the far west of the region. It is often found on soft spinifex (Triodia pungens and T. epactia) plains in red sand where it commonly forms large, dense, pure stands (which may be overtopped by, and obscured by, spinifex).
Flowering and fruiting period
It is probable that flowering in this species is dependent upon the timing and intensity of rainfall events. Plants have been collected in flower from February to August but the main flowering flush appears to be between about April and July. Plants with mature seeds occur in September and October.
Variation
A variant from south of the Coongan River (about 100 km southwest of Marble Bar) between Hillside and Woodstock Stations is characterized by having more compact heads containing more flowers than is normal for this species (up to 45). These plants form populations on Kylena basalt, high in the landscape in hard spinifex (Triodia wiseana). Typical A. stellaticeps (with 7-25 flowers per head) occurs in the vicinity, but it occurs lower in the landscape and does not grow with the variant.
Affinities
Acacia stellaticeps has affinities to a number of Pilbara species and it hybridizes with some of them. The most common of these hybrids is called A. sphaerostachya , which represents a hybrid between A. stellaticeps and A. ancistrocarpa. Putative hybrids between A. stellaticeps and both A. arida and A. trachycarpa have been reported from near Roebourne but these are very rare and have not been collected in recent years. In the extreme north west of the Pilbara A. stellaticeps appears to hybridize with A. hilliana (see A. hilliana x stellaticeps).
Acacia stellaticeps can easily be confused with A. translucens which does not occur in the Pilbara but which is most readily distinguished by having more numerous flowers in the more compact heads. Acacia translucens does not occur in the Pilbara.
Notes
Acacia stellaticeps can coppice from the base following fire or regenerate profusely from seed.
The species has some horticultural potential as a low, drought tolerant spreading shrub on account of its prolific flowering followed by bright green, erect young pods.
As the name suggests Poverty Bush is unpalatable and has no forage value (Mitchell and Wilcox 1994).
Indigenous peoples prepared a topical wash from A. stellaticeps to help stop itching, skin sores and irritations by boiling the phyllodes in water. This wash also helps alleviate the symptom of a cold.
Conservation status
Not considered rare or endangered.
Origin of name
The botanical name is derived from the Latin stellatus (starry) and -ceps (head) in allusion to the characteristic star-shape of the immature heads, produced by the large, wide-spreading flower buds. The common name is derived from the same source.
References
Mitchell, A.A. and Wilcox, D.G. (1994). Arid shrubland plants of Western Australia. Edn. 2. pp. 478. (University of Western Australia Press in association with the Department of Agriculture: Perth.)