Botanical name

Acacia murrayana F. Muell. ex Benth., Fl. Austral. 2: 370 (1864)

Common name

Murray's Wattle (preferred common name), Colony Wattle, Sandplain Wattle, Powder Bark Wattle, Fire Wattle, and more

Description

Large shrubs or trees 2-6 (-8) m, single- or multi-stemmed from the base, main stems straight or sometimes rather crooked and with dbh to about 15-20 cm (note: few measurements made therefore needs confirming), commonly suckering to form clonal thickets; crowns bushy and often wide-spreading 3-8 m across. Bark smooth becoming fissured on trunks and main branches with age, grey or brown with a distinctive powdery white bloom (pruinose) at least when young. Branchlets glabrous, often pruinose. Phyllodes linear to narrowly elliptic, sometimes oblanceolate, 5-15 cm long, 1.5-8 mm wide, sometimes to 12 mm, thinly coriaceous, often drying finely longitudinally wrinkled, glabrous, pale green to glaucous, midrib not prominent, lateral nerves obscure and longitudinally anastomosing; gland basal, also at base of the minute, thickened, ącurved apical point. Inflorescences 2-10-headed racemes; raceme axes 1-6 cm long, slender and glabrous; peduncles 4-10 mm long, sometimes to 15 mm, slender, glabrous; heads globular, light- to mid-golden, densely 25-50-flowered. Flowers 5-merous; sepals ąfree. Legumes narrowly oblong, prominently rounded over seeds, to 9 cm long, 8-12 mm wide, chartaceous, sometimes pruinose, glabrous. Seeds transverse to oblique, obloid, ellipsoid, ovoid or ąorbicular, 4-5.5 mm long, shallowly depressed at centre, dull, black; funicle not expanded into an aril.

Distribution and ecology

Widely distributed in the arid and semi-arid zones of Australia where it extends from the central-west coast of Western Australia (North West Cape and Shark Bay areas) eastwards through all mainland states (except Victoria) to the western margin of the Great Divide near Mitchell (Queensland) and Narrabri (New South Wales). This species does not occur in the Pilbara region, however, it comes close to the southwestern boundary in the vicinity of Nanutarra. Over its extensive range A. murrayana occurs predominantly on deep red sands but it may also occur on clay loams. It favours well-drained sites with access to run-on water such as the base of dunes, road verges and stream levees. It is tolerant of alkaline soils and is relatively salt-sensitive. Further details on its ecology are given in Doran and Turnbull (1997), Cunningham et al. (1981) and Whibley and Symon (1992).

Flowering and fruiting period

The main flowering period is from August to November (but will vary within this range depending upon geographic location) with pods maturing several months later, between November and January (Maslin et al. 1998). Plants flower profusely, commencing at an early age and produce heavy pod crops during favourable seasons.

Affinities

Acacia murrayana is closely related to A. pachyacra which differs most obviously in having narrower phyllodes.

Notes

An adaptable, fast-growing species with life-span of about 10-25 years, during which time in its natural habitat it rarely produces a trunk with a diameter over 10 cm (Maconochie 1982). It is highly fire-tolerant and drought-adapted, however, it is not especially drought-tolerant and is relatively salt-sensitive. It forms colonies from subsurface adventitious sprouts often a considerable distance from the parent plant. Established plants resprout readily after wildfires from epicormic buds in the relatively thick bark at the stem base, or from stem and major roots.

Although Central Australia plants of this species is reported to contain high levels of protein and phosphorus and reasonably low levels of fibre, it is only lightly grazed there by cattle in that area (Chippendale and Jephcott 1963). According to Cunningham et al. (1981) in western New South Wales the foliage of this species is seldom browsed. Similarly Allen (1949) and Mitchell and Wilcox (1994) report that the phyllodes are rarely consumed by stock, but the pods are sought after. Dry matter digestibility of foliage was assessed by Vercoe (1989) as being below maintenance levels.

Acacia murrayana is one of the most promising species suggested by Maslin et al. (1998) for trialing in southern Australia as a source of seed for human food. Maslin et al. (1998) provide summary of the macronutrient composition of seeds.

In the past, seed and gum of A. murrayana was a food source for Central Australian Aborigines (Latz 1995, House and Harwood 1992).

Acacia murrayana flowers profusely and may prove useful for ornamental purposes and as a pollen source for bees (Doran and Turnbull 1997).

Much of the above information is taken from Maslin and McDonald (2004) where further information can be found concerning this species.

Conservation status

Not considered rare or endangered.

Origin of name

This species is named for Dr James Patrick Murray who was surgeon and plant collector on Howitt's Expedition to Coopers Creek 1862 where he collected 96 species, including the Acacia that bears his name (Hall 1984).

References

Allen, G.H. (1949). Notes on plants of south western Queensland. Mimeo. pp. 83.

Chippendale, G.M. and Jephcott, B.R. (1963). Topfeed. The fodder trees and shrubs of Central Australia. Extension Article No. 5. pp. 51. (Northern Territory Administration, Animal Industry Branch: Alice Springs.)

Cunningham, G.M., Mulham, W.E., Miltnorpe, P.L. and Leigh, J.H. (1981). Plants of western New South Wales. pp. 766. (Government Printing Office: Sydney.)

Doran, J.C. and Turnbull, J.W. (1997). Australian trees and shrubs: species for land rehabilitation and farm planting in the tropics. ACIAR Monograph No. 24. pp. 384. (Australian Centre for International Agricultural Research: Canberra.)

Hall, N. (1984). Botanists of Australian Acacias. pp. 64. (CSIRO: Melbourne.)

House, A.P.N. and Harwood, C.E. (1992). Australian Dry-zone Acacias for Human Food. Proceedings of a workshop at Glen Helen, Northern Territory, Australia, 7-10 August 1991. pp. 151. (Australian Tree Seed Centre, CSIRO Division of Forestry: Canberra)

Latz, P.K. (1995). Bushfires and Bushtucker: Aboriginal plant use central Australia. pp. 400. (IAD Press: Alice Springs.)

Maconochie, J.R. (1982). Regeneration of arid zone plants: a floristic survey. pp. 141-144. In: W.R. Barker and P.J.M. Greenslade (eds) Evolution of the Flora and Fauna of Arid Australia. pp. 392. (Peacock Publications: Frewville.)

Maslin, B.R., Conn, E.E. and Dunn, J.E. (1987). Cyanogenic Australian species of Acacia: a preliminary account of their toxicity potential. pp. 107-111. In: J.W. Turnbull (ed.) Australian Acacias in developing countries. Proceedings of an international workshop held at the Forestry Training Centre, Gympie, Australia, 4-7 August 1986. ACIAR Proceedings No. 16. pp. 196. (Australian Centre for International Agricultural Research: Canberra.)

Maslin, B.R. and McDonald, M.W. (2004). AcaciaSearch: Evaluation of Acacia as a woody crop option for southern Australia. RIRDC Publication No. 03/017. pp. 267. (Rural Industries Research and Development Corporation: Canberra.)

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.)

Vercoe, T.K. (1989). Fodder value of selected Australian tree and shrub species. pp. 187-192. In: D.J. Boland (eds) Trees for the tropics. Growing Australian multipurpose trees and shrubs in Developing Countries. pp. 247. ACIAR Monograph No. 10. (Australian Centre for International Agricultural Research: Canberra.)

Whibley, D.J.E. and Symon, D.E. (1992). Acacias of South Australia. Handbook of the flora and fauna of South Australia Series. pp. 328. (South Australian Government Printer: Adelaide.)