Cole's Wattle is widespread in inland northern Australia from the Pilbara across the Great Sandy Desert and Tanami Desert to western Queensland. The latitudinal range is 14-23o S and it is found from near sea level to 450 m. (QLD, WA, NT).
This fast-growing, short-lived, nitrogen-fixing shrub or small tree reaches heights of up to 9 m tall. Its branchlets are very angular and have a dense covering of short, white hairs. Phyllodes are 10-19 cm long and 20-55 mm wide, usually with three prominent longitudinal nerves. A dense covering of short hairs on the phyllodes gives the plant a characteristic silvery-blue appearance. The bright yellow flowers are in spikes 4-6 cm long in pairs. Mature pods are 5-10 cm long and 3-5 mm wide, usually slightly curved but sometimes tightly coiled. The shiny black seeds have a bright yellow aril. The main flowering period is June - July and large masses of reddish brown pods are present September - November. There are about 74 000 viable seeds per kilogram and pre-treatment with boiling water for one minute is needed to promote germination.
Ecology/Way of Life:
It occurs in the hot, semi-arid zone in areas that are mainly frost-free. Mean annual rainfall is 230-725 mm with a strong summer maximum and a dry season typically lasting 8-9 months. It is most commonly found along seasonally dry watercourses and adjacent to sandy plains and stony ridges on a wide variety of soil types. The soils are typically neutral but range from slightly acidic to alkaline. In watercourses it typically forms dense, almost pure stands. It is widespread in tall open-shrublands dominated by Acacia in north-western Australia.
Interaction with Humans/Threats:
Cole's Wattle is a very useful species for fuelwood, charcoal, windbreaks, land rehabilitation and as a human food source. In recent years it has been widely planted, under the name Acacia holosericea in West Africa. The seeds are nutritious containing 21% protein, 10% fat and 57% carbohydrate, and in the past were a quite important food source for Aborigines in Central Australia. Aborigines also extracted a red dye from the seed aril by soaking them in water. Fresh phyllodes are not palatable to cattle and sheep but dry foliage has greater palatability. Acacia colei makes an attractive ornamental with its silvery foliage and mass flowering. The heavy seeding and rapid growth of this colonising species suggest it has high potential to become a weed.
Other Comments:Acacia colei was named by Bruce Maslin and Lex Thomson in 1992 after Mr E.G. Cole (1927 -), a CSIRO tree seed collector who made extensive botanical and seed collections of this species. The genus is based on the Greek akakia = a thorny plant, specifically Acacia arabica; and the species name honours Mr Cole.
Doran, J.C. and Turnbull, J.W. (eds.) 1997. Australian trees and shrubs; species for land rehabilitation and farm planting in the tropics. ACIAR Monograph no. 24. Australian Centre for International Agricultural Research, Canberra. 384p.
Latz, P.K 1995. Bush fires and bush tucker; Aboriginal plant use in Central Australia. IAD Press, Alice Springs, Australia. 400p.
Maslin, B.R and Thomson, L.A.J. 1992. Reappraisal of the taxonomy of Acacia holosericea, including the description of a new species, A. colei, and the reinstatement of A.neurocarpa. Australian Systematic Botany 5: 729-743.
Topics:Aboriginal resources Firewood Soils Germination Plant structure Climatic zones Aboriginal resources Nitrogen- fixation Windbreak Human food production Ornamental Timber Nitrogen-fixation
Text & map from Australian Trees and Shrubs, courtesy Australian Centre for International Agricultural Research; text edited by J. Turnbull; photo courtesy Maurice McDonald
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