|
Acacia farnesiana (L.) Willd. |
  |
Leguminosae
Aromo (Panama); espino blanco, espino ruco (El Salvador), huisache (Mexico), opoponax (southern United States); mimosa bush, needle bush (Australia); klu (Hawaii); Ellington curse, vaivai vakavotona, ban baburi (Fiji).
|
Author: Le Houérou
A. Stem (showing leaves and thorns), B. Stem and pods, |
|
Woody shrub up to 7 m high, but usually 1-3 m, very branched with an intricate habit, very spiny. Bark grey-brown smooth or scaly, twigs often zigzagged (sympodic growth), leaves alternate, shortly petiolated, bipinnate with 2-4 pairs of pinnulae having 8-10 (20) pairs of leaflets each leaflets obtuse of a green-bluish colour, 3-6 x 1-2 mm. Stipulate axillary pairs of thorns 0.2-3 cm long, sometimes lacking. Flowers of an orange color, very fragrant with a smell of violet, grouped in 50 or more globose heads 1.5-2.0 cm in diameter, grouped by 2-3, or isolated on an 8-35 mm long slender, hairy-downy peduncle. The fruit is a green pod, turning black or dark brown at maturity, thick, indehiscent, cylindrical, 4-8 cm long and 0.8-1.5 cm in diameter, each contains 12 to 14 seeds. Seeds transversally set in the pods, ovoid, compressed, 6-7 x 4-5 mm, coated with a characteristic whitish medulla. Life span 10-50 years. It's often inadvertent introduction and subsequent naturalization is due to its flexible ecological requirements and readily high germination rate which makes it able to colonize disturbed land left open by the elimination of native vegetation. It is one of the few woody plants which grows naturally on the heavy, cracking calcareous clay grasslands in north-west Queensland and along stream banks in northern Australia. It is also one of the few species which can persist along highly saline artesian watering drains for sheep and cattle, where it also provides valuable shade. A. farnesiana originates from North and Central American tropics and subtropics : South USA, North Mexico where it is known as "Huisache". It was introduced to Europe in the 17 th century, thence spread and became naturalized in many of the world's subtropical and tropical arid lands : North Africa, Sahel, East Africa, Arabian Peninsula, Pakistan, India, Australia. Now common throughout the tropics. Formerly a garden plant. Common in Viti Levu (Fiji), and northern Australia, southern Australia, southern France and Africa. Considered one of the worst weeds in Fiji (Mune and Parham, 1967) and is also a problem in the Northern Territory of Australia (Hall, 1967). In Fiji, it is controlled manually by digging out roots and seedlings; by building a fire around the stems at ground level and maintaining a fierce heat for several hours; or by spraying seedlings and young plants with 1.6 kg. acid equivalent of 2,4,5-T ester diluted in 180 litres of water or diesel fuel oil applied as a fine spray to the leaves and stems. Spraying will most likely need to be repeated. Mature bushes should be sprayed with a basal application of 2,4,5-T ester at the rate of 1.6 kg. acid equivalent diluted in 270 litres of diesel fuel oil. The mixture is applied as a fine spray or painted on the dry bark at the base of the stems from ground level to a height of 1 metre, to thoroughly wet the bark. Shrubs so treated take three to six months to die. Hall (1967) recommends treating cut stumps with a mixture of 1 kg. of 2,4,5-T in 45 litres of diesel oil. Seed propagation easy, without any treatment. It is of considerable value in supplementing the diet of roughage provided by the Astrebla and Dichanthium native grasses in the dry season (Everist, 1969). Fine textured heavy wood, amenable to a nice polish, pods are eaten by stock before maturity, at maturity they become woody, hard, unpalatable. A. farnesiana makes good defensive hedges, it is sometimes planted for its flowers that provide a fragrant essential oil used in the perfume industry as a violet scent substitute. Nutritional Quality and Animal Production It has a crude protein content of 18.4 percent.
Berhaut 1975 ; Delwaulle 1979 ; Simmons 1981 ; Dommergues et al. 1999. |
