Classification of the genus Acacia (in the wider sense) has been subject to considerable debate. It is generally agreed that there are valid reasons for breaking it up into several distinct genera, but there has been disagreement over the way this should be done. As of 2017, it is widely (but not completely) accepted that the section that includes the majority of the Australian species (including this one) should retain the name Acacia, whilst other sections of the genus should be transferred to the genera Acaciella, Mariosousa, Senegalia and Vachellia[
Acacia numerosa Maiden & Blakely
Racosperma plectocarpum (A.Cunn. ex Benth.) Pedley
Acacia plectocarpa is a single-stemmed shrub or a tree usually growing to 9 metres tall but reaching 13 metres on selected sites[
]. Although it produces leaves as a seedling, llike most members of the genus the mature plant does not have true leaves but has leaf-like flattened stems called phyllodes[
The plant can be used in land restoration work following open cast mining and also has the potential to supply wood in semi-arid areas.
Especially in times of drought, many Acacia species can concentrate high levels of the toxin Hydrogen cyanide in their foliage, making them dangerous for herbivores to eat.
Australia - northern Western Australia, northern Northern Territory
Grows in sandy soil mostly near watercourses, in open-forest, woodland, low woodland, open-woodland, and tall shrubland on sandstone or laterite soils; at elevations up to 300 metres[
|Other Uses Rating||
|Cultivation Status||Cultivated, Wild
Acacia plectocarpa is a plant of the sub-arid to humid regions of the tropical zone in northern Australia, where it is found at elevations up to 300 metres. It grows best in areas where annual daytime temperatures are within the range 22 - 35°c, but can tolerate 12 - 44°c[
]. It does not experience frost in its native range. It prefers a mean annual rainfall in the range 600 - 1,400mm, but tolerates 400 - 1,600mm[
]. The rainfall pattern is monsoonal, with a dry season that can be 5 - 7 months long[
Requires a sunny position. Prefers a well-drained sandy soil, succeeding also in loamy soils and tolerant of seasonal inundation of the soil. Succeeds in dry soils and in low fertility[
]. Moderately tolerant of drought and saline soils[
]. Prefers a pH in the range 5 - 6, tolerating 4.5 - 6.5[
The plant is fast-growing when young and can flower when 12 - 24 months old from seed[
Plants coppice well when cut with a 1 metre stem remaining, but do not coppice well if cut lower[
This species has a symbiotic relationship with certain soil bacteria; these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[
The bark of all Acacia species contains greater or lesser quantities of tannins and are astringent. Astringents are often used medicinally - taken internally, for example. they are used in the treatment of diarrhoea and dysentery, and can also be helpful in cases of internal bleeding. Applied externally, often as a wash, they are used to treat wounds and other skin problems, haemorrhoids, perspiring feet, some eye problems, as a mouth wash etc[
Many Acacia trees also yield greater or lesser quantities of a gum from the trunk and stems. This is sometimes taken internally in the treatment of diarrhoea and haemorrhoids[
The tree is used for mine-site rehabilitation in northern Australia[
The tree is suitable for providing light shade and low shelter, and could be used to form the lower component of windbreaks[
The heartwood is brown; it is clearly demarcated from the pale yellow sapwood. The wood properties have not been studied in detail, but it is probably suitable for posts and small poles[
The dense wood is suitable for fuelwood and charcoal production[
The seed of most, if not all, members of this genus has a hard seedcoat and may benefit from scarification before sowing to speed up germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing.
Acacia seeds that have matured fully on the bush and have been properly dried have a hard seed coat and can be stored in closed containers without deterioration for 5 - 10 years or more in dry conditions at ambient temperatures. It is best to remove the aril, which attracts weevils and can lead to moulds forming. The arils are easilyremoved by placing the seeds in water and rubbing them between the hands, then drying the seeds and winnowing them[
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