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[
Racosperma orarium (F.Muell.) Pedley
Acacia oraria is a tree with a spreading crown; it can grow from 3 - 10 metres tall[
]. The tree usually has a well-defined main stem, which is seldom more than 30cm in diameter and has a fissured, fibrous bark[
]. Although it produces true leaves as a seedling, llike most members of this section of the genus, the mature plant does not have true leaves but has leaf-like flattened stems called phyllodes[
The tree has sometimes been grown in soil stabilization projects and for weed control. The wood is used for fuel and house posts.
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.
Southeast Asia - Indonesia in Flores and Timor to northeastern Australia
Sandy soils along beaches, often near the high tide mark, and along the sides of streams inland[
]. Occasionally found on the margins of monsoon forest and dry rain forest[
|Other Uses Rating
|Cultivated, Ornamental, Wild
Acacia oraria is a plant of the warm to hot, humid tropics, where it can be found at elevations up to 700 metres. The mean maximum temperature of the hottest month is 32 - 34°c, dropping to around 14 - 17°c in the coolest month. Frosts are absent, The mean annual rainfall can range from 900 - 2,150mm[
Requires a sunny position. Found in the wild in deep, calcareous beach sands with shell grit or yellow earths - the soils are usually infertile, ranging from acidic to alkaline, and may be saline or subsaline. In Indonesia it is common on shallow soils over limestone[
]. The plant is highly tolerant of saline soils[
]. Plants are tolerant of seasonal inundation of the soil[
The plant is grown as an ornamental in Indonesia, where it is often used for street planting[
The plant coppices fairly well[
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 suitable for growing in order to provide soil protection and a fire-break in savannah areas[
Acacia oraria is one of the woody species that invades fire-degraded grasslands of Imperata cylindrica and Themeda triandra on spurs in the coastal foothills when they are protected from frequent fires[
]. Its dense foliage and heavy litter fall can suppress the plant within 2 yearsl[
]. It has been less successful in trials for weed control in teak plantations. Its use has also been restricted by its susceptibility to Corticium salmonicolor[
The heartwood is dark brown; the sapwood is pale. The heavy and hard wood is attractively marked. It is used locally for house posts[
The wood has been used for fuel[
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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