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[].

Common Name:

General Information

Acacia omalophylla is a tree that can grow from 5 - 10 metres tall[]. The tree produces a single, straight trunk[]. 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 is sometimes harvested from the wild for local use as a source of materials.

Known Hazards

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.

Botanical References

Range

Australia - Victoria, New South Wales, Queensland

Habitat

Found in Casuarina cristata communities in brown soils with calcareous nodules, in Bimble Box (Eucalyptus populnea ) open woodland in red earth and in various other soil and semi-arid vegetation types[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Tree
Height	7.00 m
Pollinators	Insects
Cultivation Status	Wild

Cultivation Details

Acacia omalophylla is native from the temperate to the subtropica zones of eastern Australia, growing in moist to arid regions. In Queensland it is found in regions where the mean annual rainfall is within the range 500 - 626mm[]. It the south of its range it can experience several frosts a year.
Requires a sunny position. This species is found in the wild on clay and clay-loam soils[].
The smell of the tree when in flower is abominable, and just before rain almost unbearable, and on this sign people frequently foretell the approach of rain. There have been stories of men who were employed in cutting down a tree of this species and who became so sick as rain approached that they were compelled to leave the tree[].
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[].
Closely related to Acacia melvillei which has broader pods with transverse seeds, generally larger flower-heads and commonly broader phyllodes[].

Edible Uses

None known

Medicinal

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[].

Other Uses

Produces a large quantity of a good quality gum from the trunk and stems during the summer season[, ]. The gum is entirely soluble in water and has very good adhesive qualities[, ]. A remarkably light and clean gum[].

The bark from an oldish tree contained around 9% tannic acid[]. Bark harvested for its tannins should only be taken from mature stems, and only when the sap is rising at the beginning of the growing season - which is when the tannin content is highest and the bark is most easily removed from the wood[].

The dark-coloured wood is hard, with a scent of violets[].
This dark-brown wood is much sought after for turners' work on account of its solidity and fragrance; perhaps its most extensive use is in the manufacture of tobacco-pipes[]. It is well adapted for cabinet-making purposes, and fancy articles, such as rulers and napkin rings, are often made from it. Traditionally, it was used for making spears.
In Western New South Wales the wood is considered very durable, and is, therefore, used for the lining of wells, but then it is said to give the water a bad taste for several years[].

Propagation

Seed - best sown as soon as it is ripe in a sunny position in a warm greenhouse[].The dried 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. Sow the seed in Spring in a greenhouse. As soon as the seedlings are large enough to handle, prick them out into individual pots and grow them on in a sunny position in the greenhouse for their first winter. Plant them out in late spring or early summer, after the last expected frosts, and consider giving them some protection from the cold for their first winter outdoors.
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[].