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 prainii is a dense, spreading shrub or a tree that usually grows 1.5 - 3 metres tall, occasionally reaching 5 metresl[]. Plants usually branch at or near ground level to form multi-stemmed shrubs that are about as wide as they are tall[, ]. 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[].
This species has been suggested as a potential commercial seed crop for areas such as Western Australia[].

Known Hazards

The seed of many Acacia species, including this one, is edible and highly nutritious, and can be eaten safely as a fairly major part of the diet. Not all species are edible, however, and some can contain moderate levels of toxins[]. Especially when harvesting from the wild, especial care should be taken to ensure correct identification of any plants harvested for food[].
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 - Western Australia, Northern Territory, South Australia

Habitat

Arid and semi-arid regions, growing in sand or sandy clay in open scrub, mallee communities, Eucalyptus woodland or spinifex country[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Shrub
Height	2.50 m
Growth Rate	Medium
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Acacia prainii is native to the semi-arid and arid, Mediterranean-type climate of southwestern Western Australia where it experiences a low frequency of frosts[].
Requires a sunny position[]. Grows best in a well-drained sandy soil, tolerating clay-loams, and also tolerating some salt in the soil[, ]. Established plants are drought tolerant[].
A moderately fast-growing plant, flowering profusely from a young age[, ].
A. highly floriferous and aromatic plant that flowers from a young age - it would appear to have some horticultural potential as an ornamental and as a visual screen for use in arid and semi-arid areas[].
The plant's coppicing ability is unknown, and it has not been recorded to root sucker under natural conditions[].
The seeds of most acacia species can be quickly and efficiently harvested at full maturity without the need for any specialised equipment. Small seed-bearing branches can be cut and beaten on sheets, or bushes can be beaten or shaken directly onto large sheets[].
Acacia prainii, together with Acacia anthochaera, Acacia camptoclada, Acacia dorsenna and Acacia hemiteles comprise the informal ‘Acacia prainii group’. Members of this group are most readily distinguished by their phyllode shape and size. Acacia prainii is sometimes sympatric with Acacia anthochaera[].
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[].

Edible Uses

Seed - cooked[, ]. It can be eaten in the same ways as other small legume seeds and is also ground into a powder then used as a flavouring in desserts or as a nutritious supplement to pastries and breads[]. The seedpods are up to 85mm long and 5 - 7mm wide, with black, oblong-elliptic to ovate seeds 3.5 - 6mm long[].
Acacia seeds are highly nutritious and contain around 26% protein, 26% available carbohydrate, 32% fibre and 9% fat. The fat content is higher than most legumes with the aril providing the bulk of fatty acids present. These fatty acids are largely unsaturated. The energy content is high in all species tested, averaging 1480 ±270 kJ per 100g. The seeds are low glycaemic index foods - the starch is digested and absorbed very slowly, producing a small, but sustained rise in blood glucose and so delaying the onset of exhaustion in prolonged exercise[].

The ground seed can be used to produce a high quality, caffeine-free coffee-like beverage[].

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[].

Agroforestry Uses:

Acacia prainii has good potential for use in revegetation projects because of its large growth form, moderately fast growth rate and its occurrence on a wide range of soil types (including those that are slightly to moderately saline). It
normally produces large quantities of seed which are easily collected. This species would be useful for salinity and erosion control, visual screens, windbreaks and shelter belt planting[].

Other Uses

None known

Propagation

Seed - best sown as soon as it is ripe in a sunny position in a warm greenhouse[].The plant has proven to be easy to germinate even without pre-treatment[]. 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[].