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: Salt Wattle
Acacia ampliceps is a shrub or a tree with a dense, spreading crown; it can grow from 2 - 9 metres tall and 6 - 12 metres wide, usually with 1 - 4 main stems. Prostrate forms of the plant are also sometimes found[
, ]. The plant often spreads by means of suckers and can form thickets[
]. 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 plant is traditionally harvested from the wild for local use as a food and also has medicinal applications. It has potential for wider use as a food source, is a good fuel crop and can be used for soil stabilization.
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.
Australia - Western Australia, Northern Territories
Found in sand or clay soils along watercourses, or in swales between coastal sandhills[
]. Found on plains, sand dunes, along drainage lines or on low-lying or hilly country, often in places where it recieves additional water[
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Acacia ampliceps is a plant of arid to subhumid regions of the subtropical and tropical zones, where it is found at elevations up to 400 metres. It grows best in areas where annual daytime temperatures are within the range 14 - 36°c, but can tolerate 5 - 46°c[
]. The tree is not tolerant of frost[
]. It prefers a mean annual rainfall in the range 400 - 600mm, but tolerates 200 - 800mm, with a dry period that can last 5 - 9 months[
Requires a sunny position. Succeeds in a wide range of soils, and is tolerant of alkaline, highly saline and seasonally waterlogged conditions. Prefers a pH in the range 7 - 8, tolerating 6.5 - 8.5[
]. Plants can grow in highly alkaline soils with a pH of 10 or more[
Mature specimens can yield about 0.5 - 2 kg of seed per year.
A fast-growing but short-lived species which can spread by root-suckering and which frequently forms monospecific stands on moist sites[
]. Trees can live for 20 years or more in well-watered sites[
The plant responds well to coppicing.
The foliage is very susceptible to insect attack[
This species hybridises in the wild with Acacia bivenosa and probably also with Acacia sclerosperma[
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[
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.
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[
]. A traditional food for the native Australians who roasted and ground the seeds to a paste prior to consumption[
]. The rather soft-coated mature seeds may be chewed without preparation. The more or less woody seedpods are up to 100mm long, 5 - 6mm wide, containing greyish brown to black, oblong seeds 5 - 6.5mm[
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[
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[
This species has great potential for use in the reclamation of salt-affected areas[
The plant has a wide-ranging root system, produces suckers and also fixes atmospheric nitrogen. It can be used for stabilizing dunes on rocky coastal sites, creating conditions for other species to become established[
The plant is an effective low windbreak[
The wood is hard and tough. It has the potential for use as posts, poles etc[
The wood is a good fuel, burning with great heat and leaving a fine grey ash.
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[