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 maconochieana is an erect tree with a somewhat rounded canopy; it grows up to 12 metres tall with a usually 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 plant is a potential source of edible seeds and wood for fuel and small items. It is a useful ornamental and shade tree.
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 - eastern Western Australia, western Northern Territory
Grows mainly in loam and in clay depressions, some of which are periodically waterlogged, in open scrub, low open forest and woodland; at elevations up to 400 metres.
|Other Uses Rating||
|Cultivation Status||Ornamental, Wild
Acacia maconochieana is a plant of the hot, arid zone of northern Australia where it is found at elevations up to 400 metres. The mean daily maximum temperature of the warmest months is 38 - 40°c and the mean daily minimum temperature of the coldest month is 8 - 9°c. Frosts only occur very infrequently and are very light, though in trials plants are said to have withstood temperatures down to about -5°c. Mean annual rainfall ranges from 150 - 350mm, with most of that falling in the warmest months.
Requires a sunny position. Plants are typically found in fine-textured alluviums of neutral to alkaline reaction. Recorded soil types include loams, clays with a thin covering of sand, and stony heavy clays. The plant has also shown good survival on a highly saline soil. Tolerant of periodic inundation of the soil.
A useful species for amenity plantings, whilst larger specimens make excellent shade trees.
A moderately fast-growing and moderately long-lived species.
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. The soft-coated flat seeds are easily ground and the species may have some limited potential as a source of human food. The pods are up to 13cm long, 4 - 5mm wide, with black, oblong to broadly elliptic seeds 4 - 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[
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 heartwood is dark brown; it is sharply demarcated from the narrow to broad band of pale yellowish sapwood. The heavy wood would be well suited for conversion into smaller decorative items. The trunk is typically straight and reaches suitable dimensions for use in the round as posts and small poles.
The heavy wood (800 - 850 kg/m3) makes an excellent firewood, having a good upper calorific value but leaving a large quantity of ash. The wood is not especially suitable for 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 species, however, has a soft seedcoat and could be damaged by scarification. Nicking of the seedcoat may enhance the germination percentage, alternatively soak them for 24 hours in cold water prior to 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[