Acacia macradenia

Benth.

Zig-zag wattle

Fabaceae Edible: Seeds, Gum Potential hazards — see below 360 iNaturalist observations

iNaturalist· cc-by

iNaturalist· cc-by-nc

Summary

Acacia macradenia is also known as the zig-zag wattle, which derives from its zig-zag stem growth pattern. Another name used to identify A. macradenia is the 'bed of rivers'. Distinguishing features include alternating phyllodes, yellow globular clusters growing at the forks of the branches and a 'zig-zag' stem.

Description

A shrub or small tree. It grows 5 m tall. There are prickles along the stem. The leaves are twice divided and there are 8-18 pairs of pinnae. There are up to 50 pairs of pinnules on each pinnae. The flowers are yellow. They are in large clusters at the ends of branches. The pods are flattened.

Edible Uses

The seeds and gum are edible.

Medicinal Uses

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.

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.

Distribution

It is a tropical plant. It grows in sandy soils on hillsides.

Where It Grows

Australia*,

Cultivation

It can be grown by seeds.

Propagation

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.

Other Uses

A beautiful, hard, blackish, close-grained wood, which takes a very high polish. According to this report, the tree can grow up to 15 metres tall, but according to the Flora of Australia, it grows from 3 - 5 metres tall. It is possible that this report refers to Acacia fasciculifera, which was at one time mis-identified as Acacia macradenia.