Acacia is a genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

s and tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

s belonging to the subfamily Mimosoideae
Mimosoideae is a subfamily of the flowering plant family Fabaceae characterized by flowers with small petals and numerous prominent stamens...

 of the family Fabaceae
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...

, first described in Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 by the Swedish
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

 botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

n acacias are not. They are pod-bearing, with sap and leaves typically bearing large amounts of tannin
A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.The term tannin refers to the use of...

s and condensed tannins that historically in many species found use as pharmaceuticals and preservatives.

The generic name derives from ακακία (akakia), the name given by early Greek botanist-physician Pedanius Dioscorides
Pedanius Dioscorides
Pedanius Dioscorides was a Greek physician, pharmacologist and botanist, the author of a 5-volume encyclopedia about herbal medicine and related medicinal substances , that was widely read for more than 1,500 years.-Life:...