Acacia, important genus of trees or shrubs of the legume family. Most of the 1,200 species of the genus are native to tropical Africa or Australia. The normal type of leaf is bipinnate, but it is often modified, especially among the species that have had to adapt to the intense heat and drought of Australia. The Australian species have vertical phyllodes that are modified leaves. The genus is of great and varied economic importance, yielding edible seeds and valuable timber and gum.

Scientific classification: Acacias belong to the subfamily Mimosoideae of the family Fabaceae (formerly Leguminosae).