Acacia, commonly known as wattles or acacias, is a genus of about 1,084 species of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa, South America, and Australasia, but is now reserved for species mainly from Australia, with others from New Guinea, Southeast Asia, and the Indian Ocean.
The genus name is Neo-Latin, borrowed from Koine Greek ἀκακία (akakia), a term used in antiquity to describe a preparation extracted from Vachellia nilotica, the original type species. Several species of Acacia have been introduced to various parts of the world, and two million hectares of commercial plantations have been established.
Description
Plants in the genus Acacia are shrubs or trees with bipinnate leaves, the mature leaves sometimes reduced to phyllodes or rarely absent. There are 2 small stipules at the base of the leaf, but sometimes fall off as the leaf matures. The flowers are borne in spikes or cylindrical heads, sometimes singly, in pairs or in racemes in the axils of leaves or phyllodes, sometimes in panicles on the ends of branches. Each spike or cylindrical head has many small golden-yellow to pale creamy-white flowers, each with 4 or 5 sepals and petals, more than 10 stamens, and a thread-like style that is longer than the stamens. The fruit is a variably-shaped pod, sometimes flat or cylindrical, containing seeds with a fleshy aril on the end.
Taxonomy
The genus was first validly named in 1754 by Philip Miller in The Gardeners Dictionary. In 1913 Nathaniel Lord Britton and Addison Brown selected Mimosa scorpioides L. (≡ Acacia scorpioides (L.) W.Wight = Acacia nilotica (L.) Delille), a species from Africa, as the lectotype of the name.
Etymology
The genus name comes from Neo-Latin; Gaspard Bauhin in his book Pinax (1623) writes it coming from Dioscorides; the Koine term ἀκακία akakía is the name he uses for Vachellia nilotica, the original type species...
