ACACIA, a genus of plants of the natural order Legumirwstr, sub-order Miramar. The genus A. differs from Mimosa in the greater number of its stamens (10-200), and iu the want of transverse partitions in the bivalvular legumes. The acacias are diffused over all quarters of time globe except Europe. The greater number of them have a singular appearance, because of the leaf-stalks spreading out in a leaf-like form (phyllodium); while the leaflets aro more or less stunted in appearance, and frequently are altogether absent. Other species have bipinnate leaves, with a k,rreat number of leaflets, and are extremely beautiful. Many are of great importance in an economical point of view, because of the juice which flows from them, which, when inspissated, becomes an article of commerce under the name of gum (q.v.). The species called A. gumaufera, A. eeyal, ehrenbergii, A. tortitis, A. nilottca, and A. vera, natives of Africa, produce gum-arabic, also A. speciosa and A. arabica, natives of the south of Asia. A. arabica is called the Babul-tree In India, and its gum, babul. A gum similar to gum-arabic is produced by A. A. mollissima (the silver wattle), and A. affinie (the black wattle), in New Holland, and by A. karroo, at the cape of Good Hope. Gum senegal is the produce of A. Derek and A. adansonii, natives of the western coast of Africa. Yet A. verek is also
said to yield true white guru-arabic. Catechu (q.v.) is obtained from the wood of A. catechu. The astringent bark and pods of some species are used for tanning. The bark of A. arabica is administered in India as a powerful tonic medicine. The pods of A. concinna form au article of commerce...in, India, its seeds being saponaceous and used in washing. A decoction of the pods of A. ambled is sometimes used in the same way. A considerable number of species afford useful timber. The flowers of many species are fragrant. A number of species from New Holland and other countries have been introduced into the south of Europe. Some are of frequent occurrence in greenhouses in Britain; and a few of the Australian species succeed tolerably in the open air in the south of England. The foliage of the acacias with bipinnatc leaves shows a peculiar sensitiveness to changes of weather; when a thick cloud obscures the sun, the opposite leaflets close together, and so remain till the sun reappears. The locust-tree of North America (1?olftinne is often called A. both in Britain and upon the continent of Europe. Other' species of robinia also receive the same name. See LOCUST-TREE and ltosE A. Flores acacia (A. flowers) is an old medical name for sloe flowers.