Acacia, a-kasha, a genus of shrubs and trees belonging to the pea family. There are between four and five hundred species. The acacia is a native of every continent except Europe; but it has been introduced into England and southern Europe from Africa and from Australia. The North American locust is closely related to the acacias, as are also the mimosae, or sensitive plants, the lupines, sennas, and laburnums, as well as all the varieties included under the general name leguminosae, or pod-bearing plants. In some species the twice-pinnate leaves are reduced to mere rudiments, and the leaf stalk is broad and flat, with one edge toward the sun. Several kinds yield the gum arabic and gum senegal of commerce. The bark and pods of one or more kinds are used for tanning leather. The seeds of one species are used for soap. Catechu, an astringent extract much used by the tanner, and in medicine as a remedy for diarrhoea and dysentery, is obtained from a species found in India. Florists list over fifty acacias as desirable conservatory plants. Some kinds yield valuable and lasting lumber. One species is thought to be the shittim-wood of the Bible. See LOCUST; MIMOSA; LEGUMINOSAE.