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a genus of plants of the natural order Leguminosoe,
sub-order Mimoseoe. The genus Acacia
differs from Mimosa in the greater number of its stamens (10-200), and in
the want of transverse partitions in the bivalvular legumes. The acacias are
diffused over all quarters of the 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 are more or less stunted
in appearance, and frequently are altogether absent. Other species have
bipinnate leaves, with a great 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. The species called A. gummifera, A. seyal, A.
ehrenbergii, A. tortilis, A. nilotica, 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.
decurrens, A. mollissima (the silver wattle), and A. affinis (the
black wattle), in New Holland, and by A. karroo, at the cape of Good
Hope. Gum senegal is the produce of A. verek and A. adansonii,
natives of the western coast of Africa. Yet A. verek is also said to
yield true white gum-arabic. Catechu 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 an article of commerce in India, its seeds being
saponaceous and used in washing. A decoction of the pods of A. arabica is
sometimes used in the same way. A considerable 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 bipinnate 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 (Robinia pseud-acacia) is often called acacia both in
Britain and upon the continent of Europe. Other species of robinia also
receive the same name. Flores acacioe
(acacia flowers) is an old medical name for sloe flowers.
Source: The American Universal Cyclopedia, 1882
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