178 
ACACIA VERA. 
Dioscorides was certainly well acquainted with the tree of which 
we are treating ; and the accounts left by Alpinus, and other subse- 
qoent naturalists, leave no doubt on the subject. It is worthy of 
remark, that the barks of all the trees which furnish this kind of 
gum are highly astringent; and in India and other places, they are 
employed in tanning. Although the Acaciae and Miniosae grow in 
s^rfeat absmdance over the vast extent of Africa, yet gum arabic is 
obtained chiefly from those trees that are situated near the equa- 
torial regions, and we are told, that in Lower Egypt the solar heat 
is never sufficiently intense to produce it. 
This species of Acacia rises several feet in height ; the stem is 
covered with a grey smooth bark; on the younger branches the 
bark is yellowish green, with a reddish or purplish tinge; the 
leaves are placed alternately, they are bipinnate and composed of 
several pairs of opposite pinnae; the leaflets are numerous, in pairs, 
linear, and of a bright green colour; at the base of the leaves are 
two long, spreading, awl-shaped spines, furnished with a small glan- 
dular swelling below ; the flowers are collected together so as to 
assume a globular form, and stand upon slender foot-stalks, which 
proceed from axillae of the leaves; a small distance below each 
head of flowers is placed a pair of small ovate bracteas ; the calyx 
is small, bell-shaped, and divided into five segments ; the corolla 
consists of five narrow yellow segments ; the stamens are numerous; 
the filaments are ihread-like, capillary and support roundish yellow 
anthers ; the germen is conical ; the style slender, and crowned with 
a simple stigma ; the fruit is a smooth pod or legume, four or five 
inches long, nearly flat, of a pale yellowish brown colour, and con- 
tracted into orbicular portions. 
The gum exudes in a liquid state from the bark of the trunk and 
branches of the tree in a similar manner to the gum which is often 
produced upon cherry trees, &c. in this country; by exposure to the 
air it soon acquires solidity and hardness. In Senegal the gum 
begins to flow when the tree first opens its flowers,* and continues 
during the rainy season until the month of December, when it is 
collected for the first time ; another collection is made in the month 
of March from incisions in the bark, which the extreme dryness of 
the air at that time is said to render necessary. f 
There are two kinds of gum found in the shops, and sold promis- 
* Adamson, Mem. de I'Acad. de Science de Paris 177, 3. p. 8. 
t Demanet, Noavelle Hist, de I'Afrique Fian9oise, torn. i. p. 56. 
