LEGUMINOS^E. CCXXXIII. ACACIA. 



ing heat of July and August, and the hotter the weather, and the 

 more sickly the tree appears, the more gum it yields. 



The gum is highly nutritious. During the whole time of the 

 gum harvest, of the journey, and of the fair, the Moors of the 

 desert live almost entirely upon it, and experience has proved 

 that six ounces are sufficient for the support of an adult during 

 twenty-four hours. The characters generally given of gum as a 

 vegetable principle belong only to fine gum-arabic, which is 

 transparent and colourless, easily reduced to powder, without 

 smell, and of a slightly sweetish taste. The solution of gum in 

 water constitutes mucilage ; it is thick and adhesive, and soon 

 dries when exposed to the air. Gum is also soluble in weak 

 acids, but is totally insoluble in alcohol. Gum is very little dis- 

 posed to spontaneous decomposition. By oxygenizement with 

 nitric acid it forms successively mucic, malic, and oxalic acid ; 

 with oxymuriat acid it forms citric acid. By exposure to heat 

 it does not melt, but softens, swells, and becomes charred. 



In medicine gum-arabic possesses the powers of a mucila- 

 ginous demulcent in a high degree. It is useful in all cases where 

 there seems to be a natural deficiency of mucus in the intestinal 

 canal ; dissolved in milk, barley-water, or almond emulsions, it 

 removes tcnesmus. It is useful in an irritable state of the res- 

 piratory passages in catarrh, hoarseness, and cough ; for this 

 purpose it may be either administered in substance as a troche, 

 or in a strong solution, and maybe combined with a little opium. 

 It is also useful in salivation after mercury, or in small pox. 

 Externally it is applied in powder to bleeding vessels of a small 

 size as a styptic, operating by gluing them up. It is also used 

 in solution as an injection in gonorrhoea. 



True Acacia or Gum-Arabic-tree, or Egyptian- thorn. Clt. 

 1596. Tree 20 feet. 



179 A. AHA'BICA (Willd. spec. 4. p. 1085.) spines twin; 

 branches and petioles pubescent ; leaves with 4-6 pairs of pinnae, 

 each pinna bearing 10-20 pairs of oblong linear leaflets, with a 

 gland on the petiole beneath the lower pair of pinnae, and usually 

 with one between the upper pair ; heads of flowers pedunculate, 

 axillary, usually 3-together ; legume moniliform. Tj . S. Native 

 of the East Indies, Senegal, Egypt, and Arabia. Mimosa Ara- 

 bica, Lam. diet. 1. p. 19. Roxb. cor. 2. t. 149. A. Nilotica, 

 Delil. ill. fl. aegypt. p. 31. Legume at length smooth. Flowers 

 yellow, polyandrous. This is the tree from which the white 

 transparent gum-arabic, called gum-thur, is obtained ; the brown 

 or common gum-arabic being the produce of the preceding spe- 

 cies. The wood is strong, tough, and durable, and makes ex- 

 cellent knees and crooked timber in ship building. Tlie bark is 

 astringent and is used for tanning leather, and to dye various 

 shades of brown. A decoction of the bark is used as a substi- 

 tute for soap. According to Dr. Roxburgh, a large portion of 

 East India gum is also obtained from this species. Perhaps the 

 Arabian plant is distinct from the East Indian one. 



Arabian Acacia or Gum-thur- tree. Clt. 1820. Tr. 30 to 40 ft. 



180 A. HEBE'CLADA (D. C. monsp. p. 73.) spines twin: 

 branches, petioles, and peduncles pubescent, and rather hispid ; 

 leaves with 3-5 pairs of pinnae, each pinna bearing 10 pairs of 

 oblong-linear, glabrous leaflets ; gland petiolar ; heads of flowers 

 pedunculate, 2-3-together, axillary. Tj . G. Native of the south 

 of Africa. A. stolonifera, Burch. cat. no. 2267. The heads of 

 flowers are very like those of A. Farnesiana, but without scent. 



Young-branched Acacia. Clt. 1816. Shrub 3 to 6 feet. 



181 A. MAUROCE'NIA (D. C. cat. hort. monsp. p. 74.) spines 

 twin ; branches, petioles, and peduncles pubescent ; leaves with 

 3-8 pairs of pinnae, each pinna bearing 10-20 pairs of oblong, 

 linear, glabrous leaflets, with a gland on the petiole beneath the 

 lower pair of pinnae ; heads of flowers solitary or 2-4-together, 

 axillary, pedunculate. (7 . G. Native of Morocco. Mimosa 

 Maurocenia, Desf. cat. 181. Heads of flowers white. 



Moor's Acacia. Shrub 4 to 6 feet. 



IS:.' A. FAKNESIA'NA (Willd. spec. 4. p. 1083.) spines twin; 

 tops of branches, petioles, and peduncles rather pubescent ; leaves 

 with 5-8 pairs of pinnae, each pinna bearing from 15-20 pairs of 

 linear glabrous leaflets, with a gland on the petiole between the 

 lower pair of pinnae, and usually between the extreme pair ; 

 heads of flowers axillary, usually twin, on unequal peduncles ; 

 legume terete, rather attenuated at both ends. ^ . G. Native 

 of St. Domingo, but now cultivated in the south of Europe and 

 the north of Africa. Aid. farn. p. 2. 4. and 7. with a figure. 

 Mimosa Farnesiana, Lin. spec. 1506. Duham. ed. nov. 2. p. 28. 

 Mimosa scorpioides, Forsk. Heads of flowers yellow, sweet- 

 scented, sessile when in a young state, but at length becoming 

 pedunculate. This species of Acacia has been dispersed through 

 most parts of Europe, has been made familiar to the Italian gar- 

 dens since it was introduced to the Farnese garden in 1616, and 

 is cultivated in great plenty in Spain and Portugal. In Italy it 

 is called gazia. 



Var. ft, pedunculata (Willd. spec. 4. p. 1084.) branches and 

 petioles hardly pubescent ; peduncles a little longer than those 

 of the species, scarcely glabrous at the apex. Tj . S. Native of 

 Java and Timor. Perhaps this is hardly different from A. 

 Giraftae of Sieb. pi. exsic. seneg. no.. 45. which only differs from 

 Willdenow's specimen in the situation of the glands. 



J ar. j, curvisiiina (D. C. prod. 2. p. 462.) spines somewhat 

 incurved ; leaves with 2 pairs of pinnae ; leaflets ovate. A. Far- 

 nesiana, Coll. hort. rip. p. 2. Perhaps a distinct species. 



Farnesian Acacia. FL July, Aug. Clt. 1656. Shrub 6 to 

 10 feet. 



183 A. PARVIFO'LIA (Willd. spec. 4. p. 1086.) spines stipu- 

 lar ; branches glabrous ; petioles pubescent ; leaves with 5-9 

 pairs of pinnae, each pinna bearing 10-20 pairs of small linear 

 leaflets, with a gland situated on the petiole beneath the lower 

 pair of pinnae ; heads of flowers axillary, solitary, pedunculate. 

 Jj . S. Native of the West Indies, in sandy places by the sea 

 side. Mimosa parvifolia, Swartz, fl. ind. occ. 2. p. 984. Mimosa 

 Antillarum.Poir. suppl. 1 . p. 80. Mimosa Mangensis, Jacq. amer. 

 267. ? The spines, according to Jacquin, are stipular and dis- 

 tinct, but according to Swartz they are solitary under the branch- 

 lets. Heads of flowers white and green, void of scent. 



Small-leaved Acacia. Tree 20 feet. 



184 A. A'LBA (Willd. ex Steud. nom. phan. 1. p. 1.) spines 

 stipular; leaves with 7-10 pairs of pinnae, each pinna bearing 

 16-20 pairs of leaflets ; heads of flowers globose, disposed in a 

 panicle ; legumes compressed, linear, tomentose. 17 . S. Native 

 of the East Indies. Mimosa alba, Roxb. ex Rottl. et Willd. 

 nov. act. nat. cur. berol. 1813. vol. 1. p. 208. Heads of flowers 

 white. 



While Acacia. Tree 20 feet. 



185 A. A'LBICANS (Kunth, mim. 87. t. 27. nov. gen. amer. 6. 

 p. 272.) spines twin ; branchlets and petioles pubescent ; leaves 

 with 8-9 pairs of pinnae, each pinna bearing 19-32 pairs of oblong- 

 linear glabrous leaflets, with glands on the petiole, one between 

 the superior and another beneath the inferior pair of pinnae ; 

 heads 2-5, aggregate, rising in racemes from the axils of the 

 leaves. T? . S. Native of Mexico, on the sea shore near Cam- 

 peachy. Flowers white, polyandrous. Legume unknown. 



JJ'/iitish Acacia. Shrub. 



186 A. LEUCOPHLCE'A (Roxb. cor. 2. t. 150.) spines twin; 

 branches, leaves, and peduncles glabrous; leaves with 8-12 pairs 

 of pinnae, each pinna bearing 20-30 pairs of linear-oblong leaf- 

 lets, with a gland on the petiole between the lower and higher 

 pairs of pinnae ; heads of flowers racemose ; the racemes dis- 

 posed in a terminal panicle, fj . S. Native of Coromandel, on 

 dry mountains. Flowers pale yellowish, polyandrous. Legume 

 linear, compressed, rather falcate. The specimen in Willdenow's 



