This colossus of the vegetable world was discovered in Senegal by the French botanist Adanson, in 1749. He measured the trunks of several individuals, and found them from 65 to 78 feet in circumference, with mighty branches, each of which was equal to a great oak or magnificent chestnut. One baobab he computed at 90 feet in girth, and its rounded crest extended over an area of upwards of 170 yards in circuit. A root which was exposed to view, through the washing away of the superjacent soil, measured 110 feet in length. Adanson estimated the age of some of these Anakim of trees at 1500 years. They were just shooting above the ground, if this reckoning be true, at the time that Constantine, the first Christian emperor, removed the seat of empire from Rome to Constantinople.
There are other gigantic trees in the forests of Senegambia, as, for instance, the Khaya Senegalensis, which rears its crest to a height of 50 or 60 yards, whose hard reddish-coloured timber belongs to the species known in commerce under the name of Mahogany. Another kind of mahogany, but less valuable, called Senegal Mahogany, is furnished by the Swietenia Senegalensis (family of Meliaceæ, tribe of Cedrelaceæ), named after Baron von Swieten, a Dutch botanist. It forms a stately tree, some 60 or 80 feet high. Swietenia Mahogani, a native of the warmer regions of America and the West Indies, yields the mahogany of commerce. The first discovery of the existence of this kind of wood is ascribed to the carpenter on board Sir Walter Raleigh’s vessel, when lying off Trinidad in 1595. It is not considered to reach perfection under the venerable age of two hundred years. The seeds prepared with oil are used by the modern Mexicans, as they were by the ancient Aztecs, for cosmetic purposes; and the bark is considered a febrifuge.
Among the most curious trees of the Senegal, whose Flora has quite a character of its own, travellers have singled out the Butter Tree (Bassia butyracea, family of the Sapotaceæ), whose fruits contain an edible fatty substance, used by the natives as a substitute for butter; and the Henna (Lawsonia inermis), which also flourishes on the eastern coast and in Upper Egypt. The henna is a shrub from six to seven feet high. Its flowers exhale a goat-like odour, which seems much affected by the Orientals and the natives of Africa. Its roots, of a deep red hue, are distinguished by a bitter taste and astringent properties. Finally, its leaves supply an orange-red colouring matter, with which the Arabs and negroes tint their hair, beard, and nails.
Let us not pass over without the tribute of our respectful notice the numerous tribe of Acacias, which form vast forests in the districts north of the Senegal, and yield the gum-arabic of commerce. The best known species of this important and useful group are the Acacia Arabica, or Red Gum-tree, the Acacia Adansoni, the Acacia vera, and the Acacia verek.
We also meet at Senegal with a tree which I ought, perhaps, to have ranked of right among those of India, and which, like many others, belong rather to the whole zone of the Tropics than to any particular country; I refer to the Tamarind (Tamarindus Indica),[166] whose well-known name is supposed to be derived from the Arabic Tamar, signifying “dates,” and Indus, in allusion to its original habitat. There is only one species of the genus, but the East Indian variety has long pods, with six to twelve seeds, while the West Indian has much shorter pods, containing one to four seeds. It is a tree of graceful appearance, with elegant pinnated foliage and numerous racemes of fragrant flowers. The pods are slightly curved, and consist of a brittle brown shell, enclosing a soft, acid, brown pulp, traversed by strong woody fibres; a thin membranous covering wraps up the seeds. The pulp has a savour at once acid and sugary, and acts as a gentle laxative. The timber is useful for building purposes, and furnishes excellent charcoal for the manufacture of gunpowder.
The Sterculiaceæ have numerous representatives at the Senegal. These tall and handsome trees remind the traveller in their appearance of our English oaks. The seeds of the Sterculia acuminata and tomentosa are masticated by the negroes until reduced to a fluid paste, in which form they employ it to dye their cotton-stuffs yellow. The dye is very bright, and, it is said, extremely durable.
We know that a great part of the Gaboon is occupied by virgin forests, where Fig-trees are predominant, and in marshy soils the Mangle or Mangrove trees (Rhizophora mangle), which must not be confounded with the savoury-fruited Mangoes of Eastern India. The Mangroves form, in the family of the Rhizophoras, a genus distributed in the moist localities of the Tropics, and we shall hereafter meet with them in South America.
Equatorial Africa possesses several species of Palm-trees peculiar to it. Such are the Thorny Date-tree, the Borassus of Ethiopia, the Raphia vinifera of Congo, which, as its name “wine-bearing” indicates, furnishes a wine analogous to that extracted in other regions from other trees of the same family; the Elæis Guinensis, or Guinea Palm, whence we obtain the well-known product of palm oil. This oil, or palm-tree butter, forms an important article of food among the Guinea negroes. It is imported into Europe in large quantities, and employed in the manufacture of soap.
The forests of the Hottentot and Bechuana countries, and in general of all those regions bordering on the Cape Colony, are frequently of great extent, but mainly composed of trees of small stature, or even of shrubs, such as the Cape Olive, a few Acacias, some Compositæ and Conifers. Forests, as I have said, are rare in the explored portions of the west African coast; they become denser and more numerous as we leave the great ocean in our rear, and penetrate into that vast interior which for ages has been haunted by so many mysteries. Their Flora, however, offers no special character, and does not materially differ from that of Guinea and Senegambia.
