120 NORTH-WEST AFRICA. the last century calculated at 300 species, consists, according to M. Cosson, of 1,780 varieties, of which a few only ore indigenous. From west to east, i.e. from Tunis to Marocco, the special varieties of plants gradually diminish, a fact due to the gradual lowering of the land. Amongst the 563 species found at Cabes, there are only 25 which are not to be met with in the Algerian Sahara. Some of these plants are so numerous that they impart their colour to the plains, which hence are visible for a distance of several miles. Large tracts covered with bind- weed, and other pale blue flowers, appear in the distance like extensive lacustrine basins. The mountains of the Mejerda basin, and those which command the Mediter- ranean watershed between Bizert^ and Calle, are still covered with vast forests. Thanks to the relative moisture of the climate, here are found huge oaks, amongst others the zcoi (^qnerci(s Mirbeckii^, whilst the holly flourishes in the midst of the brushwood, and the wild cherry amongst the fruit-trees. If the Mejerda has plenty of water throughout the year, it is due to the woods which clothe its sides. But in central Tunis, and in the vicinity of the Syrtes waters, the country is almost entirely deforested. The only trees to be found in this region are the olive and the tig, which grow round the towns, overtopping the hedges of nopal, as in Algeria, the plateaux having no other varieties than the wormwood and alfa grass, which is used to manufacture paper. In some spots the ground is completely naked, and has even lost its superficial humus, the hard rock ringing w'ith a metallic sound under the foot of the traveller. However, in these barren regions, at the southern base of the Bu-IIedma mountains, there lies a forest of gum-bearing acacias, which covers a space of some 18 miles long by 7 broad. This is the most northern region of Africa in which is met one species of these gum-bearing trees, viz., the acacia xnyal. But the}- scarcely amount in round numbers to 40,000, the trees being so far distant from each other. They are occasionally used in the preparation of food, but the gum is allowed to run waste, and serves as food to wild animals. The gum which exudes from certain varieties of mastics, as in the island of Ohio, is not employed in the manufacture of mastic or other perfumed essences. The banks of the great shotts, w^hich are separated from the Syrtis Minor only by a narrow isthmus, are covered with the beautiful " groves," as the natives call them, of the Beled-el-Jerid, or " Country of Dates," which contain over a million palms, belonging to more than 150 varieties. The dates vary in taste in a most astonishing manner, according to the climatic conditions. Whilst the palms at Sfakcs and Jerba island are little more than ornamental trees, whose fruit is mostly given as food to the animals, those at Cabes produce excellent dates ; the fruit yielded by the El-llamma oasis is excellent, while that obtained in Jcrid and Suf is even still better. The cause of this is doubtless due not so much to the difference of temperature, as to the different proportion of the atmospheric moisture. Amongst all the varieties of dates, a great difference in taste is noticeable according to where they are grown. In the Jerid the finest is the deglet-nur or *' luminous date," so called on account of its transparent appearance ; the Suf, however, can show dates which are preferable to it. The inhabitants of the oases love their
