FLORA OF OAZAIAND. 226 veers round to another quarter the conflict of the opposing movements results iu storms and tremendous downpours. On the uplands the changes of temperature are often very sudden. The heats, especially before the ruiny season, are most oppressive. A great change sets in with the cold southern breezes, and in the space of a few hours the glass will at times abruptly rise or fall as much as 50° or even 60° F. Thanks to the copious rainfall, the region of the inland plateaux is very fertile. Here the forests present a great variety of siiecies, whereas the low-lying plains offer but a scanty vegetation, far less varied than the animal kingdom. In the wooded districts of the south the trees, usually of small size and growing far apart, are all alike, whether living or dead, covered with a grey moss, which gives them a fantastic appearance. In some of the Ga/uland forests, as along the banks of the middle Zanibese, a prevailing species is the mopnue, a large odoriferous tree, which affords travellers very little shade, its leaves being disposed in a vertical position, like the wings of a butterfly at rest. The coast properly so-called is a mere strip of arid sands, but farther inland the ground, covered with a reddish arenaceous soil, is much more productive, yielding abundant crops in the well- watered bottom lands. But such tracts are rare, and the waters which during the passing rains lodge in the depressions of the surface, soon evaporate after the return of fine weather. Throughout nearly the whole extont of the low-lying plains savannahs everywhere alternate with scrub and thorny plants. In such a region the inhabitants might be expected to settle chiefly along the courses of the streams, where they might procure the water indispensable for field operations; yet the river banks are mostly deserted, and the tribes have taken refuge for the most part in remote and inaccessible retreats, in order to avoid the too frequent visits of their oppressive Zulu rulers. Hence, through long experience, the natives have become extremely skilful in discovering the smallest reservoir where the precious fluid may ooze out drop by drop. They are acquainted with all the forest plants whose leaves or berries contain water, and specially value the imbiinya, a caoutchouc creeper, the fruit of which serves to quench their thirst. As in many other parts of Africa, such as the Fazogl district of Senaar, in the Nile basin, and on the Quissama plateau on the west coast, the cavities formed in the trunk of the baobab are also carefully utilised as cisterns. These cavities are enlarged and deepened with the axe and fire until the whole stem becomes, as it were, converted into a sort of aerial well. But the winter rains do not always suffice to replenish it ; the water also gradually becomes foul, and at last evaporates altogether ; and when this happens, the inhabitants are fain to quit their forest retreats and remove to the more open riverain tracts. Wherever the population is thinly scattered over wide spaces, the fauna, free from the attacks of its worst enemy, is both numerous and diversified. The elephant still abounds throughout Gazaland, the hippopotamus and crocodile swarm in all the streams, large herds of antelopes bound over the plains, while the uplands are frequented by large numbers of buffaloes. The hyajnas, and especially the leopards, are much dreaded by the herdsmen. Erskine traversed some 112— AF
