Page:Africa by Élisée Reclus, Volume 2.djvu/443

 FLORA. 801 Atlantic seaboard is d^ncnilly distinguiMluHl bv un almost complcto abaence of extreme variations. Few iM>iiitH on the surface of the globe enjoy a more uniform temperature than Mogador, where the OHcillutions reconlt-d during a wries of nine years scarcely exceetled 6^ or 7° F. This remarkable equability explains the rarity of diseases of the chest. Consumption is almost unknown in this part of the continent, whose climate is also found to be highly beneficial to Kun>iHan invalids. In the interior, where the marine breezes are but slightly felt, the variations of temperature increase in proportion to the distance from the seaboard, while on the south coast the climate is influenced by the proximity of the Sahara with its intense heats during the day and active radiation at night. Altogether, ^larocco is disjwseil in three climatic zones by the relief and aspect of the land. In the north the Moluya basin, the Rif, and peninsula of Tangier, belong to the Mediter- ranean Tell, presenting nearly the same phenomena as the corres|>onding parts of Algeria ; in the centre and south, the main Atlas range separates two distinct regions, one exj^sed to the Atlantic, the other to the 8j»hara atmospheric influences. The rainfall is on the whole far more abundant than in Eastern Mauritania, and the Atlas highlands are often visited by heavy snowstonns. Everywhere along the seaboard the atmosphere is saturated with moisture ; but showers are rare on the southern slopes tunied towards the Sahara. The coastlands are also frequently visited by those showers of red dust, which are now known to consist mainly of silicious aniinalculae wafted by the trade winds from the South American Ilacos across the Atlantic. Flora. To the varied climate of Marocco corresponds a no less diversificnl flora, which, however, belongs mainly to the Mediterranean zone. Of the 248 local genera, all, with a solitary exception, are found in one or another of the regions border- ing the great inland sea. Fully a third of the species occur even in the British Isles and Central Europe. On the other hand, very few species are common also to the African floras south of the great desert. Thus in the jiroducts of its soil, no less than in its physical constitution. Western Mauritania maintains its European character. Physical geography was consequently in complete harmony with the political divisions when Mauritania Tingitana was by Diocletian attached to the Iberian peninsula. The vegetation of Marocco most resembles that of Sjmin, although the analogy is not so complete as was at one time supposed by botanists. Of G.*U species collected in the Atlas highlands, as many as 181 are not found in Spain, and the divergence increases as we ascend towards the higher regions of the Atlas. The contrast with the Canaries, Madeira, and the Azores is almost complete. Most of the plants common to the islands and mainland are such as are elsew^hero also found diffusetl throughout vast regions with the most varied climates. Of the 1,G27 flowering plants hitherto enumerated in Marocco, not more than fifteen 65— ▲»