234 AFRICA 



of the Nyassa, south to the lower Zambezi. The region 

 thus defined embraces a manifold scenery: it differs 

 alike from the Somali half-desert, from the Bahr-al- 

 Ghazal savana, from the Congo forest, from the Zambezi 

 savana, and from the drier lowlands of Mozambique: 

 yet despite its diverse aspects, from the forest-clad hills 

 of the Shire to those of the Upper Nile province, it has 

 a certain unity. 



Several factors, such as the varying but generally high 

 altitudes, the equatorial and tropical situation, the 

 unequal influence of the south-east trade- winds, the 

 diversity of the drainage, and the nature of the soil, 

 combine to make this region one of the most varied of 

 the continent. The background and general theme of 

 the picture is always some kind of savana or thorn 

 woodland, corresponding to a for the tropics moderate 

 rainfall. From this rise light tropical woods and even 

 high forests, but by reason of the great elevation of the 

 plateau on the west and of the drought nearer the coast, 

 the savanas are generally poor, and the deciduous thorn- 

 brush or wood of the caatinga form is the typical vege- 

 tation except in the south, where a dotting of acacias 

 with the umbrella shape prevails. Thus this part of 

 Africa offers a great similarity to the northern Brazilian 

 highlands, and for similar physical reasons. 



As a rule, the eastern and southern slopes possess 

 a richer vegetation than those of the west and north, 

 most of the rainfall coming from the south-eastern 

 trades and monsoons. Light kinds of tropical forests 

 do not fail in the hill-land. The best known is the 

 Mau forest, large portions of which are only of moderate 

 height, 60-70 feet, trees with thin light crowns and thick 

 gnarled trunks, and few lianas, few climbers, but a dense 

 undergrowth of shrubs and grass : other parts approach 



