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AFRICA 



Senegambia is a low tract of land of a decided savana 

 type, while retaining a number of semi-desert plant 

 forms. South of the Gambia, the vegetation increases 

 in variety and luxuriance as it approaches the high- 

 forest region ; yet the intervening sandstone plateaus 

 offer but stunted forms of woods and scrub, in which 

 acacias are predominant. Farther east, to the south of 



Fig. 81. High Savana Brush — Nigeria. 



the Niger, the high tablelands are mantled with tall 

 grass interspersed with bushes, among which is the 

 landolphia rubber-bush. Trees are comparatively rare 

 and scattered, so that an open tree-steppe is formed : 

 towards the south, they fail entirely. In the plateau, 

 rivers have cut deep and narrow valleys the slopes of 

 which are forest-clad. 



