FLORA OF EAST AND MIDDLE AFRICA 37 



Apocynacece, Burseracece, Tiliacece, and several others, all 

 of which are unfamiliar to botanists from north-temperate 

 zones. The conifers are found only in the highlands, where 

 they are represented by a typical juniper, a tree of wide 

 range, and by two species of yews of the tropical genus 

 Podocarpus. Palms are quite an inconspicuous feature in 

 East Africa; but four or five species occur and they are 

 only abundant locally. 



Large areas in the highlands of British East Africa and 

 in Uganda and the Nile Valley are covered by a heavy 

 growth of grass, forming treeless plains of considerable 

 extent. One or two species of grass usually predominate 

 in the plains, but many different species are represented 

 in the various districts where grass veldt occurs. 



The whole region falls naturally into five floral or faunal 

 zones based primarily on climatic differences due to mois- 

 ture and altitude and characterized by peculiar tree or plant 

 species. The zones succeed one another as the country 

 rises from the coast to the highlands in the interior and 

 extend parallel with the coast as broad bands of territory. 

 The higher zones, which are found only on mountain slopes 

 or summits, occur as islands in the lower zones. 



The animal life is dependent chiefly upon certain plant 

 species, and on this account conforms quite closely in 

 distribution to the floral zones in which such species occur. 

 Throughout the zones the distribution of the plants com- 

 prised in each is by no means uniform, for each zone is made 

 up of several distinct plant associations. Because of the 

 dependence of the animals upon certain plant associations 

 they seldom occur generally distributed in the zone. Plant 

 associations are really the most important floral factors in 



