472 PLANT DISTRIBUTION 



phenomenon of vegetation types as distinct from the 

 geographical distribution of species or flora. The latter 

 is more intimately related to the possibilities of migra- 

 tion or spreading, whereas the former depends more 

 largely on the possibilities of adaptation. To put it 

 another way, the one is largely determined by what 

 species can get to a place, and the otlier by the arrivals 

 which can actually compete successfully and so maintain 

 themselves. 



