160 ZONATION 



cable, as it has no reference to zonation, and is used much 

 more frequently as a term of general application. Its use 

 tends to obscure also the essential identity of the so-called 

 vertical zones of mountains with the major continental 

 zones, an identity which can not be insisted upon too 

 strongly. For the sake of clearness, it is important to dis- 

 tinguish all belts of vegetation as zones, though it is evi- 

 dent that these are not all of the same rank. The following 

 division of the vegetation of North America is based upon 

 the fundamental principles of continental symmetry, and 

 the community of continental and mountain zones. 



I. Polar-niveal zone — zona polari-nivalis 



II. Arctic-alpine zone — zona arctici-alpina. 



Arctic province — provincia arctica. 

 Alpine province — provincia alpina. 



III. Boreal-subalpine zone — zona boreali-subalpina. 



Alaska province — provincia alaskana. 

 Cordillerah province — provincia cordillerana. 

 Ontaria province — province ontariensis. 



IV. Temperate zone — zona temperata, 



Atlantic province — provincia atlantica. 

 Appalachian province — provincia appalachiana. 

 Nebraska province — provincia nebraskensis. 

 Utah province — provincia utahensis. 

 Coast province — provincia litoralis. 

 Pacific province — provincia pacifica. 



V. Subtropical zone — zona subtropicalis. 



Florida province — provincia floridana. 

 Mexican province — provincia mexicana. 



VI. Tropical zone — zona tropicalis. 



Antilles province — provincia antilleana. 



Andean province — provincia andeana. 

 ^ The investigation of zones rests upon the instrumental 

 study of the factors of ecotones, and upon the quadrat ex- 

 amination of contiguous zones and of the transition area be- 

 tween them. As the methods are essentially the same as 

 for alternation, their detail will be found under the dis- 

 cussion of this principle. 



