CHAPTER LIII. 



ARCTIC AND ALPINE PLANT SOCIETIES. 



I. Arctic Plant Societies. 



1064. The arctic zone of plant life extends from the limit of 

 tree growth to perpetual ice and snow. The arctic zone is some- 



Fig. 512. 



Northern limit of tree growth, Alaska. (Copyright, 1899, by E. H. Harriman.) 



times spoken of as the "cold waste," because in general there 

 are some of the aspects of the desert in the character of the vege- 

 tation. The analogy, however, is not fully carried out because 

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