482 RELATWiV TO ENVIRONMENT. 



severe than in the arctic region. This is principally due to the 



Fig. 4£>i. 

 Polar tundra with scattered flowers, AKiska. (Copyriglit by E. H. Harriman.) 



fact that during the summer while the plants are growing they 



Fig. 4U.. 

 Perennial rosette plant Irom alpine lloru ..I the .\njes, showing short stem 

 eisette of lea\-es, anil large liower. (Aiter Sehiniper.) 



,re subject to a high temperature during the day and a \-ery low 



