THE ARCTIC REGION 263 



brown, assumed by the algae are ascribed to the pro- 

 duction of substances apparently destined to absorb heat, 

 and sanction the names of red, brown, yellow and green 

 snows given to colonies of such hardy organisms. 



Arctic-Alpine Tundras and Fjelds. Arctic condi- 

 tions such as make tree-growth, and even shrub-growth, 

 impossible are only found in Europe along a narrow strip 

 of coast facing the polar seas. This is due to the com- 

 paratively low latitudes of the northern shores and to the 

 moderating influence of the south-westerly winds which 

 penetrate far into the Arctic Circle. The immediate shores 

 of the frozen sea, deprived of the benefit of those winds 

 by the lofty barrier of the Scandinavian Alps, and bearing 

 the full onslaught of the circumpolar winds, alone possess 

 a climate severe enough to preclude the extension of the 

 hardy northern trees and shrubs. 



The most telling features of the arctic climate are the 

 shortness of the vegetative period, which is reduced to 

 two or three months in the year, not so much by the long 

 winter night as by the freezing of the ground and the 

 icy and drying winds. Those features are reflected by 

 the usual characteristics of the tundra belt : the absence 

 of arboreal vegetation ; the shortness of growth in length 

 of the shoots and internodes ; the consequent crowded 

 foliage close to the ground ; the strong development of 

 the underground root-stock, woody or fibrous, which 

 serves as a store of reserve materials ; the thick, com- 

 pact, and leathery nature of the foliage, and its re- 

 duction in size; the frequent provision of a woolly 

 covering on the leaves ; the vivid colours of herbaceous 

 shoots due to the presence of heat- storing substances; 

 the bright coloration of the blossoms associated with the 

 duration of the long summer day ; and a wealth of finer 

 devices both superficial and internal. The tundra also 



