240 HISTORY OF THE EUROPEAN FAUNA. 



perhaps in early Tertiary times chiefly in the Arctic 

 Regions, which at that time had a mild climate. 

 They have since become adapted to live in cold 

 countries where they flourish, provided they receive 

 sufficient moisture in the summer, and are protected 

 from severe frost in the winter by a covering of snow. 



When we carefully examine the present range 

 of Arctic plants in the British Islands, a curious 

 fact presents itself which no doubt has frequently 

 been noted by botanists, viz., that some of the most 

 characteristically Arctic species, and some which 

 are often quoted by glacialists in support of their 

 theories, flourish at the present moment in very 

 mild situations. I have already referred to the fact 

 that the Mountain Avens (Dryas octopetala) abounds 

 in the west of Ireland (County Galway) down to sea- 

 level. Now it is well known that the mean winter 

 temperature of that part of Ireland resembles that 

 of Southern Europe, being no less than 12 F. 

 ( = 7 Cent.) above freezing point. The plant, of 

 course, is here a native, and not introduced. This 

 instance shows clearly, that as long as more vigorous 

 competitors are absent, and as long as it is not 

 exposed to severe frost or undue dryness, this and 

 allied species do just as well in a mild climate as in 

 their native Arctic home. 



In his interesting essay on the distribution of the 

 Arctic plants in Europe during the Glacial period, 

 Professor Nathorst adduces the fact that all the 

 localities but one, in which remains of such plants 



