30 POPULAR GEOGRAPHY OF PLANTS. 



As no researches seem to have been made, as yet, in the 

 North American portion of this zone, we will start from the 

 most westerly land in the old continent Iceland : the Faroe 

 Islands may be spoken of at the same time, as their vegeta- 

 tion is much the same as that of Iceland ; and it may be 

 farther remarked, that it " agrees very closely " with the 

 coast flora of Norway. The absence of trees is a charac- 

 teristic of all ; for though the Birch and the Alder (Alnus) 

 grow in Iceland, they only attain the height of shrubs, and 

 these are the nearest approach to trees to be seen in the 

 island, together with the Juniper, which is the only conife- 

 rous plant found there : Firs however grow in the Faroe 

 Islands, and Willows are not wanting. The mountains in 

 these islands are often covered with long mosses ; and both 

 here and in Iceland com is cultivated, though it does not 

 always ripen. 



But Iceland was not always the treeless island it is now, 

 nor, as there is reason to suppose, was the temperature 

 always so low as at the present day; for there are facts 

 which prove that there were once high Birch forests stand- 

 ing where now the ground is changed into moors and bogs ; 

 and not Birch-trees only, but Oaks probably as well; for 

 Mackenzie, in his Travels in Iceland, speaks of seeing fossil 



