226 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



It is a common belief that alpine plants will grow where 

 montane or littoral plants could not exist for the cold, and 

 general appearances favour this idea. For instance, when we 

 explore an extensive tract of country in the north of Europe, or 

 very high mountains in any part of the world, we find, as we 

 ascend, that the temperature falls and the aspect of the vegetation 

 changes, so that those plants found near the perpetual snow in 

 India have a close resemblance to those found near the perpetual 

 snows in the arctic regions, and this is so markedly seen with 

 certain trees and shrubs that they form what are termed belts, 

 such as the " Pine Belt," the " Birch Belt," and the " Willow 

 Belt," and lend a veiy characteristic feature to the landscape when 

 viewed from a distance. We have this now only in a very 

 limited degree in Scotland, so limited, in fact, that it is almost 



