greatest Heights of the Himahyah and Upper Peru. 89 



proof of my original proposition ; for it thus appears that the 

 temperature in the warm season is never so low as to destroy 

 potatoes, but is unfortunately never so high as to admit of the 

 ripening of wheat. The potato does not require so high a 

 temperature as the finer kinds of grain, but it requires a longer 

 period of a corresponding lower temperature than those annual 

 grasses, some of which, in a very elevated summer temperature, 

 ripen in a space of three weeks. 



The plateau of Chuquito, round the great lake, is naturally 

 destitute of trees, although it has only a height of 12,700 feet; 

 hence it might be believed that the climate is severe, and it 

 might be concluded, that, on this account, the finer grains would 

 not ripen ; but tJie whole phenomenon is local, and the absence 

 of trees is, as we may say, an accident produced by peculiar 

 causes, just as we find such an occurrence in the vegetation of 

 plains. Thus, the Falkland Islands lie in a zone which corre- 

 sponds perfectly to the subarctic zone of northern Europe, and 

 the physiognomy of the vegetation of these islands bears the 

 most striking resemblance to that of northern Denmark and 

 southern Sweden and Norway, but trees are awanting. That 

 the want of trees is there a local phenomenon, is proved by their 

 abundant occurrence at no great distance, and in a more southern 

 latitude, viz., on both sides of the Straits of Magellan, where 

 evergreen box-trees, with trunks having a circumference of 12 

 to 17 feet, form most luxuriant forests. 



In the Northern Hemisphere, especially in northern Europe, 

 evergreen-trees as well as shrubs, follow more or less, the sea coast ; 

 and in southern Europe, where all the countries, by their peculiar 

 configuration, are surrounded by the sea, we have a great predo- 

 minance of these vegetable forms. In the Southern Hemisphere, 

 on the contrary, the appearance of evergreen-trees and shrubs 

 is quite an unusual phenomenon ; perhaps such vegetable pro- 

 ductions stand in more intimate connexion than we suppose, with 

 the predominating influence of the sea. Here it is not only 

 the subtropical zone, not only the warmer portion of the tem- 

 perate zone, which corresponds to our southern Europe, but we 

 find this form of trees with evergreen-leaves extending even to 

 Magellan's Straits and beyond them ; and our tender-leaved box 

 of northern Europe corresponds to the evergreen box-trees o 



