IN OTHER COUNTRIES. 103 



leaves in June. (Mean temperature of the earth below 

 36°, at 800 feet.) 



3. (Sub.) The Subsylvan Region (regio subsylvatica) 

 is known by the presence of Pinus sylvestris, without P. 

 Abies. It is a narrow region not very distinctly marked. 

 Prunella vulgaris fails here, and Thalictrum alpinum and 

 Salix lanata appear. The lakes and larger rivers of this 

 region are situate about 1000 French feet above the level 

 of the sea. (Mean temperature of the earth about 35°, 

 at 1200 feet; mean of the air at 1340 feet only 27°, of 

 summer 55°, of winter 0°.) 



4. (Sub.) The Subalpine Region supports Betula alba, 

 but is without Pinus sylvestris. The region is considered to 

 terminate where the birch does not attain 6 feet. Populus 

 tremula and Prunus Padus cease before Betula alba, Pyrus 

 Aucuparia attaining almost the same limit. It is a dry 

 region much covered with Lichen rangeriferinus. Azalea 

 procumbens, Juncus trifidus, and Luzula spicata begin to 

 grow here. (Mean temperature of the earth 34£ at 

 1800 feet.) 



5- (Alp.) The Lower Alpine Region is that portion of 

 the mountains rising above the line of Betula alba, and 

 where the patches of snow disappear before the middle of 

 July. Silene acaulis begins to abound over the plains 

 (per campos). Betula nana grows erect in marshy places. 

 (Mean temperature of the earth 34° — 33°.) 



6. (Sno.) The Higher, or Snowy Alpine Region, has 

 patches of snow in many places during the whole summer, 

 moistening the ground by its constant melting. (Mean 

 temperature of the earth 33°— 32°.) 



The limit of perpetual snow is found at about 3300 

 French feet above the sea level. Crossing the chain of 

 mountains, and descending the Norwegian side towards 

 f 4 



