64 



[Vol. 2 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



The distribution northward and height above 



sea-level of 



the various vegetable species, will be dependent mainly upon 

 the temperature during the summer months. 



The rainfall, which in various other countries plays so 

 important a part as a factor in vegetation, is of less import- 



ing. 3. The annual rainfall in Norway (in centimeters). — After M. Mohn. 



ince in Norway, as even on the Dovre , ._. 



ainfall is smallest (about 300 mm. per annum), there is 



sufficient 



occasion, on account of 



de 



evaporation, swamps and peat-bogs, where even entirely 

 hydrophilous communities thrive. 



