256 



RIKARD STERNER 



much the temperature in and immediately beneath the surface of the ground 

 may difter from that measured at a height of one metre above the ground. 



Meteorological data such as those given below are not, however, without their 

 value to a study in phytogeography like the present. A certain relation may 

 exist between the former and the local climatic amplitudes. 



The South Swedish highland do, of course, in a high degree determine the 

 temperatures in South Sweden. 



Our attention ought especially to be directed to the fact that during summer 

 and autumn this highland has a remarkably much lower temperature than 



Fig. 



The mean temperature in South Sweden in May (a). July (^6), and September (r) (at the 

 le\el of the meteorological stations), according to Hamberg 1908. 



the surrounding coast and lowland districts. Besides, the fact may be observed 

 that the lowlands of Central Sweden are separated by isotherms from the more 

 elevated forest region of Norrland that commences to the north thereof. Figs, i 

 and 2 give more exact information on this subject. 



As to the degree of continentality of the temperature of South Sweden a 

 comparison with the state of things in adjacent parts of Europe yields the follow- 

 ing results. 



The July-isotherms, which as a rule are used as characteristics of summer 

 temperature, have in northern Europe a general trend from north-east to south-west 

 (see, for instance, Ekholm 1889.) 



In the Scandinavian North the course of the isotherms is rather complicated, 

 owing to the Baltic Sea and the Scandinavian highlands. In northernmost 

 Russia the isotherms run close together, nearly parallel to the coast-lines of the 

 Arctic Ocean and the White Sea. In northern Finland they are more diverse. 



