THE CONTINENTAL FLORA OF SOUTH SWEDEN 255 



Chapter IV. 



Continental features in the physiography of South Sweden. 



It would seem to be a justifiable assumption that continental species are gene- 

 rally more or less confined by their ecology to habitats of continental character 

 and that their distribution would thus be in a measure determined. 



In order to establish in detail how far this is the case, and how far other 

 causes may determine the distribution of species, it would be best to analyse 

 the distribution of species, and their mode of occurrence within a comparatively 

 small area and to investigate carefully its geographical conditions: an analysis 

 of the climatic character, especially locally, of this area and the nature of the 

 soil within it. 



It is not the purpose of the present work to make any new contributions to 

 the knowledge of the climatic character and soil quality of South Sweden. Facts 

 already collected, however, will be set forth in a brief form. 



The degree of continentality of the South Swedish climate. 



a. Temperature conditions in South Siveden. »Es kann nicht laut genug in 

 die Welt gerufen werden, dass die nach der allein herrschenden Methode bisher 

 angestelhen meteorologischen Beobachtungen, den gegenwartigen Auff"orderungen 

 biologischer Studien nicht im Geringsten genugen», Middendorff wrote in 1867 

 in »Eine Reise in den aussersten Norden und Osten Sibiriens» (IV\ p. 776I. 

 Even in our own days such a statement would seem to be justified to a con- 

 siderable extent. 



The figures which Meteorology at present usually places at our disposal only 

 give an outline of the general features of the temperature of the air. When, 

 on the other hand, it is a question of finding a possible relation between the 

 character of the vegetation and the temperature within a certain area, they 

 hardly ofi"er any reliable bases of discussion whatever. 



For such a purpose it is the purely local climate conditions that have to be 

 investigated. What temperature amplitudes can be established within a suitable 

 number of special areas with regard to the difterences in topography, quality of 

 soil, vegetation cover, etc. within these areas .^ 



Furthermore a phytogeographer is little benefited by accounts of temperature in 

 an air-layer with which the bulk of plant species has not the slightest contact. 

 Several investigations of late \-ears (see especially Kraus igii) have shown how 



