308 RIKA RD STERNER 



a water course has made its way through them, there are slopes composed of 

 sand and fine gravel even here. I have no detailed knowledge of the composi- 

 tion of the vegetation on these slopes. But steppe species are almost totally 

 absent. Only Artemisia campestris (Plate 5) (it is perhaps uncertain whether 

 this is quite spontaneous here), Veronica spicata (p. 310), and Ranunculus polyan- 

 themos (p. 319) (according to a report from Phil. kand. Hard av Segerstad) have 

 a few occurrences here. The marked absence of steppe species would seem to 

 be caused chiefly by the climate as will be proved later on. 



The OSes are naturally of great importance for the distribution of steppe spe- 

 cies in other parts of South Sweden than eastern Smaland. The sole occurrences 

 in Blekinge of Phleum Boehmeri (Plate 5) and Trifolium montanum (p. 301) are 

 at Ronneby, where there are numerous os slopes. The numerous oses in the 

 plains of Ostergotland and the provinces around Lake Malar harbour in pre- 

 sent time many occurrences of steppe species and probably steppe species might 

 have some possibilities of occurring on them in a fully original vegetation, too. 



The great importance of the oses for the distribution of the steppe species 

 rests on the facts that on the southerly slopes the species can have their demands 

 for light satisfied, and that the dry and warm sand or gravel soil satisfies their 

 demands in the matter of the nature of the soil. Naturally slopes of other 

 kinds may be of the same importance if they satisfy the said demand. 



Slopes of rock hills, however, are generally less dry than the ones of the oses. 

 Because the rock-ground does not let the water through, the forest on them be- 

 comes denser and more shading, and hence the ground vegetation comes to be 

 formed of less heliophilous and xerophilous species. The southerly slopes will 

 be occupied by wooded hillsides, less sparse and xerophilous and more shaded 

 than the vegetation on the os slopes. 



The flora of these wooded slopes is of great interest in the estimation of the 

 continental element in the vegetation. For several species form part of it that 

 have otherwise a great distribution in Eastern Europe^ where they belong to the 

 dry, sparse woods that form oases on the steppes or form the transition between 

 these and the forest region proper. The distribution of these species will, 

 however, be treated further on (Chapter x). Here it will only be pointed out 

 that some of the species treated as steppe species may in South Sweden form 

 part of similar, wooded slopes and have a distribution which is in certain districts 

 connected with the distribution of broken country, viz. Crepis praemorsa (p. 315) 

 and Ranunculus polyanthemos (p. 319) and, in a smaller degree, Fragaria viridis 

 and TrifoUum montanum (p. 301). The distribution in Smaland of the two first- 

 named species to a certain extent reflects the main features of the topography 

 (cf. later on pp. 342 fif.). 



