THE CONTINENTAL FLORA OF SOUTH SWEDEN 285 



parts of the North German plain there are specially suitable localities on the 

 slopes of marly, sandy, or gravell}- moraine hillocks and alongside the »Strom-» 

 or »Urstromtaler» traversing glacio-fluvial deposits or loess formations (e. g. 

 Loew 1879, Scholz 1905, Preuss 19 12). In Central and South Germany the 

 » 7 /7//» -formations are preferably housed on rocky grounds. They form inter alia 

 part of the vegetation which popular speech here calls ■»IIeide» (»Garchinger 

 Heidc» near Munich, Scndtner 1854, PP- 447 ff-! »Wachauer Heide» in Lower 

 Austria, Kerner 1863; Gradmann lyoo, I, pp. 113 fif. ; Drude 1902, pp. 159 fif.). 

 In the east of Central Europe the flora shows a very great likeness to that of 

 the meadow steppe, for instance, »Die podolische Trift-formation» in Hayek (1914, 

 pp. 286 ff.) and the so-called »Pontische Hugclformation» rich in steppe species 

 (Preuss 1909 and 1912, Scholz 1905, Graebner 1901, Drude, e. g. 1002, etc.). 



In southern parts of Central Europe a Mediterranean weft in the flora be- 

 comes more and more prominent; see, for instance, Kerner's and Beck's descrip- 

 tions of the flora in the valleys of the Eastern Alps (Kerner 1888, Beck »i907») 

 and the corresponding descriptions of Jaccard (1895) and Briquet (1898) from the 

 Western Alps. 



In Western Europe the » 7";7/?» -formation becomes rarer and more feebly de- 

 veloped and its existence is more dependent on the mineralogical composition of 

 the soil. In south-eastern England, however, there is still to be found a fairly 

 rich » 7)'z//»-flora in which even a few steppe species can be met with. (Tansley 

 1911, pp. 95, 158, 175.) 



The second type of the herb communities outside Eastern Europe corresponds 

 to the sand-steppe. These communities are characterized by grasses [Sand-grasses] 

 which form tufts or have long creeping rhizomes, and of a fairly rich herb flora 

 composed partly of perennial herbs which often have widely ramified shoots, 

 })artly by annual and biennial species. The principal grasses are Festucae ovinae 

 and F. rubra, Corynephorus canescens, Koeleria-species, Phleum-species (Ph. Boeh- 

 meri), and certain Carices, such as C. arenaria, ligerica, praecox Schreb., and eri- 

 cetorum [Drude 1896, pp. 346 ff. ; 1902 e. g. pp. 450 fi". ; Warming 1909, pp. 

 265 ff.; Scholz 1905; Hayek I.e., e.g. pp. 128, 276; Graebner 1901 (»Heidekrautlose 

 Sandfelder», »Grasheide», partly)]. They differ from the sand-steppe in respect 

 of the composition of the phanerogamous flora and through the fact that the 

 plant cover is more closed, largely owing to the abundant occurrence of shrub 

 lichens (Cladoniae, Cetrariae). 



This psammophilous vegetation may be referred to the ygrass hcathsi> but occu- 

 pies a position apart on account of their floristic composition. Stress may be laid 

 upon the important part the sand-grasses play and the abundance of the herb 

 flora. 



It would seem to be confined to sandy areas in districts with comparatively 



20 Geo^afiska Annaler ig22. 



