284 RIKARD STERNER 



The stock of species belonging to the steppe flora decreases naturally farther 

 to the north. Nevertheless steppe species are still to be found not far from the 

 coast of the Arctic Ocean. Pohle (1903, p. 93) has described from an area south 

 of the Kania Peninsula xerothermous hillside communities, surprisingly rich in 

 species and including many steppe species; and from the lower Lena in Siberia 

 Cajander (1906 a) mentions as growing on calcareous hillsides a vegetation rich in 

 species which comprises several in common with the southern Siberian steppe 

 vegetation. 



The xerophilous herb and grass communities in other parts of Middle Europe 

 which contain steppe species attach themselves more or less to the steppe com- 

 munities. As outposts of real East European Stipa-associations might be con- 

 sidered a vegetation rich in Stipa pennata or S. capillata and a great number of 

 steppe herbs, which are found in a few scattered, minor districts: north-eastern 

 Germany on the Vistula (in southern West Prussia and north-eastern Posen; 

 description in Scholz 1905, pp. 168 ff., and Preuss 19 12, pp. 460 {[.), in Central 

 Germany (south-east of Harz; Drude 1902), and above all in Bohemia, Moravia 

 and Lower Austria (Hayek 19 14, Podpera 1904, Laus 1910, Beck 1890 and others). 



Plant communities in which steppe species are found outside the steppes may 

 generally be divided into two types of xerophilous herbaceous vegetation. One 

 of these belongs to the vegetation which is often called the •)>Trift-formaHon-», 

 ^^Triftgrasflurenf) , or -^Grasige Triftem^ for instance, by Drude 1890, 1896, 1902 

 etc. and by Hayek 1914. Diels (191 8) calls it ^'>xerophorbiiim->\ Warming (1909) 

 ■i>7vaste herbage >^ ; Brockmann-Jerosch and Riibel (19 12) call it ^Hartnnesen'>\ 

 •A Duriprata^^ . The second type corresponds to the sand-steppe vegetation and is 

 shortly to be characterized as herbaceous sand-grass heaths {j> Sandgrasfluren>^ Drude, 

 Hayek a. o.). 



The composition of the » Trift-fonnatiom in Middle Europe varies to a great 

 extent, according to the geographical position and the nature of the soil. In 

 the central parts of Middle Europe, where it is abundantly distributed and often 

 has a flora rich in species, it may, according to Drude, be characterized thus: 

 a xerophilous fairly closed vegetation of low grasses and a very abundant herb 

 flora. The grasses do not here form a cover as they do in the meadow; but 

 the separate individuals are scattered about and the place between them is more 

 or less taken up by the numerous herbs. The grasses (» Triftgrdser>^ Drude, 

 ■nhillside-grassesy, Swed. y>backgrds-») consist principally of Festucae ovinae, F. rubra, 

 Avenae (in the first place A. pratensis), Bromus inermis and erectus, Brachypodium 

 pinnatum, Koeleria »cristata», Phleum Boehmeri, and Sesleria coerulea. The herbs 

 are almost exclusively perennial (Drude 1896, p. 344; 1902, pp. 174 fl".). 



It is found on slopes exposed to the sun or on rocky ground with only a thin 

 layer of loose soil. Within the region of the inland ice in the central and eastern 



