306 R I K A R D S T E R N E R 



Among other os sections remarkable for their flora there may be mentioned: 

 the OS at Hogsby, which on one side descends abruptly into the broad valley, 

 formerly occupied by a lake; the os inside Skaggenas in the parish of Ryssby 

 on the Straits of Kalmar (here grow Artemisia campestris, Centaurea jacea, 

 Myosotis micrantha, Poa bulbosa, Potentilla arenaria, leucopolitana and Tabernae- 

 montani, Scleranthus perennis, Sedum album and rupestre, Thymus serpyllum, 

 and Trifolium montanum). At Skogsjo in Ostergotland (a few kilometres north of 

 Mjolby) there is an os-cavity in the large, thick Skanninge-os, forming a smallish 

 lake. A low but marked ridge stretches from the north and south shores out 

 into the lake, almost dividing it into two parts. On the more northerly of the 

 two promontories thus formed, the south-western slope is occupied by a sparse 

 pine forest with a thicket layer and a ground vegetation of a sparse dry meadow. 

 In the latter the following plants form part: Astragalus glycyphyllus, Avena pra- 

 tensis, Carex montana, Oxytropis pilosa, Potentilla Tabernaemontani, and Sca- 

 biosa columbaria. 



The above statements will have shown that os-slopes may, even in a quite 

 natural vegetation, play a fairly important part in the distribution of the steppe 

 species in eastern Smaland. 



In the existing vegetation, which has been influenced by human action, the 

 importance of the os for the distribution of species is very great. The distribu- 

 tion of a great number of species within the district is entirely determined by 

 the OSes. That the occurrences of Veronica spicata are to a great extent located 

 on the OSes would seem to appear even from the map in fig. 7, p. 310. The 

 dots also mark certain large stretches of oses. 



A still more striking example is the distribution of Potentilla arenaria in south- 

 eastern Smaland. 



Potentilla arenaria is an important constituent of the Stipa steppe. In Europe 

 it has a strongly South-East European distribution, a Pontic — Sarmatian distribu- 

 tion, which, however, resembles a Pontic — Hercynian one. Its South Scandinavian 

 distribution appears from the maps in the Plates 3 and 6. The distribution is 

 rather unique with regard to the strong concentration of occurrences in south- 

 eastern Smaland. A closer examination of these occurrences shows that they 

 are to a great extent located on the oses. 



Plate 3, map 2 shows the distribution in eastern Smaland of the oses and a few- 

 rare species: Pulsatilla pratensis, Dracocephalum Ruyschiana, Oxytropis campestris, 

 Phlemn Boehmeri, Pulmonaria angnstifolia, and Veronica spicata. That there is 

 an intimate relation between the distribution of the species and the oses would 

 seem to appear clearly. 



The following steppe species have their occurrences in eastern Smaland more 

 or less solely located on the oses: Artemisia campestris (Plate 5), (Carex erice- 



