ALPINE FLORA. 211 



few vestiges of the Alpine flora remained in mountain-ravines, 

 on hill-ranges, and in cold damp moory grounds. Of these re- 

 mains of the former Alpine flora of the plain, individual species 

 have disappeared century by century, as is proved by the fact 

 that in the pile-dwellings of Robenhausen are found the cones 

 of Pinus montana and the seeds of a small mountain water-lily 

 (Nuphar pumilum] . It may also be observed that the sycamore 

 (Acer pseudoplatanus) was, in remote times, spread everywhere 

 over the plains, as appears from its frequent occurrence in all 

 the ancient tufts. 



The dispersion of the Alpine flora in the plain took place at 

 the period of the greatest extension of glaciers, which comes 

 between the Pliocene period and the time of the formation of 

 the lignites. At that period Alpine plants were probably diffused 

 not only over the plain of Switzerland, but also over Germany. 

 This is indicated by the remarkable fact that nearly half of the 

 Swiss Alpine flora reappears in Scandinavia, and generally in 

 high northern latitudes. The northern flora shows a great uni- 

 formity, consisting principally of the same species, forming, as it 

 were, a girdle round the earth. Of these northern species many 

 appear on the North- German mountains, on the Hartz and the 

 Sudetes (in Silesia,), where they constitute the Alpine flora. 

 The Sudetes possess no peculiar plants ; all the species which do 

 not occur in the plain have been obtained from Scandinavia. 

 Some few species stop there (Rubus chamcemorus, Saxifraga 

 nivalis, and Pedicularis sudetica*) ; but most of them are met 

 with further south, and reappear upon the high mountains of 

 Switzerland. The same facts are observed in America and Asia. 

 On the Rocky Mountains, and even on the mountains of North 

 Carolina, plants are found which are identical with those of the 

 northern flora. Similarly on the Altai f, and even on the Hima- 



* In the Snow-cavity of the Giant Mountains (north-west of the Sudetes) 

 Pupa arctica, Wahlbg., has been found. This is a native of Lapland, and of 

 the localities Where Saxifrcuja niralis is met with. 



t In Ledebour's ' Flora Altaica ' there are 80 Phanerogamous plants of the 

 Swiss Alps, 54 of which belong to the Arctic and Laplandic flora. The 

 flora of Ajan, in the north-east of Siberia, on the sea of Ochotsk, includes 62 

 plants of the Swiss Alps, among which 45 are Arctic-Laplandic species. 

 Lapland possess 115 flowering plants in common with the Swiss mountain- 

 flora. 



p 2 



