SCHOUW'S PHYTO-GEOGEAPHIC REGIONS. 679 



nance of certain characteristic forms or families of plants. His 

 system is founded on the three following requisites : ^ 1. That at 

 least one-half of the known species of plants of that part of the earth, 

 constituting a botanical region, should be peculiar to it. 2. That one- 

 fourth part of the genera of the region should be peculiar to it, or at 

 least should have so decided a maximum as to be only represented in 

 other regions. 3. That individual families should either be peculiar 

 to the region, or at least reach their maximum in it. The regions 

 are divided into provinces according to minor differences in the vege- 

 tation ; ' one-fourth of peculiar species, or some peculiar genera, being 

 suflScient to form a province. 



Schouw's PUyto-Oeoffraphic Regions. 



1. The Region of Saxifragaceae and Musci, or the Alpine Arctic Flora 

 (Wahlenberg's Region). — This region is characterised by the abundance 

 of Mosses and Lichens, the presence of Saxifragacese, Gentianacese, 

 Oaryophyllacese, Gyperacese, ; Salices ; the total absence of tropical 

 families ; a notable decrease of the forms peculiar to the temperate 

 zone ; by forests of Tir and Birch ; the small number of annual 

 plants, and the prevalence of perennial species ; and finally, a greater 

 liveliness in their simple colours. In this region there is no cultiva^ 

 tion. The region is divided into two provinces : — 1. The province of 

 the Carices, or the Arctic Flora, which comprehends all the countries 

 within the polar circle, with some parts of America, Europe, and Asia, 

 which are to the south of it, more especially Lapland, the north of 

 Russia, Siberia, Kamtschatka, New Britain, Canada, Labrador, Green- 

 land, and the mountains of Scotland and Scandinavia. Kane in his 

 Arctic Explorations gives a list of plants collected on the western coast 

 of Greenland, 73° to 80° N. Among the interesting plants may be 

 noted Ranunculus Sabirii, Hesperis Pallasii, Vesicaria arctica, Arenaria 

 arctica, Potentilla frigida, Pedicularis Kanei, Diapensia lapponica, and 

 only one fern, Oystopteris fragilis. In latitude 82° N., on the east side 

 of Smith's Sound, Dr. Bessel gathered Draba alpina, Cerastium alpinum, 

 Leontodon Taraxacum var., and Poa flexuosa. In the Iceland Flora 

 Babington enumerates 467 Phanerogams, the great bulk of the species 

 Scandinavian, and all but 62 British. There are 3 purely Arctic 

 species, Gentiana detonsa, Pleurogyne rotata, and Epilobium lati- 

 folium ; Bellis perennis (the daisy) is a great rarity ; it was only once 

 found. In Spitzbergen there are 117 Phanerogamous plants, and 50 

 Oryptogamous. In Nova Zembla andWaigatsch Island the Phanerogams 

 amount to 146, and the Cryptogams to 144. 2. The province of 

 PrimulacesB and Phyteumse, or the Alpine Flora of the south of Europe, 

 which embraces the flora of the Pyrenees, Switzerland, the Tyrol, 

 Savoy, the mountains of Greece, the Apennines, and probably the 



