34 THE AMERICAN BOTANIST. 



The home of the saxifrages is the far north, — the dreary, 

 wind-swept "barren grounds" of the Arctic tundra. On the 

 product maps of our school geographies there used to be a 

 dotted line marked "northern limit of trees." The vast region 

 north of this line stretching from Cape Prince of Wales, to 

 Labrador was labeled "Mosses and saxifrages." This great 



expanse in the bleak dwelling place of the genus Saxifraga. 



Many of the species of these Arctic regions extend their 

 range far to the southward along the great mountain systems 

 of the northern hemisphere. Those farthest south are found 

 as isolated colonies on lofty mountain peaks. Saxifraga op- 

 posififolia has been found on the Green Mountains of Vermont 

 and along the crest of the Tetons in the West. It makefe its 

 home on the heights of the Pyrenees, among the Alpine peaks, 

 and on the Jura Mountains. Botanists have found it on Ingle- 

 borough Hill in Yorkshire and on Snowdon in Wales. These- 

 are its southern outposts; northward it is found in increasing 

 abundance to the shores of the Arctic Sea. 



vS. tricuspidata is found in both Europe and America. In 

 the eastern part of North America it comes as far south as 

 Lake Superior. In the West it lives among the Bryanthus and 

 Arctic willows on the lofty volcanic crater of Mt. Hood. 

 5. steUaris grows along the margin of the Greenland ice-sheet 

 and on the cold Labador uplands. Its most southerly stations 

 are on Mt. Katahdin in Maine and on Mt. Evans in Colorado. 

 A few species are confined to the United States and two or 

 three are found as far south as North Carolina or Georgia. 

 The habits of these southern species show their northern 

 origin. They cling to the margins of cold mountain brooks 

 or the edges of bogs. 



To account for the wide spread dissemination of northern 

 species of plants and for their occurrence in isolated colonies 

 on the mountains of the northern hemisphere is one of the 

 fascinating problems in the realm of plant life. It would 



