314 MIXXESOTA BOTANICAL STUDIES 



ranges, is low (700-750 m.), but narrow. The bottom-lands and 

 bench-lands of the valley seldom occupy more than 10 km. and 

 often the foothills on the two sides of the river approach each other 

 much more closely than this. Even these foothills have, to a large 

 extent, the characteristic vegetation of the range to which they 

 belong. 



During the past twelve years the author has spent much time 

 in botanical exploration of the region in question, and has become 

 familiar not only with the country close to the main line of the 

 Canadian Pacific Railway, but also with considerable regions both 

 north and south of that line. It has gradually seemed evident to 

 him, for reasons which will appear later, that the differences in 

 vegetation of the two ranges can be attributed only partially to the 

 combined effects of historical causes and the differences in climate. 



It seems well, first, to set forth the peculiar features of the 

 vegetation of three special areas within the Selkirk range, viz. : 

 The moraines of the Sir Sandford glacier, in the northern Selkirks ; 

 the limestone ledges of the Cougar valley, near Glacier: and the 

 limestone ledges at the head of Downie creek about 50 km. north- 

 west of Glacier. 



1. The A'^egetatigx of the ]\Ioraixes of the Sir Saxdford 



Glacier 



The Sir Sandford glacier is located in the Selkirk range, about 

 40 km. north of the main line of the Canadian Pacific railway. 

 With its tributaries it drains extensive snowfields lying along the 

 easterly flanks of the Selkirk divide. ^ 



During the summers of 1910 and 1911 the author was in camp 

 for about nine weeks on the south moraine of this glacier. Frequent 

 excursions were made throughout the alpine region about Mt. Sir 

 Sandford, and extensive collections were brought back to the Her- 

 barium of the University of Minnesota, where they have since been 

 determined. During these summers the moraines on the north side 

 of the glacier were frequently visited. It soon became evident 

 that the two moraines differ remarkably in vegetation, and with 

 the object of setting forth these differences, thorough collections 

 were made, and numerous field notes were taken relating to various 



1 For accounts of the geography of this region, see papers by Howard Palmer, Ex- 

 plorations about Mount Sir Sandford, British Columbia: The Geographical Journal 27: 

 170, Feb. 1911, and Observations on the Sir Sandford Glacier, 1911: The Geographical 

 Journal 29:446, May 1912. 



