22D 



BULLETIN UNIVERSITY OF MONTANA 



found at rather high altitudes, although it was not seen to overlap in its 

 distribution the white-bark pine of the higher altitudes. It is said to 

 reach its best development in the bottom-lands of streams tributary to 

 Lake Pend d'Oreille. 



The white-bark pine (Pinus albicaulis Engelm.) : It is distinctly an 

 alpine form. (Fig. 9.) The leaves are in clusters of five, and from one 



Fig. 9. White-bark pine on the slope of Sinvaieamin Mountain, at 

 altitude of 7800 feet, showing the struggle thej make for an existence. Photo 

 b\ Prof. L. A. Youtz. 



and a half to two and a half inches in length. They are said to persist 

 for from five to eight years, most of them remaining on the trees from 

 seven to eight years. The bark is very thin. It is quite smooth and is 

 creamy white in appearance, hence the name white-bark pine. It is 

 easily destroyed by fire. The white-bark pine grows on the most ex- 

 posed ridges in high altitudes. It is confined to the western continental 

 ■divide, where it is usually associated with the alpine fir. 



