34 



THE CONIFERS OP THE NORTHERN ROCKIES. 



Observation, however, has borne the conviction that there are no 

 real or constant marks distinguishing the two species. This tree has 

 an extensive range. It is found from the Yukon to Arizona and 



FIG. 17. Engelmann Spruce, in the upper Bitter Root Valley, Montana. 



New Mexico, over the higher elevations of the Rocky Mountains, and 

 in the Cascades to northern California. In Montana it occurs at 

 altitudes from 3,000 feet to timber line, where it often forms dwarfed 



