228 



BULLETIN UNIVERSITY OF MONTANA 



tional cases two feet. By its thick bark (Fig. 7) the tree is well pro- 

 tected from fires. It does not tolerate shade. In this respect it may 

 be classed with the western larch and lodgepole pine. In the Flathead 

 valley the tree is associated with the western larch in moister soils and 

 with the bull pine in drier soils. It does not, however, reach the dimen- 

 sions here that it does on the Pacific coast, where, with the western hem- 

 lock and arbor-vitae, it forms luxuriant forests. The Douglas spruce is 



Fig. i6 The Yew, showing leaves and berries. Photo by M.J. E. 



distributed throughout the western part of the United States, but in dry 

 climates it is small and stunted in growth. 



The lowland fir (Abies grandis Lind.) : This tree is also known as 

 the white fir and the balsam fir. The leaves have already been described. 

 On the horizontal branches they are conspicuously two ranked. They 

 persist from eight to ten years. The cones are erect on branches near 

 the top of the tree, and vary in length from two to four inches. The 

 scales of the cones, as in all firs, are deciduous, the cone axis being shed 

 later. The fruit matures in one season. The bark is smooth at first, 

 with the characteristic balsam blisters. Later the bark splits into low 



