50 



THE CONIFERS OF THE NORTHERN ROCKIES. 



the twigs are arranged in a flat spray or branching system, the ulti- 

 mate divisions of which are almost contiguous laterally. The leaves 

 would hardly be recognized as such by the uninitiated ; they are very 

 small scales, less than an eighth of an inch in length, closely applied 

 to the surface of the slender twig which they entirely cover. The 

 leaves stand opposite in pairs and lengthwise of the twig are arranged 



FIG. 31. Alpine Fir. The smooth bark is characteristic, even to maturity. 



in four* ranks. An interesting feature of the arbor vita? is the fact 

 that in its seedling stage the first season it produces flat, sharp- 

 pointed, outstanding leaves, a fourth of an inch or more in length. 

 In an axil of an upper one of these a branch appears which bears 

 leaves that are scalelike and continue so in the subsequent growth. 



