PINACE.E 



13 



a regular spire-like head, or in arid regions a broader often round-topped head surmount- 

 ing a short trunk, and 

 stout orange-colored 

 branchlets frequently 

 becoming nearly black 

 at the end of two or 

 three years. Bark for 

 80-100 years broken 

 into rounded ridges 

 covered with small 

 closely appressed 

 scales, dark brown, 

 nearly black or light 

 cinnamon-red, on older 

 trees becoming 2'-4' 

 thick and deeply and 

 irregularly divided in- 

 to plates sometimes Fig. 13 

 4-5longandl2'-13' 



wide, and separating into thick bright cinnamon-red scales. Wood hard, strong, com- 

 paratively fine-grained, light red, with nearly white sapwood sometimes composed of 

 more than 200 layers of annual growth; largely manufactured into lumber used for all 

 sorts of construction, for railway-ties, fencing, and fuel. 



Distribution. Mountain slopes, dry valleys, and high mesas from northwestern Ne- 

 braska and western Texas to the shores of the Pacific Ocean, and from southern British 

 Columbia to Lower California and northern Mexico; extremely variable in different parts 

 of the country in size, in the length and thickness of the leaves, size of the cones, and in the 

 color of the bark. The form of the Rocky Mountains (var. scopuhrum, Engelm.), ranging 

 from Xebraska to Texas, and over the mountain ranges of Wyoming, eastern Montana 

 and Colorado, and to northern New Mexico and Arizona, where it forms on the Colorado 

 plateau with the species the most extensive Pine forests of the continent, has nearly black 

 furrowed bark, rigid leaves in clusters of 2 or 3 and 3' -6' long, and smaller cones, with thin 

 scales armed with slender prickles hooked backward. More distinct is 



Pinus ponderosa var. Jeffrey! Vasey. 

 This tree forms great forests about the sources of the Pitt River in northern California, 



Fig. 14 



