16 TREES OF NORTH AMERICA 



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

 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 into plates sometimes 4-5 long and 12'-18' wide, and sepa- 

 rating into thick bright cinnamon-red scales. Wood hard, strong, comparatively 

 tine-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 

 Nebraska 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 color of the bark. The form of the Rocky Mountains (var. scopulorum, 

 Engelm.), ranging from Nebraska to Texas and over the mountain ranges of Wy- 

 oming, eastern Montana, and Colorado, and to northern New Mexico and Arizona, 

 where it forms on the Colorado plateau the most extensive Pine forests of the conti- 

 nent, has nearly black furrowed or bright cinnamon-red 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. Jeffreyi, Vasey. 



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

 California, along the eastern slopes of the central and southern Sierra Nevada, 



growing often on the most exposed and driest ridges, and in southern California on 

 the San Bernardino and San Jacinto ranges up to elevations of 8000 above the sea, 

 on the Cuyamaca Mountains, and in Lower California on Mt. San Pedro Martir. 



A tree, 100 to nearly 200 high, with a tall massive trunk 4-6 in diameter, 

 covered with bright cinnamon-red bark deeply divided into large irregular plates, 

 atiffer and more elastic leaves 4'-9' long and persistent on the glaucous stouter 

 branchlets for six to nine years, yellow-green staminate flowers, short-stalked usually 



