8 



TREES OF NORTH AMERICA 



broken into nearly square plates separating on the surface into small closely appressed 

 scales. Wood light, soft and brittle, pale reddish brown. 



Distribution. California, on rocky slopes and ridges, forming scattered groves on 

 Scott Mountain, Siskiyou County, at elevations of 5000-6000; on the mountains at the 

 head of the Sacramento River; on Mt. Yolo Bally in the northern Coast Range, and on 

 the southern Sierra Nevada up to elevations of 11,500, growing here to its largest size 

 and forming an extensive open forest on the Whitney Plateau east of the canon of Kern 

 River, and at the highest elevations often a low shrub, with wide-spreading prostrate stems. 



7. Pinus aristata Engelm. Foxtail Pine. Hickory Pine. 



Leaves stout or slender, dark green, lustrous on the back, marked by numerous rows 

 of stomata on the ventral faces, l'-l' long, often deciduous at the end of ten or twelve 

 years or persistent four or five years longer. Flowers male dark orange-red; female dark 



purple. Fruit 3'-3' long, with scales 

 armed with slender incurved brittle prick- 

 les nearly \' long, dark purple-brown on 

 the exposed parts, the remainder dull red, 

 opening and scattering their seeds about 

 the 1st of October; seeds nearly oval, 

 compressed, light brown mottled with 

 black, j' long, their wings broadest at the 

 middle, about f ' long and \f wide. 



A bushy tree, occasionally 40-50 high, 

 with a short trunk 2-3 in diameter, 

 short stout branches in regular whorls 

 while young, in old age growing very 

 irregularly, the upper erect and much 

 longer than the usually pendulous lower 

 branches, and stout light orange-colored, 

 glabrous, or at first puberulous, ulti- 

 mately dark gray-brown or nearly black 

 branchlets clothed at the ends with long compact brush-like tufts of foliage. Bark 

 thin, smooth, milky white on the stems and branches of young trees, becoming on old 

 trees '-f thick, red-brown, and irregularly divided into flat connected ridges separating 

 on the surface into small closely appressed scales. Wood light, soft, not strong, light red; 

 occasionally used for the timbers of mines and for fuel. 



Distribution. Rocky or gravelly slopes at the upper limit of tree growth and rarely 

 below 8,000 above the sea from the outer range of the Rocky Mountains of Colorado to 

 those of southern Utah, central and southern Nevada, southeastern California, and the 

 San Francisco peaks of northern Arizona. 



8. Pinus cembroides Zucc. Nut Pine. Pinon. 



Leaves in 2 or 3-leaved clusters, slender, much incurved, dark green, sometimes marked 

 by rows of stomata on the 3 faces, l'-2' long, deciduous irregularly during their third and 

 fourth years. Flowers: male in short crowded clusters, yellow; female dark red. Fruit 

 subglobose, l'-2' broad; seeds subcylindric or obscurely triangular, more or less com- 

 pressed at the pointed apex, full and rounded at base, nearly black on the lower side and 

 dark chestnut-brown on the upper, \'-\' long, the margin of their outer coat adnate to 

 the cone-scale. 



A bushy tree, with a short trunk rarely more than a foot in diameter and a broad round- 

 topped head, usually 15-20 high, stout spreading branches, and slender dark orange- 

 colored branchlets covered at first with matted pale deciduous hairs, dark brown and some- 

 times nearly black at the end of five or six years; in sheltered canons on the mountains of 

 Arizona and in Lower California occasionally 50 or 60 tall. Bark about \' thick, irregu- 



Fig. 7 



