A tree, usually 40°—50°, occasionally 80° high, with a short trunk 2°—5° in diameter, stout long-persistent branches ultimately forming a low wide round-topped head, and stout branchlets orange-green and covered at first with soft fine pubescence, usually soon glabrous and darker colored; at high elevations often a low spreading shrub. Bark of young stems and branches thin, smooth, light gray or silvery white, becoming on old trunks 1′—2′ thick, dark brown or nearly black, and divided by deep fissures into broad ridges broken into nearly square plates covered by small closely appressed scales. Wood light, soft, close-grained, pale clear yellow, turning red with exposure; occasionally manufactured into lumber. Distribution. Eastern slope of the Rocky Mountains from Alberta to western Texas and westward on mountain ranges at elevations of 5000° to 12,000° to Montana, and southern California, reaching the western slopes of the Sierra Nevada at the head of King’s River near the summit of San Gorgonio Mountain and in Snow Cañon, San Bernardino Range; usually scattered singly or in small groves; forming open forests on the eastern foothills of the Rocky Mountains of Montana and on the ranges of central Nevada; attaining its largest size on those of northern New Mexico and Arizona. 5. Pinus albicaulis Engelm. White Pine. [Illustration: Fig. 5] Leaves stout, rigid, slightly incurved, dark green, marked by 1—3 rows of dorsal stomata, clustered at the ends of the branches, 1½′—2½′ long, persistent for from five to eight years. Flowers opening in July, scarlet. Fruit ripening in August, oval or subglobose, horizontal, sessile, dark purple, 1½′—3′ long, with scales thickened, acute, often armed with stout pointed umbos, remaining closed at maturity; seeds wingless, acute, subcylindric or flattened on one side, ⅓′—½′ long, ⅓′ thick, with a thick dark chestnut-brown hard shell. A tree, usually 20°—30° or rarely 60° high, generally with a short trunk 2°—4° in diameter, stout very flexible branches, finally often standing nearly erect and forming an open very irregular broad head, and stout dark red-brown or orange-colored branchlets puberulous for two years or sometimes glabrous; at high elevations often a low shrub, with wide-spreading nearly prostrate stems. Bark thin, except near the base of old trunks and broken by narrow fissures into thin narrow brown or creamy white plate-like scales. Wood light, soft, close-grained, brittle, light brown. The large sweet seeds are gathered and eaten by Indians. Distribution. Alpine slopes and exposed ridges between 5000° and 12,000° elevation, forming the timber-line on many mountain ranges from latitude 53° north in the Rocky Mountains and British Columbia, southward to the Wind River and Salt River Ranges, Wyoming, the mountains of eastern Washington and Oregon, the Cascade Range, the mountains of northern California and the Sierra Nevada to Mt. Whitney.