161 



is amoDg the bardiest of the Conifers, and grows in tlic most arid and 

 exposed sites, usually occupying soutliern exposuies. It occurs at ele- 

 vations between 4,500 and 6,500 feet. It does not attain as large a size 

 in the Eocky Mountains as in the California Sierras, although in Mon- 

 tana sometimes reaching 100 feet in height, and G to 7 feet in diameter. 

 The wood is quite resinous, of a reddish color, with a handsofue grain, 

 and is largely employed for lumber, raih'oad ties, mining timber, and 

 somewhat for interior finish. 



Description. — Leaves in threes (often in twos), 3 to 6 inches long, hrnsh-like at the 

 ends of the branchlets; persistent three years. Cones 2 to 3 inches h)ng (or more), 

 gray-hro\yn, with strong prickles. Bark very thick, in old trees, :3 to 4 inches. 



8. — Chihuahua Pine. {Pinus Chihuahnana, Engelm.) 



Somewhat rare and of limited range ; found on rocky slopes of south- 

 western i^'ew Mexico (extending into southern Arizona and northern 

 New Mexico), at elevations between 5,000 and 7,000 feet ; 30 to 70 feet 

 high, 1^ feet in diameter. Wood light and strong. 



Description. — Leaves mostly in threes (t\A^os and fours also"), 24^ to 3^ inches long: 

 cones on stems to f an inch long, 1| to 2^ inches long; dark brown, with short del- 

 icate xn'ickles. 



0.— Black Pine. Lodge-Pole Pine. Tamarack. [Plnus Mur- 

 ray ana^ Balfour.) 



Eather abundant throughout the Kocky Mountain region, extending 

 westward and northward, but more common in the northern portion, 

 forming large forests of pure growth. It is said, however, to attain its 

 greatest size in southern California — GO to 100 feet, with a diameter of 

 over 3 feet.* 



Usually found growing in slightly moist or dry gravelly soil between 

 0,000 and 9,000 feet elevation. The wood is soft and light, not unlike 

 that of the White Pines ; employed to some extent for lumber, railroad 

 ties, and much for " lagging " in mines. 



Description. — Leaves in twos, 1 to 3 inches long, but chiefly 2 inches, with fine 

 teeth. Cones 2 to 3 inches long, reflexed, and with delicate recurved prickles. Bark 

 very thin and scaly, grayish-brown. Crown conical. Resembles the Scrub Pine 

 ( Finns contorta, Dough), but distinguished from it by having longer and wider leaves, 

 as well as by a much thinner bark. 



10.— White Spruce. Single Spruce. {Picea alba, Link.) 



A large and important timber tree, growing in rather wet soil on the 

 borders of ponds and streams, reaching over 100 feet in height and 2 to 

 3 feet in diameter. In the Eocky Mountain region it occurs only in 

 northern Montana, and attains its greatest size in the Flathead region 



* When growing in thickets it is often imperfectly developed, and is called " Lodge- 

 pole Pino ; " such trees somefcioies being over fifty years old, with a diameter of not 

 more than 6 to 8 inches. 



21738— Bull 2 11 



