46 TREES OF NORTH AMERICA 



separated by shallow fissures into narrow flat plates broken into delicate scales, becoming 

 on fully grown trees l'-l' thick and deeply divided into broad flat connected ridges cov- 

 ered with closely appressed brown scales more or less tinged with cinnamon-red. Wood 

 light, hard and tough, pale brown tinged with yellow, with thin nearly white sapwood; 

 stronger and more durable than the wood of the other American hemlocks; now largely 

 manufactured into lumber used principally in the construction of buildings. The bark is 

 used in large quantities in tanning leather; from the inner bark the Indians of Alaska obtain 

 one of their principal articles of vegetable food. 



Distribution. Southeastern Alaska, southward near the coast to southern Mendocino 

 County, California, extending eastward over the mountains of southern British Columbia, 

 northern Washington, Idaho and Montana, to the western slopes of the continental divide, 

 and through Oregon to the western slopes of the Cascade Mountains, sometimes ascend- 

 ing in the interior to elevations of 6000 above the sea; most abundant and of its largest 

 size on the coast of Washington and Oregon; often forming a large part of the forests of the 

 northwest coast. 



Frequently planted as an ornamental tree in temperate Europe. 



4. Tsuga Mertensiana Sarg. Mountain Hemlock. Black Hemlock. 

 Leaves standing out from all sides of the branch, remote on leading shoots and crowded 

 on short lateral branchlets, rounded and occasionally obscurely grooved or on young 

 plants sometimes conspicuously grooved on the upper surface, rounded and slightly ribbed 



Fig. 49 



on the lower surface, bluntly pointed, often more or less curved, stomatiferous above and 

 below, with about 8 rows of stomata on each surface, light bluish green or on some indi- 

 viduals pale blue, '-1' long, about fa' wide, abruptly narrowed into nearly straight or 

 slightly twisted petioles articulate on bases as long or rather longer than the petioles; 

 irregularly deciduous during their third and fourth years. Flowers: male borne on slender 

 pubescent drooping stems, violet-purple; female erect, with delicate lustrous dark purple 

 or yellow-green bracts gradually narrowed above into slender often slightly reflexed tips 

 and much longer than their scales. Fruit sessile, oblong-cylindric, narrowed toward the 

 blunt apex and somewhat toward the base, erect until more than half grown, pendulous or 

 rarely erect at maturity, f '-3' long, with thin delicate oblong-obovate scales gradually 

 contracted from above the middle to the wedge-shaped base, rounded at the slightly 

 thickened more or less erose margins, puberulous on the outer surface, usually bright 

 bluish purple or occasionally pale yellow-green, four or five times as long as their short- 

 pointed dark purple or brown bracts; seeds light brown, |' long, often marked on the 



