Alaska Birch 



249 



it is used for barrel-hoops, shoe-pegs, largely for spools, and somewhat for paper- 

 pulp. The tree grows fast but is short-Uved. 



2. BLUE BIRCH Betula coerulea W. H. Blanchard 



This recently described species is very closely related to the Gray birch, and is 

 reported from moist mountain sides at altitudes of about 550 meters in Vermont 

 and Maine, and probably occurs in simi- 

 lar situations throughout the north- 

 eastern portion of our area. It reaches 

 a height of 20 meters, with a trunk di- 

 ameter of 4.5 dm. in its large-leaved 

 form, or about half these dimensions in 

 the smaller-leaved form. 



The rather small branches are nearly 

 upright at first, but become spreading. 

 The bark is about 6 mm. thick, its outer 

 layer somewhat shining, white with a 

 reddish tinge, the inner bark yellowish. 

 The twigs are slender, slightly long-hairy 

 and purplish at first, becoming reddish 

 brown and quite smooth, except for nu- 

 merous pale lenticels. The leaves are 

 ovate, 5 to 7 or 9 cm. long, sharply and 

 quite regularly -toothed toward the long, 

 taper-pointed apex, quite entire near the 

 rounded or wedge-shaped, sometimes un- 

 equal base, pale glandular at first, soon 



Fig. 204. Blue Birch. 



becoming smooth and dull bluish green above, pale yellowish green and slightly 

 hairy along the principal veins beneath; the leaf-stalk is slender, 2 to 3 cm. long, 

 often reddish. The staminate catkins, sometimes in pairs, are cylindric, 3 to 5 cm. 

 long or longer. The fruiting catkins are drooping, slender, cylindric, 2 to 3 cm. 

 long, slightly tapering at the blunt apex, their stalks about i cm. long. The nut 

 is oval, its wing much broader than the body. 



The large form with leaves more rounded at the base, thicker fruiting catkins, 

 and generally larger in all its parts, has been called Betula ccerulea-grandis by 

 Blanchard, and B. coerulea var. Blanchardi by Sargent. 



3. ALASKA BIRCH Betula alaskana Sargent 



The Alaska birch, abundant in the interior of Alaska and the Yukon Territory, 

 extends southward to the Saskatchewan valley and eastward to the Mackenzie 

 River and perhaps to Quebec. It is said to occur also on the Alaskan coast. 



