TREES OF NORTH AMERICA 



below with axillary tufts of pale hairs, l|'-3' long, l'-2'wide; petioles glabrous or rarely 

 villose, ^'-f in length. Fruit: strobiles f '-2' long and f '-|' thick, on villose peduncles up 

 to f in length; scales glabrous or pubescent. 



A tree rarely more than 30 tall, with slender glabrous or pubescent branchlets, and at 

 high altitudes on the New England mountains reduced to a low shrub. Bark separating 

 in thin layers, white or dark reddish brown. 



Distribution. Labrador and Newfoundland to northern New England, and westward 

 to the shores of Green Bay, Wisconsin, and those of Lake Superior, Minnesota (Grand 

 Marais, Cook County); on Mt. Mitchell, North Carolina, at an altitude of 5550 (W. W. 

 Ashe). 



Betula papyrifera var. subcordata Sarg. 

 Betula subcordata Rydb. 



Leaves ovate, acute or acuminate at apex, slightly cordate or rounded at base, rarely 

 slightly lobed above the middle, finely often doubly serrate with teeth pointing forward or 

 spreading, glabrous, 2'-2^' long, I'-l^' wide; petioles sparingly villose or glabrous, ^' f' 

 in length. Fruit: strobiles drooping on slender peduncles 1'-!$' long, about $' thick, 



Fig. 201 



their scales puberulous, ciliate on the margins, the middle lobe acute, rather longer than the 

 broad truncate lateral lobes; nut obovoid, cuneate at base, iV long, narrower than its 

 wings. 



A tree 25-40 or occasionally 60 high, with a trunk 12'-18' in diameter, and slightly 

 glandular glabrous red-brown branchlets. Bark separating freely into thin layers, white or 

 occasionally dark reddish brown or orange color. 



Distribution. Alberta (Crow Nest Pass, neighborhood of Jasper and Cypress Hills), 

 through northern Montana and Idaho to western Washington, northeastern Oregon 

 (Minum River Valley) and British Columbia. 



Betula papyrifera var. montanensis Sarg. 

 Betula montanensis Butler. 



Leaves broadly ovate, acute at apex, truncate or rounded at base to oblong-ovate or 

 lanceolate and long-pointed and acuminate at apex, narrowed and rounded at base, coarsely 

 doubly serrate, thick, dark green above, paler, sparingly pubescent and furnished with 



