BETULACEAE 

 Paper Birch 



Betula papyrifera Marsh. 



HABIT. A tree 60-70 feet high and 2-3 feet in diameter 

 (max. 1 20 by 4 feet) ; old trees with open crowns and short, 

 pendulous branches. 



LEAVES. Ovate; 2-5 inches long; coarsely, irregularly, and 

 usually doubly serrate; dull dark green and glabrous above, 

 light yellow-green, black-glandular and glabrous or puberulous 

 below. 



FRUIT. Strobiles cylindrical, pendant, on slender peduncles, 

 1-1 V^ inches long; scales about as long as broad, puberulous; 

 nutlet narrower than wings. 



TWIGS. At first green, hairy, and marked by scattered, 

 orange-colored, oblong lenticels; becoming dark orange-brown 

 and lustrous; not aromatic. Winter buds: K inch long, obo- 

 void, acute, dark chestnut-brown, glabrous. 



BARK. Cream-white; separating into thin, papery layers; 

 marked by long, narrow, raised lenticels; inner bark orange. 



WOOD. Moderately important; used for pulp, lumber, 

 turned articles, and fuel. 



SILVICAL CHARACTERS. Canadian zone; intolerant; 

 short-lived; spreading roots; reproduction vigorous, taking over 

 extensive areas following fire; rich or sandy soils. 



GENERAL. Six varieties have been differentiated and are 

 included in the distribution map: 



1. commutata (Reg.) Fern, from Idaho to Washington and British 

 Columbia. 



2. cordifolia (Reg.) Fern, from Labrador to Minnesota and New York. 



3. humilis (Reg.) F. & R. in western Canada and Alaska. 



4. kenaica (Evans) Henry in Alaska. 



5. montanensis (But.) Sarg. in Montana and Idaho. 



6. subcordata (Rydb.) Sarg. from Idaho to Oregon and western 

 Canada. 



* * * 



Blueleaf Birch, Betula caerulea-grandis Blanchard, is a small 

 tree found in Nova Scotia, Maine, and Vermont. It is char- 

 acterized by ovate, blue-green leaves and pink-white bark which 

 is not papery or exfoliating but slightly. 



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