57 



Bark scaling off in white strips and layers, but not in nearly as 

 large sheets as that of the rarer canoe birch (B. papyri/era). The 

 commonest birch of New England. 



5. B. alba L. EUROPEAN WHITE BIRCH, CUT-LEAVED BIRCH. 

 A tree 50-60 ft. high, often with drooping branches. Leaves 

 triangular-ovate, truncate, rounded or somewhat heart-shaped at 



E 



FIG. 11. Gray birch (Betula populifolia) 



A, catkins, natural size : s, staminate ; p, pistillate. B, cluster of ripened 

 fruits; G, bract with three staminate flowers; D, bract with three pistil- 

 late flowers ; E, fruit. (B, C, D, E, somewhat magnified) 



the base, not strongly taper-pointed except in the cut-leaved form. 

 Commonly cultivated from Europe. Resembles No. 4, but has whiter 

 bark and (the weeping form) much more slender branches. 



Var. papyrifera. CANOE BIRCH, PAPER BIRCH. A large tree, 

 often 60-70 ft. high, with chalky-white papery bark, peeling off in 

 large thin sheets. Leaves ovate, acute or taper-pointed, coarsely 

 serrate or dentate, but entire at the base, dark green and usually 

 without glands on the upper surface, on the lower surface light 

 yellowish-green and nearly smooth, but with tufts of hairs in the 



