BIRCH FAMILY 



57 



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

 large sheets as that of the rarer canoe birch (5. papyrifera). 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 



Fig. 11. Gray birch (Betula populifolia) 



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

 fruits; C, bract with three staminate flowers; J), 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. 3, 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 



