74 KEY TO GENERA AND SPECIES 



115. Young branches perfectly smooth. Northern 

 New England, Quebec, and northwestward, 

 (Fig. 130.) White Birch, Blue Birch, Betula 

 pendula Roth. 



115. Young branches minutely hairy 116. 



Fig. 132. Cordate-leaved Birch. 



116. Branches pendulous.* Cult. Weeping Birch, 

 Betula alba var. pendula Hort. 



116. Branches not pendulous 117. 



117. Leaves rounded or slightly wedge-shaped at 



base 1 1 8. 



* Betula alba var. glutinosa (Wallr.) Traut., with pendulous 

 branches, is local near Mt. Katahdin and in Washington Co., Me. 



