113 



KEY TO THE SPECIES. 



Page. 

 1. Bark usuaUy separating into thin film-Jike papery layers 2 



1. Bark close, not separating into tbin film-like papery layers 4 



2. Outer bark white in color B. alba var. papyriifera 114 



2. Outer bark not white in color 3 



3, Oater bark yellow in color; strobiles usually sessile; leaves usually rounded at 



base, B. latea 115 



3. Outer bark roddish -brown, close, inner bark tinged with red; strobiles * slender- 



stalked; leaves usually wedge-shaped at base, B. nigra 116 



4. Bark chalky white covered with black triangular spots below insertion of lateral 



branches; small tree, often in clumps; leaves long-acuminate B. populifolla 117 



4. Bark dark reddish brcwn; large tree, usually occurs singly; leaves ovate with acute 



apex; twigs and inner bark with wiiilergreen-like taste, B. lenta 118 



