and Old World Birches. 173 
by the Red Indians of Canada.”* There is, then, no evidence 
from the descriptions and comparisons of Michaux and other 
well-informed European authors that the American Betula 
papyrifera is separable from the true &. alba of northern 
urope. 
Betula alba, forma occidentalis. 
In the discussion of Betula papyrifera in his Silva, Pro- 
fessor Sargent refers} to the tree of the northwest coast, a form 
which “differs from the eastern [ papyrifera] in its greater 
height and rather darker colored bark, in its more pubescent 
branchlets, which sometimes do not beeome glabrous until their 
second season, although vigorous shoots of young plants in the 
east are often clothed with thick pubescence, and in its rather 
larger leaves, which, on the lower surface, are also more pubes- 
cent.” Later, however, the same author has identified{ this 
large tree with B. occidentalis, Hooker,§ not the small tree or 
“half-shrab taken for B. occidentalis by Nuttall and other 
American authors, including Sargent, Silva, ix, 65, t. 453; 
and he concludes that the bark “is very different from that 
of the eastern tree, and it is probably best to consider it a 
species.” . 
* Syme, English Botany, viii, 184. + Sargent, Silva, ix, 59. 
} Sargent, Bot. Gaz., xxxi, 238 (1901). § Fl. Bor.-Am., ii, 155 (1839). 
