10 
SIRCHES (IrGure 3) 
A genus of about thirty species, mainly trees, though a few are 
shrubs, with simple, toothed leaves which are not distinctive. A 
prominent feature is the bark, separable in some species into thin, 
papery plates, and characterized by longer or shorter, transverse 
dashes which contain the lenticels. The naked catkins of staminate 
flowers are mostly erect on the branches during the winter. 
One of the most distinctive botanical characters of the birch is 
us 
— 
its fruit, borne in a cylindrical structure called a fruit spur. T 
is composed of bracts having winged nutlets in their axils, and 
arranged in a close spiral. The shape of the bracts is fairly con- 
stant for each species, also the size of the nutlets and the com- 
parative width of their wings. 
During the winter these fruit spurs stand more or less erect on 
the branches. The jarring effect of winds and storms causes them 
gradually to lose the bracts and nutlets, which one can find sown 
on the snow beneath. A knowledge of the shape of the bracts is 
an important aid in determining the species. 
Among the trees of northern New England and New York and 
westward as far as the Rockies, the Paper Birch or Canoe Birch 
(Betula papyrifera) is perhaps the most beautiful, certainly the 
most striking of all. With its gleaming white bark and tall, straight 
trunk it stands out in marked contrast to its neighbors. This is 
the tree whose light, strong bark, in separable sheets, was used by 
the Indians for canoe manufacture. Although a lover of the cool 
tivation as an ornamental 
— 
northern woods, it takes kindly to cu 
tree. In North America no other tree grows farther north than 
the paper birch. In Europe, Betila pubescens goes nearly as far 
north as the North Cape, and is still a small forest tree at 70°, 
north latitude. 
The birches, though useful as timber trees, are popular for 
ornamental planting, particularly the white-barked species, as much 
for their graceful branching habits as for the coloration of their 
bark. 
