ov4 TREES OF MINNESOTA. 
and led to the impression that it is not so hardy as the Cotton- 
wood. The foliage seems to resist the attacks of the leaf fungus 
better than the Cottonwood. 
BETULACEAE. BIRCH FAMILY. 
Genus BETULA. 
Flowers monoecious, apetalous, appearing before or with the 
leaves; the staminate in long pendulous catkins; stamens two; 
the pistillate in erect cylindrical catkins; ovary naked, two- 
celled. Fruit a small nut, surrounded by a wing and covered 
by the enlarged scale of the catkin, ripening in autumn. Leaves 
alternate, simple, dentate or serrate. Trees or shrubs with 
watery juice. A large genus represented by many species. 
The bark contains a resinous balsamic oil sometimes used in 
tanning leather. In parts of this country and Canada the bark 
and leaves of various birches are esteemed as domestic reme- 
dies for diseases of the skin, for rheumatism and gout. An oil 
obtained from the inner bark by distillation is also used ex- 
ternally for the same purpose. The sweet sap of many species 
is used as a beverage, and is sometimes made into wine. 
Propagation.—By seeds, which should be sown when gathered 
or stratified over winter and sown in the spring and the seed- 
lings given some shade during the first season. The varieties 
are propagated by budding, grafting and inarching on the parent 
species. 
Betula papyrifera. Paper Birch. Canoe Birch. White 
Birch. 
Leaves ovate or heart-shaped, dark green on the upper side. 
The bark is reddish on the twigs under four or five years old 
and white on the older branches and trunk, and readily sep- 
arated into papery sheets. A good sized tree, frequently sixty 
or seventy feet high, with a trunk from two to three feet in 
diameter, or perhaps in severe locations dwarfted to a mere 
shrub. 
Distribution.—Throughout Canada to Arctic Ocean (“Widest 
range of any Canadian tree’), south to northern Pennsylvania, 
