FOREST TREES. 123 
This is also a large and lofty tree, and grows in the 
same soils and situations as the preceding, which it 
greatly resembles. So much are they alike, that 
they are not only confounded by the Western 
people generally, but some botanists are strongly 
inclined to doubt the existence of more than one 
species. 
There is a variety called the Yellow Cottonwood, 
which is not uncommon, the heart-wood of which is 
of a yellowish color, like that of the Tulip Tree. It 
grows in the same situations as others of its kind, 
and is split without difficulty into rails. Shingles 
have been manufactured from it, which lasted a con- 
siderable time. When sawed into lumber, it does not 
warp, like the Cottonwood generally. If P. angulata 
and P. monilifera are really distinct, it is a matter of 
uncertainty to which this variety belongs. The sub- 
ject deserves investigation. 
3. P. tremuloides—American Aspen. 
Leaves, roundish, heart-shaped, with a short, sharp 
point, and small, regular teeth, smooth on both sides, 
with downy margins; scales cut into three or four 
deep linear divisions, fringed with long hairs. 
This species of Poplar is abundant in the British 
Provinces, and common in the northern part of the 
United States. Itseldom exceeds thirty feet in height, 
and is a short-lived tree. The wood resembles that 
of other species. 
