168 TREES OF THE NORTHERN UNITED STATES 
C. Leaves roundish heart-shaped; bark on trunk greenish- 
PIG 256 fee nb Ao Ad Molebdeveant id aden Mnem da iteemank GS ans 2. 
C. Leaves large, ovate, with large, irregular, sinuate 
HOCH: cera sotasanreaiee aia Kehoe niaeakeee CaaS 3. 
B. Buds covered with aromatic, glutinous resin. (D.) 
D. Tree tall, spire-shaped...............cce eee eee eee 5. 
D. Not very spire-shaped; young twigs sharply angled or 
winged, leaves 6 to 10 in. long, broadly deltoid, serrate 
with incurved teeth ....... 0.0... c eee eee eet eee 6. 
D. Not spire-shaped; young twigs not angular ........ 7. 
A. Leafstalk not decidedly flattened; leaf-margin crenate. (E.) 
E. Buds not glutinous; leaves white-woolly beneath when 
E. Buds very glutinous; leaves large, shining green on both 
BIOS 4 Saye es dais bons view Mimienes cAsaceatec eee ees 8. 
“I 
P. alba. 
1. Pépulus alba, L. (WHITE PoPLaR oR 
ABELE TREE.) Leaves roundish, slightly 
heart-shaped, wavy toothed or lobed, soon 
greer above, very white-cottony beneath 
even when old; buds without the sticky 
coating common in the genus. Branches 
very white with down when young. Root 
creeping and producing numerous suckers. 
A large tree, 50 to 80 ft. high, of rapid growth, 
often cultivated; from Europe. Leaves and 
branches very variable, forming several 
named varieties in the catalogues of the nurseries. 
2. Pépulus tremuloides, Michx. (QUaK- 
ING-ASP. AMERICAN ASPEN.) Leaves round- 
ish heart-shaped, with w short sharp point, 
and small, quite regular teeth; downy when 
young, but soon smooth on both sides; 
margins downy. Leafstalk long, slender, 
L 
4 
P. tremuloides. 
compressed, causing the leaves to tremble continually in the slight- 
est breeze. Leaf with 2 glands at the base on the upper surface ; buds 
varnished. A medium-sized tree, 30 to 60 ft. high; bark greenish- 
white outside, yellow within, quite brittle. 
and in cultivation. 
Common both in forests 
3. Populus grandidentata, Michx. (LARGE-TOOTHED ASPEN.) 
Leaves large, 3 to 5 in. long, roundish-ovate, with large, irregular, sinu- 
