ducing 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.

[Illustration: P. tremuloides.]

2. =Populus tremuloides=, Michx. (QUAKING-ASP. AMERICAN ASPEN.) Leaves
roundish heart-shaped, with a short sharp point, and small, quite
regular teeth; downy when young, but soon smooth on both sides; margins
downy. Leafstalk long, slender, compressed, causing the leaves to
tremble continually in the slightest 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.
Common both in forests and in cultivation.

[Illustration: P. grandidentata.]

3. =Populus grandidentata=, Michx. (LARGE-TOOTHED ASPEN.) Leaves large,
3 to 5 in. long, roundish-ovate, with large, irregular, sinuate teeth;
and when young densely covered with white, silky wool, but soon becoming
smooth on both sides; leaf, when young, reddish-yellow; petiole
compressed. A large tree, 60 to 80 ft. high, with rather smoothish gray
bark. Woods; common northward, rare southward, except in the
Alleghanies. Wood soft and extensively used for paper-making.

[Illustration: P. heterophylla.]

4. =Populus heterophylla=, L. (DOWNY-LEAVED POPLAR.) Leaves heart-shaped
or roundish-ovate with small, obtuse, incurved teeth; white-woolly when
young, but soon becoming smooth on both sides except on the veins
beneath. Leafstalk slightly compressed. Shoots round, tomentose. Buds
not glutinous. A large tree, 70 to 80 ft. high, not very common; found
from western New England to Illinois, and southward.

[Illustration: P. dilatata.]

5. =Populus dilatata=, L. (LOMBARDY POPLAR.) Leaves deltoid, wider than
long, crenulated all round, both sides smooth from the first; leafstalk
compressed; buds glutinous. A tall tree, 80 to 120 ft. high; spire-like,
of rapid growth, with all the branches erect; the trunk twisted and
deeply furrowed. Frequently planted a century ago, but now quite rare in
the eastern United States. From Europe. It is thought to be a variety of
Populus nigra (No. 7).

[Illustration: P. monilifera.]

6. =Populus monilifera=, Ait. (COTTONWOOD. CAROLINA POPLAR.
NECKLACE-POPLAR.) Leaves large, broadly heart-shaped or deltoid, serrate
with cartilaginous, incurved, slightly hairy teeth. The rapid-growing
youn