G. 92] CLASSIFICATION AND DESCRIPTION 169 
ate teeth; and when young densely cov- 
ered with white, silky wool, but soon be- 
coming smooth on both sides; leaf, when 
young, reddish-yellow; petiole com- 
pressed. A large tree, 60 to 80 ft. high, 
with rather smoothish gray bark. Woods; 
common northward, rare southward, ex- 
cept in the Alleghanies. Wood soft and 
extensively used for paper-making. P, grandidentata. 
4. Populus heterophylla, L. (Downy- 
LEAVED PopLaR.) Leaves heart-shaped 
or roundish-ovate with small, obtuse, in- 
curved teeth; white-woolly when young, 
but soon becoming smooth on both sides 
except on the veins beneath. Leafstalk 
slightly compressed. Shoots round, to- 
mentose. Buds not glutinous. <A large 
tree, 70 to 80 ft. high, not very common; 
found from western New England to Illinois, and southward. 
P. heterophylla. 
5. Pépulus dilatata, L. (LOMBARDY 
Poptar.) Leaves deltoid, wider than 
“long, crenulated all round, both sides 
smooth from the first; leafstalk com- 
pressed; 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 Eu- 
rope. It is thought to be a variety of 
Populus nigra (No. 7). 
P. dilatata. 
6. Pépulus monilifera, Ait. (Cor- 
TONWOOD. CAROLINA PoPLaR. NECK- 
LACE-POPLAR.) Leaves large, broadly 
heart-shaped or deltoid, serrate with car- 
tilaginous, incurved, slightly hairy teeth. 
The rapid-growing young twigs very an- 
gular and bearing very large (6 to 9 in. 
long) leaves. A very large (80 to 100 ft. 
high) tree, common in the Mississippi val- 
ley, but found in western New England 
P. monilifera, and often planted, 
