The _leaves_ are simple, alternate, broadly triangular, pointed and
coarse toothed on the edges, 3 to 5 inches across, thick and firm
supported by flattened slender petioles, 2 to 3 inches long. The _winter
buds_ are large and covered with chestnut-brown shining resinous scales.
The _flowers_ are in catkins, of two kinds, on different trees and
appear before the leaves. The _fruit_ ripens in late spring, appearing
as long drooping strings of ovoid capsules filled with small seeds.
These strings of fruit, 5 to 8 inches long, give to the tree the name of
"necklace poplar." The seeds are covered with white cottony hairs.
The swamp cottonwood, _Populus heterophylla_ L., occurs in swamps in
the southern part of Illinois, and may be known by its broadly ovate
leaves, 3 to 5 inches wide and 4 to 7 inches long with blunt-apex and
cordate base. A few trees of the balsam poplar, _Populus tacamahaca_
Mill., are found in Lake County near the shores of Lake Michigan. The
leaves are ovate-lanceolate, pointed, and cordate. The large buds are
covered with fragrant resin.
The European white poplar, _Populus alba_ L., with light gray bark and
leaves, white wooly beneath, is often found near old houses and along
roadsides. The Lombardy poplar, a tall narrow form of the European
black poplar, _Populus nigra_ var. _italica_ Du Roi, is often planted
and is a striking tree for the roadside.
+BLACK WILLOW+ _Salix nigra_ Marsh.
THE black willow is not only a denizen of the forest but it is at home
on the prairies and on the plains and even invades the desert. It grows
singly or in clumps along the water courses, a tree 40 to 60 feet in
height with a short trunk.
[Illustration: BLACK WILLOW