COTTONWOOD
Leaf, one-third natural size. Twig, one-third natural size.
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.