This dioecious, deciduous tree reaches 100 feet tall. It has grayish, furrowed bark. Its 1 1/4- to 2 3/4-inch finely toothed, ovate leaves are dark green above and paler green beneath. Its inconspicuous flowers bloom in 1 1/4- to 3 1/4-inch catkins from February through April. The 1/8- to 1/2-inch fruit is a dry capsule with hairy seeds. Black cottonwoods are found at streamside places.