Growth Form: Large rapidly growing tree up to 100 feet tall; trunk diameter up to eight feet; crown spreading or broadly rounded, with some drooping branches. The largest tree in Illinois, in Grundy County, is a Cottonwood measuring twenty-eight feet six inches in circumference.
Bark: Smooth and gray when young, becoming furrowed at maturity.
Twigs: Yellow-green, gray, or tan, smooth, moderately stout, with numerous pale “dots”; leaf scars alternate, triangular, with 3 large bundle traces.
Buds: Lance-shaped, long-pointed, up to ½ inch long, sticky, chestnut-colored.
Leaves: Alternate, simple; blades to 5 inches long and often nearly as broad, triangular, abruptly pointed at the tip, cut straight across or even slightly heart-shaped at the base, with coarse rounded teeth along the edges, green, smooth, and shiny on the upper surface, paler on the lower surface; leafstalks to 4 inches long, smooth, often yellow, flat.
Flowers: Staminate and pistillate borne on separate trees, the staminate crowded in rather thick, reddish catkins, the pistillate crowded in narrower, greenish-yellow catkins, both sexes appearing before the leaves begin to unfold.
Fruit: Elliptic, greenish-brown capsules up to ¼ inch long, grouped in elongated clusters, containing numerous seeds with cottony hairs attached.
Wood: Light weight, soft, readily warping.
Uses: Pulpwood, fuel.
Habitat: Bottomland woods, along streams.