Range: Connecticut to southern Michigan, southwestward across southern Illinois to central Louisiana, east to northern Florida.
Distinguishing Features: The broad, heart-shaped, toothed leaves readily distinguish the Swamp Cottonwood from other trees in Illinois.
QUAKING ASPEN
Populus tremuloides Michx.
Growth Form: Medium tree up to 50 feet tall; trunk diameter up to 2 feet; crown rounded or occasionally spreading.
Bark: Pale yellow-green or white, becoming grayish and divided into dark scaly ridges at maturity.
Twigs: Pale yellow-green or white, slender, smooth; leaf scars alternate, crescent-shaped, each with 3 bundle traces.
Buds: Lance-shaped, short-pointed, smooth, sticky, up to ⅓ inch long.
Leaves: Alternate, simple; blades ovate to nearly round, short-pointed at the apex, rounded at the base, up to 4 inches long, nearly as broad, with many small round teeth along the edges, green, smooth, and shiny on the upper surface, not shiny on the lower surface; leafstalks to 3 inches long, smooth, flat. The flat leafstalks allow for the leaves to tremor at the slightest wind.
Flowers: Staminate and pistillate borne on separate trees, the staminate crowded in catkins up to 4 inches long, the pistillate crowded in catkins up to 6 inches long.