quaking aspen Salicaceae Populus
Leaf: Alternate, simple, 1 to 3 inches long, green above and paler below, heart-shaped to nearly round with a fine toothed margin, petiole is flattened.
Flower: Species is dioecious; male and female hanging catkins 1 to 3 inches long.
Fruit: Catkin (2 to 4 inches long), with attached light green capsules which contain many small hairy seeds.
Twig: Slender, glabrous, reddish brown often with a gray, waxy film; buds conical, reddish brown, terminal bud 1/4 inch long, may be slightly resinous.
Bark: At first smooth, creamy yellowish-white to very light green; later developing thick furrows and becoming dark, especially near the base.
Form: Small (30 to 40 feet tall) upright tree, which often occurs in thickets.
Looks like: bigtooth aspen - black cottonwood - balsam poplar - Fremont cottonwood