Flat-topped white aster flower clusters are usually, but not always, flat -- occasionally the plant has a dome-shaped flower cluster. The disk flowers turn gray with age, and the grayish flower heads persist late into fall. Cornel-leaf aster looks similar, but it has broader leaves, and it tends to have very few flower heads.
• Family: Aster (Asteraceae)
• Habitat: moist thickets and meadows, swamp edges
• Height: 2-7 feet
• Flower size: flower heads 1/2 to 3/4 inch across
• Flower color: white rays around a yellowish disk
• Flowering time: August to September
• Origin: native