Flattop Aster in Cowles Bog
The flowers of the Flattop aster closely resemble those of its relative, the Bigleaf aster. As you might suppose from the name, the Bigleaf aster has large, serrated leaves, while the Flattop has long, skinny leaves - - as here.
Photo taken September 2007 in Cowles Bog, Indiana Dunes NL.