I went looking for this one. I had seen it in a couple of spots in the 1980s. The first place I went to this day had been taken over by cattails. No aster. The second place hadn't changed much, but no aster. I gave up. I no longer remember why I made the third stop in a place I had visited many times. And there it was. White asters are many and tricky. On other visits I just took it for granted that it was something else. These flower heads are about a half inch across. They grow in bottomlands in AL, AR, DE, GA, IA, IL, IN, KS, KY, MI, MN, MO, MS, NC, ND, NE, NM, NY, OH(E), OK. SD, TN, TX, WI, WV, ON, and QC. Ives Fen Preserve, Lenawee Co MI, 10/9/11.