Flattop Aster (Presumed)

This is, I believe, a Flattop aster (Aster umbellatus). I wish I'd thought to take a better picture of the leaves, but these look relatively long and skinny compared to the Big-leaf aster. The white flowers (the Big-leaf are lavender) also suggest the Flattop. But I wish I could see the leaves better to confirm. Kids, let this be a lesson to you - - take one picture of the *whole* plant, even if you only want to use the flower! You might want more information to confirm the identification. Scoville Point, near Tobin Harbor, Isle Royale, August 2007.