This one probably isn't for the faint of botanical heart. I've included several photos to hopefully give someone enough to come up with the name of this plant. Tony shouldn't participate by providing an answer, as he was with me when we saw this plant in Douglas County, Wisconsin. Good luck!
Underside of leaf
Top of leaf
Below are a couple of additional photographs of this plant.
The best that I can tell, this is Aster lanceolatus var. hirsuticaulis, a hairy-stemmed variety of Aster lanceolatus. Aside from the fairly densely pubescent stem and pubescent leaf undersides, this variety looks like Aster lanceolatus var. lanceolatus. I have only ever seen this hairy-stemmed variety in Douglas County, Wisconsin, though it is said to occur also in Illinois, Iowa, Michigan, and Minnesota, as well as in Ontaria and Manitoba.
Anonymous had guessed Aster lanceolatus ssp. hesperius, a more western species that ranges east into Wisconsin. The stems of this species are said in Flora of North America to be "glabrous or at most hairy in lines." In addition, the flowering heads of this species are subtended by large leaf-like bracts, and the outer phyllaries are 2/3 as long as the inner ones (versus 1/3 to 2/3 as long as the inner ones in A. lanceolatus var. hirsuticaulis). Without the last two photos that I've posted, you wouldn't have been able to see these floral characters.
Nice job to all who made guesses, as all were very close and my photos weren't that good.