Here's the answer! The mystery plant in yesterdays blog turns out to be narrowleaf vervain. It was indeed an impoverished individual in difficult circumstances. I had previously seen it in bloom near that site in 1986. These plants normally get a little over two feet tall. The flowers can be pale like this, or more purplish or blue. The flowers are about a quarter inch across. Narrowleaf occurs in AL, AR, CT(S), DE, FL, GA, IA, IL, IN, KS, KY, MA(E), MD, MI, MN, MO, MS, NC, NE, NH, NJ(E), NY, OH, OK, PA, SC, TN, TX, VA, WI, WV, ON, and QC(L). McMinn Co TN, 7/6/18. Vervain family, Verbenaceae.