In Ky. this midwestern species is rare, mostly found in remnants of thin woodland or grassland on rather infertile, acid soils. It has been confused with gronovii, and hybrids may be expected (Y). Hairs on lower stem are longer (6-15 mm versus 1-4 mm); inflorescences are more elongated (with l/w = 4-7 versus 2-4).