In Ky. this largely midwestern species is a moderately conservative remnant of dry native grasslands, mostly in western regions on medium acid soils. It is unknown in Appalachian regions, but plants were recently discovered on dolomitic foothills of the Knobs region, at the Blue Grass Army Depot in MADI (BE; JC for KY). P. pilosum has short calyx teeth (ca. 0.6-1 mm), pilose to villous pubescence, and moderately broad leaves (ca. 0.8-2 cm).