In Ky. this widespread northeastern species is generally restricted to subxeric woods and thickets on limestone, and it is relatively frequent along the Kentucky River Palisades. Variation deserves further study (Cr, Y). Colls. from BELL (BEREA), ESTI (KY), EDMO (NCU) and PULA (JC) are referable to the relatively eastern var. glaucescens Wieg., which has relatively glabrous leaves. Colls. from ANDE (KY), CRIT (MUR) and MERC (KY) are referable to the relatively western var. illinoense (Wieg.) Palmer & Steyermark, which has longer hairs. The only variety in Mo. is illinoense (Y).