This has a broad northeastern range, similar to paniculatum, but occurs in more open habitats. H. umbellatum L., is a closely related northern (circumboreal) species that is unknown in or near Ky.; synonyms include H. kalmii L. and H. canadense Michx. (FNA 19, W). Short's (1840) report of kalmii may well have been based on scabrum (M).