Typical whartoniae is known only from the Knobs region of Ky. and from Claiborne Co. in e. Tenn. Similar plants in Md. and elsewhere in eastern states have been included by some authors but probably in error. The taxon may be relatively distinct in form and habitat (Medley 1986). However, H.A. Davis (pers. comm. to MM) indicated that the coll. from CLAR cited as a paratype in Bailey's description is in fact the superficially similar species, roribaccus. F (largely following Bailey) treated whartoniae in a mostly northern group of species characterized by relatively large inflorescences, with generally shorter but more spreading (versus erect) pedicels, and dense pubescence on lower leaf surfaces; see also indianense, with less pubescent leaves. In F's key, whartoniae is close to several other somewhat obscure species with densely pubescent leaves that are reported mostly from northeastern regions, but extending south to Ky., W.Va. and Va. In recent accounts, the only member of this group that has been widely recognized is R. curtipes Bailey, across northeastern states and south to Mo., Ky.,Tenn. and Va. (Widrelechner 1998; Y; Riley et al. 2020); Also, R. arenicola Blanch. has been widely mapped in New England, but including curtipes (Angelo & Boufford 2020). And Widrelechner & Riley (2017) have recently established the name R. beamanii for rare plants in this group from s. Mich and n. Ohio [= R. vagus Bailey, misapplied]. More revision of this group is needed.