This has a more northern range than typical pusillus. Although treated as a distinct species or subspecies of pusillus in several treatments (from F to FNA 22), it may be preferable to treat these plants as var. tenuissimus F.K. Mertens & W.D.J. Koch; see also W. Most records from Ky. remain uncertain, and they are provisionally mapped here with typical pusillus. FNA 22 mapped typical pusillus across Ky., but indicated virtually no records of "ssp. tenuissimus." The only known colls. verified by authorities are from JEFF (DHL) and NICH (EKY).