In its strict sense, this "prickly pear" species occurs mostly from the northern Ridge-and-Valley to the mid-Atlantic Coast (c. Va. and e. W.Va. to Mass. and adventive in s N.H.), but with disjunct records in Miss. (Majure 2007, Majure et al. 2017). It is largely restricted to coarse or rocky soils, especially on slate but also on limestone or sandstone in some localities, Majure showed that humifusa differs from cespitosa in its all-yellow flowers (versus yellow with reddish flower centers), and the generally yellowish-brown (or "tan") color of the much smaller bristles known as glochids (versus reddish-brown). Also, cladodes (the broadly flattened stems or "pads") are generally not broadly obovate (versus often so), and they are dark or yellowish green (versus strongly glaucous when developing, to gray-green when mature). The ephemeral leaves are dark green (versus glaucous, gray-green) and mostly 6.5-9.5 mm long (versus 5.5-6.5 mm). Spines are absent (versus usually present except in shade). Roots are fibrous or merely forming root thickenings proximal to the point of origin (versus fibrous or tuberous, thickened distally to the point of origin). Based on recent research by Adanick & Medley (2020), colls. of humifusa have now been confirmed from Pine Mountain in HARL.(Gross #151 at MDKY; Adanick & Buskirk #194 at EKY) and from the Rugged Hills of PIKE (Browne & Browne #8641; Adanick & Deskins #193 at EKY). It is also expected in LETC (with unverified report).