This largely neotropical species has spread into southeastern states as far north as c. Tenn. (Ch, W). There is coll. from Land-Between-the-Lakes in Stewart Co., a few miles south of the state line (J. Stack #761 at APSU). The synonymous P. obscura Michx. was listed by Short (1833) but no voucher is known (M). P. cordata is close to pubescens but differs as follows (Ch, W, Y): leaf margins strongly dentate with 7-10 or more teeth per side (versus entire to dentate with 1-8 teeth); fruiting pedicels 10-35 mm long (versus 6-15 mm); mature fruiting calyx 2.5-4 cm long (versus 2-3 cm), the lobes long-acuminate to attenuate (versus triangular-acuminate); corolla pubescent internally (versus glabrous).