Amer. J. Sci. Arts, Ser. 2, 25: 427 (1858).

Type locality: USA, North Carolina, Forsyth Co., Salem, (Bennett's Rocks?), L. von Schweinitz s.n. (FH-Tuck - lectotype; UPS - isolectotype). Lectotypification in Ahti (1973).

Race II: Lacking squamatic acid (Hodkinson et al. 2009: 69).