Basionym Name:Placodium ferrugineum f. discolor Willey ex Tuck., Syn. N. Amer. Lich. (Boston) 1: 178 (1882)
Homotypic synonyms:Caloplaca discolor (Willey ex Tuck.) Fink, Lich. Fl. U.S.: 356 (1935)Caloplaca ferruginea var. discolor (Willey ex Tuck.) Zahlbr., Cat. Lich. Univers. 7: 124 (1930)