Deutschl. Fl. 2: 120 (1796).

Basionym: Lichen deformis L., Sp. Pl.: 1152 (1753).

Type locality: Sweden, Uppland, Värmdön, Hasseludden, 1915, G. O. A. Malme, Malme: Lich. Suec. Exs. 533 (S - neotype; B, H, S - isoneotype).
Chemistry: Dimethyl sulfone (Culberson 1969, Huneck & Yoshimura 1996: 131).