Enum. Lich. Byssac. Scandin.: 7 (1843).

Basionym: Lichen arcticus L., Spec. Plant. 2: 1148 (1753).

Type locality: Sine loc. (LINN 1273. 180! - lectotype). Selected by James & White (1987: 223). [TLC: Nephroarctin, phenarctin, hopane-6alpha,22-diol (T3=zeorin), + usnic acid (tr.)].

Thallus: foliose, terricolous, musciccolous or saxicolous, loosely attached, large, to ca. 18 cm diam., yellow-green, main lobes ....