Bull. Acad. Roy. Sci. Belgique, Ser. 2, 19: 43, 49 (1865).

Basionym: Cenomyce portentosa Dufour, Ann. Gén. Sci. Phys. 8: 69 (1821).

Type locality: France, Département Landes [Region Aquitanien], St.-Sever, J. Dufour s.n. (PC-Desm - lectotype; H-ACH 1952, TUR-V 13303 - isolectotypes). Lectotypified by Ahti (1978).

Coordinates: 43°45'27"N, 0°34'23"W; 43.7575°, -0.573056°.

Chemistry: Usnic acid, perlatolic acid (Hillmann HBG). Usnic acid, perlatolic acid in different amounts, an unidentified substance in traces (not identical with ursolic acid) (Kümmerling 1991: 123). Lactone carboxylic acid from Cladonia impexa (Huneck & Yoshimura 1996: 146).

Note: The subspecies Cladonia portentosa subsp. pacifica (Ahti) Ahti is here accepted as the species Cladonia pacifica Ahti (see there).