Deutschl. Fl., Zweiter Theil (Erlangen): 133 (1796) [1795].

Basionym: Lichen articulatus L., Sp. Pl. 2: 1156 (1753).

Chemistry: (Swinscow & Krog 1976, Culberson 1969, Culberson 1970, Culberson et al. 1977 all fide Posner 1990: 115)
Race I: Usnic acid, without medullary substances
Race II: Usnic acid, fumarprotocetraric acid, protocetraric acid, diffracta acid, barbatic acid, salazinic acid.
Race III: Usnic acid, salazinic acid, norstictic acid, galbinic acid, barbatic acid.
Race IV: Usnic acid, psoromic acid.
Race V: Usnic acid, stictic acid agg.

Note: Hernández Padrón (2010: 84) distinguishs the subsp. mediterranea Motyka in the Canary Islands.