Lich. Univ.: 442, tab. 10, fig. 1 (1810).
Basionym: Lichen prunastri L., Sp. Pl. 2: 1147 (1753).
Type locality: [Sweden] (LINN 1273.125 - lectotype). Designated by Jørgensen et al., Bot. J. Linn. Soc. 115: 380, 1994).
Type locality coordinates: Data lacking.
Type locality photo: Data lacking.
Type scan: Data lacking.
Molecular barcode: Data lacking.
Thallus: forming erect or pendent, loose tufts, to 10 cm high. Lobes irregularly branched, strap-shaped, often slightly convex. Upper surface pale greenish grey to yellow (rarely ashgrey), rather smooth. Lower surface whitish. Soralia ? capitate to confluent, especially in polluted areas abundant; soredia farinose. Apopthecia rare, to 1.5 cm diam.; disc concolorous with the upper surface. Spores broadly ellipsoid, 7-11 x 4- 6 μm. Pycnidia laminal and marginal, immersed. Conidia bacilliforrn, 6- 7 x 0.5 μm.
Photobiont: Data lacking.
Chemistry: Nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, 2-methylpentadecane, hexadecane, hepatdecane (sic!), pentadec-1-ene, (Z)-heptadeca-1,8-diene, (Z), (Z)-heptadeca-1,8,11-triene, dec-1-yne, cyclohexanol, hexadecanol, heptadecanol, mesityloxide, 4,6-dimethyldec-4-en-3-one, 2-methyldecaline, 3-methylundec-5-ene, tetradec-1-ene, 4,8-dimethyltridecane, 2-methyltridecane, methyl trans-dodec-9-enoate, tetradec-1-ene, 3,5-dimethyldec-3-en-2-one all in small amounts (Huneck & Yoshimura 1996: 140). Caproic acid, caprylic acid (Gavon & Tabacchi 1975 , Huneck & Yoshimura 1996: 143). Linoleic acid (Solberg 1975 b, Huneck & Yoshimura 1996: 147). Oenanthic acid = Heptanoic acid, oleic acid, palmitic acid, pentadecanoic acid (Huneck & Yoshimura 1996: 151). Stearic acid, Atranol, Chloroatranol, 1,1-Dimethylnoneicosyl everninate, Divarinol, Divarinolmonomethylether, ethyl everninate (Gavin & Tabacchi 1975, Huneck & Yoshimura 1996: 154, 155, 156, 157). Orcinol (Huneck & Yoshimura 1996: 162). ß-Orcinol (Huneck & Yoshimura 1996: 162). Orcinoldimethylether (Huneck & Yoshimura 1996: 163). Orcinolmonomethylether, 3-Hydrocy-5-methoxytoluene (3-Hydroxy-5-methoxytoluen (Huneck & Yoshimura 1996: 163). ß-Orcinolmonomethylether (Huneck & Yoshimura 1996: 162). Phthalic acid (Huneck & Yoshimura 1996: 164).
Ecology: On deciduous trees and shrubs, less often on conifers and lignum, rarely on rocks or over soil on sand dunes, northwards mainly in anthropogenic habitats.
Distribution type: Widespread in westem Eurasia, extending to West Siberia. Also in Far East, Macaronesia and North Africa. One of the most common species in the southem parts of Fennoscandia to the middle boreal zone but rare towards the north. In North America primarily eastern, with scattered localities along the east coast and around the Great Lakes.
Taxonomy: Data lacking.
Note:
Consortium of North American Lichen Herbaria
Lichens of the Pacific Northwest
Race I: With usnic acid (common race).
Race II: Without usnic acid or little usnic acid ("Evernia herinii").
Race III: With evernic acid (major), usnic acid (minor), atranorin (minor) and chloratranorin (minor) (from Morocco (Aoussar et al. 2017: 1973)