Description: Thallus foliose, dorsiventral, rather closely adnate, forming very irregular patches. Lobes 4-10 mm wide, elongated, usually concave, with raised, white-sorediate margins. Upper surface yellowish green, smooth and somewhat shiny; lower surface tan to pale brown, with scattered, simple or forked, pale brown rhizines, without pseudocyphellae. Upper and lower cortex paraplectenchymatous, rather thin, with thick-walled cells; medulla white. Apothecia extremely rare (not found in Italian material), zeorine, usually submarginal, up to 7 mm across, with a pale brown disc. Asci 8-spored, clavate, Lecanora-type. Ascospores 1-celled, hyaline, subglobose, c. 5 μm wide. Pycnidia rare, black, marginal, projecting. Conidia sublageniform, 7-11 x 0.8-1 μm. Photobiont chlorococcoid. Spot tests: upper cortex and medulla K-, C-, KC- P-. Chemistry: upper cortex with usnic acid; medulla with caperatic, lichesterinic and protolichesterinic acids.
Note: a cool-temperate to boreal-montane, incompletely circumpolar species found on basal parts of conifers in humid-cold montane forests, more rarely on lignum (e.g. on stumps); restricted to the Alps in Italy. It is included in the Italian red list of epiphytic lichens as “Vulnerable” (Nascimbene & al. 2013c).
Growth form: Foliose, broad lobed
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)
Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)