Description: Thallus crustose, endosubstratic in non-sorediate parts to thinly episubstratic, greyish white to greenish grey, sometimes with a pale brown tinge, forming irregular patches up to several dm across, usually sorediate, without a distinct prothallus. Soralia first scattered and irregular, soon confluent and forming a discontinuous subleprose crust. Soredia farinose, 10-30 μm in diam. Apothecia lecideine, 0.3-0.6(-1) mm across, sometimes tuberculate, with a black, often bluish-pruinose, convex disc and a thin, soon excluded proper margin. Exciple blue-green near the hymenium, colourless to brown in lower part, N+ violet; epithecium greenish to blue-green, inspersed with ochraceous, 5-10 μm thick granules, N+ violet; hymenium hyaline to pale green, 25-40 μm high; paraphyses to 1 μm thick at base, moderately branched and anastomosing, hardly swollen at tips; hypothecium pale yellow to reddish brown. Asci 8-spored, clavate, Bacidia-type. Ascospores 1-celled, hyaline, narrowly ellipsoid, straight or slightly curved, 7-11.5 x 2.5-3.5(-4) µm. Photobiont chlorococcoid. Spot tests: all negative in thallus. Chemistry: pseudoplacodiolic acid.
Note: a rare, mainly boreal species of acid bark in upland areas, closely related to L. turgidula (Schmull & al. 2011).
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)