Bih. K. Svenska Vetensk.-Akad. Handl., 18, 3, 3: 42, 1892. Basionym: Lecidea fuscescens f. boligera Norman ex Th. Fr. - Lichenogr. Scand., 2: 461, 1874.
Synonyms: Biatora nylanderi auct. non Anzi
Distribution: N - Frl.
Description: Thallus crustose, granular to verrucose-areolate, sometimes reduced to sparse granules near the apothecia, grey-white to greenish grey, often delimited by a grey-white prothallus. Medulla white, I-. Apothecia sessile to constricted at the base, 0.3-0.7 mm across, with an orange brown to dark reddish brown, rarely blackish brown, concave to flat, rarely convex, epruinose disc, and a thin, smooth, entire, finally excluded thalline margin coloured as the thallus or as the disc. Thalline exciple ecorticate, lacking crystals, with a few algal cells, mostly concentrated at the base; proper exciple colourless, lacking crystals; epithecium reddish to blackish brown or olive-brown, with pigment and fine crystals dissolving in K; hymenium colourless, not inspersed with oil droplets; paraphyses up to 3 µm thick apically, brown-pigmented; hypothecium colourless, not inspersed. Asci 8-spored, clavate, very thin-walled, with a K/I+ blue, tall tholus penetrated by a faintly amyloid apical cushion, the wall K/I-, surrounded by a blue outer layer, Lecanora-type. Ascospores 1-celled, hyaline, globose, 5-7 µm wide, the wall <1 µm thick. Photobiont chlorococcoid. Spot tests: thallus K+ pale yellow, C-, KC-, P+ orange-red. Chemistry: lobaric acid (major), fumarprotocetraric acid (major or absent), and unknown substances (minor).
Note: a circumboreal-montane species found on twigs of Rhododendron and other shrubs in open, often windy situations, on the top of small branches, sometimes on plant debris and lignum, with optimum near treeline; certainly widespread throughout the Alps.