Synonyms: Aspicilia alpina (Sommerf.) Arnold; Aspicilia cinereorufescens sensu Körb. non (Ach.) A. Massal.; Aspicilia cinereorufescens var. macrocarpa Anzi non Aspicilia calcarea var. alpina Anzi; Lecanora alpina var. sulphurata Th. Fr.
Description: Thallus crustose, episubstratic, rimose-areolate, rather thick, white to lead-grey or rarely pale brown, forming 1-5 cm wide, more or less orbicular patches or mosaics, sometimes delimited by a black prothallus. Areoles flat to convex, (0.2-)0.5-2(-3) mm wide, contiguous or rarely dispersed, sorediate in some forms. Soredia sometimes present in sterile specimens, blue-grey, arranged in well-delimited soralia developing at the margin of the areoles. Cortex 10-30 µm thick, brownish in upper part, with a thin epinecral layer; algal layer discontinuous below the hypothecium; medulla white, I+ blue. Apothecia aspicilioid, 0.2-1.5 mm across, immersed, 1-2(-4) per areole, round to angular, with a concave to slightly convex, brown-red (when wet) or brown-black (when dry) disc, and a thin thalline margin. Proper exciple poorly developed, colourless, I+ blue; epithecium reddish brown to olive-brown, N-; hymenium colourless, 60-110 µm high, I+ blue; paraphyses branched and anastomosing in upper part, 2-2.5(-3) µm thick, the apical cells up to 4 µm wide, usually with a thin, dark brown cap; hypothecium colourless, 30-60 µm high, pale I+ blue. Asci 8-spored, clavate, approaching the Porpidia-type, with a less distinct tube structure. Ascospores 1-celled, hyaline, ellipsoid or slightly fusiform, 8-15(-23) x 6-8(-13) µm, the inner wall I+ blue, with a thin halonate epispore, often of differerent sizes and shapes within the same ascus. Pycnidia dark, immersed. Conidia bacilliform, 4-6 x 1-1.5 µm. Photobiont chlorococcoid. Spot tests: thallus K+ yellow rapidly turning red (needle-like crystals), C-, KC-, P+ golden yellow. Chemistry: norstictic acid.
Note: a mainly arctic-alpine, circumpolar lichen of hard, acid siliceous rocks wetted by rain near or above treeline; almost certainly restricted to the Alps in Italy.