Thallus: conspicuously areolate-cracked, rather thick, 1-5 cm in diam., ±orbicular, at times spreading irregularly among other lichens; different thalli often growing adjacent to each other in a mosaic pattern areoles: flat to convex, angular or rounded, often fertile, (0.2-)0.5-2(-2.7) mm in diam., contiguous, separated by cracks or ±dispersed, especially at margins; prothallus: black surface: whitish to beige, fawn, or pale brown, or gray to blue-gray, dull, without soredia cortex: 10-30 µm thick, uppermost part ±brown, 5-12(-15) µm thick, with cells 5-7 µm in diam., covered with a thin epinecral layer, (0-)1-5 µm thick photobiont: chlorococcoid, cells ± round, 7-18 (-20) µm in diam. Apothecia: immersed, aspicilioid, numerous, (0.2)0.5-1.5 mm in diam., 1-2(-5) per areole, round to irregular or ±angular, concave at first, becoming plane or convex and ±sessile in older fruits disc: brown-red to red-brown when wet or blackish brown to brown-black when dry, rather often pruinose thalline margin: thin, ±elevated, concolorous with thallus exciple: thin or absent, (0-)1025(-30) µm wide, I+ blue; uppermost cells: brown, ±globose, 4-5(-6) µm in diam. epihymenium: brown, N- hymenium: hyaline, I+ blue, (60-)70-100(-110) µm tall; paraphyses: 2-2.5(-3) µm wide, with ±swollen apices 2.5-4 µm wide, usually with a thin, dark brown cap; subhymenium and hypothecium: pale, I+ blue, together 30-60 µm thick asci: clavate, (35-)40-50 x (12-)15-20 µm, Porpidia-type, 8-spored ascospores: hyaline, simple, ellipsoid, (8-)10-17(-20) x (5-)6-13 µm Pycnidia: often present, immersed, 1-6/areole conidia: bacilliform, at times ±fusiform, (4-)5-6 x 1-1.5 µm Spot tests: thallus K+ red, C-, KC-, P+ yellow-orange; medulla I+ blue Secondary metabolite: norstictic acid. Substrate and ecology: on ±exposed, siliceous rock, crystalline schist or volcanic rock as basalt in alpine areas and upper coniferous forests World distribution: bipolar; arctic-alpine; Eurasia; North America (south to California, Arizona), Australia, New Zealand Sonoran distribution: central and northern Arizona. Notes: Bellemerea alpina is a rather common and abundant species at high elevation, at least in the Pacific NW. It is quite variable, but easily recognizable by its typical thallus and the K+ red reaction (norstictic acid).