Thallus: areolate, thin, often small, to 2(-4) cm in diam., ±orbicular or spreading irregularly among other lichens areoles: 0.2-0.7(-1) mm in diam., round to angular, ±dispersed, rarely contiguous, usually fertile; prothallus: black, visible between areoles and at margins surface: light to dark gray, often with a ±reddish tinge, sometimes brown, without soredia cortex: 10-20(-25) µm thick, uppermost part ±brown, 5-12(-15) µm thick, with cells 5-7 µm in diam., covered with a thin epinecral layer, (0-)1-4 µm thick photobiont: chlorococcoid, cells ±round, (5-)8-17(-20) µm in diam Apothecia: immersed, aspicilioid, numerous, 0.2-0.4(-0.7) mm, 1-2(-4) per areole, round, at times irregular or ±angular disc: concave, rarely flat, brown-red when dry, red when wet, epruinose thalline margin: thin, sometimes ±prominent, concolorous with thallus exciple: very thin or absent, (0-)10-15 µm wide, I+ blue; uppermost cells: brown, ±globose, 4-5 µm in diam. epihymenium: brown, N- hymenium: hyaline, I+ blue, (65-)70-100 µm tall; paraphyses, 1.5-2(-3) µm wide below, with ±swollen apices 3(-4) µm wide, usually with a thin, dark brown cap; subhymenium and hypothecium: pale, I+ blue, together 30-50 µm thick asci: clavate, (40-)45-70 x (12-)16-32 µm, Porpidia-type, 8-spored ascospores: hyaline, simple, ellipsoid, (12-)14-21 x 6-13 µm Pycnidia: rarely present, immersed conidia: bacilliform, at times ±fusiform, 5 x 1(-1.5) µm Spot tests: thallus K-, C-, P-; medulla I+ blue Secondary metabolites: none detected by TLC. Substrate and ecology: on exposed siliceous rocks, including crystalline schist, in higher coniferous forests or in open situation World distribution: montane, boreal, arctic-alpine in Eurasia and North America, including northern California Sonoran distribution: Arizona and Baja California at 1300-2750 m. Notes: Bellemerea sanguinea seems to be rather rare in the Sonoran area but rather common further north in California. It is often inconspicuous; as the thallus often grows intermingled with other saxicolous lichens. Bellemerea sanguinea is closely related to B. cinereorufescens, but differs from that species by its smaller and dispersed areoles which usually are fertile; small, immersed, concave apothecia with intensive brown-red disc, higher hymenium and larger spores. Several specimens in the herbaria from California where filed as B. cinereorufescens.