Thallus: crustose, warted-areolate, sorediate areoles: irregular in outline, often incised and subsquamulose, 0.1-0.25 mm in diam., convex surface: grayish green to dark green, dull upper cortex: poorly developed, c. 10 µm thick; algal layer and medulla: (50-)100-500(-750) µm tall soralia: rounded only when very young, soon confluent, rarely thallus completely leprose-sorediate, yellowish green to light green, 0.25-0.7 mm in diam. soredia: 1540 µm in diam., often forming consoredia of 50-75 µm in diam. Apothecia: rare (not seen in Sonoran material), rounded to irregular in outline, sessile with a constricted base, 0.4-0.85(-1.1) mm in diam margin: not prominent, slightly lighter than disc, dull, soon excluded disc: pale pink to red brown, dull, epruinose, moderately to strongly convex or tuberculate exciple: laterally 50-95 µm, basally 70-180 µm wide, composed of radiating, hyaline hyphae with lumina 1.5-2.5 µm wide epihymenium: lacking hymenium: hyaline or rarely pale yellowish brown, (40)50-55 µm tall; paraphyses: hyaline, simple, lumina 1.5-2 µm, apically 2-3 µm wide; subhymenium: 50-85 µm thick; hypothecium: hyaline or pale yellowish brown, 95-300 µm thick asci: clavate, 8-spored ascospores: hyaline, simple, (10-)11.9-15.6(-19.5) x (3-)3.8-5.9(-7.5) µm Pycnidia: not seen Spot tests: thallus and soralia K-, C+ red, KC+ red, P- Secondary metabolites: gyrophoric acid (major), ±lecanoric acid (accessory). Substrate and ecology: on corticolous bryophytes or on bark and rotting wood at the base of trees, in montane and subalpine forests, (Sonoran specimens are from bark of Abies lasiocarpa) World distribution: Europe, North America and SW Asia Sonoran distribution: Arizona, Mt. Baldy Wilderness, at around 2800 m. Notes: Sterile collections of Biatora chrysantha might be confused with Trapeliopsis granulosa. That species has a more distinctly areolate, grayish thallus and occurs directly on wood, bark or detritus and not on bryophytes.