Thallus: crustose, discontinuous, of discrete granules or low convex areoles, or continuous and composed of contiguous granules or ±rimose surface: pale to medium gray, yellowish or greenish gray, gray-green, brown-green, rarely ±pure brown, wrinkled, warted, or tuberculate Apothecia: at first flat, eventually becoming convex, 0.3-1.2 mm in diam. disc: usually black, blue-black, or brown-black, rarely paler, purple-brown, gray-brown, brownish pink, or almost pure pink (±pigment deficient apothecia), epruinose margin: concolorous with disc or slightly paler or darker, at first distinct, level with or raised above disc, finally excluded exciple: laterally 40-75 µm wide, without crystals, orange-brown, red-brown, or black-brown (K+ purplish, N+ orange), often with a green or blue-green tinge (K-, N+ purple) in uppermost part, rim concolorous or paler than interior (to almost colorless), both slightly fading below; edge with single cell layer of enlarged cell lumina (up to 5 µm wide) epithecium: usually blue-green to olive-green, containing a blue-green (K-, N+ purple) in the hymenial gel and occasionally small amounts of a brown-gray (K+ purplish, N+ orange) pigment in some paraphyses; crystals not present hymenium: hyaline, 50-105 µm tall; paraphyses: 1.2-2.4 µm wide in mid-hymenium, apices not swollen or ±clavate, 1.6-6.5 µm wide, without distinct hoods of pigment or with diffuse brown-gray hoods hypothecium: pale to dark (often reddish) brown (K+ purplish, N+ orange), fading below asci: clavate, 8-spored ascospores: hyaline, 3-13-septate (often Pycnidia: ±immersed in thallus, bluish or black, c. 50 µm in diam. conidia: filiform, curved, non-septate, 10-20 x c. 0.8 µm Spot tests: all negative Secondary metabolites: none detected. Habitat and ecology: on bark and wood of Populus and Abies, rarely other trees, in mixed conifer forests at high elevations (22003200 m) World distribution: North America, Europe, and Asia Sonoran distribution: relatively widespread in the mountains of the eastern half of Arizona. Notes: Most specimens of Bacidia subincompta from the region have a ±granular thallus. Bacidia subincompta is similar to B. coruscans, which differs mainly in the dominance of a blue-green pigment in the exciple See also B. veneta.