Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: crustose, continuous, thin, immersed or superficial, then varnish-like or ±warted, without cracks surface: pale gray or almost white Apothecia: at first flat but soon becoming convex, 0.15-0.35 mm in diam. disc: black, often with thin white pruina margin: black at first distinct, level with disc, soon excluded exciple: laterally 15-40 µm wide, without crystals or with a few coarse ones, pale olive-green, sometimes gray-green or dark green in uppermost part (K+ violet, C+ violet, N+ red), usually diffusely pigmented; edge: without zone of enlarged cell lumina epithecium: olive-green to gray-green (K+ violet, C+ violet, N+ red), sometimes overlain by crystals hymenium: hyaline, 35-45 µm tall; paraphyses: 1-2 µm wide in mid-hymenium, apices narrowly clavate or not at all thickened, 1.5-2.5 µm wide, without distinct hoods of pigment hypothecium: hyaline asci: clavate, 8-spored ascospores: hyaline, 3-(7-)septate, bacilliform or sometimes tending towards acicular, straight, 15-25 x 2-2.7 µm Pycnidia: half-immersed in thallus, black around ostiole, c. 60 µm in diam. conidia: simple, ellipsoid to almost drop-shaped, 3-4.5 x c. 1.5 µm Spot tests: all negative Secondary metabolites: none detected. Habitat and ecology: on bark of Abies lasiocarpa and Populus tremuloides in mixed conifer forests at 2800-3000 m World distribution: North America, Europe and Asia Sonoran distribution: rare in the mountains of east and southeastern Arizona.