Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.

Thallus: crustose, effuse, continuous or +rimose, usually thin and continuous but sometimes well developed and almost cracked-areolate, ecorticate and without a differentiated medulla surface: white, smooth or somewhat granulose, tartareous, somewhat pulverulent (but not sorediate) Ascomata: numerous, scattered or +crowded, immersed or subimmersed in the thallus, seldom adnate, very variable in form, apothecioid and +round, 0.3-0.5 mm in diam., or somewhat lirelliform, broadly or narrowly oblong, 0.3 disc: black, broad and expanded, plane or somewhat convex; often blue-gray pruinose exciple: shallow and usually undulating, scarcely raised, not very prominent, becoming slightly flexuous, +excluded at maturity, carbonaceous black, closed or, when young sometimes open at the bottom, K+ dark green 0.8 x 0.3-0.5 mm, simple or slightly branched, straight or curved and wavy pseudothecium: pale brown, 15-25 µm thick hymenium: hyaline, 65-87 µm tall, I+ pale red or +blue; paraphysoids: up to 1.5 µm wide, richly branched and anastomosing, not or slightly widened at the apices, with granular external brown pigmentation subhymenium: brown, 20-35 µm thick, I+ pale blue asci: cylindrical-clavate, 60-80 x 12-14 µm, when young 38-50 x 10-12 µm, grumulosa-type, the entire endoascus amyloid, 8-spored ascospores: hyaline, becoming brown only when old, transversely (6-)7-9(-12)-septate, narrowly fusiform, vulgata-type, (17-)23-35 x 3-4 µm; wall: thin, not swollen at the septa, with gelatinous sheath layer (c. 1 µm thick) Pycnidia: not seen Spot tests: thallus K-, C-, KC-, P- Secondary metabolites: two unknown substances, orange and greenish gray after sulfuric acid and heat. Substrate and ecology: on dry, rough and brittle, slightly acidic bark, and or wood, in forested areas and on isolated trees, especially in oceanic areas or other places with humid, shady microclimates World distribution: Mediterranean and western Europe and western North America Sonoran distribution: southern California, Baja California, Baja California Sur, and Sonora. Note: Typically the Sonoran population has spores on the shorter end of the range given above.