Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.

Thallus: small-squamulose, forming compact mats over the substrate; hypothallus: poorly developed and inconspicuous squamules: small, up to 1 mm wide and up to 200 µm thick, often imbricate upper surface: gray, bluish gray to dark brown (when wet), sometimes with a reddish tinge upper cortex: paraplectenchymatous, 40-50 µm thick medulla: composed of intricately interwoven, lax plectenchyma, 20-40 µm thick and merging into the hypothallus below photobiont: a cyanobacterium (Nostoc, forming clumps) Apothecia: common, often aggregated, up to 2 mm in diam., flat to convex, with a strong crenulate thalline margin; disc: bright orange-brown to dark brown; exciple: subparaplectenchymatous, up to 40 µm thick; hymenium: I+ dark blue, up to 150 µm high; paraphyses: simple, septate, slightly clavate at apices asci: clavate to subcylindrical, 8-spored. ascospores: simple, colorless, ellipsoid, 25-30 x 9-12 µm (including the distinct, warted epispore; otherwise 19-25 x 8-10 µm) Conidiomata: pycnidial Spot tests: all reactions negative Secondary metabolites: none detected. Substrate and ecology: on damp mosses or soil, mainly in montane regions World distribution: widespread in the cool, temperate regions of the Southern and Northern Hemispheres, mountains of East Africa Sonoran distribution: high elevations in Douglas fir and spruce-fir zones above 2500 m in the mountains of central and eastern Arizona. Notes: It is characterized by the numerous, conspicuous brightly colored apothecia with a pertsistant granular thalline margin, and the often brownish, nearly crustose thallus, though often confused with Psoroma hypnorum, a species found in similar habitats, which is easily distinguish on its greenish squamulose thallus and large, convex apothecia with squamulose thalline margin. Protopannaria pezizoides contains a cyanobacterium and hence is very dark bluish brown when wet; whereas P. hypnorum is bright green when wet due to its chlorococcoid alga.