Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Thallus: crustose, evanescent or thin and scabrid, sometimes areolate, areoles <0.2 mm wide, plane to minutely rugose surface: gray to brownish, dull; margin: indeterminate; prothallus: lacking; vegetative propagules: absent Apothecia: adnate, becoming sessile, frequent, sometimes contiguous, up to 0.4-0.9 mm in diam. disc: black, plane sometimes becoming convex thalline margin: 0.05-0.1 mm wide, concolorous with thallus, entire, rarely incompletely formed, then crenulate with excipular ring: raised thalline exciple: 40-65 µm wide laterally; cortex: 5-15 µm wide; cells: up to 4-6 µm wide, pigmented or not; algal cells: up to 10-17 µm in diam.; thalline exciple: c. 60-90 µm wide below; cortex: to 20-30 µm thick, hyphae intricate to columnar proper exciple: hyaline, (5-)10-15 µm wide laterally, expanded to 20-30 µm at periphery hymenium: 70-100 µm tall; paraphyses: c. 2.5 µm wide, not conglutinate, with apical cells up to 3.5-5 µm wide, pigmented and immersed in dispersed pigment forming a red-brown epihymenium; hypothecium: hyaline, 40-90 µm thick asci: clavate, 50-70 x 17-18 µm, 8-spored ascospores: brown, 1-septate, ellipsoid, type A development, Physciatype, (14-)17-18.5(-21) x (7-)8.5-9.5(-10.5) µm, lumina becoming inflated but retaining thickened apical wall, cells sometimes with slightly pigmented bands; torus: present; walls: ornamented or not Pycnidia: not seen Spot tests: all negative Secondary metabolites: not reported. Substrate and ecology: mostly on small twigs of deciduous trees World distribution: Scandinavia and adjacent Russia and western North America (Alaska to California, frequent in coastal ranges) Sonoran distribution: coastal ranges of southern California. Notes: Northern populations correspond closely to material from Scandinavia (Mayrhofer and Moberg 2002) although the spores may be somewhat larger. The Californian population often has smaller spores with more persistently angular lumina and sometimes better developed thalli, that may be gray rather than pale brown. Smaller apothecia, typical of this population, have a less well-developed lower apothecial cortex. It may prove to be a separate taxon upon further study.