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

Life habit: lichenized Thallus: ±crustose, sometimes almost granular, areolate, rimose, or entirely without cracks, rarely discontinuous, composed of discrete to contiguous areoles; prothallus: absent or present, forming a thin dark line when present surface: smooth, wrinkled, or warted, without isidia but sometimes with soredia cortex: a ±welldeveloped phenocortex and epinecral layer with variable amounts of dead algal cells, or in some species a +well developed prosoplechtenchymatic eucortex, inspersed with minute crystals medulla: white, composed of irregularly interwoven hyphae, sometimes very thin and almost indiscernable photobiont: primary one chlorococcoid green alga, secondary one absent Ascomata: apothecial, biatorine, lecanorine, or zeorine, up to c. 2 mm wide disc: usually yellow, pink, blue- or brown-gray, pale brown to purplish brown to black, sometimes with thin white pruina, containing combinations of a green (K-, N+ purple) and a brown (K+ purplish, N+ orange) pigment exciple: when present annular, colorless to pale yellow, composed of radiating, ±branched and anastomosed hyphae with thick, gelatinized, conglutinated walls, and cylindrical, almost globose, or irregular lumina; crystals: usually present, minute to rather coarse epithecium: distinct containing pigment and often crystals hymenium: hyaline, 35-60 µm tall; paraphyses: straight, unbranched or sparingly branched in upper part, often also somewhat anastomosed; apical cells: often swollen hypothecium: colorless, chondroid or not asci: clavate, surrounded by a gelatinous, amyloid sheet, with a well-developed, amyloid tholus containing a deeper amyloid, conical zone around the axial body and a well-developed, conical ocular chamber (Biatora-type), 8-spored ascospores: hyaline, 1-3-septate, narrowly ellipsoid, narrowly oblong, or bacilliform, straight, smooth, without a halo or perispore Conidiomata: pycnidial, ±immersed, colorless to black, uni- or multilocular, with rather short, branched conidiophores and ampulliform conidiogenous cells; sterile, slender, ±branched hyphae mixed with conidiophores conidia: acro- or pleurogenous, drop-shaped, ellipsoid, short-bacilliform, or ampulliform Secondary metabolites: ß-orcinol depsides, orcinol depsidones, ßorcinol depsidones, dibenzofurans, triterpenes, or (higher) aliphatic acids Geography: temperate and subtropical regions of the world Substrate: mostly on bark, sometimes on rock.