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, uniform, homiomerous, composed of densely interwoven hyphae, corticate or ecorticate, attached by medullary or prothallial hyphae; prothallus: gray to black, separating the thalli surface: white-gray to dark olive-green or brown, smooth or cracked-areolate, frequently forming mosaics Ascomata: pseudothecia, immersed in stroma or adnate, single or grouped, punctiform, ellipsoid, irregular or +lirellate, rarely stellate disc: pale or dark brown to black, epruinose exciple: absent or poorly developed, brown or colorless hymenium: hyaline; paraphysoids: very slender, anastomosing, becoming more branched above, conglutinated, without swollen tips hypothecium: hyaline or pale orange asci: cylindrical or cylindrical-clavate, fissitunicate, I-, 8-spored; apical dome: with short ocular chamber surrounded by a minute, K/I+ dark blue ring; remaining part of dome and inner wall often K/I+ pale blue ascospores: hyaline, 3-25-septate, fusiform to acicular, 8-75 x 3-4.5 µm, with thin walls and septa and cylindrical locules Conidiomata: pycnidial, immersed, visible as pallid to brown, minute specks; conidiogenous cells: cylindrical, enteroblastic, arising singly conidia: bacilliform or filiform, arising terminally, simple, colorless Secondary metabolites: orcinol depsides, ß-orcinol depsidones, unidentified pigments or secondary metabolites absent Substrate: on rock, bark, or leaves Geography: mainly tropical. Note: Sclerophyton has a dark hypothecium in most species and always has wider spores (5-7 µm) with rounded ends.