Thallus: crustose, determinate, coarsely rimose to areolate, up to 4 cm across, 0.6(-0.8) mm thick; areoles: sub-angular, plane to somewhat bullate in non blastidiate parts, +contiguous, up to 0.5 mm across; surface: yellow-brown, brownish gray to brownish green, dull to rarely slightly shiny, somewhat greenish when wet, epruinose, with concolorous edges, thickly and partly densely blastidiate; cortex: developed in non-blastidiate parts, mostly paraplectenchymatous, overall 10-30 µm thick, either with an epinecral layer or covered with a thin, 5-15 µm thick one; medulla: indiscernible, hyphae unoriented; algal layer: irregular in thickness, 50-300 µm thick; algal cells 7-17 µm; Apothecia: broadly sessile, sometimes +partially obscured by blastidia, single or in small clusters and then often deformed, 0.5-1.2 mm in diam.; disc: red-brown to black, convex to flat, ±densely gray-pruinose, concolorous when wet; margin: thalline, brown, well developed, irregular, swollen, irregularly cracked to incomplete and partially hidden (crowded back), densely and minutely granular with blastidia; amphithecium: with a paraplectenchymatous cortex; parathecium: not evident from above, weakly developed; epihymenium: pale brown, densely granular; hymenium: hyaline, 60-70 µm tall; paraphyses: simple, 2.5 µm wide below, short-celled toward the apices, becoming submoniliform in upper third, with often noticeably vacuolate cells, tips, with gradually thickened, hyaline tips up to 5-7 µm wide, with weak deposit of brown epipsamma; hypothecium: hyaline, paraplectenchymatous, 25-40 µm thick; asci: clavate, Bacidia-type, 45-50 x 10 µm, 8-spored; ascospores: hyaline, (1-)3-septate, oblong-fusiform, straight to slightly curved, 12-15 x 4-5 µm, thin-walled, somewhat narrowed at the apices; Pycnidia: very rarely found; +globose, c. 120 µm in diam., reddish brown around the ostiole; ostiole: c. 80 µm wide, conidiogenous cells: elongate, branched at base; 10-12 x 2-2.5 µm; conidia: relative short filiform, straight to slightly curved, 10-14 x 0.8 µm; Spot tests: all negative; Secondary metabolites: none detected.; Substrate and ecology: mostly on walls, on old, crumbling mortar, rarely on sandstone; World distribution: central and western Europe and western U.S.A.; Sonoran distribution: only known from one locality in Arizona (Coconino National Forest).; Notes: Lecania coeruleorubella forms a thick thallus of abundant blastidia and may be sterile, and may consequently be overlooked. The ascospores of the Arizonan specimen are somewhat shorter than those given in the original description; however, the most recent collections of this species from Luxemburg also have the same rather short ascospores. Lecania coeruleorubella is not likely to be confused with any other Lecania in the Sonoran region; even if the blastidia are few or not recognized as such, the species can be easily distinguished from L. cuprea, which also has 3-septate ascospores, by its paler, thicker and more gray thallus, its larger, dark, pruinose apothecia with a well-developed amphithecium, its taller hymenium, and its shorter but wider ascospores.
Regularity: Regularly occurring