Thallus: within substrate, not visible (endophloedal) Apothecia: sessile and flat when occurring singly, constricted at the base and flexuose when mature or crowded, 0.4-1.2(-1.5) mm in diam. disc: pale brown to black, heavily pruinose, (therefore disc apparently bluish), smooth margin: prominent or even with disc, smooth, uniform, entire, pruinose, paler than disc to white amphithecium: thick, corticate, algae filling amphithecial medulla, algal layer continuous below hypothecium; cortex: distinctly delimited, strongly expanded at base, 16-20 µm thick laterally and 60-100 µm thick basally, composed of adglutinated hyphae or gelatinous; cortical granules sparse, more abundant at top of margin (pol+, insoluble in K, soluble in N) epihymenium: in shades of yellow or brown, granular, granules superficial (pol+/- insoluble in K, soluble in N), in some specimens additional coarse granules present above epihymenium (pol+, soluble in K, insoluble in N) [those granules are easier to observe in thick cross sections] hymenium: hyaline, 60-50 µm tall; paraphyses: simple, rarely branched, at tips slightly expanded or capitate and colorless or pale brown; subhymenium: distinct, granulose; hypothecium: hyaline, composed of adglutinated hyphae, 40-50 µm thick asci: clavate, 8-spored ascospores: hyaline, simple, ellipsoid, 8.9-13.3 x 4.5-5.9 µm Pycnidia: not seen Spot tests: apothecial margin K-, C-, KC-, P-; disc K-, C-, KC-, P-; apothecia UV- Secondary metabolites: sometimes traces of xanthones detected. Substrate and ecology: on tree bark (Juniperus, Populus, Quercus, Salix) and wood, mostly at higher elevations (600 to 3150 m) World distribution: northern and western part of North America Sonoran distribution: eastern and central Arizona. Notes: Although Lecanora wetmorei is a distinctive western North American species, it was previously identified by most of collectors as L. hagenii due to its heavily pruinose apothecial discs. Lecanora wetmorei, however, is distinguished by considerably larger apothecia, 0.4-1.2(-1.5) mm in diameter, entire thalline margin, pale brown to black, sessile or constricted at the base, plane to flexuose discs, and cortex considerably expanded at the base (60100 µm thick). Lecanora hagenii has smaller (0.3-0.9 mm) apothecia, usually dentate apothecial margin, pale to distinctly brown, widely sessile discs, and cortex uniform in thickness or at most expanded up to 60 µm in the base. Moreover, L. wetmorei occurs only in higher elevations, over 600 m.