Thallus: areolate-squamulose, 1.5 cm across, 5 mm thick; prothallus: occasionally present squamules: 1.5-2.5 mm across, +rounded to irregular; at most indistinctly stipitate; stipes: short (to 2 mm), non-cariose, corticate, lacking rhizinose strands, upper parts gradually broadened from a narrow base, not strongly swollen, often only weakly rugose or plicate, not distinctly foveolate surface: mostly yellowish brown, mostly dull on raised parts, darkened in depressions or crevices, esorediate cortex: with hyphae having indistinct lumina, not staining in cotton blue, with granules soluble in K, 75-100 µm thick medulla: solid to moderately loose, with hyphae 3-5 µm wide, lumina 5-10 x 1 µm; algal layer: continuous, c. 30 µm thick, with algae 8-10 µm in diam. Apothecia: usually numerous, distinct and conspicuous, soon adnate to sessile, usually distinctly darker than the thallus, mostly up to 1.5 mm in diam. disc: black, flat to slightly convex or undulate, usually dull, epruinose margin: concolorous with the thallus, usually distinct and somewhat raised, visible on undersides of apothecia, +raised and conspicuous, then thin and less conspicuous to disappearing, shiny, becoming and crenulate-lobulate amphithecium: present, with a discontinuous algal layer marginally and extending below the hypothecium, with clumps of yellowish brown granules in the medulla, similarly corticate to that of the thallus parathecium: hyaline internally, black externally, 0.1(-0.2) mm wide, with conglutinated hyphae +parallel to sides of the margin (perpendicular to the disc) 3-5 µm wide and with 0.5-1 µm wide lumina epihymenium: blue-black, K+ blue-green, N+ red-violet, without granules, 10-15 µm thick hymenium: I+ blue throughout, c. 40 µm tall; paraphyses: somewhat loosely coherent, simple to several-times furcate, constricted at septa, the tips capitate, 3-4(-5) µm, with light blue then brown or green-black caps; subhymenium: hyaline to yellowish brown tinged, up to 100 µm thick; hypothecium: hyaline, c. 40 µm thick, with hyphae 3-4 µm wide and lumina 1-2 µm wide asci: clavate, 35-40 x 12 µm, 8-spored ascospores: hyaline, simple, broadly ellipsoid, ellipsoid to ovoid-ellipsoid, (6-)8-10(-11) x (2.5-)3-5(-6) µm Pycnidia: ostiole: pale yellowish brown; wall: distinctly brown, conidiophores: +type III of Vobis (1980), bearing conidia apically, but basal cells short and unbranched conidia: hyaline, filiform, mostly 10-16 µm long Spot tests: cortex K+ yellow, C-, KC-, P-; medulla I-, K-, C-, KC+ red, P+ yellow Secondary metabolites: cortex with atranorin; medulla with psoromic acid, +alectorialic acid. Substrate and ecology: on siliceous rocks, often growing on surfaces perpendicular to the plane of foliation, occasionally on soil in crevices in rocks, frequently on massive outcrops on exposed, windy ridgetops, but sometimes on undersides of rocks or under overhangs on large boulders, alpine, to 3200-3750 m World distribution: North America (New Mexico to Montana) Sonoran distribution: Although the report of Lecidea brandegei from Arizona (Fink, 1935) has not yet been confirmed, ssp. brandegei does occur in New Mexico and Colorado, and is treated here because it is likely to occur in the San Francisco Peaks (where the closely related species L. cavicola occurs); reports of L. brandegei from southern California (Hasse 1895; McClatchie 1897; Hasse 1898a; Orcutt 1907) are based on misidentifications of species of Lecidea s. l. (probably the L. atrobrunnea group). Notes: As discussed by Ryan (1997), L. pringlei, together with L. cavicola and possibly some additional species, form a natural group, that eventually should be segregated from Lecanora. Although L. pringlei is somewhat similar to Rhizoplaca at least in terms of the stipitate thallus with very loose to hollow medulla, the synonymization of L. brandegei under R. melanophthalma (Esslinger, 1996, citing Weber) is quite incorrect; L. pringlei (including ssp. brandegei) differs from R. melanophthalma in the thallus color (due to the absence of usnic acid), consistently having epruinose apothecia, and thallus morphology (crustose vs. umbilicate). Subspecies brandegei [Type: Colorado: Rocky Mountains near St. Elmo, 1880, Brandegee, s.n, Lectotype (FH!), isolectotype (US!)] differs from the typical subspecies of L. pringlei (which occurs primarily from California to British Columbia), in having thallus units that are barely stipitate, rather than becoming dwarf fruticose. A very similar taxon is L. subcavicola; see notes under that name for comparisons. The report of Lecidea brandegei from Arizona may be based on that species, or else on a misidentification of species of Lecidea s. lato.