Thallus: crustose, areolate, to rimose-areolate, effuse; prothallus: sometimes ±distinct, pale; areoles: surface of areoles divided into cracked-rimose verruculose parts, not lobulate at the margin, 0.4-3 mm wide, up to 0.5 mm thick; surface: pale gray or pale gray-brown to cream-colored, edges concolorous with the center, not discolored when wet, dull, often white pruinose, sometimes with a powdery appearance cortex: not clearly differentiated, with indiscernible hyphae, filled with granular crystals, overall up to c. 40 µm thick, without an epinecral layer medulla: with indiscernible hyphae; algal layer: up to 250 µm thick, with algae 6-18 µm in diam. Apothecia: usually frequent, constricted at base, raised and somewhat stipitate, rarely sessile, situated on areoles in groups or scattered, 0.5-1.5 disc: red-brown to black-brown, paler (reddish brown) and dark-spotted when wet, +concave to mostly plane, sometimes weakly convex, weakly to mostly heavily white pruinose margin: flexuous, persistent or rarely nearly excluded, up to 0.25 mm wide, concolorous with thallus or grayish white to gray, swollen when young, narrower when old, persistent, often crenulate (1.8) mm in diam. amphithecium: outer edge anatomically similar to cortex of the areoles, algae filling the entire margin and also abundant under the hypothecium, sometimes filled with granular crystals below, c. 100 µm high parathecium: absent or visible as a small rim (up to 20 µm wide), containing strongly conglutinate cells epihymenium: brown to red-brown with a granular epipsamma, the pigment in places more strongly concentrated around the coherent groups of paraphyses, spotty colored hymenium: hyaline below, 65-85(-90) µm tall; paraphyses: coherent, 1.5-2 µm wide below, apically clavate, 3 to 5 µm wide, with short-cells and short branches, and bound in a mainly hyaline gelatinous matrix; hypothecium: hyaline, with intricate hyphae, up to 120 µm thick in center including subhymenium asci: narrowly to broadly clavate, 8-spored, 40-50 x 15-25 µm, Bacidia-type ascospores: hyaline, 1(-2)-septate, short to relatively long, ellipsoid, oblong to fusiform, straight or curved, 12-25 x 4-5(-7) µm, thin-walled; measurements of ascospores strongly variable within the ascus, in some asci are found short spores of 12-14 x 6 µm or relatively long spores of 22-25 x 4-5 µm which are rarely 2 septate Pycnidia: immersed, c.100 µm in diam., irregularly globose, with a black ostiole, hyaline below; conidiogenous cells: elongate conidia: filiform, 10-16 x c. 0.8 µm Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on calcareous, outcrops, in grassland on gentle hills (type collection) with Lecania dudleyi and Buellia aff. epipolia. The latter species has been found on and among the areoles of L. ryaniana, so it could be growing parasitically World and Sonoran distribution: found on only on two Channel Islands of southern California. Notes: Lecania ryaniana is distinguished by its generally relative large, pruinose apothecia, that are strongly constricted at base and its often discrete, rimose-areolate thallus. The thallus anatomy is comparable with that of L. chalcophila, a species also known from the Channel Islands, which has a white thallus, wider areoles, black epruinose apothecia and different ascospores. Another species in the Sonoran region, with which L. ryaniana might be confused, is L. turicensis, that also grows on calcareous rocks but differs by having smaller, broadly sessile apothecia with discs becoming convex and immarginate, a thicker parathecium, narrower asci, shorter ascospores, and a +granular-areolate thallus with the upper layer lacking crystals.