Life habit: lichenicolous Thallus: inconspicuous, weakly delimited, thin, only present in very small patches under apothecia, up to 2 mm wide surface: pale grayish brown, not discolored if wet, dull cortex: not developed, without an epinecral layer medulla: indiscernible; algal layer: containing chlorococcoid green alga, cells mostly globose, 7-17 µm in diam. Apothecia: adnate, broadly sessile becoming constricted at base, scattered to often clustered, up to 0.5-1.2(-1.5) mm in diam. disc: deep yellowish brown to dark grayish yellowish brown or brownish black, concave to plane, densely blue-white pruinose to almost bare margin: thalline, concolorous with thallus or light to moderate brown, slightly raised to level, +densely pruinose, entire to flexuous or crenate, 0.1-0.2 mm wide amphithecium: cortex not developed, with a broad algal zone of 50-100 µm high parathecium: not developed epihymenium: hyaline to spotted red-brown pigmented hymenium: hyaline, up to 70 µm tall; paraphyses: simple to rarely forked, slightly conglutinante, mid-hymenium cells 10-15 x (1-)1.5-2 µm, with clavate apices 2-4(-5) µm wide, apical cells sometimes with an internal dark reddish brown pigment ; hypothecium: hyaline to pale yellowish, up to c. 120 µm thicl; asci: clavate to broadly clavate, Bacidia-type, 30-50 x 15-20 µm, 8-spored ascospores: hyaline, 3-septate, ellipsoid to ovoid or fusiform (sometimes narrowed towards one or both ends), straight to slightly curved, 12-18 x 5-6 µm Pycnidia: irregular, rounded to somewhat pyriform, line, up to 70 µm tall; paraphyses: simple to rarely forked, slightly conglutinate, mid-hymenium cells 10-15 x (1-)1.52 µm, with clavate apices 2-4(-5) µm wide, apical cells sometimes with an internal dark reddish brown pigment; hypothecium: hyaline to pale yellowish, up to c. 120 µm thick c. 120 µm high and c. 60 µm wide; conidiogenous cells: elongate conidia: filiform, strongly curved, c. 15 x 0.8 µm long Spot tests: all negative Secondary metabolites: containing an unknown substance (UV*+ blue 6ABC). Substrate and ecology: in grassland, on thallus of Caloplaca sp. (whitish thallus, orange apothecia), on caliche or detritus over caliche World and Sonoran distribution: Santa Rosa Island in southern California (Santa Barbara Co.). Notes: The type specimen of L. caloplacicola has been collected in the same spot as the type of L. ryaniana; however, specimens of both new species are clearly different, L. caloplacicola having 3-septate ascospores and being lichenicolous on Caloplaca, with an inconspicuous autonomous thallus. Lecania ryaniana has 1-septate ascospores (very rarely 2-septate) and a clear areolate effuse, non-lichenicolous thallus. Lecania caloplacicola is compared with two lichenicolous species from Asia, with 3-septate ascospores, L. ferganae Oxner and L. triseptata (Vain.) Zahlbr. Lecania ferganae is known from Placidium species occurring on rocks, and it has an almost invisible thallus (developed in its host) and its ascospores are much longer, 17-23 µm and somewhat narrower, 4-5 µm. Lecania triseptata is only known from the Caloplaca polycarpoides group occurring on bark, and it does not have an autonomous thallus. The apothecia of the new species have the aspect of a Rinodina species. Its disc is epruinose, its amphithecium is very thin to excluded, its paraphyses are not conglutinated in water, its epihymenium is dark reddish brown, and its paraphyse tips are subglobose and up to 7µm wide.