Thallus: bullate-squamulose, effuse; prothallus: sometimes visible, black squamules: +round to irregular, becoming crenate to lobed when large, closely appressed, irregular, flattened to subglobose or difform and wart-like, irregularly convex to undulate or occasionally concave, (0.5-)2-3 mm across, (0.5-)1-2(-3) mm thick, sometimes +contiguous, but always rather sparsely distributed, when growing on soil, base of squamules +immersed in the substrate upper surface: pale to very dark red or red-brown, light to deep brown, grayish to yellowish brown, grayish brown, yellowish gray, pale orangish yellow or light yellowish brown to brownish orange, unchanged or reddish brown when wet, often rimose in places, sometimes warty, dull to slightly shiny, sometimes +pruinose on raised parts or edges or covered with a whitish dust when growing on caliche upper cortex: mostly prosoplectenchymatous, with conglutinated, unoriented to anticlinal hyphae 5-10 x 2.5-3 µm, overall 40-75 µm thick, completely filled with granular crystals, covered with an epinecral layer 15-40 µm thick medulla: with indiscernible, sometimes prosoplectenchymatous hyphae; algal layer: very irregular in thickness, 50-200 µm high; algal cells often clustered, algal cells: 5-15 µm diam. lower cortex: not developed, consisting of discontinuous tissue without crystals lower surface: sometimes present and poorly developed towards the outer rim, pale yellow Apothecia: often few or mostly immature but sometimes numerous, 1-5(-7) per thalline wart, erumpent, borne laminally to submarginally, up to 1.5(-2) mm in diam., plane, soon becoming elevated, protuberant and subglobose, at first immersed (appearing as a small dark depression), then becoming adnate disc: medium brown, deep brown, or occasionally light brown, finally becoming dark grayish brown, dark brown, or brownish black, sometimes moderate reddish brown, dark-spotted when wet, epruinose, concave to plane then soon becoming moderately convex margin: thalline, concolorous, with thallus or sometimes white or next to disc sometimes medium brown, thin, 0.1-0.2 mm wide, entire to flexuous, level with disc, persistent or soon excluded amphithecium: with conglutinate cortex with prosoplectenchymatous cells (5-10 x 2-3 µm), with a compact algal layer up to 120 µm thick parathecium: not evident from above, without a separated tissue epihymenium: red or reddish brown, not interspersed, intensifying in K, darker in some spots, covered by 10-15 µm thick hyaline layer above the pigmented part hymenium: hyaline, 65-80 µm tall; paraphyses: coherent, 2-3 µm thick below, septate, apically clavate to globose and 4-5 µm wide, with thin; hypothecium hyaline, with intricate hyphae, up to 100 µm thick (including subhymenium) asci: clavate, probably Bacidia-type, 50-75 x 12-20(-25), 8-spored ascospores: hyaline, (0-)1-septate [rarely a few 3-septate], ellipsoid or ovoid, (9-)11-15(16) x (5-)6-7(-7.5) µm; wall and septum: 0.5-1 µm thick Pycnidia: +globose, immersed, c. 0.25 mm in diam., pale brown around the ostiole, hyaline below; ostiole: concave, pale brown, rugulose; conidiogenous cells: elongate, 8-12 x 2 µm conidia: relative long filiform, sometimes straight to often curved, 18-28 x 0.8 µm Spot tests: all negative Secondary metabolites: containing 2 unknown terpenes. Substrate and ecology: on sedimentary rock, soil, clay, or caliche, above the sea at 30-75 m World distribution: west coast of North America from central California to Baja California Sonoran distribution: southern California to Baja California, including Isla Cedros. Notes: Lecania dudleyi is one of the more distinctive species of Lecania, characterized by its coarse, bullate-squamulose thallus, its broad ascospores, containing terpenes, and its occurrence on soil. Weber's exsiccat of L. dudleyi is not that species, but instead is L. brunonis, that differs in having smaller, flatter thallus subunits with edges often partly raised, smaller apothecia, that are not erumpent, narrower ascospores, and lacking secondary metabolites, and it usually occurs on acidic rock rather than soil. A lichenicolous fungus, Toninia subtalparum (see lichenicolous section), has been found on two specimens of L. dudleyi, and a Stigmidium sp. has been found on one specimen.