Thallus: crustose, thin, areolate-granular, effuse, sometimes almost disappearing (endosubstratesl), rarely granular-scurfy, up to 0.4 mm thick; containing scattered coarse crystal clusters up to 15 µm across surface: whitish gray, sometimes slightly ochraceous, pale grayish brown or glaucous white, not discolored when wet but somewhat translucent cortex: not developed medulla: not developed; algal layer: filling the upper part of the thallus and reaching almost the upper surface Apothecia: dispersed or grouped, often crowded, sessile, strongly constricted at base, attached with c. 30% of the undersurface, up to 0.7 mm in diam. disc: pale brown, pinkish brown, yellowish red, then becoming moderately brown to brown-black, more rarely pale gray (shaded form), plane to slightly convex, epruinose, unchanged when wet margin: thalline, definite, at least at first thin (< 0.1 mm), entire, level with disc, mostly persistent, sometimes finally excluded amphithecium: lowermost part consisting of hyaline cells in an amorphous swollen gelatinous matrix, 20-50 µm high parathecium: paraplectenchymatous, with slightly conglutinate cells 2-6 µm in diam. epihymenium: +pale to deep red-brown, K+ intensifying, with a gelatinous matrix; without granules hymenium: hyaline, (45-)65-70 µm tall; paraphyses: strongly conglutinate, 2-2.5 µm wide below, simple to sometimes forked, apically +slightly swollen and up to 6 µm in diam.; hypothecium: hyaline to pale yellow, up to 50 µm thick in the center asci: slightly clavate, 8spored, 15-20 x 35-50 ascospores: hyaline, (0-)1-septate, straight or sometimes curved, oblong, oblong-ellipsoid, fusiform-ellipsoid with abruptly rounded ends, 10-15(-18) x 3-4(-5) µm Pycnidia: immersed, rarely found, +globose, c. 140 µm in diam., red-brown around the ostiole, hyaline below; ostiole: c. 100 µm wide; conidiogenous cells: elongate, branched at base, 8-12 x 2 µm conidia: relative short filiform, slightly to moderately curved, 10-12 x 0.8 µm Spot tests: all negative Secondary metabolites: none detected. Substrate and ecology: on trunks or branches of shrubs with neutral bark such as Acer; mostly found together with L. fuscella and Caloplaca cf. holocarpa; rarely found on wood of fence posts World and Sonoran distribution: southern California, only collected on the Channel Islands and once on the mainland, near the small town of Guadalupe. Notes: Lecania fuscelloides resembles L. fuscella, that differs in having 3-septate and larger ascospores. They are difficult to distinguish in the field, even when both species are growing together. Lecania fuscelloides also has the aspect of a species of the Lecanora chlarotera group.and is recorded only as an epiphytic or on wood. Confusion with L. cyrtella is possible, particularly if this new species is not well developed, but L. cyrtella has smaller, more broadly attached and more convex apothecia with a more variable amphithecium, and it lacks a lower excipular layer with strongly conglutinated cells. Both of these species occur in the same habitats.