Life habit: lichenized Thallus: squamulose, subsquamulose, without elongated lobes; prothallus: absent surface: olive-gray, smooth, without asexual propagules cortex: cellular, 28-77 Ám thick, granules absent; medulla without granules Apothecia: adnate, 0.2-1 mm in diam., lecanorine disc: orange, flat, epruinose margin: persistent, slightly raised; thalline margin present, concolorous with thallus; proper margin not visible parathecium: elongate to oval cells; exciple below hypothecium irregular hyphae epihymenium: golden, K+ red, H-, 10%N-, cN-, C- hymenium: hyaline, 55-70 Ám tall paraphyses: 2-3 tip cells slightly swollen, with some branching; subhymenium hyaline asci: cylindrical, 8-spored ascospores: hyaline, 2 locules, ellipsoid, 11-14 x 5.5-7 Ám, isthmus 3-4 Ám, spore end wall thin Pycnidia: present, totally immersed Spot tests: apothecial margin K+ violet, H+ violet, 10% N+ violet, cN+ violet, C+ violet; thallus K+ violet, H+ violet, 10%N+ violet, cN+ violet, C+ violet Secondary metabolites: unidentified anthraquinones and thalloidima green. Substrate and ecology: on non-calcareous rocks or occasionally on calcareous rocks World distribution: western North America Sonoran distribution: Arizona, southern California, Baja California, Baja California Sur, and Sonora. Notes: Caloplaca pellodella in its typical form is a very distinctive species with its orange apothecia and dark greenish gray squamulose thallus. The thallus margin is usually distinctly squamulose with slightly lobed, convex squamules. Some collections have a poorly developed thallus and might be mistaken for C. sideritis but that species is usually areolate at the thallus margins, has a lighter gray thallus, has fewer elongated thick walled cells in the proper exciple. In addition, C. pellodella has a thick, smooth necral layer on the thallus and a thicker cellular cortex below the colored layer. The shiny appearance of the thallus is due to the smooth necral layer. Caloplaca hueana has a strictly brown thallus and lacks the necral layer on the thallus cortex and the thallus is completely K-.