Life habit: lichenized, sometimes lichenicolous Thallus: usually thick, +continuous, farinose or cracked-areolate surface: grayish white to pale brownish gray Ascomata: subimmersed then sessile, scattered or sometimes contiguous, +round to angular, 0.2-1.2 mm in diam., or ellipsoid to elongate, up to 2 mm long, mostly irregularly substellate or occasionally stellate disc: black, plane to convex, usually white or bluish white-pruinose margin: thin, often prominent, distinct, +undulating, rarely excluded at maturity exciple: well developed, dark brown, K+ dark green dothecium: dark or grayish brown, K+ pale green hymenium: hyaline, 50-70(-85) µm tall, I+ pale red; paraphysoids: branched and anastomosing, up to 2(-2.5) µm wide, with apical cells somewhat swollen (3-4.5 µm), +coralloid with granular external brown pigmentation (grayish to pale brown under polarized light) subhymenium: pale brown, 15-40 µm thick asci: cylindrical-clavate, 50-75 x 11-13 µm at maturity, with inconspicuous ring, 8-spored ascospores: hyaline, becoming brown only when old, transversely (2-)3-septate (4-5-septate when mature), ellipsoid to oblong-fusiform, with the tips narrowed/pointed, asymmetrical, with the central cells larger, at the center somewhat constricted, 3-4(-5) µm wide, 14-23 x 3-4(-5) µm; walls: thin and uniformly swollen or slightly swollen at septa, with a thin gelatinous sheath Pycnidia: not seen Spot tests: thallus and apothecial pruina K-, C+ red, KC+ red, P- Secondary metabolites: gyrophoric and lecanoric acids and erythrin. Substrate and ecology: on dry, usually +calcareous rocks and mortar (var. grumulosa), less often on acidic rocks ('var. monstrosa'), or parasitic on species of Dirina and Roccella; often on sheltered underhangs and shaded walls; rarely on bark ('var. dirinaria') World distribution: Europe, Macaronesia, western Africa (Senegal) and North America Sonoran distribution: Baja California. Notes: Lecanographa grumulosa is a rather variable species. Specimens which colonize limestone rocks are characterized by a thick, whitish thallus with a well differentiated medulla; those on acid rocks have a thin thallus with fissures and areoles and a scarcely differentiated medulla, while the parasitic population does not have a thallus at all. See Egea and Torrente (1989) for more details.