Magnusson, AH. 1939. Studies on Species of Lecanora, Mainly the Aspicilia gibbosa Group. Kongl. Svenska Vetenskapsakad. Handl. 17: 34-35.
Thallus broadly expansive, indeterminate, uniform, dark or becoming yellow grey, rimose-areolate, areoles minute, plane, thin, KOH+ red. Apothecia sparse, immersed, solitary, disc black, depressed, proper margin lacking, surrounded by non-prominent thalline margin. Cortex and medulla +/- opaque. Excipulum I becoming blue. Hymenium tall, paraphyses indistinct, 1-septate. Spores minutely large.
Thallus probably covering wide areas without distinct hypothallus, uniform almost to the margin, C.U.C. 233, 495, areolae rather regularly about 0.5 mm broad (though dividing through new cracks), 0.2-0.3(0.4) mm thick, angular with perpendicular edges (Fig. 35).—Cortex (15)25-30 µ, partly +/- transparent, generally quite opaque with invisible cells but transparent in KOH, exterior 4-5 µ brownish-olive, amorphous stratum +/- developed and continuous, 8-12 µ. Hyphae, especially in KOH, mainly perpendicular, about 3.5 µ thick, perhaps thick-walled, lumina indistinct. Gonidia 6-12 µ, stratum 35-70 µ, surfaces rather even. Medulla +/- opaque, thicker sections K+ rusty needles (also in the cortex), hyphae dense, +/- intricate and thick-walled with much oil in the indistinct lumina which in KOH + HCl are rounded, 1.7-2 µ as in the cortex.
Apothecia absent in large areas, in other parts scattered, De 45-85, discs 0.3-0.5 mm broad, plane or concave, in thallus level, generally not distinctly marginate.—Apothecia 150-200 µ deep. Exciple rather indistinct at the surface but in KOH about 20 µ with only the surface olive, at the base 20-30 µ, I+ blue like hypothecium or indistinctly stained. Hypothecium 35-50 µ, opaque from oil. Hymenium (100)120-150(180) µ high, I+ wine-red; upper 15 µ dark olive. Paraphyses in much gelatin, indistinct, 1.5-1.7 µ, discrete in KOH, not or rarely branched but anastomosing, apices 2-2.5 µ, not much thickened, cells indistinct, in KOH + HCl 4-6-10 µ long, 1 µ thick, cylindric, paraphyses in water apparently non-septate. Asci 100-130 X 25-35 µ, clavate. Spores 8, (22)25-27 X 16-18 µ.
Pycnidia globular, about 100-120 µ in diam. Conidia 15-20 µ, straight.
Habitat. On gneisseous rock without accompanying species.
Locality. Norway. Nordland, on irrigated rocks near the shore.
After the positive K-reaction and the conidia belonging to the cinerea-group but differeing from L. cinerea by its dark colour, small apothecia, simply septate paraphyses, high hymenium and larger spores.Some parts of the specimen with a faint or no positive K-reaction, otherwise agreeing.