Magnusson, AH. 1939. Studies on Species of Lecanora, Mainly the Aspicilia gibbosa Group. Kongl. Svenska Vetenskapsakad. Handl. 17: 34-35.
Thallus uniform, continuous, pale, becoming yellow-ashy grey or almost lavender blue, very thin or thin, rarely rimulose, KOH-. Apothecia unequally dispersed, minute, immersed. Disc black, convcave, surrounded by regular to subobtuse, slightly dark and prominent margin. Hymenium almost tall. Paraphyses dense, thin, submoniliform. Excipulum indistinct, iodine not becoming blue. Spores moderately sized.
Thallus probably covering large areas as a smooth, only occasionally faintly cracky film over the unevennesses of the stone 0.1-0.2 mm thick, C.U.C. 190, 234, 340.—Cortex (20)30-35 µ thick, transparent, exterior 6-8 µ brownish-yellow or almost colourless, amorphours stratum 8-10 µ, even, or indistinct. Cells distinct, 3-3.5(4) µ globular, thin-walled. Gonidia 7-10 µ, stratum at least 35 µ thick. Medulla +/- poorly developed, transparent, cellular, with distinct, thin-walled cells, K-.
Apothecia De 100-140 towards the centre, disc 0.2-0.4(0.5) mm broad, the margin slightly prominent above the thallus surface and its dark colour +/- expanding on the outer side, which passes into the thallus without cracks.—Apothecia about 150 µ deep. Exciple distinct at the surface, 40-50(100) µ broad, dark greenish-brown, gradually narrower to a depth of 70-100 µ, at the base thin, 10-15 µ, yellowish, I-. Hypothecium about 35 µ, dense, opaque. Hymenium 90-100 µ high, I+ copper red or blue; upper 15-20 µ brownish yellow. Paraphyses +/- branched in KOH, about 1 µ thick, apices 2.5(3) µ, +/- globose, lower cells broadly ellipsoid or even narrow, submoniliform. Asci 85-95 X 17-20 µ, clavate. Spores 8, 16-18 X 9-10(12) µ.
Pycnidia (in a specimen from Kalofer) 150-170 µ deep, 100 µ broad, mouth +/- dark brown. Conidia 8-10 X 0.8 µ, straight.
The appearance and structure agrees well with the type but the colour is much darker. The thallus may be somewhat thicker at the centre with circumscissed apothecia, thus resembling L. laevata very much. But ther is no trace of a positive K-reaction. The paraphyses are submoniliform.
Attached to sandstone. Spores 17-25 µ.
Finland, Czechoslovakia, France.
These specimens are very puzzling on account of their resemblance with L. laevata and hardly determinable without conidia which have not been found by me.