Lecanora helicopis (Wahlenb.) Ach. forme sciaphile.

    Thallus rimose and more or less verrucose, dirty whitish, slightly bluish greyish, hypothallus sometimes large, bluish. Apothecia usually numerous, at first immersed in the thallus then sessile, 0.2-0.7 mm in diameter, disc flat to slightly convex, brown then blackish and often black at the end, margin entire then irregular, disappearing at the end, concolorous to the thallus. Epithecium yellow-brown to brown. Simple or slightly branched paraphyses, with a raised apex. Asci clavate with 8 spores. Spores elliptical, colorless, simple or 1-septate (or appearing 1-septate by the presence of 2 guttules? but the photographs taken on fresh samples that we present do not support this statement), 9-15 x 4- 6 µm according to the literature; 10-17 x 4-5 µm according to our measurements. Thallus: C-, K-, KC-, P-, UV-. Not very rare species growing on relatively sheltered siliceous rocks with little sunlight in the mesic zone at the level of Hydropunctaria maura agg..

N.B. The shape of the asci and the sometimes 1-septate spores mean that this species is considered by some authors as a Lecania.