Lecanographa abscondita (Th. Fr.) Egea & Torrente Cf.

    Thallus crustose, rather thin, continuous and homogeneous, or cracked and verrucose, areolate, areoles clustered, dull grey-yellowish, dull grey-greenish, greyish, sometimes tinged purple as other species belonging to the Roccellaceae family, prothallus dull greyish. Apothecia usually scarce and localized mainly towards margins, rounded, sessile with a constricted base, 0.3-1 mm diam., disc flat, brown-black, blackish to bluish pruinose, exciple conspicuous, prominent, also bluish pruinose. Ascospores clavate, 3-5-septate, constricted at septa, dotted with brown when mature, 18-23 x 5-7 µm. Pycnidia more or less numerous, appearing as minute black dots, 80-120 µm diam.. Photobiont: Trentepohlia. Thallus and pruine of apothecia: C+ red, K+ pale yellow, KC+ pale yellow, Pd-; Medulla: I+ blue. On neutral or slightly acid sheltered stones of old walls, notably chapels, also found under dry overhangs of more or less neutral rock walls. N.B. Same habitat and aspect as Lecanographa grumulosa that is often mistaken (although the latter is I-) and very difficult to distinguish. Also, not to be confused with Lecanactis dilleniana which is Pd+ orange.*