Myriolecis antiqua (J.R. Laundon) Śliwa, X.Zhao & Lumbsch
in Zhao Xin & al., Fungal Divers., 78: 300, 2016. Basionym: Lecanora antiqua J.R. Laundon - Lichenologist, 42: 631, 2010.
Synonyms: Lecanora conferta auct. non (Duby) Grognot; Lecanora conferta f. terricola H. Olivier; Myriolecis antiqua (J.R. Laundon) Sliwa, X.Zhao & Lumbsch
Distribution: N - TAA, Piem (Matteucci & al. 2013, Giordani & al. 2014). S - Camp, Cal (Puntillo 1996), Si (Grillo 1998, Grillo & Caniglia 2004).
Description: Thallus crustose, granular-warty to inconspicuous and hardly evident, pale grey to cream-coloured, without a distinct prothallus. Apothecia lecanorine, sessile, 0.3-1 mm across, usually crowded in small clusters, round or irregular in outline due to mutual compression, with a flat to slightly convex, pale brown to pale grey-brown, sometimes pruinose disc, and a thick, smooth, often crenulate, white-pruinose, finally often excluded thalline margin. Thalline exciple rich in algae, with a few crystals; epithecium brownish yellow, 10-13 µm thick, with abundant granular crystals which are insoluble in K but soluble in N; hymenium colourless, 50-70 µm high; paraphyses sparingly branched, 1-2 µm thick in lower part, the apical cells somewhat wider but not swollen; hypothecium colourless. Asci 8-spored, clavate, very thin-walled, with a K/I+ blue, tall tholus penetrated by a faintly amyloid apical cushion, the wall K/I-, surrounded by a blue outer layer, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, (8-)11-13 x 4-7 µm. Photobiont chlorococcoid. Spot tests: thallus K- or K+ pale yellow, C- or C+ pale yellow, KC+ pale yellow, P-; apothecial margin K+ yellow, C+ and KC+ orange-brown, UV+ bright pink: apothecial disc C+ brown-orange. Chemistry: xanthones, mainly concentrated in the apothecial margin.
Note: on steeply inclined surfaces of basic siliceous rocks (especially basalt), sometimes on calciferous rocks. For further details see Laundon (2010).