Synonyms: Bagliettoa sphinctrina auct. non (Ach.) Körb.; Protobagliettoa grummannii (Servít) Servít; Verrucaria bosniaca Servít; Verrucaria ceracea J. Steiner; Verrucaria limborioides (A. Massal.) Clauzade & Cl. Roux; Verrucaria sphinctrina auct. p.p. non Ach.; Verrucaria subconcentrica (J. Steiner) Servít var. euthallina Servít f. genovensis Servít
Distribution: N - VG (TSB 2461), Ven, TAA, Lig (Lazzarin 2000b, Halda 2003). C - Umb (Genovesi & Ravera 2001, Ravera & al. 2006). S - Pugl (Nimis & Tretiach 1999), Si (Nimis & al. 1994, Caniglia & Grillo 2005, 2006, Grillo & al. 2007b).
Description: Thallus crustose, fully endolithic, usually covering large surfaces, white to pale grey. Upper cortex (lithocortex) densely prosoplectenchymatous, of conglutinated hyphae intermingled with microcrystals; algal layer discontinuous, photobiont cells in clusters; medulla prosoplectenchymatous, with oil cells (macrospheroids) in the lower part. Perithecia completely immersed in thallus and leaving pits in the rocks when they fall off. Involucrellum black, prominent, with radial cracks around the ostiole, broader than the body of the perithecium (0.3-0.4 mm wide), with a distinctly raised, convex center; excipulum 0.3-0.35 mm wide, colourless to brown; hymenium colourless, K/I+ blue. Hamathecium of periphyses in the ostiolar canal, and short periphysoids in the half upper part of the perithecial cavity. Asci 8-spored, two-layered, fissitunicate, with a thin tholus reacting I-, Verrucaria-type. Ascospores 1-celled (very rarely some 1-septate spores have been observed), hyaline, ellipsoid, often poorly developed, 17-35 x 10-13 µm. Photobiont chlorococcoid. Spot tests: all negative. Chemistry: no lichen substances.
Note: a mild-temperate to Mediterranean lichen found on steeply inclined faces of compact calcareous rocks below the subalpine belt; probably more widespread but overlooked, or confused with similar species.