Synonyms: Protobagliettoa steineri (Kušan) Servít ex J. Nowak & Tobol.
Distribution: N - VG (Tretiach & Navarro-Rosinés 1996, Geletti 1997, Tretiach & Pecchiari 1995), Frl (Breuss 2008), Lomb, Lig (Giordani & al. 2016). C - Umb (Genovesi & Ravera 2001, Ravera & al. 2006). S - Si (Caniglia & Grillo 2005, 2006).
Description: Thallus crustose, fully endolithic, usually covering large surfaces, white to pale grey, often delimited from adjacent thalli by a dark prothalline line. Upper cortex (lithocortex) densely prosoplectenchymatous, of conglutinated hyphae intermingled with microcrystals; algal layer discontinuous, photobiont cells in clusters; medulla prosoplectenchymatous, sometimes with oil cells (macrospheroids) in the lower part. Perithecia numerous, completely immersed in thallus and leaving pits in the rocks when they fall off. Involucrellum black, 0.15-0.33 mm diam., disc-shaped, with radial cracks around the ostiole, c. as large as or slightly larger than the excipulum (0.2-0.3 mm); excipulum colourless throughout, becoming pale brown only in old perithecia; 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, hyaline, ellipsoid, often poorly developed, 13-26 x 8-15 µm. Photobiont chlorococcoid. Spot tests: all negative. Chemistry: without lichen substances.
Note: a rarely collected, but probably much more common, mild-temperate species found on compact calcareous rocks, especially limestone, in natural habitats; frequently confused with B. baldensis, it should be looked for further throughout the country.
Zschacke, H. (1934) Epigloeaceae, Verrucariaceae und Dermatocarpaceae. In: Dr. L. Rabenhorst‘s Kryptogamen-Flora, Band 9, Abt. 1, Teil 1. Akademische Verlagsgesellschaft, Leipzig, 695 pp. - Public Domain