Distribution: C - Marc. S - Camp (Aprile & al. 2003b), Pugl (Nimis & Tretiach 1999), Si (Nimis & al. 1994).
Description: Thallus crustose, endosubstratic or very thinly episubstratic, when visible forming small, inconspicuous, ochraceous flecks around the apothecia. Apothecia biatorine, sessile and constricted at base, 0,15-0.3 mm across, brown to black when dry, brown with a black margin when wet, somehow glossy, with a moderately to strongly convex, epruinose disc, and a very thin, soon excluded proper margin. Proper exciple thin, of strongly branched and anastomosing hyphae, dark red-brown in outer part, somewhat paler within, K+ faintly reddish, N+ purple-red; epithecium pale yellowish brown to violet-brown, 8-11 µm high, the pigment diffuse in the gel, N+ purple-red; hymenium colourless, 50-75 µm high, I+ blue; paraphyses strongly coherent, simple or sparingly branched and anastomosing, 1.5-2.5(-3) µm thick, the apical cells up to 5 µm wide, surrounded by a pigmented gel; hypothecium colourless to pale brown in older apothecia, 75-110 µm high, I+ blue. Asci 8-spored, cylindrical-clavate, surrounded by a gelatinous I+ blue coat, with a well-developed I+ blue tholus, a I+ darker blue tube and a well-developed ocular chamber, approaching the Bacidia-type. Ascopores, 1-septate, hyaline, ellipsoid, 9.5-13.5 x 4-5.5 µm. Photobiont chlorococcoid, the cells 9-15(-20) µm wide. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a temperate species growing on calcareous rocks in open situations at relatively low elevations, which probably does not belong to Catillaria s.str. Ecology and distribution need further study, and the indicator values are tentative.