Description: Thallus crustose, thinly episubstratic, usually inconspicuous. Ascomata perithecioid, 0.3-0.5 mm across, pale yellowish brown, translucent when wet, the area around the apical pore dark brown. Proper exciple thick, yellowish, much darker around the ostiole; hymenium colourless, the hymenial gel I+ dull red (I+ blue at low concentrations of I), K/I+ blue; paraphyses slender, loose, septate, mostly simple, arising from the base of the ascocarp. Asci 8-spored, narrowly cylindrical, thin-walled, without apical thickenings, the wall K/I+ blue. Ascospores 20-30-septate, hyaline, needle-like, 100-140 x 3-4 μm, with cylindrical cells. Photobiont trentepohlioid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on bark of broad-leaved trees, especially Fagus, usually near the base of trunks; rare in SE Europe, with a single record from the Eastern Alps (Slovenia). To be looked for in Italy.
Source: Keissler K. von 1938. Pyrenulaceae, Mycoporaceae, Coniocarpineae. In: Rabenhorst G L: Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. 2nd, IX, Die Flechten, Abt. 1, 2. Gebr. Borntraeger, Leipzig, pp. 1-846.