Distribution: N - Piem (E.C.I. 2: 722, Ravera 2014c, 2014d).
Description: hallus crustose, endosubstratic, usually inconspicuous and poorly visible, not lichenized. Perithecia black, more or less elliptical in outline, 0.2–0.26 x 0.14-0.2 mm. Involucrellum dimidiate, brown both in water and K; exciple colourless; pseudoparaphyses persistent, 1.5-2.5 μm thick, richly branched, the cells c. 4–10 μm long. Asci 8-spored, obpyriform, fissitunicate, 55–80 × 19–30 μm. Ascospores 3-septate, hyaline nut sometimes turning brownish and warted when overmature, 22–31 × 7–9 μm, with a <1 μm thick or indistinct perispore. Pycnidia black, 0.4–0.6 mm across. Conidia bacilliform, 4–5 x 0.8–1 μm. Photobiont absent. Spot tests: all negative. Chemistry: without lichen substances.
Note: a mainly boreal-montane, non-lichenised species occurring on the bark of Betula; known from Scandinavia, the United Kingdom, Galicia, and the Alps. For further details see Ravera (2014c, 2014d).