Mycoporellum microscopicum (Müll. Arg.) Zahlbr.

Syn.: Dermatina microscopica (Müll. Arg.) Zahlbr., Mycoporum microscopicum (Müll. Arg.) Nyl., Pyrenula microscopica Müll. Arg.
Non- or doubtfully lichenised. Poorly known taxon.
Substrate: bark
Altitudinal distribution: submediterranean/colline belt (potential vegetation: mixed deciduous forests dominated by Quercus and Carpinus)
Note: doubtfully lichenised with trentepohlioid algae, with a thallus forming olivaceous-grey patches, minute ascomata (c. 0.1 mm in diam.), the interascal filaments lacking in mature ascomata, fissitunicate, 8-spored asci, and hyaline to pale brownish, 3-(to 5-)septate ascospores (11-13 × 4-5 µm); on the smooth bark of twigs of deciduous trees (Populus tremula, Quercus, Juglans); rare in Central Europe at low elevations, with a single historical record (regarded as “common” at the type locality) from the Western Alps of France (locality erroneously assigned to Switzerland).
France: Haute-Savoie;