Arthopyrenia pithyophila Th. Fr. & Blomb.

Non- or doubtfully lichenised.
Substrate: bark
Altitudinal range: from the montane belt (potential vegetation: deciduous forests dominated by Fagus sylvatica and closed coniferous forests with Picea abies) to the subalpine belt (potential vegetation: open, taiga-like forests dominated by Larix decidua and/or Pinus cembra and Rhododendron)
Note: a pioneer, non-lichenised species growing on the bark of coniferous and deciduous trees; the sample from Italy was collected by G. Thor in the Adamello Natural Park, on Sorbus aucuparia.
Italy: Trentino Alto Adige;