Verrucaria xylophila Croz.

Lichenised. Poorly known taxon.
Substrate: lignum
Altitudinal distribution: montane belt (potential vegetation: deciduous forests dominated by Fagus sylvatica and closed coniferous forests with Picea abies)
Note: a species with a granular, grey-brown thallus, black and somewhat protruding ascomata (to 0.3 mm in diam.), an adpressed involucrellum, and globose to subglobose ascospores (c. 10 µm in diam.); on wood near a stream, so far only known from the type locality in the Western Alps (France).
France: Haute-Savoie;