Arthonia tenellula Nyl.

Syn.: Allarthonia tenellula (Nyl.) B. de Lesd., Arthonia horaria Norman
Lichenised. Poorly known taxon.
Substrate: lignum
Altitudinal range: from the submediterranean/colline belt (potential vegetation: mixed deciduous forests dominated by Quercus and Carpinus) to the montane belt (potential vegetation: deciduous forests dominated by Fagus sylvatica and closed coniferous forests with Picea abies)
Note: differing from A. apatetica mainly in the hypophloeodic thallus; the taxonomic value of this species is in need of re-evaluation: it was described from a site near the sea shore in western France; specimens from the Alps are in need of verification, and the distribution is insufficiently known.
Austria: Tirol; Kärnten; Steiermark;