Verrucaria muelleriana Servít

Lichenised. Poorly known taxon.
Substrate: calciferous rocks
Altitudinal distribution: montane belt (potential vegetation: deciduous forests dominated by Fagus sylvatica and closed coniferous forests with Picea abies)
Note: a calcicolous species resembling V. cinereorufa, with an endolithic to thin-epilithic, white thallus with a reddish tinge, immersed or only slightly protruding ascomata (to 0.5 mm in diam.), an involucrellum spreading around the ostiole, and ascospores to c. 40 µm long; only known from the type locality in the Western Alps (France).
France: Haute-Savoie;