Verrucaria illinoisensis Servít

Lichenised.
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 with an epilithic, greyish-white, rimose to areolate thallus, hemispherically protruding, immersed ascomata (c. 0.2 mm in diam.), involucrellum spreading and reaching down about half the perithecium, and oblong to ellipsoid ascospores (to c. 20 µm long; specimens from NE Europe reported to c. 25 µm long); based on a type from North America, and also reported for NE Europe, with a single reord from the Eastern Alps (Austria).
Austria: Oberösterreich;