Thelidium helveticum (Servít) Hafellner

Syn.: Involucrothele helvetica Servít
Lichenised. Poorly known taxon.
Substrate: siliceous rocks
Altitudinal distribution: montane belt (potential vegetation: deciduous forests dominated by Fagus sylvatica and closed coniferous forests with Picea abies)
Note: a species resembling Th. methorium, with an epilithic, whitish, spreading, rimose to areolate thallus, hemispherically protruding, often crowded to laterally fusing perithecia (to 0.5 mm in diam.), an involucrellum which is loosely attached to the perithecial wall almost down to the base, and 1-septate, broadly ellipsoid ascospores (mostly to c. 25 µm long); on siliceous schists, only known from the type locality in the Western Alps (Switzerland).
Switzerland: Bern;