One of the few representatives of the difficult genus Verrucaria that can be identified fairly reliably after careful microscopic examination. It is characterized by a greenish, glossy, superficial to subgelatinous thallus which, when wet, is at least partly translucent and may largely overgrow the fruiting bodies. In section, a thin, clearly delimited cortex is evident. The perithecia have a relatively thin, dark involucrellum reaching down to the bases of the fruiting bodies; there it no longer envelops the perithecial wall, diverges slightly outward, and thus exposes the unpigmented excipulum, which is thickened at the base. The most diagnostic character is the periphyses – septate filaments around the perithecial ostiole. These are unusually broad (c. 3.5 µm) and may be further thickened apically up to about 4.5 µm.
As a pioneer, it often colonizes the surface of small, partly embedded stones in shaded sites with a stable microclimate. It is probably a locally frequent lichen of shaded calcareous rocks. The species is reported from central and northern Europe as well as from North America. In the Czech Republic, only a single record is known, from Obora Hvězda in Prague, where it grew on calcareous sandstone in an oak–hornbeam woodland.
Literature: Oïhénart M., Clerc P. & Breuss O. (2018): New and Interesting Species of the Lichen Genus Verrucaria (Verrucariaceae, Ascomycota) for Switzerland and France. – Herzogia 31: 209–218. Palice Z. & Malíček J. (2025): Lišejníky přírodní památky Obora Hvězda v Praze. – Bohemia centralis 39: 99–135.
taxonomic classification:Ascomycota → Eurotiomycetes → Verrucariales → Verrucariaceae → Verrucaria
All records: 1, confirmed 1. One click on a selected square displays particular record(s), including their source(s).