Immersaria athroocarpa (Ach.) Rambold & Pietschm.

Probably a partly overlooked lichen with a frequently glossy, brown, areolate thallus, an amyloid medulla (I+ blue), presence of confluentic acid (including its derivatives), and black immersed apothecia. It resembles several unrelated species: Clauzadeana macula, Lecidea fuscoatra, L. fuscoatrina, Miriquidica deusta, and Lecidea atrobrunnea. Its identification relies on secondary metabolites and microscopic characters of the apothecia, which makes determination of sterile material rather difficult.

Immersaria athroocarpa grows on exposed siliceous or volcanic rocks, often rich in iron, mostly at higher elevations. It sometimes begins its life cycle on thalli of lichens of the genus Aspicilia s. l. In Europe, it is widely distributed from Scandinavia to the mountains of the Mediterranean region. The species was previously reported from the Czech Republic only from mountain areas (Krkonoše Mts, Králický Sněžník), but it has recently been found also in lower elevations (Manětínsko, České středohoří Mts, Jihlava Valley, Prague).

Ascomycota → Lecanoromycetes → Lecanorales → Lecideaceae → Immersaria