''Catapyrenium boccanum'' is a species of

squamulose A squamulose lichen is a lichen that is composed of small, often overlapping "scales" called squamules. If they are raised from the substrate and appear leafy, the lichen may appear to be a foliose lichen, but the underside does not have a "skin ...

(scaley), rock-dwelling lichen in the family

Verrucariaceae The Verrucariaceae are a family of mostly lichenised fungi in the order Verrucariales. The lichen-forming species, which comprise the vast majority of the family, have a wide variety of thallus forms, and include crustose (crust-like), foliose ( ...

. It grows on mortar or on

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an a ...

rock. Its squamules are up to 4 mm wide, pale to dark brown with black margins and a black underside.

Ascospore An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera o ...

s measure 11–15 by 5–8

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Uni ...

. Because of its combination of squamulose thallus, simple ascospores (without any

septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates transit bus, bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people ...

), and lack of

alga Algae ( , ; : alga ) are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from u ...

e in the

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others som ...

, this species is a "catapyrenioid" lichen, of which more than 80 exist in the Verrucariaceae. The lichen was first formally described as a new species in 1955 by Czech lichenologist Miroslav Servít. Othmar Breuss transferred it to ''

Catapyrenium ''Catapyrenium'' is a genus of lichens in the family Verrucariaceae. The genus was circumscribed by German botanist Julius von Flotow in 1850. Species *''Catapyrenium adami-borosi'' *'' Catapyrenium boccanum'' *''Catapyrenium chilense'' *'' ...

'' in 1990 as part of a revision of that genus. In Europe, the lichen has a largely

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on th ...

distribution, although scattered records are known from western and southern Europe. It is also found in Turkey.

References

Verrucariales Lichens described in 1955 Lichens of Europe Lichens of Western Asia Lichen species {{Eurotiomycetes-stub