''Arthopyrenia degelii'' is a species of

corticolous lichen A corticolous lichen is a lichen that grows on bark.Alan Silverside's Lichen Glossary (a-f), Alan Silverside/ref> This is contrasted with lignicolous lichen, which grows on wood that has had the bark stripped from it,Alan Silverside's Lichen Glos ...

in the family Arthopyreniaceae. It was formally described as a new species by Richard Clinton Harris in 1995. The type specimens, originally collected in 1939 by Swedish lichenologist

Gunnar Degelius Gunnar Bror Fritiof Degelius (né Nilsson until 1932; 27 January 1903 – 22 July 1993) was a Swedish lichenologist. Between the publications of his first and final scientific papers, Degelius had a 70-year-long research career. While he was ...

(for whom the species is named), were found growing on '' Hamamelis'' in the

Great Smoky Mountains The Great Smoky Mountains (, ''Equa Dutsusdu Dodalv'') are a mountain range rising along the Tennessee–North Carolina border in the southeastern United States. They are a subrange of the Appalachian Mountains, and form part of the Blue Ridge ...

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

. The lichen forms brown, rarely

tan Tan or TAN may refer to: Businesses and organisations * Black and Tans, a nickname for British special constables during the Irish War of Independence. By extension "Tans" can now also colloquially refer to English or British people in general, es ...

, blotches on smooth bark. It has superficial

ascomata An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mos ...

that are range in shape from hemispherical to flattened, and measuring 0.3–0.5 mm diameter. The asci are narrowly elliptical, measuring 48–60 by 11–13 μm, with 8 biseriate to subbiseriate spores. The

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 or ...

s are narrowly elliptical, and 2-celled; either one or both of the cells are constricted near the middle. They typically measure 12–15 by 4–5 μm, with a thin sheath. Micro conidia are rod-shaped, measuring 6–8 by 1 μm.

References

Dothideomycetes Lichen species Lichens described in 1995 Fungi of the United States Fungi without expected TNC conservation status {{Dothideomycetes-stub