A Rinodina with granular coralloid to squamulose thallus, resembling the unrelated species Protoparmelia hypotremella. From similar lichens, it is distinguished based on the presence of pannarin in the thallus (Pd+ orange). Apothecia are rare.
It occurs on deciduous tree bark, mainly oaks, in open forests or on solitary trees from low to lower-montane elevations. In the Czech Republic, R. excrescens has only been collected in a couple of localities, however, its sterile thalli are probably partly overlooked. Although its distributional range covers a great part of the Northern hemisphere, it is one of the rarest epiphytic Rinodina species in Europe.
Literature: Malíček J. & Palice Z. (2013): Lichens of the virgin forest reserve Žofínský prales (Czech Republic) and surrounding woodlands. – Herzogia 26: 253–292.
taxonomic classification:Ascomycota → Lecanoromycetes → Caliciales → Physciaceae → Rinodina
Red List (Malíček 2023):C2 – strongly endangered
Occurrence in the Czech Republic
All records: 14, confirmed 14. One click on a selected square displays particular record(s), including their source(s).