A rare sorediate boreal epiphytic lichen, usually seen sterile. The continuously sorediate light yellow-green thallus may resemble the common Lecanora expallens. However, it may be distinguished thanks to the prominent dark pycnidia, up to 0.5 mm in diameter. The yellowish apothecia with usnic acid are formed rarely. Its thallus contains atranorin and caperatic acid. The same metabolites can be found in the non-sorediate C. corrugatum, which however differs in both the appearance and ecology. Also Lecanora mughosphagneti contains the same thallus substances, but it has a white cotton-like sorediate thallus without pycnidia and prefers peatbogs.
Cliostomum leprosum is an important bioindicator of humid old-growth coniferous forests, especially spruce ones. In central Europe, the lichen is very rare and rarely recorded. It prefers humid microclimate of climax spruce forests and old-growth fir-beech forests and requires presence of old dying trees. Relatively recently, the species has been discovered as new for the Czech Republic in the remains of the best-preserved primeval spruce and fir forests of the Šumava and Novohradské hory Mts.
Literature: Tønsberg T. (1992): The sorediate and isidiate, corticolous, crustose lichens in Norway. – Sommerfeltia 14: 1–331. Ekman S. (1997): The genus Cliostomum revisited. – Symbolae Botanicae Upsalienses 32/1: 17–28. 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 → Lecanorales → Ramalinaceae → Cliostomum
Red List (Malíček 2023):C1 – critically endangered
Occurrence in the Czech Republic
All records: 9, confirmed 9. One click on a selected square displays particular record(s), including their source(s).