: Arthonia fusca.

Arthonia fusca is a species growing on calcareous and base-rich rocks including anthropogenic substrates. The species is characterized by minute convex, black apothecia growing on a scurfy-granular thallus, chlorococoid photobiont, and colorless, 1-septate spores. It is difficult to distinguish from similar species without microscopical examination.

Arthonia fusca (A. Massal.) Hepp
Creative Commons Attribution | Andreas Frisch | NTNU Vitenskapsmuseet | Håkon Holien | NORD Universitet
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