Lecanora muscigena (Lichenized Ascomycota, Lecanorales), a new lichen species in the Lecanora fuscescens group from South Georgia

Compared to continental Antarctica, the lichen biota of the various subantarctic islands and island groups is poorly documented. Here we describe the new species Lecanora muscigena ovstedal & Fryday from the subantarctic island of South Georgia from a collection made in 1980 that was previously included as Trapeliopsis sp. A. by ovstedal & Lewis Smith in their comprehensive account of the Lichens of Antarctica and South Georgia. It is similar to Lecidea globulispora Nyl., which occurs on the nearby Falkland Islands, in having globose ascospores but is clearly distinguished from that species by having a well-developed, creamy-white thallus composed of +/- dispersed areoles with effigurate margins containing fumarprotocetraric acid, larger ascospores (c. 7-8 mu m diam.) and by its habitat of overgrowing terricolous bryophytes. The new species belongs in the Lecanora fuscescens group, the species of which were usually described in the genus Lecidea due to their poorly developed thalline margin. This group is not congeneric with the type species of Lecanora (L. subfusca (L.) Ach.) but we refrain from erecting a new genus for the group pending a full molecular investigation of its delimitation and systematic position.