This is a key to all species of three unrelated, but superficially similar genera known to occur in Italy. They are:
Bilimbia De Not. - This genus, widely used in the XIX century, fell into disuse because of conflict with an earlier use of the name for a genus of phanerogams (which, however, recently proved to be invalid), so that the species were subsumed into the “supergenus” Bacidia by Zahlbruckner (Veldkamp 2004). It differs from Bacidia, Biatora and Mycobilimbia in a slightly different tholus structure of the asci, the stout paraphyses, and the finely warted perispore, and presently includes c. 6 species (Cannon & al. 2021). Molecular data suggest that it forms a well-supported group within the Ramalinaceae (see Reese Naesborg & al. 2007, and Miadlikowska & al. 2014).
Bryobilimbia Fryday, Printzen & S. Ekman - This recently-described genus with 5 species includes the former Lecidea hypnorum and some closely related taxa. It is still included in the Lecideaeceae, but a phylogenetic analysis based on molecular data suggests that the genus is most closely related to a group of genera (including Clauzadea, Farnoldia, Lecidoma and Romjularia) that could be excluded from the Lecideaceae s.str. (Fryday & al. 2014).
Mycobilimbia Rehm - This genus of the Ramalinaceae (see Hafellner 1984, 1989) has faced several taxonomic complexities, and many species have been transferred to other genera. Three main groups were recognised: the first is now assigned to Bilimbia (formerly Myxobilimbia), which differs in having a warted perispore, the second contains M. tetramera (the type) and relatives, while the third, now segregated into Bryobilimbia, comprises the Lecidea hypnorum-group with simple ascospores (Fryday & al. 2014).
The present key includes all species known to occur in Italy (Nimis 2016), a few species known from neighbouring countries and to be looked for in Italy, plus two unrelated but superficially similar species, Lecania subfuscula and Lecidea berengeriana, for a total of 15 species.

References

Cannon P., Ekman S., Kistenich S., LaGreca S., Printzen C., Timdal E., Aptroot A., Coppins B., Fletcher A., Sanderson N., Simkin J. 2021. Lecanorales: Ramalinaceae, including the genera Bacidia, Bacidina, Bellicidia, Biatora, Bibbya, Bilimbia, Cliostomum, Kiliasia, Lecania, Megalaria, Mycobilimbia, Phyllopsora, Ramalina, Scutula, Thalloidima, Toninia, Toniniopsis and Tylothallia. Revisions of British and Irish Lichens, 11: 1-82.
Fryday A., Printzen Ch., Ekman S. 2014. Bryobilimbia, a new generic name for Lecidea hypnorum and closely related species. Lichenologist, 46, 1: 25-37.
Hafellner J. 1984. Studien in Richtung einer natürlischen Gliederung der Sammelfamilien Lecanoraceae und Lecideaceae. Beih. Nova Hedwigia, 79: 241-371.
Hafellner J. 1989 Die europäische Mycobilimbia-Arten - eine erste Übersicht (lichenisierte Ascomycetes, Lecanorales). Herzogia, 8: 53-59.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.
Reese Næsborg R., Ekman S., Tibell L. 2007. Molecular phylogeny of the genus Lecania (Ramalinaceae, lichenized Ascomycota). Mycol. Res., 111: 581-591.
Veldkamp J.F. 2004. Bilimbia (Lichenes) resurrected. Lichenologist, 36, 3-4: 191-195.

Last modified: September, 4, 2022

Project Dryades, Department of Life Sciences, University of Trieste - CC BY-SA 4.0