KEYS TO THE LICHENS OF ITALY - 40) LECANORA (incl. Bryodina, Bryonora, Myriolecis, Protoparmelia, Protoparmeliopsis, Rhizoplaca, Tephromela)
Pier Luigi Nimis
Apparatus of images: Andrea Moro - Software and databases: Stefano Martellos

Lecanora, in the traditional sense of Zahlbruckner, was an artificial assemblage of species, and several genera have been split off over the years, some of which do not belong to the Lecanoraceae. Among the segregated genera the following ones occur in Italy:
Bryodina: a monotypic genus primarily distinguished from Bryonora by the distinctly separated hypothecium and excipulum, and by the thin-walled ascospores.
Bryonora: segregated from Lecanora mainly on the basis of the morphology of the apothecia. It consists of c. 11 species occurring on acid substrata (soil, plant debris, mosses), mostly above treeline, and has the highest diversity in the mountains of Central Asia.
Myriolecis: a recently-resurrected genus including species which are most common on rocks and bark, that has been shown to form a clade separate from Lecanora s.str. (see Zhao & al. 2016). The species either contain chlorinated xanthones, often accompanied by depsidones, or lack secondary metabolites. The group is notoriously difficult, and identification requires the observation of fine morphological and chemical details (see e.g. Śliwa 2007, Śliwa & al. 2012). The genus has a worldwide distribution, but is most diverse in temperate to arctic-alpine regions of the Northern Hemisphere. The North American species were monographed by Śliwa & al. (2007). A key to European coastal species with a C+ reaction was published by Bertrand & al. (2018). Useful information, especially on the coastal species, is provided by Bertrand & Roux (2011), and Bertrand & al. (2010).
Protoparmelia: a cosmopolitan genus with c. 25 species, differing from Lecanora in the grey- to reddish-brown thallus, the generally smaller, narrower ascospores, and the straight conidia. The structure of the exciple is similar to that found in the Parmeliaceae, and the genus has been included in that family by various authors, also on the base of recent molecular investigations (Arup & al. 2007, Crespo & al. 2007). The phylogenetic study by Singh & al. (2015) confirms that, in the present circumscription, the genus is heterogeneous: five previously described species and one species putatively new to science are close to Miriquidica. In contrast to members of Protoparmelia s.str., which produce lobaric or alectoronic acids, these taxa synthesize norstictic acid, and often parasitize other lichens. The taxonomic consequences will be drawn in a future revision of Miriquidica by E. Timdal & al., so that here these species are still placed into Protoparmelia s.lat. In Protoparmelia s.str. the analysis of Singh & al. (2015) suggest the presence of a tropical and an extra-tropical lineage, and eleven previously unrecognised distinct species-level lineages within P. badia s.lat. and P. montagnei s.lat.
Protoparmeliopsis: this genus, which was resurrected to accommodate the Lecanora muralis-group, although heterogeneous in the present circumscription, could be largely retained on the basis of molecular data (Kondratyuk & al. 2014).
Rhizoplaca: this genus of c. 19 species, in the traditional circumscription, was characterised by an umbilicate thallus with an upper and a lower cortex, as well as a cupulate hypothecium. The genus occurs in the Northern Hemisphere, South America, and Antarctica, but is absent from Australasia. It has the centre of distribution in western North America. Within the past decade, a number of studies have indicated that traditional phenotype-based species circumscriptions fail to recognize multiple species-level lineages within this genus, e.g. in the analysis by Arup & Grube (2000), most species form a well-supported clade, but Rh. peltata proved to be more closely related to Protoparmeliopsis. Furthermore, molecular data suggest that many cryptic species may be present, such as in the Rh. melanophthalma-group (Leavitt & al. 2013, 2016). In a recent study by Zhao & al. (2016) Rhizoplaca was emended to include three placodioid taxa previously classified in Lecanora, whereas R. aspidophora and R. peltata were excluded from Rhizoplaca, the latter having been transferred into Tephromela.
Tephromela - a cosmopolitan genus of c. 30 species found in temperate to tropical regions on bark, wood, rock or on other lichens. Its familial placement was for a long time unclear: preliminary molecular data (Miadikowska & al. 2006, Arup & al. 2007) indicated that it does belong neither in the Lecanoraceae nor in the Ramalinaceae, but is related to Mycoblastus, being currently placed in the Tephromelataceae (see also Miadikowska & al. 2014). The T. atra-complex was studied by Muggia & al. (2008). In its present circumscription, Lecanora remains one of the largest genera of lichenised ascomycetes, with c. 550 species traditionally characterised by hyaline, non-septate ascospores, Lecanora-type asci, the presence of a thalline apothecial margin (lecanorine apothecia), and predominantly crustose, more rarely lobate thalli containing green-algal photobionts.
Lecanora still remains a heterogeneous assemblage of different groups, several of which probably deserve generic rank, but comprehensive molecular work on the phylogeny of the Lecanoraceae is still in preliminary stages and hampered by the sheer size of the genus. Several groups have been recognised at various taxonomic levels, such as the L. polytropa- and L.varia-groups (Pérez-Ortega & al. 2010), the L. rupicola-group (Grube & al. 2004), and the L. subfusca-group (the core of the genus, see e.g. Brodo 1984, Malíček 2014). Although the phylogenetic relationships among groups are still largely unresolved, recent molecular studies largely confirmed the notion that some are in itself heterogeneous. The phylogenetic relationships between the major clades of Lecanora are still largely unresolved, and require more intensive taxon and character sampling.
The present key, with 180 infrageneric taxa, includes all species reported from Italy (Nimis 2016), plus the following species known from adjacent territories (see e.g. Nimis & al. 2018): Lecanora albula, L. barkmaniana, L. cerebellina, L. chloroleprosa, L. compallens, L. jemesii, L. freyi, L. leptacinella, Protoparmelia hypotremella, P. loricata, P. olivascens, Tephromela pertusarioides.

References

Aptroot A., Cáceres M.E., Lumbsch H.T., Schmitt I. 2015. Coalescent-based species delimitation approach uncovers high cryptic diversity in the cosmopolitan lichen-forming fungal genus Protoparmelia (Lecanorales, Ascomycota). PlosOne, DOI:10.1371/journal.pone.0124625 May 1, 2015.
Arup U., Grube M. 1998. Molecular systematics of Lecanora subgen. Placodium. Lichenologist, 30, 4-5: 415-425.
Arup U., Ekman S., Grube M., Mattsson J.-E., Wedin M. 2007. The sister group relation of Parmeliaceae (Lecanorales, Ascomycota). Mycologia, 99: 42-49.
Bertrand M., Roux C. 2011. Lecanora oyensis sp. nov., une nouvelle espèce de lichen maritime. Bull. Ass. Franç. Lichénol., 36, 2: 107-117.
Bertrand M., Roux C., Barbero M. 2010. Lecanora bandolensis B. de Lesd., une espèce peu connue. Bull. Ass. Fr. Lichénol., 35, 1: 1-16.
Bertrand M., Monnat J.-Y., Lohézic-Le Dévéhat F. 2018. Myriolecis massei, a new species of Lecanoraceae from the coasts of the Armorican Massif in Western Europe. The Bryologist, 121, 3: 253-263.
Brodo I.M. 1984. The North American Ssecies of the Lecanora subfusca group. Beih. Nova Hedwigia, 79: 63-185.
Crespo A., Lumbsch H.T., Mattsson J.-E., Blanco O., Divakar P.K., Articus K., Wiklund E., Bawingan P.A., Wedin M. 2007. Testing morphology-based hypotheses of phylogenetic relationships in Parmeliaceae (Ascomycota) using three ribosomal markers and the nuclear RPB1 gene. Mol. Phylogenet. Evol., 44, 2: 812-824.
Grube M., Baloch E., Arup U. 2004. A phylogenetic study of the Lecanora rupicola group (Lecanoraceae, Ascomycota). Mycol. Res., 108, 5: 506-514.
Kondratyuk S.Y., Kim J., Kondratuk A.S., Jeong M.-H., Hwa Jang S., Pirogov M.V., Hur J.S. 2014. First data on molecular phylogeny of the genus Protoparmeliopsis M. Choisy (Lecanoraceae, Ascomycota). Modern Phytomorph., 5: 63-68.
Leavitt S.D., Fernández-Mendoza F., Pérez-Ortega S., Sohrabi M., Divakar P.K., Lumbsch H.T., St. Clair L.L. 2013. DNA barcode identification of lichen-forming fungal species in the Rhizoplaca melanophthalma species-complex (Lecanorales, Lecanoraceae), including five new species. MycoKeys, 7: 1-22.
Leavitt S.D., Kraichak E., Vondrák J., Nelsen M.P., Sohrabi M., Pérez-Ortega S., St. Clair L.L., Lumbsch H.T. 2016. Cryptic diversity and symbiont interactions in rock-posy lichens. Mol. Phylog. Evol., 99: 261-274.
Malíček J. 2014. A revision of the epiphytic species of the Lecanora subfusca group (Lecanoraceae, Ascomycota) in the Czech Republic. Lichenologist, 46, 4: 489-513.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.
Nimis P.L., Hafellner J., Roux C., Clerc P., Mayrhofer H., Martellos S., Bilovitz P.O. (2018) The lichens of the Alps - an annotated checklist. MycoKeys 31: 1-634.
Pérez-Ortega S., Spribille T., Palice Z., Elix J.A., Printzen Ch. 2010. A molecular phylogeny of the Lecanora varia group, including a new species from western North America Mycol. Prog., 9, 4: 523-535.
Singh G., Dal Grande F., Divakar P.K., Otte J., Leavitt S.D., Szczepanska K., Crespo A., Rico V.J., Śliwa L., 2007. A revision of the Lecanora dispersa complex in North America. Polish Botanical Journal 52(1): 1-70.
Singh G., Dal Grande F., Divakar P.K., Otte J., Leavitt S.D., Szczepanska K., Crespo A., Rico V.J., Aptroot A., Cáceres M.E., Lumbsch H.T., Schmitt I. 2015. Coalescent-based species delimitation approach uncovers high cryptic diversity in the cosmopolitan lichen-forming fungal genus Protoparmelia (Lecanorales, Ascomycota). PlosOne, DOI:10.1371/journal.pone.0124625 May 1, 2015.
Śliwa L., Miadlikowska J., Redelings B.D., Molnar K., Lutzoni F. 2012. Are widespread morphospecies from the Lecanora dispersa group (lichen-forming Ascomycota) monophyletic? The Bryologist, 115, 2: 265-277.
Zhao X., Leavitt S.D., Zhao Z.T., Zhang L.L., Arup U., Grube M., Pérez-Ortega S., Printzen Ch., Śliwa L., Kraichak E., Divakar, P. K., Crespo A., Lumbsch H.T. 2016. Towards a revised generic classification of lecanoroid lichens (Lecanoraceae, Ascomycota) based on molecular, morphological and chemical evidence. Fungal Divers., 78: 293-304.


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