KEYS TO THE LICHENS OF ITALY - 22) GYALECTOID LICHENS (Coenogonium, Cryptodiscus, Gyalecta, Gyalectidium, Gyalidea, Gyalideopsis, Jamesiella, Neopetractis, Petractis, Ramonia, Sagiolechia)
Pier Luigi Nims
Apparatus of images: Andrea Moro - Software and databases: Stefano Martellos

This is a key to all gyalectoid lichens hitherto reported from Italy (see Nimis 2016), plus several species known from neighbouring territories (e.g. see Nimis & al. 2018), for a total of 60 infrageneric taxa. The term ‘gyalectoid’ is used here in a very broad sense, for a taxonomically rather heterogeneous group of 10 genera, belonging to at least four different families of Ostropales: Gyalectaceae (Gyalecta, Ramonia), Gomphillaceae (Gyalectidium, Gyalidea, Gyalideopsis, Jamesiella), Coenogoniaceae (Coenogonium), and Sagiolechiaceae (Sagiolechia). The systematic position of the genus Petractis, which is also included in this key, is still uncertain (Jaklitsch et al 2016; Lücking et al. 2016). Not included in the key is the genus Thelopsis, formerly classified in the family Stictidaceae but found to form a monophyletic group within Gyalecta as currently accepted, in spite of the obviouos morphological differences (see Ertz & al. 2021). The following genera are included in the key:
1) Coenogonium Ehrenb. , a fairly large genus of more than 90, mainly tropical species, characterised by biatorine (rarely zeorine), yellow to orange apothecia with paraplectenchymatous excipulum, partially amyloid hymenium, thin-walled unitunicate asci, 1-septate or rarely non-septate ascospores, and a trentepohlioid photobiont. Originally, it included only species with a filamentous thallus, while crustose taxa were separated in the genus Dimerella. However, the discovery of some species which have both a filamentous and a crustose thallus, and the fact that Dimerella and Coenogonium have the same type of apothecia, while the morphological differences are due to the photobiont, led Lücking & Kalb (2000) to unite both genera under the older name Coenogonium. Molecular data (Kauff & Lutzoni 2002) confirm the monophyly of the genus, which is placed in the family Coenogoniaceae, as circumscribed by Lücking & Kalb (2000).
2) Cryptodiscus Corda. This is a monophyletic group of saprotrophic and lichenized fungi characterized by small, urceolate apothecia, mostly hyaline ascomatal walls without any embedded crystals, no clear periphysoids, and with oblong to narrow cylindrical, septate ascospores. Cryptodiscus forms a well-supported clade together with Absconditella and the remaining Stictidaceae (see Baloch & al. 2009).
3) Gyalecta Ach. , with c. 50 species, has the highest diversity in the Northern Hemisphere. All species occur in humid, rather shaded situations, and prefer base-rich or subneutral substrata (bark, rock, and soil). In their revision of the Gyalectales, Kauff & Lutzoni (2002) transferred two species of Petractis into Gyalecta. The concept of the genus was further broadened to include Belonia and Pachyphiale, which were shown to be nested within Gyalecta (see Baloch & al. 2013).
4) Gyalectidium Müll. Arg. is a genus of foliicolous, mainly tropical lichens belongs to the Gomphillaceae, owing to the branched and highly anastomosing paraphyses and the highly specialised conidiomata (hyphophores). A world monograph of the genus, that currently includes 52 species, was published by Ferraro & al. (2001).
5) Gyalidea Vězda includes c. 50 species characterised by gyalectoid apothecia, non-amyloid hymenium, simple, septate paraphyses and hyaline, submuriform or transversely septate ascospores. Most of the species grow on soil, rocks, mosses or plant debris. Aptroot & Lücking (2003) have shown that Solorinella Anzi belongs to the species traditionally assigned to Gyalidea (a name which is now conserved against Solorinella).
6) Gyalideopsis Vězda In an extensive phenotype-based phylogenetic analysis of the family Gomphillaceae, including almost all species described in Gyalideopsis s.lat., Lücking & al. (2005) retained the genus in a more restricted sense, excluding taxa growing on inorganic substrata with immersed apothecia (Diploschistella), species with campylidioid hyphophores (Ferraroa), taxa with isidioid hyphophores termed “thlasidia” (Jamesiella), and species on inorganic substrata with lecideine apothecia, small transversely septate ascospores and Aulaxina-type hyphophores (Lithogyalideopsis). Gyalideopsis s.str. remains the largest genus of the family, with c. 100 currently recognised species. The genus is poorly known in Italy.
7) Jamesiella Lücking, Sérus. & Vězda , with c. 5 species, was segregated from Gyalideopsis s.str. by the presence of isidiiform hyphophores (thlasidia) in which the diahyphae are produced internally, so that the entire hyphophore is dispersed.
8) Neopetractis Ertz - A genus currently including 2 species, segregated from Petractis due to its different phylogenetic position and different photobiont (Ertz & al. 2021).
9) Petractis Fr. , after the segregation of Neopetractis, this genus includes the type species, P. clausa, and P. farlowii (which, like P. clausa, bears cyanobacteria as symbionts). Kauff & Lutzoni (2002) have transferred two species of Petractis into Gyalecta.
10) Ramonia Stizenb. includes c. 24 species occurring in tropical, subtropical and oceanic-temperate areas. A world key was published by Aptroot & al. (2015).
11) Sagiolechia A. Massal. is a genus of 3 species with a mainly circumpolar distribution. The new family Sagiolechiaceae was proposed by Baloch & al. (2010) to accommodate Rhexophiale and Sagiolechia within the Ostropales.

References

Aptroot A., Lücking R. 2003. Phenotype-based phylogenetic analysis does not support generic separation of Gyalidea and Solorinella. Bibl. Lichenol., 86: 53-78.
Aptroot A., Sobreira P.N.B., da Silva Caceres M.E. 2015. A remarkable new Ramonia (Gyalectaceae) from Brazil, with a key to the species. Lichenologist, 47, 1: 21-29.
Baloch E., Gilenstam G., Wedin M. 2002. Phylogeny and classification of Cryptodiscus, with a taxonomic synopsis of the Swedish species. Fungal Diversity 38: 51-68.
Baloch E., Lumbsch H.T., Lücking R., Wedin M. 2013. New combinations and names in Gyalecta for former Belonia and Pachyphiale (Ascomycota, Ostropales) species. Lichenologist, 45, 6: 723-727.
Ertz D., Sanderson N., Lebouvier M. 2021. Thelopsis challenges the generic circumscription in the Gyalectaceae and brings new insights to the taxonomy of Ramonia. Lichenologist, 53,1: 45-61.
Ferraro L.I., Lücking R., Sérusiaux E. 2001. A world monograph of the lichen genus Gyalectidium (Gomphillaceae). Bot. J. Linn. Soc., 137: 311-345.
Jaklitsch W., Baral H.-O., Lücking R., Lumbsch H.T., Frey W. (eds.) - 2016 - Engler's Syllabus of Plant Families. Part 1/2: Ascomycota. - G. Borntraeger, Stuttgart, 322 pp.
Kauff F., Lutzoni F. 2002. Phylogeny of the Gyalectales and Ostropales (Ascomycota, Fungi): among and within order relationships based on nuclear ribosomal RNA small and large subunits. Mol. Phylogen. Evol., 25: 138-156.
Lücking R., Kalb K. 2000. Foliikole Flechten aus Brasilien (vornehmlich Amazonien), inklusive einer Checkliste und Bemerkungen zu und Dimerella (Gyalectaceae). Bot. Jahrb., 122: 1-61.
Lücking R., Aptroot A., Umaña A., Chaves J.L., Sipman H.J.M., Nelsen P. 2006. A first assessment of the Ticolichen biodiversity inventory in Costa Rica: the genus Gyalideopsis and its segregates (Ostropales: Gomphillaceae), with a world-wide key and name status checklist. Lichenologist, 38, 2: 131-160.
Lücking R., Hodkinson B., Leavitt S.D. - 2016 - The 2016 classification of lichenized fungi in the Ascomycota and Basidiomycota - Approaching one thousand genera. - Bryologist, 119, 4: 361-416.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT. Trieste
Nimis P.L., Hafellner J., Roux C., Clerc P., Mayrhofer H., Martellos S., Bilovitz P.O. 2018. The Lichens of the Alps. An Annotated Catalogue. Mycokeys, 31: 1-634.

Last modified: April, 4, 2022


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