KEYS TO THE LICHENS OF ITALY - 22) GYALECTOID LICHENS (Gyalecta, Gyalectidium, Gyalidea, Gyalideopsis, Jamesiella, 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), for a total of 49 infrageneric taxa. The term ‘gyalectoid’ is used here in a very broad sense, for a taxonomically rather heterogeneous group of 9 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).
1) Gyalecta, 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).
2) Ramonia includes c. 24 species occurring in tropical, subtropical and oceanic-temperate areas. A world key was published by Aptroot & al. (2015).
3) Gyalectidium 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).
4) Gyalidea 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).
5) Gyalideopsis 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.
6) Jamesiella, 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.
7) Coenogonium, 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). 8) Sagiolechia 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.
9) Petractis, which includes the type species, P. clausa, P. farlowii (which, like P. clausa, bears cyanobacteria as symbionts), and P. luetkemuelleri (with a trentepohlioid photobiont), remains heterogeneous. Kauff & Lutzoni (2002) have transferred two species of Petractis into Gyalecta.
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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., 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.
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