The genus Parmelia, earlier monographed by Hale (1987), presently comprises c. 40 species, mostly restricted to the Northern Hemisphere (see Crespo & al. 2010). It is characterized by having a foliose thallus with simple to furcate and squarrose rhizines, a non-pored epicortex, effigurate to elongate pseudocyphellae on the upper surface, isolichenan, and cylindrical or bifusiform conidia (Crespo et al. 2010; Thell et al. 2012). In recent times, several cryptic species were newly described on the basis of molecular data (see e.g. Feuerer & Thell 2002, Crespo & al. 2002, Molina & al. 2004, Divakar & al. 2005, Thell & al. 2017), which were purported to differ in subtle morphological, chemical and/or ecological characters. While in the sorediate Parmelia sulcata-complex the morphological differences between P. sulcata and P. barrenoae appear now quite clear (see e.g. Hodkinson & al. 2010, Molina & al. 2011), those between P.sulcata and P. encryptata are quite weak (see Ossowska & al. 2021). The isidiate species of the Parmelia saxatilis-complex (P. ernstiae, P. serrana and P. saxatilis) proved to be almost indistinguishable on the basis of morphological features, chemical variation using TLC being perhaps the best way to distinguish most specimens, although overlap in chemosyndromes among species exists as well (Ossowska & al. 2018, Corsie & al. 2019). To complicate the picture, a further cryptic, saxicolous species (P. rojoi) has been recently described from Spain, which is virtually indistinguishable from the others (Crespo & al. 2020). The ecology and distribution of Italian species of this group are still poorly known, most records of P. ernstiae and P. serrana being hidden among those of P. saxatilis. In the P. omphalodes group (Kukwa 2019, Ossowska & al. 2019), the distinction between P. omphalodes and P. pinnatifida seems to be confirmed by molecular and morphological data, while the status of P. discordans is still not clear.
The entire genus is poorly known in Italy. Also the revision of the isidiate species by Castellani & al. (2021) did not permit to assess the relative frequencies of the different cryptic species in the Country: the statement by these authors that P. sulcata is the most widespread species in Italy being not supported by molecular data. The present key includes all species known to occur in Italy (Nimis 2016), plus P. discordans, which is known from Corsica, for a total of 11 species.

References

Castellani M., Bianchi E., Coppi A., Nascimbene J., Benesperi R. 2021. Revision of the Parmelia saxatilis group in Italy based on morphological, chemical and molecular data. Phytotaxa 512, 1: 28-40.
Corsie E.I., Harrold P., Yahr R. 2019. No combination of morphological, ecological or chemical characters can reliably diagnose species in the Parmelia saxatilis aggregate in Scotland. Lichenologist, 51: 107-121.
Crespo A, Molina M.C., Blanco O., Schroeter B., Sancho L.G., Hawksworth D.L. 2002. rDNA ITS and beta-tubulin gene sequence analyses reveal two monophyletic groups within the cosmopolitan lichen Parmelia saxatilis. Mycol. Res., 106: 788-795.
Crespo A., Kauff F., Divakar P.K., del Prado R., Pérez-Ortega S., Amo de Paz G., Ferencova Z., Blanco O., Roca-Valiente B., Núñez-Zapata J., Cubas P., Argüello A., Elix J.A., Esslinger T.L., Hawksworth D.L., Millanes A., Molina M.C., Wedin M., Ahti T., Aptroot 2010. Phylogenetic generic classification of parmelioid lichens (Parmeliaceae, Ascomycota) based on molecular, morphological and chemical evidence. Taxon, 59, 6: 1735-1753.
Crespo A., Rico V.J., Garrido E., Lumbsch H.T., Divakar P.K. 2020. A revision of species of the Parmelia saxatilis complex in the Iberian Peninsula with the description of P. rojoi, a new potentially relict species. Lichenologist, 52: 365-376.
Divakar P.K., Molina M.C., Lumbsch H.T., Crespo A. 2005. Parmelia barrenoae, a new lichen species related to Parmelia sulcata (Parmeliaceae) based on molecular and morphological data. Lichenologist, 37, 1: 37-46.
Feuerer T., Thell A. 2002. Parmelia ernstiae: A new macrolichen from Germany. Mitt. Inst. allgem. Bot. Hamburg, 30-32: 49-60.
Hale M.E. 1987. A monograph of the lichen genus Parmelia Acharius sensu stricto (Ascomycotina: Parmeliaceae). Smithsonian Contrib. Bot., 66: 1-55.
Hodkinson B.P., Lendemer J.C., Esslinger T.L. 2010. Parmelia barrenoae, a lichen new to North America and Africa. North American Fungi, 5, 3: 1-5.
Kukwa M. 2019. Morphology and secondary chemistry in species recognition of Parmelia omphalodes group – evidence from molecular data with notes on the ecological niche modelling and genetic variability of photobionts. MycoKeys, 61: 39-74.
Molina M., Crespo A., Blanco O., Lumbsch H.T., Hawskworth D.L. 2004. Phylogenetic relationships and species concepts in Parmelia s.str. (Parmeliaceae) inferred from nuclear ITS rDNA and-tubulin sequence. Lichenologist, 36, 1: 37-54.
Molina M.C., Divakar P.K., Millanes A.M., Sanchez E., Del Prado R., Hawksworth D.L., Crespo A. 2011. Parmelia sulcata (Ascomycota: Parmeliaceae), a sympatric monophyletic species complex. Lichenologist, 43: 585-601.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.
Ossowska E., Guzow-Krzemińska B., Dudek M., Oset M., Kukwa M. 2018. Evaluation of di¬agnostic chemical and morphological characters in five Parmelia species (Parmeliaceae, lichenized Ascomycota) with special emphasis on the thallus pruinosity. Phytotaxa, 383: 165–180.
Ossowska E., Guzow-Krzemińska B., Kolanowska M., Szczepańska K., Kukwa M. 2019. Morphology and secondary chemistry in species recognition of Parmelia omphalodes group – evidence from molecular data with notes on the ecological niche modelling and genetic variability of photobionts. MycoKeys, 61: 39-74.
Ossowska E., Guzow-Krzemińska B., Szymczyk R., Kukwa M. 2021. A molecular re-evaluation of Parmelia encryptata with notes on its distribution. Lichenologist, 53:341–345.
Thell A., Crespo A., Divakar P.K., Kärnefelt I., Leavitt S.D., Lumbsch T.H., Seaward M.R.D. 2012. A review of the lichen family Parmeliaceae Nordic J. Bot., 30, 6: 641-664.
Thell A., Tsurykau A., Persson P.-E., Hansson M., Åsegård E., Kärnefelt I., Seaward M.R.D. 2017. Parmelia ernstiae, P. serrana and P. submontana, three species increasing in the Nordic countries. Graphis Scripta: 29, 24-32.

Last modified: April, 7, 2024

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