Pier Luigi Nims
This genus of the Lecanoraceae includes species most common on calciferous rocks and bark, which were mostly placed in the Lecanora dispersa-group, that has been shown to form a clade separate from Lecanora s.str. and to be congeneric with Arctopeltis thuleana, for which the genus Myriolecis Clem. was resurrected by Zhao & al. 2016. However, the type species of Polyozosia, P. poliophaea, proved to stay in the same clade as the Myriolecis-species (Kondratyuk & al. 2019), which makes Myriolecis a later synonym of Polyozosia. While most species have a crustose and often inconspicuous thallus, a few taxa form placodioid to umbilicate thalli. 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). This key includes 26 species, i.e. those known from Italy (see Nimis 2016) and neighbouring countries in the Alps (see Nimis & al. 2018).


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.
Kondratyuk S.Y., Lőkös L., Jang S.-H., Hur J.-S., Farkas E. 2019. Phylogeny and taxonomy of Polyozosia, Sedelnikovaea and Verseghya of the Lecanoraceae (Lecanorales, lichen-forming Ascomycota). Acta Bot. Hungarica 61, 1-2: 137-184.
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 Catalogue. MycoKeys, 31: 1-634.
Śliwa L., 2007. A revision of the Lecanora dispersa complex in North America. Polish Botanical Journal 52(1): 1-70.
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.

Last modified: September, 1, 2023