Pier Luigi Nimis
The genus Thelopsis, which was monographed by Vězda (1968) is characterised by short and stiff periphyses, long and simple paraphyses, unitunicate polysporous asci, and simple to transversely septate, rarely submuriform ascospores. It is classified in the Stictidaceae and it includes c. 13 species worldwide. Good descriptions and a key to the British species are in Orange (2013). Topelia, which currently includes 9 species (Jørgensen & Vězda 1984, Aptroot & al. 2014), mainly differs in the 8-spored asci, and the muriform rather than simple or transversely septate ascospores. With the recent addition of more or less intermediate species, the distinction between the two genera has become somehow arbitrary. A world key to all species of both genera was provided by Aptroot & al. (2014).
This key includes the 7 species known to occur in Italy (see Nimis 2016), plus 2 species which are known from neighbouring countries and whose presence in Italy is probable: Thelopsis lojkana and Th. foveolata,


Aptroot A., Mendonça C., Ferraro L.I., Cáceres M. 2014. A world key to species of the genera Topelia and Thelopsis (Stictidaceae), with the description of three new species from Brazil and Argentina. Lichenologist, 46, 6,: 801-807.
Jørgensen P.M. Vězda A, 1984. Topelia, a Mediterranean lichen genus. Beih. Nova Hedwigia, 79: 501-511.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.
Orange A. 2013. British and Other Pyrenocarpous Lichens. Vers. II. August 2013.
Vězda, A. 1968. Taxonomische Revision der Gattung Thelopsis Nyl. (Lichenisierte Fungi). Folia geobot. phytotax. 3, 363.406.