This key includes all crustose lichen species with more or less lirelliform apothecia and 1-celled spores known to occur in Italy (Nimis 2016), plus 3 species known from neighbouring countries which should be looked for in Italy, for a total of 11 taxa. The following genera are included:
1) Elixia - A genus differing from Ptychographa in the more rounded apothecia and the smaller ascospores, presently placed in the Elixiaceae within the Umbilicariales. The genus was originally described as monotypic and included a single boreal-montane species, until Spribille & Lumbsch (2010) described a second species from the mountains of Crete, which should be looked for also in Italy.
2) Lithographa - This genus of the Xylographaceae (Resl & al. 2015) is closely related to Lambiella; the only character separating the two genera is the shape of the ascomata: elongate (lirelliform) in Lithographa, rounded (lecideine or lecanorine) in Lambiella (Spribille & al. 2014). The genus includes 10 saxicolous species mostly occurring in cool areas of both Hemispheres.
3) Wadeana - This genus, which currently includes 2 species (Coppins & James 1978), differs from superficially similar genera, like Lithographa, in having polysporpus, fissitunicate asci. Its taxonomic position is still unclear (Lumbsch & Huhndorf 2009).
4) Xylographa -This genus of the Xylographaceae, with 20 species, includes some of the most abundant wood-inhabiting lichens in boreal and temperate regions of both hemispheres. The genus has been recently monographed by Spribille & al. (2014), who found that it forms a strongly supported monophyletic group closely related to Lithographa and Ptychographa, as well as to rock-dwelling and lichenicolous species of Lambiella; the British species were treated by Cannon & al. (2021).

References

Cannon P., Fryday A., Spribille T., Coppins B., Vondrák J., Sanderson N., Simkin J. 2021. Baeomycetales: Xylographaceae, including the genera Lambiella, Lithographa, Ptychographa and Xylographa. Revisions of British and Irish Lichens, 17: 1-11.
Coppins B.J., James P.W. 1978. New or interesting British lichens II. Lichenologist 10, 2: 179-207.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.
Spribille T., Lumbsch H.T. 2010. A new species of Elixia (Umbilicariales) from Greece. Lichenologist, 42, 4: 365-371.
Spribille T., Resl P., Ahti T., Pérez-Ortega S., Tønsberg T., Mayrhofer H., Lumbsch H.T. 2015. Molecular systematics of the wood-inhabiting, lichen-forming genus Xylographa (Baeomycetales, Ostropomycetidae) with eight new species. Symb. Bot. Upsal., 37, 1: 1-87.
Lumbsch H.T., Huhndorf S.M. 2010. Outline of Ascomycota. 2009. Fieldiana, Life and Earth Sciences, 1: 1-60.
Resl P., Schneider K., Westberg M., Printzen C., Palice Z., Thor G., Fryday A., Mayrhofer H., Spribille T. 2015. Diagnostics for a troubled backbone: testing topological hypotheses of trapelioid lichenized fungi in a large-scale phylogeny of Ostropomycetidae (Lecanoromycetes). Fungal Divers., 73: 239-258.

* currently under revision by T. Spribille.
Last modified: September, 20, 2022

Project Dryades, Department of Life Sciences, University of Trieste - CC BY-SA 4.0