The genus Hypocenomyce Choisy, as monographed by Timdal (1984), comprised an heterogeneous group of species which were segregated from Lecidea s. lat. by Schneider (1980). A molecular study by Bendiksby & Timdal (2013) revealed that the genus was extremely polyphyletic, and that it can be subdivided into seven supported clades belonging in different genera, families, orders and even subclasses, thus representing a remarkable example of morphological and ecological convergence. The genus in the strict sense, which is sister to a clade consisting of Boreoplaca and Ophioparma, now comprises only 3 species, one of which occurs in Europe, and is included in the Ophioparmaceae within the Umbilicariales. The other species were segregated in the following genera: 1) Carbonicola Bendiksby & Timdal, which forms a sister clade to that consisting of the Cladoniaceae and Stereocaulaceae, and is now placed into its own family, the Carbonicolaceae. 2) Pycnora Hafellner, an earlier segregate from Hypocenomyce, which was found to be polyphyletic as well. In its present circumscription it includes 3 species only, and is placed in its own family, the Pycnoraceae, in the Candelariales. 3) Toensbergia Bendiksby & Timdal, a monotypic genus which includes a species that surprisingly appears to be related to A. Massal., now included in the Sporastatiaceae. 4) Xylopsora Bendiksby & Timdal, with 3 species, the phylogenetic sister of the clade consisting of the two foliose genera Lasallia Mérat and Umbilicaria Hoffm. Those three genera make up the sister clade of the genus Fulgidea Bendiksby & Timdal, another Hypocenomyce-segregate. The four genera together constitute the Umbilicariaceae (Bendiksby & Timdal 2013), extending the concept of the family to include crustose and squamulose lichens as well. Finally, some species of Waynea Moberg were treated as members of Hypocenomyce in the past (e.g. by Clauzade & Roux 1985). This genus of the Ramalinaceae, originally described to accommodate a single species from North America, presently comprises 7 species mainly occurring in areas with a Mediterranean climate (one species, however is limited to Siberia).
The present key includes all species of the genera mentioned above which are known to occur in Italy (see Nimis 2016), plus a few species known from neighbouring countries which should be looked for in Italy, for a total of 13 infrageneric taxa.

References

Bendiksby M., Timdal E. 2013. Molecular phylogenetics and taxonomy of Hypocenomyce sensu lato (Ascomycota: Lecanoromycetes): Extreme polyphyly and morphological/ecological convergence. Taxon, 65, 5: 940-956.
Clauzade G., Roux C. 1985. Likenoj de Okcidenta Europo. Ilustrita determinlibro. Bull. Soc. Bot. Centre-Ouest, N. Ser., N. Spec. 7. Royan, 893 pp.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.
Schneider G. 1980 (1979”). Die Flechtengattung Psora sensu Zahlbruckner. Bibl. Lichenol., 13: 1-291.
Timdal E. 1984. The genus Hypocenomyce (Lecanorales, Lecideaceae), with special emphasis on Norwegian and Swedish species. Nordic J. Bot., 4: 83-108.

Last modified: January, 3, 2024

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