The present key, comprising 18 species, includes all species of Hymeneliaceae (Hymenelia incl. Ionaspis, Tremolecia) known to occur in Italy (see Nimis 2016), plus the two species of Eiglera, a genus which was often considered as related to Hymenelia and Ionaspis, but differing in the amyloid apical dome of the asci and closely related to the Acarosporaceae (Miadlikowska & al. 2014), in which it was included by Jaklitsch & al. (2016), although according to Knudsen & al. (2021) it is best placed in its own family, the Eigleraceae. In spite of careful numerical taxonomic studies, the characters of Hymenelia and Ionaspis overlap considerably; the type of photobiont, which in the past was used to separate the two genera, is now considered as irrelevant for their separation (see Lutzoni & Brodo 1995), so that I prefer to treat here all species of Ionaspis under the older name Hymenelia.

References

Jaklitsch W., Baral H.-O., Lücking R., Lumbsch H.T., Frey W. (eds.) 2016. Engler's Syllabus of Plant Families. Part 1/2: Ascomycota. G. Borntraeger, Stuttgart, 322 pp.
Knudsen K., Kocourková J., Cannon P., Coppins B., Fletcher A., Simkin J. 2021. Acarosporales: Acarosporaceae, including the genera Acarospora, Caeruleum, Myriospora, Pleopsidium, Sarcogyne and Trimmatothelopsis. Revisions of British and Irish Lichens, 12: 1-25.
Lutzoni F.M., Brodo I.M. 1995. A generic redelimitation of the Ionaspis-Hymenelia complex. Syst. Bot., 20, 3: 224-258.
Miadlikowska J., Kauff F., Högnabba F., Oliver J.C., Molnár K, Fraker E., Gaya E., Hafellner J., Hofstetter V., Gueidan C., Otálora M.A.G., Hodkinson B., Kukwa M., Lücking R., Björk C., Sipman H.J.M., Burgaz A.R., Thell A., Passo A., Myllys L., Goward T., Fern 2014. A multigene phylogenetic synthesis for the class Lecanoromycetes (Ascomycota): 1307 fungi representing 1139 infrageneric taxa, 317 genera and 66 families. Mol. Phylogenet. Evol., 79: 132-168.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.

Last modified: March, 2, 2024

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