This is a key to all calicioid species (both lichenized and non-lichenized) reported from Italy (Nimis 2016), plus a few speies which are known from neighbouting countries in the Alps (see Nimis & al. 2018), for a total of 81 taxa. The term ‘calicioid’ covers a highly heterogeneous, polyphyletic group of lichenized and non-lichenized species which in the past were grouped together because of the stalked, pin-like ascomata and/or the presence of a mazaedium on their surface. Non-lichenized species were traditionally dealt with by lichenologists on account of the similarity of the stalked, pin-like apothecia with those of the lichenised Caliciaceae. A good key to the species occurring in Scandinavia was published by Tibell (1999). Most Italian species belonging to this heterogeneous group were treated by Puntillo & Puntillo (2009).
Among the lichenized species, the following genera are represented in Italy:
1) Acolium, a small group of c. 5, mainly epiphytic species formerly included in Cyphelium, characterized by a dark excipulum that is strongly thickened at the base, a distinct grey-brown thallus (absent in lichenicolous species), sessile to somewhat immersed ascomata, and often a grey pruina on the rim of the excipulum.
2) Bunodophoron, a subcosmopolitan genus of c. 25 fruticose species, with the highest diversity in moist temperate areas of the Southern Hemisphere and in the mountains of the tropics (Wedin 1993). The genus is currently included into the Sphaerophoraceae within the Lecanorales.
3) Calicium, a genus of c. 34 species, most of which grow exclusively on bark or wood, with a worldwide distribution. The multigene phylogeny of the Physciaceae-Caliciaceae clade by Prieto & Wedin (2017) brought to the re-delimitation of several genera: Cyphelium s.str. was synonymised with Calicium which, in this emended version, includes species with both stalked and sessile or immersed ascomata. Although phylogenetically very distinct, there is currently no morphological or chemical character that is unique for Calicium in the new sense.
4) Chaenotheca, a subcosmopolitan genus of c. 25 species, with the highest diversity in cool temperate areas. Most species occur on bark or wood in sheltered situations with low light intensity and high air humidity. The genus belongs to the Coniocybaceae, a previously unrecognised lichenised lineage (Coniocybomycetes, Coniocybales) related to Lichinomycetes, as shown by Prieto & al. (2013).
5) Pseudothelomma, a small, distinct group of species with immersed ascomata, growing on dry and exposed lignum, which was segregated from Thelomma by Prieto & Wedin (2017). It differs from the similar Acolium in the thin and non-sclerotised excipulum, and from the likewise similar Thelomma in the ecology, and in the thin, crystal-free cortex.
6) Sclerophora, a genus of 6 species with a broad distribution in warm-temperate to temperate areas of both Hemispheres. The genus belongs to the Coniocybaceae, a previously unrecognised lichenised lineage (Coniocybomycetes, Coniocybales) related to Lichinomycetes, as shown by Prieto & al. (2013).
7) Sphaerophorus, a bipolar genus of c. 8 fruticose species growing as epiphytes, on rocks or on the ground in arctic/antarctic-alpine and temperate to cool-temperate areas. The genus is currently included into the Sphaerophoraceae within the Lecanorales (see Wedin 1993).
8) Thelomma, a genus of the Caliciaceae which includes 5 saxicolous species in temperate and arid subtropical regions of both Hemispheres; the genus Cypheliopsis mediterranea, an extremely rare species known from France, should be probably transferred to Thelomma.
Among the non-lichenized genera, the following are represented in Italy:
1) Chaenothecopsis, a cosmopolitan genus with the highest diversity in temperate areas, including c. 60 species which are saprobic, parasites or commensals on lichens and free-living algae. Its systematic position is still poorly understood and in need of further study (Tibell 1999b, Tibell & Vinuesa 2005).
2) Microcalicium, a small genus of 4 species which belongs to the Ostropomycetideae (Prieto & al. 2013) and is now placed in the Microcaliciaceae within the Pertusariales (Jaklitsch & al. 2016).
3) Mycocalicium, widespread in cool temperate to tropical areas, with c. 12 species that are saprobic (see Tibell & Wedin 2000).
4) Phaeocalicium, which includes 17 non-lichenised saprobic and/or weakly parasitic species mostly growing on thin, decaying branches of deciduous trees or shrubs, mainly in cool temperate to temperate regions of the Northern Hemisphere, with one species each occurring in Australasia and South America (Tibell 1996).
5) Pyrgidium, a monotypic genus (Thiyagaraja & al. 2022) of the Sphinctrinaceae including a characteristic, mainly tropical species with a peculiar ascocarp shape, excipulum structure and distinctive spores, one of which was surprisingly described from northern Italy, where it might be presently exctinct.
6) Sphinctrina, which includes 5 non-lichenised lichenicolous species growing mostly on Pertusaria-species (rarely also on Lecanora and Diploschistes), mainly in temperate to tropical regions of both Hemispheres.
7) Stenocybe, a genus of the Sphinctrinaceae including c. 10 species occurring mainly in temperate areas of the Northern Hemisphere, with one species in New Zealand. The species are saprobes or possibly weak parasites on the branches of trees and shrubs, and are very host-specific. The delimitation of the genus towards Phaeocalicium needs further study.
The present key includes also the unrelated Gomphillus calycioides, belonging to a mainly tropical genus of 6 species separated from the other species of the Gomphillaceae by the vertically elongated apothecia containing very long asci and thread- to needle-like ascospores (see Lücking & al. 2005).

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.
Lücking R., Sérusiaux E., Vězda A. 2005. Phylogeny and systematics of the lichen family Gomphillaceae (Ostropales) inferred from cladistic analysis of phenotype data. Lichenologist, 37, 2: 123-170.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.
Prieto M., Wedin M. 2016. Phylogeny, taxonomy and diversification events in the Caliciaceae. Fungal Divers., 82: 221-228.
Prieto M., Baloch E., Tehler A., Wedin M. 2013. Mazaedium evolution in the Ascomycota (Fungi) and the classification of mazaediate groups of formerly unclear relationship. Cladistics, 29: 296-308.
Puntillo D., Puntillo M. 2009. Calicioid lichens and fungi of Italy: A State of the Art. Flora Medit., 19: 251-260.
Thiyagaraja V., Ertz D., Lücking R., Wanasinghe D.N., Aptroot A., da Silva Cáceres M.E., Hyde K.D., Tapingkae W., Cheewangkoon R. 2022. Taxonomic and Phylogenetic Reassessment of Pyrgidium (Mycocaliciales) and Investigation of Ascospore Morphology. J. Fungi 2022, 8, 966. https://doi.org/10.3390/jof8090966
Tibell L. 1996. Caliciales. Flora Neotropica, 69, New York Bot. Gard., New York. 78 pp.
Tibell L. 1999b. Caliciales. Nordic Lichen Flora, 1. Bohuslän, Uddevalla, pp. 20-93.
Tibell L., Vinuesa M. 2005. Chaenothecopsis in a molecular phylogeny based on nuclear rDNA ITS and LSU sequences. Taxon, 54, 2: 427-442.
Tibell L., Wedin M. 2000. Mycocaliciales, a new order for non lichenized calicioid fungi. Mycologia, 92, 3: 577-581.
Wedin M. 1993. A phylogenetic analysis of the lichen family Sphaerophoraceae (Caliciales); a new generic classification and notes on character evolution. Pl. Syst. Evol., 187: 213-241.

Last modified: December, 2, 2023