This is a first draft of a key to all Lichinaceae (incl. Gloeoheppia in the Gloeoheppiacae) known to occur in Italy (see Nimis 2016), also including several species known from neighbouring countries in the Alps (see Nimis & al. 2018) and the Mediterranean region (e.g. see Egea 1979, Moreno & Egea 1992, 1992b, 1994), for a total of 83 infrageneric taxa.
The following genera are included:
Anema Forssell - This genus, with c. 6 species somewhat resembling Psorotichia, but with different ascomata and a better developed and organised thallus, was studied by Moreno & Egea (1992a) in the Mediterranean area but is still poorly known in Italy.
Ephebe Fr. - A genus with c. 13 species of thread-like lichens, where the photosynthetic partner is Stigonema, with the highest diversity in cold regions.
Euopsis Nyl. - This genus, with 2 species widespread in cool-temperate to arctic regions of both Hemispheres, differs from Pyrenopsis in the open, disciform apothecia with glossy discs, the asci which are rostrate and parly amyloid, and more slender paraphyses (Henssen & al. 1987); Psorotichia has a different photobiont and non-amyloid asci (Schultz & Büdel 2002).
Gloeoheppia Gyeln. - This genus of the Gloeoheppiaceae (Henssen 1995) differs from Heppia in the small, squamulose to moderately peltate thalli, the reticulately branched hyphae with cylindrical or roundish cells surrounding the colonies of the small-celled cyanobiont, and the presence of interstices and cavities in the thallus. It currently includes 5 species occurring on calcareous substrata, mostly on soil, in arid and semi-arid regions of the Northern Hemisphere.
Gyrocollema Vain. - A very poorly known genus of 2 calcicolous species with an endolithic thallus. The only Italian species is known from the type collection only.
Harpidium Körb. - The inclusion of this genus, including 3 species, one in Europe the other in North America, in the Lichinaceae is supported by studies of ascus ultrastructure and ascoma ontogeny that revealed striking similarities with certain members of that family, especially Pyrenopsis (Henssen & al. 1987). Harpidium is the only genus of the family with an obligatory green algal photobiont. The Mediterranean and Californian collections indicate a Madrean-Tethyan disjunction of the genus.
Heppia A. Massal. - A genus of c. 7 species occurring on soil in arid environments, that forms a well-supported monophyletic entity differing from most members of the Lichinaceae only in the subgelatinous, corticate thallus with a vertical hyphal arrangement, and an ascoma primordium consisting of strictly vertically oriented generative hyphae (Schultz & Büdel 2001). The genus has been monographed in Europe by Egea (1989).
Lemmopsis (Vain.) Zahlbr. - A genus of 3 species occurring in arid to temperate regions of the Northern Hemisphere, on calcareous rocks and clay soil (Ellis 1981).
Lempholemma Körb. - This genus, with c. 35 species, is very heterogeneous, including both flat, foliose species resembling a Collema s.lat., and squamulose or microfruticose species. According to Jørgensen (2007), the latter could be perhaps treated as members of the genus Spilonemella Nyl. The species of the Eastern Alps were studied by Schiman-Czeika (1988).
Lichina C. Agardh - This small genus is unmistakable, due to its seaweed-like appearance and the maritime habitat. It includes 9 species in both Hemispheres.
Lichinella Nyl. - In the original circumscription, this genus included 6 species growing on base-rich siliceous rocks and/or limestone. The genus was later enlarged to include also the c. 30 species of Gonohymenia J. Steiner, a poorly delimited genus in itself, a fact that was not accepted by all authors; for example Jørgensen (2007) maintains the genus Thallinocarpon E. Dahl for the few non-Mediterranean species of this complex. Here, both Thallinocarpon and Gonohymenia are subsumed under Lichinella. Mediterranean species were treated by Moreno & Egea (1992b), North American species by Schultz (2005, 2007a).
Metamelanea Henssen - This small genus, related to Psorotichia is characterized by the chroococcoid photobionts arranged in densely aggregated and vertically oriented packetsso that vertical fissures are often observed in thin cross sections. The apothecia are also rather characteristic, having an open, umbonate to gyrose or rough, flat to somewhat depressed disc.
Paulia Fée - This still rather poorly known genus includes c. 14 species with quite disjunctive distributions. The genus as a whole has a broad biogeographical range in arid to semi-arid, tropical regions of America, Africa, Australasia and some western Pacific Islands, with a single species, described from Italy (Henssen & Tretiach 1995), known from temperate Europe. Most, but not all, of the species occur on calciferous rocks.
Peccania A. Massal ex Arnold - A still rather poorly known genus, characterised by the filiform conidia. Most of the c. 15 species occur in dry areas.
Phylliscum Nyl. - This genus, with c. 8 species, is quite polymorphic and perhaps non-monophyletic (Jørgensen 2007).
Porocyphus Körb. - A subcosmopolitan genus with 8 species occurring in arid regions, characterised by simple spores, poriform apothecia, and Calothrix as a photobiont.
Psorotichia A. Massal. - This genus, differing from Lemmopsis mainly in details of apothecial anatomy, is still very poorly known: it includes c. 50 species, many of which are poorly known as well, some of which being likely to belong to other genera. The species of the western Mediterranean region were treated by Moreno & Egea (1994), those of the Sonoran region by Schultz (2007b).
Pterygiopsis Vain. - This genus includes c. 17 species, mostly occurring in tropical areas: according to Jørgensen (2007) its delimitation is somewhat uncertain. A single species was hitherto reported from Italy, plus a second sorediate species from Puglia which is presently under study (Ongaro & al. 2016).
Pyrenocarpon Trevis. - This genus is rather similar to, and was often confused with Porocyphus, but has different apothecia which open to expose the strongly widened proper exciple, a character that also sets the genus apart from Psorotichia. The genus, which includes 2 species, seems to be closely related to Lemmopsis (Jørgensen 2007).
Pyrenopsis (Nyl.) Nyl. - According to Jørgensen (2007) this genus is insufficiently understood at all levels. Even after the removal of Cryptothele and Euopsis, the genus, which includes c. 40 species, is far from being homogeneous, and appears in need of further division. Several species are very poorly known as well.
Synalissa Fr. - A small genus of 5 species. The type species, which was frequently confused for one of the subfruticulose species of Lempholemma, is variably polysporous.
Thelignya A. Massal. - This small genus of 2 species, superficially resembles Pyrenopsis in the sunken pycnoascocarps and in the growth-form, but is easily distinguished by the dark greenish (Calothrix) rather than reddish brown colour when wet (Jørgensen 2007). It differs from Porocyphus in the poriform ascomata and the looser, weakly lichenised thallus.
Thermutis Fr. - A monotypic genus, the most primitive of the Lichinaceae (Jørgensen 2007), distinguished from other fruticose cyanobacterial lichens by having Scytonema as a photobiont. When sterile, it is difficult to distinguish from free-living Scytonema, as it is weakly lichenised.
Thyrea A. Massal. - In the traditional circumscription, this genus was very heterogeneous and has undergone major redefinitions based on ascomata characters (see e.g. Moreno & Egea 1992), which has reduced the number of species worldwide to 13, and those occurring in Italy to 3.
Zahlbrucknerella Herre - A genus with c. 10 species, occurring mostly on rocks along the banks of rivers and lakes, and in moist depressions (one species is maritime), mainly represented in the cool- to cold-temperate regions of both Hemispheres, with the greatest diversity in the Americas.
Several species are very poorly known in Italy, especially in genera such as Psorotichia and Pyrenopsis. A key to the genera of the Lichinaceae was published by Schultz & Büdel (2002). Important, partial keys to European species were published by Clauzade & Roux (1985), Wirth & al. (2013) and Jørgensen (2007).

References

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* currently under revision by M. Tretiach
Last modified: March, 15, 2024

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