KEYS TO THE LICHENS OF ITALY - 17) BUELLIA (with Amandinea, Diploicia, Diplotomma, Endohyalina, Monerolechia, and Tetramelas, incl. Coscinocladium and Epilichen)
This is a key to all species of buellioid lichens (Amandinea, Buellia, Diploicia, Diplotomma, Endohyalina, Monerolechia, Tetramelas, incl. the unrelated Epilichen) known to occur in Italy (see Nimis 2016), plus a few species known from neighbouring contries (see e.g. Nimis & al. 2018), for a total of 80 species (the poorly known Buellia myriocarpella is not included). The key also includes Coscinocladium gaditanum, a sterile species of the Physciaceae which is very similar to Diploicia (Crespo & al. 2004).
The cosmopolitan genus Buellia is currently thought to contain c. 300 species worldwide. Buellia s.str. (formerly Hafellia) is one of the few well-delimited groups within Buellia s.lat.. It is characterised by the callispora-type ascospores, bacilliform conidia, and often by a strongly oil-inspersed hymenium. The residual species of Buellia, which are not closely related, should be excluded from Buellia s.str., but a precise generic circumscription must await the results of further molecular investigations. Important nomenclatural changes are probable in the next future.
Amandinea is a subcosmopolitan genus of c. 30 species, most of which were formerly treated as members of Buellia. The genus is very heterogeneous and probably polyphyletic; furthermore, several species, especially A. punctata s.lat., await further study.
Diplotomma - Initial molecular studies indicated that Diplotomma and Diploicia formed a monophyletic clade (Molina & al. 2002, Crespo & al. 2004) and, consequently, the two genera were synonymised. This was rejected in a genetic analysis carried out by Helms & al. (2003), who also confirmed that both genera are members of the Caliciaceae. Diplotomma includes c. 30, mostly poorly known and/or problematic species, and is insufficiently known in Italy. Here I do not always follow Nordin (1996) in considering several species as synonyms.
Endohyalina, based on species formerly belonging to the -group, is characterised by crustose, autonomous or obligately lichenicolous thalli, lecideine apothecia with a hymenium often more or less inspersed with oil droplets, a brown hypothecium, small dirinaria-type ascospores developing with type B ontogeny, bacilliform conidia, and by diploicin as the major secondary metabolite. The genus is closely related to Diploicia; for further details see Giralt & al. (2010) and Nadyeina & al. (2010).
Epilichen - This genus, currently including 3 species, 2 of which occur in Europe, was originally created to accommodate the parasitic species of Buellia which had been assigned to Karschia. However, it differs in having broader, true paraphyses which are branched only at the apex, as well as in the type of asci, and belongs to the Rhizocarpaceae, being related to Catolechia. For further information see Hafellner (1978, 1979), Triebel (1989), and Ihlen (1998).
Monerolechia - This genus of 4 species was originally erected to accommodate M. badia. It is characterised by thalli which are initially parasitic on various other lichens but become autonomous, short, bacilliform conidia, a non-inspersed hymenium, and small Buellia-type ascospores which lack wall-thickenings at maturity; The ascus-type is somewhat intermediate between the Bacidia- and the Lecanora-type, with a very thin or even indistinct amyloid layer above the axial body, which is conical with converging flanks (see Kalb 2004, Giralt & van den Boom 2011). The genus is not accepted by all modern authors pending a clarification of the generic nomenclature of buellioid lichens.
Tetramelas - Phylogenetic studies based on molecular data have shown that this genus is a well founded segregate (see e.g. Helms & al. 2003). The genus was resurrected by Marbach (2000) and later it was emended with the addition of new diagnostic characters. Since then, 13 species have been combined into the genus and one new species has been described. A key to all known species was provided by Giralt & Clerc (2011).
Saxicolous species were monographed by Scheidegger (1993). A key to the species occurring in the Canary islands was published by Giralt & van den Boom (2011).
Crespo A., Blanco O., Llimona X., Fenencová Z., Hawksworth D.L. 2004. Coscinocladium, an overlooked endemic and monotypic Mediterranean lichen genus of the Physciaceae, reinstated by molecular phylogenetic analysis. Taxon, 53: 405-414.
Giralt M., Clerc P. 2011. Tetramelas thiopolizus comb. nov. with a key to all known species of Tetramelas. Lichenologist, 43, 5: 417-425.
Giralt M., van den Boom P.P.G. 2011. The genus Buellia s.l. and some additional crustose genera of Physciaceae in the Canary Islands. Nova Hedwigia, 92, 1-2: 29-55.
Giralt M., van den Boom P.P.G., Elix J.A. 2010. Endohyalina, the genus in the Physciaceae to accommodate the species of the Rinodina ericina-group. Mycol. Prog., 9: 37-48.
Hafellner J. 1978. Catolechia Flotow ex Massalongo emend. Körber und Epilichen Clements ex Hafellner - zwei nahe verwandte Flechtengattungen. Nova Hedwigia, 30: 673-692.
Hafellner J. 1979. Karschia Revision einer Sammlung an der Grenze von lichenisierten und nichtlichenisierten Ascomyceten. Beih. Nova Hedwigia, 62: 1-248.
Helms G., Friedl T., Rambold G. 2003. Phylogenetic relationships of the Physciaceae inferred from rDNA sequence data and selected phenotypic characters. Mycologia, 95: 1078-1099.
Ihlen P.G. 1998. The lichenicolous fungi on species of the genera Baeomyces, Dibaeis, and Icmadophila in Norway. Lichenologist 30: 27-57.
Kalb K. 2004. New or otherwise interesting lichens. II. Bibl. Lichenol., 88: 301-329.
Marbach B. 2000. Corticole und lignicole Arten der Flechtengattung Buellia sensu lato in den Subtropen und Tropen. Bibl. Lichenol., 74, 384 pp.
Molina M.C., Crespo A., Blanco O., Hladun N., Hawksworth D.L. 2002. Molecular phylogeny and status of Diploicia and Diplotomma, with observations on Diploicia subcanescens and Diplotomma rivas-martinezii. Lichenologist, 34, 6: 509-519.
Nadyeina O., Grube M., Mayrhofer H. 2010. A contribution to the taxonomy of the genus Rinodina (Physciaceae, lichenized Ascomycotina) using combined ITS and mtSSU rDNA data. Lichenologist, 42: 521-531.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.
Nordin A. 1996. Buellia species (Physciaceae) with pluriseptate spores in Norden. Symb. Bot. Upsal., 31, 3: 327-354.
Scheidegger C. 1993. A revision of European saxicolous species of the genus Buellia De Not. and formerly included taxa. Lichenologist, 25, 4: 315-364.
Triebel D. 1989. Lecideicole Ascomyceten. Eine Revision der obligat lichenicolen Ascomyceten auf lecideoiden Flechten. Bibl. Lichenol, 35: 1-278.
Last modified: October, 20, 2022