Anisomeridium (Müll. Arg.) M. Choisy is a large genus of more than 200, mostly tropical to warm-temperate species having thin thalli with a trentepohliod photobiont (some are non-lichenized), black perithecia, and 1-3-septate ascospores. The anastomosing paraphyses, the relatively broad, ovoid ascospores, and the macroconidia embedded in a gelatinous matrix separate this genus from Strigula, while the cellular structure of the exciple distinguishes it from Arthopyrenia and related genera. The closely related Megalotremis and Musaespora have large, rather thick-walled ascospores. The genus belongs to the Monoblastidiales, an order with a single family of chiefly tropical pyrenocarpous lichens (Dothideomycetes), with the highest diversity in tropical rain forests and periodically dry ecosystems of South America. The genus is poorly known in Italy (see Nimis 2016), so that the present key includes also some species known from neighbouring countries (see e.g. Nimis & al. 2018), which should be looked for in Italy, for a total of 7 species. Good descriptions and a key to the British species are in Orange (2013b). Further information is in Aptroot (1999), Coppins & Aptroot (2008), Harris (1973), Nordén & Aptroot (2018), Smith  & al. (2009) .

References

Aptroot A. 1999. Notes on taxonomy, distribution and ecolgy of Anisomeridium polypori. Lichenologist, 31, 6: 641-642.
Coppins B.J. & Aptroot A.. 2008. New species and combinations in the lichens of the British Isles. Lichenologist 40, 5: 363-374.
Harris R.C. 1973. The corticolous pyrenolichens of the Great Lakes region. Michigan Bot., 12: 3-68.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.
Nimis P.L., Hafellner J., Roux C., Clerc P., Mayrhofer H., Martellos S., Bilovitz P.O. 2018. The Lichens of the Alps. An Annotated Catalogue. MycoKeys, 31: 1-634.
Nordén B. & Aptroot A. 2018. Anisomeridium viridescens and Arthopyrenia callunae, two pyrenolichens new to Fennoscandia. Graphis Scripta, 30, 10: 166-169.
Orange A. 2013b. British and Other Pyrenocarpous Lichens. Vers. II. August 2013. https://museum.wales/.../Orange-A-2013-British-and-other-pyrenocarpous-lichens.pdf
Smith C.W., Aptroot A., Coppins B.J., Fletcher A., Gilbert O.L., James PW., Wolseley P.A. (eds.) 2009. The Lichens of Great Britain and Ireland. British Lichen Society, London. 1046 pp.

Last modified: September, 2, 2022

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