In the molecular revision of the Teloschistaceae by Arup & al. (2013) Blastenia, a genus described by Massalongo but subsequently forgotten, forms a well-supported clade of fairly similar species characterised by a grey crustose thallus, (mostly) rusty orange apothecia, and similar secondary chemistry. The genus has been monographed by Vondrák & al. (2020), who reconstructed its phylogeny testing species delimitation and looking for evolutionary drivers. The origin of the genus is dated to the early Tertiary, but later diversification events are distinctly younger. A total of 24 species (plus 2 subspecies) is presently recognized within 6 infrageneric groups. substrate-specificity is high (17 species occur on organic substrates, 7 on siliceous rocks), and most infrageneric groups also show a clear substrate preference. All infrageneric groups tend to have a Mediterranean-Macaronesian distribution, but some epiphytic species have much larger geographic ranges, and some evolved after a long‐distance dispersal outside that region. One infrageneric group has a marked reduction in apothecial size, associated with a substrate shift to twigs. Only 7 species have vegetative diaspores; they also produce apothecia but have smaller ascospores. Chlorinated (C+ purple) and non-chlorinated (C-) anthraquinone chemosyndromes co‐occur in apothecia of most species, and the occurrence of chlorinated anthraquinones on the apothecial disc is an important diagnostic character. Since commercial bleach is highly concentrated, and often gives a C+ reaction also in the absence of chlorinated anthraquinones, the concentration of the C‐solution must be reduced until it does not cause a red reaction on the apothecial discs of Xanthoria parietina, a species lacking chlorinated anthraquinones.
The present key includes the 11 species known to occur in Italy (Nimis 2016), plus a few species which could be confused with Blastenia, for a total of 16 species.

References

Arup U., Søchting U., Frödén P. 2013. A new taxonomy of the family Teloschistaceae. Nord. J. Bot., 31: 16-183.
Nimis P.L. 2016. The Lichens of Italy. A Second Annotated Catalogue. EUT, Trieste, 739 pp.
Vondrák J., Frolov I., Košnar J., Arup U., Veselská T., Halıcı G., Malíček J., Søchting U. 2020. Substrate switches, phenotypic innovations and allopatric speciation formed taxonomic diversity within the lichen genus Blastenia. J. Syst. Evol. 58, 3: 295–330.

Last modified: December, 29, 2022

Project Dryades, Department of Life Sciences, University of Trieste - CC BY-SA 4.0