Lobothallia praeradiosa
Lobothallia praeradiosa is a species of saxicolous crustose lichen in the family Megalosporaceae. It forms a pale, radiating crust with distinct marginal lobes, and develops pale, flat fruiting bodies. The species grows on sun-exposed rock in dry habitats and is reported from a broad range across Eurasia and North America.
Taxonomy
It was first described as a new species in 1884 by the Finnish lichenologist William Nylander, as Lecanora praeradiosa, based on material collected on siliceous-calcareous rock near Budapest, and characterized by a pale ochre, radiating thallus and pale, flat apothecia with eight simple, ellipsoid ascospores about 9–11 × 7 μm. The species was later reclassified in the genera Squamaria, Placodium, and Aspicilia. Josef Hafellner recombined it in Lobothallia in 1991.A modern revision of Lobothallia by Paukov and co-authors included L. praeradiosa among the core, lobed members of the genus and tested its relationships using DNA sequence data. In their internal transcribed spacer phylogeny, material identified as Lecanora bogdoënsis was recovered within the L. praeradiosa lineage with strong support, rather than as a separate species. On morphological and chemical grounds, Paukov et al. concluded that L. bogdoënsis does not belong with Lecanora-like taxa characterised by usnic acid or xanthones, and instead matches Lobothallia in having small spores and short conidia. Because the sequenced material from the type region of L. bogdoënsis also agreed in morphology and conidial dimensions with L. praeradiosa, they treated Lecanora bogdoënsis as a synonym of Lobothallia praeradiosa.