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A new generic name, Rexiella, is published to replace the recently published name Rexia S. Stenroos, Pino‐Bodas and Ahti, which turned out to be an illegitimate later homonym of the cyanobacterial genus Rexia D. A. Casamatta, S. R. Gomez and J. R. Johansen.

The selectivity of mycobionts and cyanobionts in lichen symbioses were examined. We analyzed symbiotic cyanobionts, collected from different sample sites, and compared them to free-living cyanobacteria Nostoc. Cyanobionts were obtained from lichens assigned to the genera Pseudocyphellaria and Sticta, in particular. Multiple gene loci were screened and direct optimization was used in the phylogenetic analyses. We show that many lichen fungi are strongly selective towards their cyanobionts. Lichenized ascomycetes seem to be able to identify and choose a specific strain, species or a species group of Nostoc with which to associate. The present analyses also suggest that some of the Nostoc taxa may be specialized in symbiotic life with only lichenized ascomycetes. Despite the selectivity observed in fungi, there appears to be no coevolution between the partners. We have also discussed the problems of using the tRNA(Leu) intron as a marker in phylogenetic analyses. (Less)

The phylogenetic relationships of the lichenised ascomycete family Stereocaulaceae were investigated with partial beta-tubulin, partial glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and SSU rDNA sequence data. Due to the marked length variation in the SSU rDNA sequences, the analyses were performed with direct optimization. The combined analysis of the beta-tubulin, GAPDH and SSU rDNA sequences as well as the separate analyses of beta-tubulin and GAPDH data recognized the monophyletic group comprising Lepraria, Muhria and Stereocaulon. In the combined analysis Stereocaulon tornense appears as a basal taxon in the Stereocaulon clade, suggesting that the crustose growth form and the absence of cephalodia are primitive features within the genus. Muhria is nested in Stereocaulon and groups with the crustose S. cumulatum and S. leucophaeopsis. The genus Lepraria is monophyletic if Leproloma is included, but species that were represented by several specimens in our study, i.e., Lepraria jackii and Leproloma membranaceun, do not appear as monophyletic entities. The genus Pilophorus is included in Cladoniaceae. Combined analysis of the three data-sets clearly led to an increase in support values compared to the separate analyses, showing high support for the monophyly of families Cladoniaceae and Stereocaulaceae and for the sistergroup relation for the two families. The relationships between higher groupings did not reach high support values probably due to the incongruencies among the three datasets. (Less)

To examine phylogenetic relationships among the "cladoniiform" lichenized fungi, i.e., the families Cladoniaceae, Baeomycetaceae, Icmadophilaceae, Stereocaulaceae, and Siphulaceae, and to provide evidence for the anticipated independent origins of podetia and pseudopodetia, we conducted phylogenetic analyses of SSU (small subunit) rDNA sequences from 39 lichen-forming fungi. These fungi represent all of the major growth forms of lichen associations, fruticose (including "cladoniiform"), foliose, and crustose. Our analysis suggests that lichen-forming fungi with a "cladoniiform" morphology arose multiple times within the ascomycetes. Additionally, each of the other thallus growth forms, crustose, foliose, and fruticose, have originated multiple times. It also seems to be clear that neither all podetiate nor all pseudopodetiate taxa form a monophyletic group. Therefore the term "podetium" should be restricted to homologous structures that are most probably limited to the genera Cladonia, Cladina, Pycnothelia, and allies. The "pseudopodetia" of Stereocaulon (Stereocaulaceae) and Cladia (Cladiaceae) may represent different states of the same homologous character. Our phylogenetic hypothesis supports the monophyletic origin of the order Lecanorales sensu stricto, including representatives of five suborders Cladoniineae, Lecanorineae, Teloschistineae, Agyriineae and Peltigerineae, but excluding representatives of the suborders Acarosporineae (Acarospora schleicheri and Megaspora verrucosa), Pertusariineae (Pertusaria trachythallina), and Umbilicarineae. The suborder Cladoniineae and the family Cladoniaceae both appear to be polyphyletic assemblages.