Species recognition in lichen-forming fungi has been a challenge because of unsettled species concepts, few taxonomically relevant traits, and limitations of traditionally used morphological and chemical characters for identifying closely related species. Here we analyze species diversity in the cosmopolitan genus Protoparmelia s.l. The ~25 described species in this group occur across diverse habitats from the boreal -arctic/alpine to the tropics, but their relationship to each other remains unexplored. In this study, we inferred the phylogeny of 18 species currently assigned to this genus based on 160 specimens and six markers: mtSSU, nuLSU, ITS, RPB1, MCM7, and TSR1. We assessed the circumscription of species-level lineages in Protoparmelia s. str. using two coalescent-based species delimitation methods – BP&P and spedeSTEM. Our results suggest the presence of a tropical and an extra-tropical lineage, and eleven previously unrecognized distinct species-level lineages in Protoparmelia s. str. Several cryptic lineages were discovered as compared to phenotype-based species delimitation. Many of the putative species are supported by geographic evidence.

To evaluate the importance of morphological and chemical characters used in the recognition of species within the Parmelia omphalodes group, we performed phylogenetic, morphological and chemical analyses of 335 specimens, of which 34 were used for molecular analyses. Phylogenetic analyses, based on ITS rDNA sequences, show that P. pinnatifida is distinct from P. omphalodes and the most important difference between those species is the development of pseudocyphellae. In P. pinnatifida, they are mostly marginal and form white rims along lobes margins, but laminal pseudocyphellae can develop in older parts of thalli and are predominantly connected with marginal pseudocyphellae. In contrast, in P. omphalodes laminal pseudocyphellae are common and are predominantly not connected to marginal pseudocyphellae. Chemical composition of secondary lichen metabolites in both analysed species is identical and therefore this feature is not diagnostic in species recognition. Few samples of P. discordans, species morphologically similar to P. omphalodes and P. pinnatifida, were also included in the analyses and they are nested within the clade of P. omphalodes, despite the different chemistry (protocetraric acid present versus salazinic acid in P. omphalodes). All taxa of the P. omphalodes group occupy similar niches, but their potential distributions are wider than those currently known. The absence of specimens in some localities may be limited by the photobiont availability. Parmelia omphalodes and P. pinnatifida are moderately selective in photobiont choice as they form associations with at least two or three lineages of Trebouxia clade S. Parmelia pinnatifida, as well as P. discordans are associated with Trebouxia OTU S02 which seems to have a broad ecological amplitude. Other lineages of Trebouxia seem to be rarer, especially Trebouxia sp. OTU S04, which is sometimes present in P. pinnatifida. This study indicates the importance of extensive research including morphology, chemistry and analysis of molecular markers of both bionts in taxonomical studies of lichens.

IntroductionThe genus Xanthoparmelia (Vain.) Hale, comprising ca. 800 species of worldwide distribution belongs to the largest family of lichenized fungi -Parmeliaceae [1,2]. The distinguishing features of the genus are: hyphal cell walls' polysaccharides with Xanthoparmelia-type lichenan [3][4][5], small ascospores with an arachiform vacuolar body [6], lack of pseudocyphellae, presence of a pored epicortex, eperforate apothecia, the presence of bifusiform conidia and usually simple rhizines [5]. This genus is further characterized by a considerable variation in cortical chemistry of individual species. Most taxa of this genus occur on the siliceous rocks in dry and well-sunlit places, in periarid, arid, semiarid and Mediterranean climates, mainly in the southern hemisphere [5].Originally the genus Xanthoparmelia included exclusively the species containing atranorin and usnic or isousnic acids in the upper cortex, causing the yellowish tinge of thallus [7,8]. Lichens currently included to Xanthoparmelia pulla group but not containing these substances, with brown thalli and upper cortex stained by HNO 3 to blue-green, were initially grouped in the Neofusca subgenus (within the Parmelia genus) [9], which was then set up as a separate genus Neofuscelia [10]. Molecular studies have shown, however, that the genus Neofuscelia was polyphyletic, with its clades scattered within Xanthoparmelia. Consequently, the species of the genus Neofuscelia have been included in the Xanthoparmelia [11].Xanthoparmelia pulla group includes about 25 taxa dispersed throughout the world, seven of which occur in Europe [12]. Due to the frequent absence of apothecia and the lack of obvious differences in their structure, these taxa are traditionally distinguished on the basis of morphological features of the thallus, such as the color of lower cortex, shape of lobes and the presence or absence of vegetative propagules [12]. However, chemical characteristics play the most important role in the identification of taxa [9,13]. Within the species of the genus Xanthoparmelia, ca. 90 secondary metabolites were identified, mainly phenolic compounds such as depsides, depsidones, antraquinones and monocilic compounds, as well as aliphatic acids [8,14], 15 of which were present within Xanthoparmelia pulla group [13].So far four species of the Xanthoparmelia pulla group were reported from Poland: X. delisei, X. loxodes, X. pulla and X. verruculifera [15]. One of them, X. loxodes, was considered to be common throughout the country, while the X. pulla and X. verruculifera were admitted as more or less rare and endangered [16]. X. delisei in general was not distinguished by Polish lichenologists and its only records from present Polish territory were of historical nature [17]. AbstractThe paper presents the results of studies of Xanthoparmelia pulla group in Poland. The morphological and chemical analysis of herbarium materials confirmed the presence of four species of this group reported from Poland before. The study however, revealed considerable change...

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