BackgroundFalse truffles are ecologically important as mycorrhizal partners of trees and evolutionarily highly interesting as the result of a shift from epigeous mushroom-like to underground fruiting bodies. Since its first description by Vittadini in 1831, inappropriate species concepts in the highly diverse false truffle genus Hymenogaster has led to continued confusion, caused by a large variety of prevailing taxonomical opinions.MethodologyIn this study, we reconsidered the species delimitations in Hymenogaster based on a comprehensive collection of Central European taxa comprising more than 140 fruiting bodies from 20 years of field work. The ITS rDNA sequence dataset was subjected to phylogenetic analysis as well as clustering optimization using OPTSIL software.ConclusionsAmong distinct species concepts from the literature used to create reference partitions for clustering optimization, the broadest concept resulted in the highest agreement with the ITS data. Our results indicate a highly variable morphology of H. citrinus and H. griseus, most likely linked to environmental influences on the phenology (maturity, habitat, soil type and growing season). In particular, taxa described in the 19th century frequently appear as conspecific. Conversely, H. niveus appears as species complex comprising seven cryptic species with almost identical macro- and micromorphology. H. intermedius and H. huthii are described as novel species, each of which with a distinct morphology intermediate between two species complexes. A revised taxonomy for one of the most taxonomically difficult genera of Basidiomycetes is proposed, including an updated identification key. The (semi-)automated selection among species concepts used here is of importance for the revision of taxonomically problematic organism groups in general.

The Tuber brumale (winter truffle) is a black truffle reported from most European countries, belonging to the Melanosporum group. Its significance in the economy is ambivalent as the winter truffle has been shown to be a frequent contaminant species in the orchards of the Perigord truffle and occasionally in those of the summer truffle, yet owing to its delicate fragrance, its trade is worthy of note. The phylogeny and phylogeography of economically important truffles are relatively well-explored; however, no thorough research has been published on these aspects of the winter truffle. Therefore, here, we report the first phylogeographic analyses based on samples representing the entire distribution of the species. ITS sequences were used in this survey for haplotype and coalescent analyses, while phylogenetic analyses were based on the ITS, LSU and PKC loci. According to all loci, the samples clustered into two big clades imply the existence of two phylogenetic species.Based on our results, one of these appears to be endemic to the Carpathian Basin. In the other more widespread species, two main phylogeographic groups can be distinguished that show east-west separation with a zone of overlap in the Carpathian Basin, suggesting that they survived the latest glacial period in separate refugia.

Symbionts and endophytes of Hungarian orchids were studied at diverse habitats. Mycobionts of roots and in situ germinated protocorms of 15 orchid species were identified by molecular methods. Four fungal groups could be distinguished from orchids living at diversely wet treeless habitats: Ceratobasidiaceae, Epulorhiza 1, Epulorhiza 2 and Sebacinaceae. While the groups Ceratobasidiaceae and Sebacinaceae were detected only at habitats with medium water supply, members of clade Epulorhiza occurred at all of the treeless study sites. These observations suggest that fungi belonging to the genus Epulorhiza are more tolerant of water-stress than the other investigated genera. An ascomycetous fungus from the family Pezizaceae could be identified from the roots of Orchis coriophora. Further Ascomycetes were identified at forest habitats. Tuber maculatum was detected from the roots of Epipactis helleborine and Cephalanthera damasonium, and Tuber excavatum from Epipactis microphylla.