Cupreoboletus (Boletaceae, Boletineae), a new monotypic genus segregated from Boletus sect. Luridi to reassign the Mediterranean species B. poikilochromus.

Cupreoboletus is erected as a new monospecific genus of Boletaceae to accommodate the thermophilic southern European species Boletus poikilochromus, characterized by discoloration toward copper-red tints overall, hymenophore forming tiny crystals on drying, a pervasive and long lasting sweet odor and presence of pseudocystidia. Macro- and microscopic descriptions of the species based on re-examination of the type material and recent Italian collections including additional topotypical samples are provided and accompanied by photos and line drawings of the main anatomical structures. In addition, an epitype specimen is selected. Phylogenetic relationships were inferred from multigene molecular analysis based on partial sequences of the nuc rDNA 28S D1/D2 (28S) and internal transcribed spacer (ITS) regions and genes for ribosomal RNA polymerase II subunits 1 (rpb1) and 2 (rpb2) and translation-elongation factor 1-α (tef1α). Ecological context, geographical range and delimitation from closely allied taxa also were elucidated. B. martaluciae is treated as a synonym of C. poikilochromus according to the morphological and molecular comparative study.

Alessioporus and Pulchroboletus (Boletaceae, Boletineae), two novel genera for Xerocomus ichnusanus and X. roseoalbidus from the European Mediterranean basin: molecular and morphological evidence.

Alessioporus and Pulchroboletus are proposed as new monotypic genera to accommodate the thermo-xerophilic European species Xerocomus ichnusanus and X. roseoalbidus respectively. The present research focused on both morphological features and multigene molecular phylogeny (nrITS, nrLSU, tef-1α datasets) to elucidate the taxonomic status of these two rare Mediterranean boletes and delineate a natural classification within the family Boletaceae. Macro- and microscopic descriptions of the two species based on inclusive taxon sampling are provided and supported by line drawings of the main anatomical features. Phylogenetic relationships, ecology, geographical distribution and delimitation from the most closely allied taxa also are highlighted. In addition, epitype specimens are selected for both species.

Reappraisal of the Genus Exsudoporus (Boletaceae) Worldwide Based on Multi-Gene Phylogeny, Morphology and Biogeography, and Insights on Amoenoboletus.

The boletoid genera Butyriboletus and Exsudoporus have recently been suggested by some researchers to constitute a single genus, and Exsudoporus was merged into Butyriboletus as a later synonym. However, no convincing arguments have yet provided significant evidence for this congeneric placement. In this study, we analyze material from Exsudoporus species and closely related taxa to assess taxonomic and phylogenetic boundaries between these genera and to clarify species delimitation within Exsudoporus. Outcomes from a multilocus phylogenetic analysis (ITS, nrLSU, tef1-α and rpb2) clearly resolve Exsudoporus as a monophyletic, homogenous and independent genus that is sister to Butyriboletus. An accurate morphological description, comprehensive sampling, type studies, line drawings and a historical overview on the nomenclatural issues of the type species E. permagnificus are provided. Furthermore, this species is documented for the first time from Israel in association with Quercus calliprinos. The previously described North American species Exsudoporus frostii and E. floridanus are molecularly confirmed as representatives of Exsudoporus, and E. floridanus is epitypified. The eastern Asian species Leccinum rubrum is assigned here to Exsudoporus based on molecular evidence, and a new combination is proposed. Sequence data from the original material of the Japanese Boletus kermesinus were generated, and its conspecificity with L. rubrum is inferred as formerly presumed based on morphology. Four additional cryptic species from North and Central America previously misdetermined as either B. frostii or B. floridanus are phylogenetically placed but remain undescribed due to the paucity of available material. Boletus weberi (syn. B. pseudofrostii) and Xerocomus cf. mcrobbii cluster outside of Exsudoporus and are herein assigned to the recently described genus Amoenoboletus. Biogeographic distribution patterns are elucidated, and a dichotomous key to all known species of Exsudoporus worldwide is presented.

Assessment of inter- and intra-specific variability in the main species of Boletus edulis complex by ITS analysis.

The Boletus edulis species complex includes ectomycorrhizal fungi producing edible mushrooms appreciated worldwide. However, species delineation is very difficult in these fungi, because it is based exclusively on a few, highly variable morphological features. As a consequence, a high number of taxa--including several varieties, subspecies and/or species sensu stricto--have been described in this species complex. In this paper we report on an extensive analysis of internal transcribed spacer of the nuclear rDNA region on a large sample of species of the B. edulis complex, mainly harvested in Italy, and representative of the European variability of this group. The molecular analysis allowed us to discriminate among and within B. edulis, B. aestivalis, B. pinophilus and B. aereus spp. and resolve their phylogenetic relationship.

Xerocomus silwoodensis sp. nov., a new species within the European X. subtomentosus complex.

A recent analysis of the Xerocomus subtomentosus complex in Europe using rDNA-ITS sequence data distinguished four taxa in Europe. Two of these corresponded to the established taxa X. subtomentosus and X. ferrugineus, and a new taxon, X. chrysonemus, was described. The fourth taxon was noted but left undescribed owing to lack of material. Here, we describe this taxon as X. silwoodensis sp. nov. X. silwoodensis is a rare but widespread taxon known from single sites in Italy and Spain, and three in the UK. The features of X. silwoodensis basidiomes are very similar to other members of the complex but the pileus colours tend to show richer red-brown tones and the stipe often radicates deeply into the substrate. The taxon also exhibits a strong preference for associating with Populus species, whereas the other taxa are associated with either Quercus (X. chrysonemus) or generalists on broadleaved hosts (X. subtomentosus) or conifers and broadleaved trees (X. ferrugineus). Microscopically, the spore characteristics of X. silwoodensis are similar to the recently described X. chrysonemus, but differ significantly from both X. subtomentosus and X. ferrugineus. X. silwoodensis is probably overlooked due to the resemblance to other taxa within the complex. The present study on the identification and description of X. silwoodensis should reduce the confusion associated with the identification of taxa within this species complex and lead to a more accurate assessment of the geographic distribution and conservation needs of the taxa.

Detection of species within the Xerocomus subtomentosus complex in Europe using rDNA-ITS sequences.

Identification of species within the boletoid genus Xerocomus has relied heavily upon the macromorphological features of the basidiomes. However, the phenotypic plasticity of these features has resulted in considerable confusion over the delimitation of taxa. In this study, we examined collections attributed to the X. subtomentosus complex in Europe using morphological and rDNA-ITS sequence data. In total, 45 European collections from a wide range of geographical areas and ecological conditions were included in the study. In spite of detecting considerable genetic variation, even within individual basidiomes of X. subtomentosus, molecular data, spore size, flesh colour, and the colour of the basal mycelium allow for the recognition of four distinct taxa: two correspond to X. subtomentosus (13 collections) and X. ferrugineus (20); one X. chrysonemus sp. nov. (10), to date only found in the UK, is described as new; and the existence of another taxon (two; Italy and UK) is noted but left undescribed owing to lack of material. Eight collections from North America were also included in the study, from which two taxa with a close affinity to X. ferrugineus were recognised.

Xerocomus cisalpinus sp. nov., and the delimitation of species in the X. chrysenteron complex based on morphology and rDNA-LSU sequences.

Species delimitation is still controversial in the Xerocomus chrysenteron complex. We have therefore established comprehensible and reliable species concepts based on statistical evaluation of morphological and ecological characters. We examined many collections from different geographical regions and different developmental stages within collections. Quantitative micromorphological characters (basidiospores, pileipellis end cells) were measured in statistically relevant numbers. The same material was used to generate 24 rDNA-LSU sequences,and the results of phylogenetic analyses clearly confirmed our species concepts: spore size and ornamentation, length of the pileipellis end cells and 'pruinatus-hyphae' are most valuable characters for the delimitation of species in this complex. Molecular data demonstrated that the X. chrysenteron complex is a monophyletic group. All the examined species (X. chrysenteron, X. cisalpinus, X. pruinatus, X. ripariellus, X. dryophilus, X. fennicus, X. porosporus, and X. rubellus) represent independent lineages. The faintly striate spores, a key character characterising species of section Striatulispori, probably evolved independently. In addition, the 'pruinatus-hyphae' have multiple origins, and truncate spore apices are derived at least twice. Xerocomus cisalpinus sp. nov. is characterised by striate spores, the presence of 'pruinatus-hyphae' and a pileipellis strongly reminiscent of X. chrysenteron. For reasons of discussion, microscopical data are presented on Boletellus episcopalis for the first time. Xerocomus fennicus (Boletellus) comb, nov. is proposed. We provide descriptions to all included taxa. Our results once more demonstrate that reliably identified and characterised voucher collections are the basic requirement for meaningful phylogenetic studies.