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Russula (Russulales) is an important ectomycorrhizal fungal genus in Arctic and alpine regions where it occurs with Salix, Betula, Dryas, and Polygonum, yet a complex phylogenetic analysis of the genus in these habitats is lacking. This research compared collections of Russula from the Rocky Mountain alpine (Colorado, Montana, Wyoming) with reference specimens from Arctic and alpine habitats, mostly in Europe, using an in-depth morphological study and a phylogenetic analysis of the nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS barcode) and the second largest subunit of the RNA polymerase II gene (rpb2). One hundred thirty-nine Russula collections were sequenced, including type material. Ten species are reported from alpine or treeline habitats in the Rocky Mountains. This is the first formal report of R. cf. altaica, R. saliceticola, and R. subrubens from the Rocky Mountains and of R. purpureofusca in North America. Russula laevis is reported for the first time under this name with a voucher, and not as an environmental sample. Previous reports of R. nana and R. laccata are molecularly confirmed. Two species are reported from subalpine habitats at treeline: R. montana with conifers and R. cf. altaica with Betula. In this study, R. laccata, R. subrubens, and R. laevis were collected in alpine habitats but have been reported below treeline in Europe; these species may also be present at lower elevations in North America. Most species have an intercontinental distribution and have been reported in other alpine or Arctic habitats. Two unidentified and potentially new species were only found in North America and are discussed. A key to the alpine Russulas of North America is provided. [ABSTRACT FROM AUTHOR]

Inocybe (Inocybaceae) is one of the most diverse ectomycorrhizal genera in arctic and alpine habitats where the primary hosts are Salix, Betula, and Dryas. Subgenus Inocybe is common in these habitats and typically characterized by the presence of thick-walled pleurocystidia. Here, we focus on species that have angular or nodulose spores. Historically, over 30 taxa from this group have been reported from arctic and alpine habitats. Many names have been synonymized, whereas molecular analysis has revealed new species. Nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS) sequence data of 26 type specimens in this group now allow for further taxonomic clarification and comparison across continents of disjunct populations. Here, we compare ITS sequence data and the D1–D2 portion of nuc 28S rDNA (28S) from Rocky Mountain specimens with those of types and European reference material. We report 10 species from the Rocky Mountain alpine zone, all of which are conspecific with known European boreal, montane, or alpine species, and four are described as new; all have intercontinental distributions. Nodulose-spored Inocybe taxa that occur in the Rocky Mountain alpine zone include I. alpinomarginata, sp. nov., I. arctica, I. giacomi, I. leonina, I. murina, sp. nov., I. occulta, I. paragiacomi, sp. nov., I. phaeocystidiosa, I. purpureobadia, and I. subgiacomi, sp. nov. Remarkably, these species occur at elevations up to 4000 m and at latitudes as low as 36°N, hundreds of miles from the Arctic, the European alpine, and original type localities. Distributions are explained in part by host distributions and historical glaciation patterns. A key and full descriptions for Rocky mountain species are provided to promote species recognition. [ABSTRACT FROM AUTHOR]

Sequence data from a broad geographical region and different habitats show that the Inocybe praetervisa clade is comprised of four closely related species. These species of section Marginatae are characterized by having nodulose spores and a stipe that is abundantly pruinose only in the upper half. Inocybe praetervisa occurs in Southern Europe in mountainous mixed coniferous forests, and is not confirmed from Northern Europe. Inocybe rivularis occurs in northern boreal forests up to the lower alpine zone, associated with Betula in moist habitats, and is not confirmed from Southern Europe. Inocybe taxocystis is confirmed as a later synonym of I. favrei . The species has a wide geographical distribution range in Europe, mainly restricted to the alpine zone and moist soils, associated with Salix herbacea . Inocybe arctica is here described as a new species. It occurs in the arctic and higher alpine zones, associated with Dryas octopetala , Salix polaris , S. reticulata and S. herbacea . All species except I. arctica are shown to have an intercontinental distribution range and are confirmed from North America. Sequence data suggest the occurrence of one additional species in the alpine zone of China. A key to the species in the I. praetervisa group is provided. [ABSTRACT FROM AUTHOR]

Three species of Cortinarius subg. Phlegmacium, Cortinarius argutus Fr. and Cortinarius hedyaromaticus C. Cripps & O.K. Mill. (section Arguti stat. nov.) and Cortinarius talus Fr. (section Multiformes), are compared from western North America and Europe. Phylogenetic analysis of the ITS region shows that C. argutus and C. hedyaromaticus are separate, closely related species with rooting stipes. Cortinarius talus is a pale species with a bulbous stipe and a sweet odor similar to that of C. hedyaromaticus; C. argutus lacks this sweet odor. All three species have intercontinental distributions and are associated with deciduous trees, primarily Populus tremuloides Michx., Populus tremula L., but also Salix spp. This study highlights the importance of the study of type specimens and molecular analysis to stabilize the application of established names. [ABSTRACT FROM AUTHOR]