Nodulose-spored Inocybe from the Rocky Mountain alpine zone molecularly linked to European and type specimens

ABSTRACT

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.

KEYWORDS:

• Arctic-alpine
• biogeography
• Colorado
• Inocybaceae
• J. Favre
• molecular systematics
• Montana
• Salix
• taxonomy
• type collections
• 4 new taxa

ACKNOWLEDGMENTS

We would like to thank Egon Horak for contributing collections and for sharing his expertise in alpine Inocybe taxonomy, and curators of herbaria G, TENN, and UTC are gratefully acknowledged for arranging loans and granting permissions for DNA extraction and sequencing. We thank Fernando Esteve-Raventós and Ditte Bandini for giving us permission to use ITS data from the isotype of I. leonina. We thank the National Science Foundation for originally initiating the Rocky Mountain Alpine Mycota project, The Swedish Taxonomy Initiative, ArtDatabanken SLU Uppsala, Sweden, and The Royal Society of Arts and Sciences in Gothenburg. We thank reviewers P. Brandon Matheny and Fernando Esteve-Raventós for their useful comments.