Atractosporocybe, Leucocybe and Rhizocybe: three new clitocyboid genera in the Tricholomatoid clade (Agaricales) with notes on Clitocybe and Lepista

Abstract

A molecular multigene analysis (ITS, 18S and 28S nrLSU ribosomal DNA, tef1, rpb2) was used to support the proposition of three new genera of clitocyboid fungi. Leucocybe is proposed to accommodate the clade formed by Clitocybe connata and C. candicans. Clitocybe inornata is invested as type species of Atractosporocybe, while the new genus, Rhizocybe, is proposed for the former species of section Vernae of Clitocybe, C. vermicularis, C. pruinosa and C. rhizoides. The three lineages are related to the families Lyophyllaceae and Entolomataceae and independent from the Clitocybeae clade. Morphologically Rhizocybe is characterized by the presence of conspicuous rhizomorphs, while Atractosporocybe presents long fusiform spores. Leucocybe includes two whitish species in the former section Candicantes of Clitocybe, but no relevant shared characteristic feature was detected. Other whitish clitocyboid species, such as C. phyllophila (= C. cerussata), C. dealbata, C. rivulosa, and Singerocybe hydrogramma, are shown to be genetically related to the core lineage of the Clitocybeae.

• Agaricomycetes
• Basidiomycota
• molecular markers
• phylogeny
• taxonomy

Acknowledgments

This work was partially financed by the Spanish Ministry of Education and Culture through the FPU grant AP2006-00890, the “Consejería de Agricultura y Medio Ambiente de la Junta de Comunidades de Castilla-La Mancha” research project PAI08-0240-5097 and the “Subprograma AGR del Ministerio de Ciencia y Innovación (Plan Nacional I + D + I)” research project AGL2009-12884-C03-03. We wish to express our gratitude to Luis Monje and Ángel Pueblas of the Department of Drawing and Scientific Photography at the University of Alcalá for their help with the digital preparation of the photographs, to Dr Javier Rejos, curator of the AH herbarium for his assistance with the specimens examined in the present study and to David W. Mitchell for reviewing the manuscript. We also want to thank Enzo Musumeci and Dr Pierre-Arthur Moreau for loaning several different samples from their private herbaria and Dr Brandon Matheny for his help and advice.