Molecular inference, multivariate morphometrics and ecological assessment are applied in concert to delimit species in the Russula clavipes complex

• Published in: Mycologia
• Main Authors: Adamcik, Slavomir, Eberhardt, Ursula, Ronikier, Anna, Jairus, Teele, Slovák, Marek, Hampe, Felix, Verbeken, Annemieke
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Biology and Life Sciences; DNA barcode; ectomycorrhizal fungi; Europe; haplotype analysis; Russula nuoljae; R. pascua; INTERNAL TRANSCRIBED SPACER; MULTIPLE SEQUENCE ALIGNMENT; PHYLOGENETIC-RELATIONSHIPS; HAPLOTYPE RECONSTRUCTION; XERAMPELINA GROUP; UNITED-STATES; RDNA REGION; FUNGI; DNA; IDENTIFICATION; Arctic
• Online Access: https://biblio.ugent.be/publication/7225256; http://hdl.handle.net/1854/LU-7225256; https://doi.org/10.3852/15-194; https://biblio.ugent.be/publication/7225256/file/7228211

Species of Russula subsect. Xerampelinae are notoriously difficult to identify and name and have not been subject to molecular study. A group of species, referred to here as the R. clavipes complex, growing in association with Salix, Betula and Populus as well as coniferous tree species from temperate to arctic and alpine habitats, were examined. Analyses of the nuc rDNA internal transcribed spacer (ITS) region and a numerical analysis of morphological characters were used. The R. clavipes complex is a monophyletic group within Russula subsect. Xerampelinae, according to molecular results. The complex includes three species: R nuoljae is a phylogenetically and morphologically well-supported species while the other two, R clavipes and R pascua, are similar based on ITS data and morphology but separate based on their ecology. Russula pseudoolivascens is conspecific with R clavipes. Several combinations of characters traditionally used in the taxonomy of R subsect. Xerampelinae are inappropriate for species delimitation in this group and the adequacy of the ITS for species identification in this group is discussed. Detailed microscopic observations on the type collection of R nuoljae are presented and illustrated, along with a key to the European members of R. subsect. Xerampelinae.