Molecular inference, multivariate morphometrics and ecological assessment are applied in concert to delimit species in the Russula clavipes complex.
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.
Institute of Botany SAS, Dúbravská cesta 14, SK-845 23 Bratislava, Slovakia slavomir.adamcik@savba.sk.
Slavomír
S
Adamčík
Institute of Botany SAS, Dúbravská cesta 14, SK-845 23 Bratislava, Slovakia.
Marek
M
Slovák
Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, DE-70191 Stuttgart, Germany.
Ursula
U
Eberhardt
Department of Mycology, W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, PL-31-512 Cracow, Poland.
Anna
A
Ronikier
Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu 51005, Estonia.
Teele
T
Jairus
Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
Felix
F
Hampe
Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
Annemieke
A
Verbeken
D001487:Basidiomycota / Q000145:classification* / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification; D029662:Betula / Q000382:microbiology; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D008853:Microscopy; D010802:Phylogeny; D032107:Populus / Q000382:microbiology; D032108:Salix / Q000382:microbiology; D017422:Sequence Analysis, DNA; D064028:Tracheophyta / Q000382:microbiology
D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer
DNA barcode; Europe; R. pascua; Russula nuoljae; ectomycorrhizal fungi; haplotype analysis