Systematic revision of the Roseinae clade of Russula, with a focus on eastern North American taxa

ABSTRACT

The Roseinae clade is a lineage of the genus Russula primarily composed of species of Russula subsect. Roseinae. Species in this morphologically distinct clade possess a white to pale cream spore print, mild taste, positive reaction to sulfovanillin, and primordial hyphae with acid-resistant crystals in the pileipellis. Here, we present a morphological and phylogenetic assessment that distinguishes seven eastern North American species of the core Roseinae lineage and a new subsection, Russula subsection Albidinae, to accommodate members of the Albida clade. We assign the previously described species R. peckii, R. rubellipes, and R. pseudopeckii to three species-level clades, and three other species, R. cardinalis, R. cordata, and R. rheubarbarina, are described as new. Comparative morphological analyses reveal differences in the conformation of terminal elements in the pileipellis, spore size, hymenial cystidia contents, and pigmentation on the stipe surface as key features to recognize species in the group. Based on the analysis of publicly available data, we recognize a potential total of nine temperate North American species within R. subsect. Roseinae, in addition to four from Central America, two from Europe, and 14 from Asia.

KEYWORDS:

• Epitypification
• global biogeography
• lectotypification
• morphometrics
• systematics
• type descriptions
• 4 new taxa
• 3 new typifications

ACKNOWLEDGMENTS

We would like to thank the curators and collection managers at the Florida Museum of Natural History (FLAS), New York State Museum (NYS), New York Botanical Gardens (NY), and University of Michigan (MICH) for loan of type collections. We especially thank Lorinde Leonardi at NYS for organizing type collection material for PDAB testing and lectotype assignment, Steve Trudell and Per Marstad for field photos, Soňa Jančovičová for inking line drawings, Karl-Heinz Rexer for assistance with SEM, and Jesko Kleine for giving nomenclatural advice. Permits for field work in the Great Smoky Mountains was provided by Paul Super, research coordinator of the Great Smoky Mountains National Park.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the author(s).

SUPPLEMENTARY MATERIAL

Supplemental data for this article can be accessed on the publisher’s Web site.

Additional information

Funding

Visit of S.A. in 2012 was supported by the Hesler Endowment Fund from the University of Tennessee Herbarium. Support for S.A. was provided by the Slovak national project APVV 15-0210. Support for B.P.L. was provided by the National Science Foundation: Doctoral Dissertation Improvement Grant program (DEB-1501293). Support for field work in the Great Smoky Mountains was provided by awards from the Hesler Endowment Fund to P.B.M.