Molecular annotation of type specimens of Russula species described by W.A. Murrill from the southeast United States

Twenty-five historical type collections of North American Russula species described by W.A. Murrill were sequenced and analyzed for placement in a phylogenetic and taxonomic framework. Molecular data was successfully obtained from sixteen type specimens (66%), of which eight species have never before been placed in an infrageneric classification system. Classifications and synonymization of taxa proposed by Rolf Singer and others are evaluated. Russula albimarginata and R. emeticiformis are suggested as synonyms of R. vinacea, a widespread and common species in the eastern United States. Four taxa of unknown classification (R. albimarginata, R. pinophila, R. subcremeiceps, R. subrubescens) have been classified to subsection level, and an alternative classification is proposed for R. westii. A morphological comparison of a collection from British Columbia (Canada) with 99% sequence similarity to R. levyana in the Internal Transcribed Spacer 1 (ITS1) region indicates that this region alone may be inadequate for species barcoding in Russula.