Re-instatement of Russula levyana Murrill as a good and distinct American species of Russula section Xerampelinae

R. levyana, R. floridana and R. praerubriceps are three species described by W.A. Murrill that are traditionally interpreted as synonyms of R. xerampelina var. semirubra Singer. As such, these species have never been reported again since their original description. In this paper the authors re-examine and illustrate the type-specimens of these species in detail and come to the conclusion that they represent 3 different species that are not synonymous with Singer's variety. Of these 3 species, only R. levyana belongs in sect. Xerampelinae and a new, modern description is provided based on recent collections from Texas. These specimens represent the first records of Murrill's species since its original description from Florida.