Taxonomy of mayapple rust: the genus Allodus resurrected.

Mayapple rust is a common, disfiguring disease that is widespread in temperate eastern North America wherever the host, Podophyllum peltatum, occurs. Puccinia podophylli, the etiological agent of this rust, has been shown to be distantly related to both Puccinia and Uromyces as exemplified by their types. A systematic study was made to determine the generic classification of P. podophylli. Phylogenetic analyses of two rDNA loci from multiple specimens support the recognition of this taxon as a separate genus of Pucciniaceae. Based on historical literature and type material, P. podophylli was found to represent the type of the forgotten genus Allodus and it is correctly named Allodus podophylli. A neotype is designated for Puccinia podophylli Schwein. (≡ Allodus podophylli) and a lectotype is designated for Aecidium podophylli.