Resolving the Melampsora epitea complex.

Melampsora epitea(Pucciniales, Basidiomycota) has been widely known as the main rust pathogen on willows, but its species boundary has been extremely confusing.Melampsora epiteawas often confused with several morphologically similar species, such asM. arctica, M. humilis, andM. epiphylla. Recent DNA-based studies using specimens from North America and Europe suggested thatM. epiteawas a complex of several phylogenetic species. In this study, we examined the species boundary ofM. epiteabased on rDNA phylogeny and the general mixed Yule coalescent (GMYC) model from 534 specimens. Twelve distinct species corresponding to 10 known species and 2 new species were recognized from East Asian specimens. We also evaluated the association of morphological characteristics, geographic origins, and host ranges with phylogenetic relationships. Our results revealed that several previously overlooked morphological characters in uredinial and telial stages were informative in delimitingM. epiteaand allied species. Two novel species,M. salicis-futuraeandM. salicis-triandrae, are described and compared with closely related species. A lectotype forM. epiteaand epitypes forM. epitea, M. epiphylla, andM. humilisare designated to stabilize the use of names. [ABSTRACT FROM PUBLISHER]