SUMMARYThe subgenusPeronosclerosporaofSclerosporais raised to generic rank and described, The following species are transferred fromSclerosporaintoPeronosclerospora: S. dichanthiicola, S. maydis, S. miscanthi, S. philippinensis, S. sacchari, S. spontanea, S. sorghi, andS. westonii. Peronosclerospora sacchariis the type species of the genus. The diagnostic characters distinguishingPeronosclerosporaandSclerosporaare the production of true conidia which always germinate by a germ tube inPeronosclerospora, and the production of typical sporangia with a modified apical area which functions as an operculum through which zoospores escape inSclerospora.The phylogeny of the Peronosporales is also discussed.