AbstractThe four names in use for Plasmopara parasitic on Geranium are lectotypified. It is recommended that the name Plasmopara pusilla should be restricted to Plasmopara occurring mostly on Geranium pratense. Plasmopara geranii–pratensis is considered a taxonomic synonym of P. pusilla. Plasmopara geranii–sylvatici, frequently treated as a synonym of Plasmopara pusilla, is reinstated. Plasmopara geranii, based on two fungi, is retained for the common downy mildew of Geranium spp. in North America.