The ephemeral vegetation dominated by Cyperus sp. pl. was surveyed and analyzed along the eastern trait of the Po River (Po Plain, Italy). Two formerly described communities were recognized: Cyperetum esculenti and Amaranthus tuberculatus-phytocoenon. A third greater cluster is assigned to a new association: Cyperetum micheliano-glomerati. It is characterized by Cyperus glomeratus, C. michelianus, C. odoratus and C. squarrosus, that have been detected on over 75 % of the relevés. The main floristic and ecological traits of these detected vegetation types are discussed.