A floristic survey of the family Hydrodictyaceae (Sphaeropleales, Chlorophyceae) was carried out for the Parque Estadual das Fontes do Ipiranga, municipality of São Paulo, São Paulo State, southeast Brazil. Six genera (Chlorotetraedron, Lacunastrum, Monactinus, Pediastrum, Stauridium, and Tetraedron), eight species, three typical varieties, and one that is not the typical from its respective species were identified. Identification of L. gracillimum and M. simplex var. echinulatum is pioneer for the park. Stauridium tetras is the best represented species in the area, being collected from three different localities (reservoirs).
coccoid green algae; periphyton; phytoplankton; taxonomy; urban reservoir
