Abstract
<title>Abstract</title> <p>This study conducted a taxonomic survey of microalgae from the class Chlorophyta in nine streams in western Paraná, Brazil. Sampling points were chosen across three watersheds (Paraná 3, Piquiri, and Baixo Iguaçu) and classified according to the stage of riparian forest regeneration: reference, intermediary, and young. Collections occurred during the dry (May/June) and rainy (September/October) seasons using surface trawling with a 20-micrometer plankton net. A total of 93 taxa were recorded, distributed across two classes, six orders, and seven families, with 32 new records, including 23 for the state of Paraná and 9 new records for Brazil, namely: Pediastrum duplex var. asperum (A. Braun) Hansgirg, Pediastrum duplex var. intermedium Vodenicharov, Sorastrum pediastriforme M. Jena & C. Bock, Radiococcus signiensis (P. A. Broady) I. Kostikov, T. Darienko, A. Lukesová, and L. Hoffmann, Coelastrum triangulare Jao & Z. Y. Hu, Desmodesmus communis var. polisicus Tsarenko & E. Hegewald, Scenedesmus smithii Chodat, Pleurastrum diplobionticum (Herndon) Sciuto, M.A. Wolf, Mistri & Mori, and Hegewaldia parvula (Woronichin) Pröschold, C. Bock, W. Luo & L. Krienitz. These results significantly expand the floristic knowledge of the region and highlight the importance of taxonomic studies in areas that have been little covered.</p>