This study aims to the knowledge of phytoplankton composition of the Tartarugas pond, located at the Botanical Garden, Porto Alegre city in Rio Grande do Sul State. The samplings were carried out monthly, from June 2007 to May 2008, at one station in three different depths in the pelagic zone. Forty-nine specific and infraspecific taxa belonging to seven classes were recorded. Cyanobacteria presented the highest number of taxa (35% of recorded taxa), followed by Bacillariophyceae (33%) and Euglenophyceae (16.3%). Descriptions, measurements and illustrations of the taxa are presented as well as their distribution during the annual cycle.
floristic composition; hypereutrophic lentic system; subtropical climate
