Natural water reservoirs in Europe are very valuable floristic sites. Among them, springs are very important for the preservation of the biodiversity of flora in Poland. The present paper presents a community of water plants that is new to limnocren karst springs in Poland – Potame-tum pectinati Carstensen 1955 from Potametea class. In Europe this community in limnocren karst springs has not been found so far. The paper presents the floristic composition and the ecological requirements of this association.