The study of water crowfoots in the Yenisei River confirmed the wide distribution of recently restored rigid-leaved North American-North Asian species Ranunculus subrigidus instead of previously mentioned European R. circinatus. The species identification as R. subrigidus was confirmed by the analysis of the ITS region nucleotide sequence and morphological data. In contrast to literature data, samples of this species collected in the Yenisei did not have sessile leaves, in half of the samples, the length between first and second bifurcation was greater than the maximum of 0.2 cm previously described for the species, in some of the samples, internodes were shorter than the leaves, also different types of pubescence were observed on plant shoot parts. The conditions under which this species grows in the Yenisei River differ from the previously reported ones, primarily, in such parameters as the water hardness and the flow regime. At the city of Krasnoyarsk, seasonal development of R. subrigidus is affected by the Krasnoyarsk Hydroelectric Power Plant. The paper presents a geobotanical description of the Yenisei River plant communities dominated by and containing R. subrigidus.