White flowers with golden centre, larger than many other water-crowfoots.
Petals usually 10-15mm. Sepals not reflexed. Young fruit pubescent.
Heterophyllus - usually both floating and submerged leaves, but sometimes only submerged (capillary). Capillary leaves with very limp segments, usually longer than internode. Form tassle when taken from water. Can form large floating clumps.
Frequent. Moderate to fast streams and rivers.
Identification confirmed by Paul Green