River Water-dropwort, Oenanthe fluviatilis (Bab.) Coleman

A native, perennial aquatic of clear rivers and streams with deep water and sufficient flow to keep them open. Occasional in the mid-reaches of the Waveney and Deben; scarce in the Stour, Gipping, Brett, Lark and Little Ouse; rare in smaller rivers such as the Hundred at Eastbridge. Few of Suffolk’s rivers have sufficient flow to suit this plant; it is however, probably under-recorded as it is largely submerged when not in flower.