Stream Water-crowfoot is found in fast-flowing rivers and streams where it forms wide patches of colour in May and June. White, 5-petalled flowers are held clear of the surface of the water, being 15-25mm across and having golden centres. There are lobed leaves which float and submerged, long, thread-like leaves. This is a native annual or perennial and is locally found in the South and the N East of Ireland. It belongs to the Ranunculaceae or Buttercup family.
I found this species in the fast-flowing River Slaney in May, 2013. It formed a large mass of white and golden flowers close to the bridge at Scarawalsh, Co Wexford, just north of Enniscorthy. I also photographed it at that time.
If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre