This is a very poisonous plant and has been fatally mistaken for celery and parsley in the past. A perennial, it is found in damp meadows, near lakes, rivers and ditches where it can reach 1.5m. Its small white 5-petalled flowers (2mm across) are borne in large, domed umbels which have 15-35 rays and sometimes bracts also. They bloom in June and July. The stout stems are hollow and grooved. The large leaves are triangular and tripinnate, with tapering, toothed lobes. This is a native plant which belongs to the family Apiaceae.
I first recorded this wildflower at Tacumshane, Co Wexford in 2005 and photographed it at the same spot in 2006.
If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre