Information on Fool's-water-cress

Common Name: Fool's-water-cress
Scientific Name: Apium nodiflorum
Irish Name: Gunna uisce
Family Group: Apiaceae
Distribution: View Map (Courtesy of the BSBI)
Flowering Period

Click for list of all flowering by month
Fool's-water-cress is not easily confused with other wild plants on this web site.

Found on riversides, ditches and streams, this is a low-growing or prostrate perennial which has leaves vaguely similar to those of Watercress, although the latter's leaves are a darker shade of green.  Fool's-water-cress has short-stalked umbels of very small white 5-petalled flowers which are opposite the leaves.  These bloom in July and August.  The leaves are pinnate having toothed, oval to lanceolate leaflets. The plant roots at nodes in its lower stems and the upper stems which are lightly ridged, are hollow.  This is a native plant and it belongs to the Apiaceae family.   

I found this plant growing on some small islands in the Caher River, Co Clare in July 2009 when I photographed it.  One of the photographs depicts it totally submerged after very heavy rain had caused the river to flood.   

If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre

Fool's-watercress is not a poisonous plant, but it could be confused with the poisonous Lesser Water Parsnip – Berula erecta – which is poisonous.  The main distinguishing feature is that Berula erecta has a distinct ring on the leaf stalk, however prudence suggests that a tasting would be better avoided.  Lesser Water Parsnip also smells quite like parsnip when the leaves are crushed thus being given its common name.  It is not yet on this website.