Fool's watercress
Helosciadium nodiflorum
Family · Apiaceae · Irritating
Read this before the sheet
This plant, or one that resembles it, is dangerous. Identifying is not authorising: no app has the authority to tell you that you may eat or touch a plant.
Emergency
The umbellifer of ditches and streams eaten for centuries in the Peninsula, growing in exactly the same metre of water as the deadliest plant in Portugal. It is here for the warning, not the recipe.
Streams and ditches · Fields and pasture
Also known aslesser marshwort, creeping marshwort
How to tell it
A hollow grooved stem, prostrate at the base and rooting at the nodes, then upright. Leaves divided only once, with five to twelve pairs of oval toothed leaflets, bright green and glossy. The umbels are small, with four to twelve rays, and sit almost stalkless opposite a leaf, which is the genus's mark.
What it is confused with
Hemlock water dropwort
Oenanthe crocata
This is the confusion that kills in Portugal. Hemlock water dropwort is far larger, a metre or more, with leaves divided two or three times into fan-shaped segments like giant parsley, big umbels on long stalks, and yellow tuberous roots exuding saffron-coloured juice. Fool's watercress is small, its leaves divided only once into oval leaflets, its umbels nearly stalkless. When in doubt, nothing is gathered from a stream.
Watercress
Nasturtium officinale
Watercress leaves have a much larger rounded end leaflet, and white four-petalled flowers in a cross; fool's watercress has all leaflets alike and tiny flowers in an umbel. If the flower has four petals in a cross it is no umbellifer at all, and that is already half the safety.
What it is for
Traditionally used in salads and soups in northern Portugal and Galicia, gathered from clean running water. This guide recommends it to no one: it grows tangled with hemlock water dropwort, the most toxic umbellifer in Europe, and a gathering mistake is fatal. There is also a liver fluke risk in pasture water.
Traditionally used as food. This is not permission to eat it.
Where it occurs
Each square is an area with recorded observations of this plant. The lighter background is the set of areas where any of the entries has been observed, and serves as a reference. Note what this is not: it is not where the plant lives, it is where people record it, so trails and towns always look fuller than the mountains. Data from GBIF.
Sources
Community
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