Water hemlock

Cicuta maculata

Apiaceae

The wetland umbel that looks like parsley and kills like a seizure — a teaching plate so fennel, dill, and watercress have a named opposite.

Poison-garden teaching plate. Often called the most violently poisonous plant in North America. No harvest, no taste-test, no wild carrot experiments.

Parts used: None. Teaching plate only.
Traditional notes: None that this folio will repeat as practice
Habitat only: Marshes, ditches, wet meadows of North America. Purple-streaked stems, compound toothed leaflets, white umbels, chambered yellow oil in the root when cut. Habitat map so you can leave it.

Chambered root with yellow oily liquid: stop.
This is not poison hemlock (Conium) and not water parsnip. You do not need to be sure of those if you are already walking away.
Wetland umbel you cannot name to species: not supper.

Safety

All use All foraging of unnamed wetland umbels

Lookalikes

Parsley — Cicuta is the deadliest plant in North American ditches. A wet-ground parsley look-alike has killed people who wanted a garnish.
Watercress — A peppery brook green and a convulsant share the same water. One is a mustard. The other is Cicuta.

Lore

Cicuta is the plant Socrates is sometimes mis-credited with; his cup was Conium. Water hemlock is worse in a hurry. American foraging deaths still cluster on this genus. The old joke about wild carrot — ‘Queen Anne’s lace has a hairy stem’ — is not enough here. If it stands in standing water and you are not a botanist, it is not lunch.

The Herbarium — a teaching catalog, not a clinic. Traditional use is history, not a prescription. USDA 6b dates are a week either way, not a promise. Do not eat, drink, or harvest a plant you cannot name.