South Dakota Native Plant Research
Apiaceae: Cicuta maculata

Apiaceae: Cicuta maculata


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Family Name


Common Name

Water hemlock

Native American Name

Lakota: yažópi hú


Cicuta maculata is a rhizomatous perennial herb with a hollow erect stem that can reach a height of 2 meters. The base of the stem is swollen, containing several chambers separated by well-developed transverse partitions, and usually mottled with purple blotches. The alternate compound bi to tripinnate leaves may be up to 40 cm long and are made up of lance-shaped, pointed, serrated leaflets. Each shiny green leaflet is 2 to 10 cm long. The inflorescences of loose compound umbels are attached to terminal and lateral branches on peduncles that exceed the leaves. The white flowers are similar in appearance to other species in the carrot family. The fruit is an oval, flattened 3-4 mm schizocarp that turns tan-brown when mature. Water hemlock flowers from July through September in wet meadows, roadside ditches, pond margins, open marshes, and freshwater swamps throughout South Dakota.

Additional Notes

Cicuta maculata is extremely poisonous. It is considered to be North America's most toxic plant. People have died from water hemlock poisoning over the centuries, but in the United States livestock are the usual victims, with ingestion of the plant causing death in as little as 15 minutes.

Horticulture Notes

Although Cicuta maculata is a very attractive plant, it is too toxic to be introduced in any garden.

Apiaceae: Cicuta maculata