Cicuta maculata [cicuta (Lat.) hemlock; maculata (Lat.) spotted or mottled]
Common Name: spotted water hemlock
Habitat: Wet areas, open marshes, prairie wetlands, roadside ditches—sometimes associated with cattails.
Notes: Very toxic, the ingestion of even small amounts are lethal to livestock and humans. The toxin ( cicutoxin) is most concentrated in the chambered roots.
Additional references: 1, 2, 3, 4, 5, 6, 7, 8, 9 10, 11.
Flowers: small (4 mm.diam.), 5 white petals, in compound umbels, two-chambered fruits mature into two, single-seed fruits, calyx teeth obvious.
Leaves: alternate, compound, 2-3 pinnate. leaflets: narrowly lanceolate. margins: toothed. veins: seem to end in the notch between teeth— on closer inspection they branch at the notch and continue to the teeth.
Stems: smooth, hollow, green or purple, when green often with purple streaks or blotches, frequently purple at leaf nodes.
Glossary: Botanical Terms
Cicuta maculata is found in moist or wet soils. It stands 3 to 6 feet tall on upright stems which are often purple or purple mottled. The compound leaves are arranged alternately on the stems, leaflets are toothed, and the veins appear to be directed to the notch between the teeth (this is an important clue since most plants with toothed leaf margins show veins ending at the teeth). Beginning in June the plant displays compound umbels of small white flowers. The secondary but not the primary umbels have involucral bracts. During the flowering and fruiting period the calyx displays acute lobes (teeth) at its margin. Two styles are apparent on top of the bicarpelate fruit (schizocarp) which produces two mericarps each with one seed. All parts of the plant contain a toxin which, like many domestic plants, can be deadly if ingested.
C. maculata (spotted water hemlock) is native to the U.S. and is important to pollinating insects. C. maculata is rated as an "obligate" wetland plant; as is a related plant, Sium suave (hemlock waterparsnip), with which it is sometimes confused. They both share the same habitat requirements and each flowers around the same time (June/July) with umbels of small white flowers. A conspicuous difference is the corrugated stem found on Sium suave compared to the smooth stem found on Cicuta maculata.
Another plant in the carrot family, Conium maculatum (poison hemlock) is equally toxic and bears some similarity to Cicuta maculata. For example, each produces small white flowers in compound umbels. One difference between the two plants is that the primary umbel in poison hemlock has involucral bracts and they are absent in spotted water hemlock. Both species are very toxic and should not be eaten. Poison hemlock toxin is believed to be the toxin used to execute Socrates.