''Cicuta douglasii'', the western water hemlock, is a very poisonous perennial plant in the family Apiaceae.

Description

Cicuta douglasii & Conium maculatum 1459205

The plant's roots are thick and tuberous, with many smaller tubers on the main one, allowing survival in wet conditions. The stem is tall with purplish spots. The inner tubers and stem bases can have horizontal chambers useful for identification. The

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are alternate and compound pinnate. The leaflets are long and wide, with jagged edges. Its inflorescences are compound umbels about across, with many small, white flowers, which have two seeds each. The seeds germinate in spring, and flowers mature near the end of June and beginning of July. Seed dispersal is by means of wind, water, machinery, clothing, and through transported soil. In addition to sprouting new plants from seeds, rootstocks can also produce new plants in the fall from the basal meristem. When these detach the following spring, they may form a new plant.

Distribution and habitat

Water hemlock is most abundant in British Columbia, and is indigenous to

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, where it grows primarily from the base of the Rocky Mountains to the Pacific coast, stretching from Alaska all the way to California. Water requirements limit this plant from inhabiting open rangelands. It grows in wet places such as marshes, stream banks, slough margins, ditches, meadows, and wet pastures.

Toxicity

The main distinguishing characteristic of western water hemlock is its toxicity.

Cicutoxin Cicutoxin is a naturally-occurring poisonous chemical compound produced by several plants from the family Apiaceae including water hemlock (''Cicuta'' species) and water dropwort (''Oenanthe crocata''). The compound contains polyene, polyyne ...

is the toxin that is produced, making water hemlock the most poisonous plant in North America. Cicutoxin is a yellowish liquid that is prevalent in the roots. This

unsaturated alcohol Saturation, saturated, unsaturation or unsaturated may refer to: Chemistry * Saturation, a property of organic compounds referring to carbon-carbon bonds **Saturated and unsaturated compounds ** Degree of unsaturation **Saturated fat or fatty aci ...

has a major impact on the central nervous system of animals. Early symptoms of cicutoxin poisoning include excessive salivation, frothing at the mouth, nervousness, and incoordination. These symptoms can progress to tremors, muscular weakness, seizures and respiratory failure. Ingestion of green materials of western water hemlock in amounts equivalent to about 0.1% of a person's body weight can even lead to death. In addition to being extremely hazardous to humans, this plant has an enormous impact on animals. As little as 0.2–0.5% body weight for sheep, 0.1% body weight for cattle, 0.5% body weight for horses, and 0.3% body weight for swine can be lethal. Death can occur within fifteen minutes of ingesting the toxin. It is one of the first plants to emerge in springtime, and has a very appealing odor. These characteristics, along with the fact that it grows in moist areas, make the plant very attractive, but deadly, to grazing animals.

References

External links

Calflora Database: ''Cicuta douglasii'' (Western water hemlock)

Jepson eFlora (TJM2) treatment of ''Cicuta douglasii''

U.C. CalPhotos gallery
{{Authority control Apioideae Flora of the Northwestern United States Flora of California Flora of Alaska Flora of Nevada Flora of Western Canada Flora of the Sierra Nevada (United States) Natural history of the California chaparral and woodlands Taxa named by Augustin Pyramus de Candolle Taxa named by John Merle Coulter Poisonous plants Flora without expected TNC conservation status