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Cicuta douglasii

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Cicuta douglasii, close-up showing part of leaf.
Leaf detail, showing distinctive venation (see text).

Cicuta douglasii

Secure  (NatureServe)[1]
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Apiales
Family: Apiaceae
Genus: Cicuta
Species:
C. douglasii
Binomial name
Cicuta douglasii

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

Description

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The leaves of Cicuta douglasii (left), along with those of Conium maculatum (poison hemlock); both species are extremely poisonous.

The plant's roots are thick and tuberous, with many smaller tubers on the main one,[2] allowing survival in wet conditions. The stem is 0.5–2 meters (1+1⁄2–6+1⁄2 feet) tall with purplish spots. The inner tubers and stem bases can have horizontal chambers useful for identification.[3] The leaves are alternate and compound pinnate; the secondary veins of the leaflets end at the bases instead of the tips of the teeth.[4][5] The leaflets are 3–10 centimeters (1+1⁄4–4 inches) long and 1–2 cm (1⁄2–3⁄4 in) wide, with jagged edges.[2][3] Its inflorescences are compound umbels about 12.5 cm (5 in) across,[3] with many small, white flowers,[2] which have two seeds each. The seeds germinate in spring, and flowers mature near the end of June and beginning of July.[2] Seed dispersal is by means of wind, water, machinery, clothing, and through transported soil.[6] 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

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Water hemlock is most abundant in British Columbia,[6] and is indigenous to North America,[2] 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.[2] It grows in wet places such as marshes, stream banks, slough margins, ditches, meadows, and wet pastures.[6][4]

Toxicity

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Main article: Cicuta toxicity

The main distinguishing characteristic of western water hemlock is its toxicity. Cicutoxin is the toxin that is produced, making water hemlock the most poisonous plant in North America.[7] Cicutoxin is a yellowish liquid that is prevalent in the roots. This unsaturated alcohol 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.[2] 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.[8] 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.[2] These characteristics, along with the fact that it grows in moist areas, make the plant very attractive, but deadly, to grazing animals.

References

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  1. ^ "NatureServe Explorer 2.0". explorer.natureserve.org. Retrieved 2023-10-20.
  2. ^ a b c d e f g h Block, N. (n.d.). (2005-07-13). "Cicuta douglasii (DC.) Coult. & Rose".
  3. ^ a b c Spellenberg, Richard (2001) [1979]. National Audubon Society Field Guide to North American Wildflowers: Western Region (rev ed.). Knopf. p. 337. ISBN 978-0-375-40233-3.
  4. ^ a b Saskatchewan Agriculture and food (2005-07-13). "Western water hemlock". Archived from the original on 2005-10-28.
  5. ^ Pojar, Jim; MacKinnon, Andrew (2004) [1994]. Plants of the Pacific Northwest Coast: Washington, Oregon, British Columbia & Alaska (Rev. ed.). Vancouver, BC: Lone Pine Publishing. p. 215. ISBN 978-1-55105-530-5.
  6. ^ a b c Weeds BC (2005-07-13). "Water hemlock, Cicuta douglasii". Archived from the original on 2002-07-30.
  7. ^ Schep LJ, Slaughter RJ, Becket G, Beasley DM (April 2009). "Poisoning due to water hemlock". Clin Toxicol. 47 (4): 270–8. doi:10.1080/15563650902904332. PMID 19514873. S2CID 21855822.
  8. ^ Ministry of agriculture, food & fisheries (2005-07-13). "Western water hemlock". Archived from the original on 2005-08-29.
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