Cicuta douglasii

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Cicuta douglasii
Scientific classification
Kingdom: Plantae (unranked): Angiosperms (unranked): Eudicots (unranked): Asterids Order: Apiales Family: Apiaceae Genus: Cicuta Species: C. douglasii
Binomial name
Cicuta douglasii (DC.) Coult. & Rose

Cicuta douglasii (Western water hemlock) is a poisonous plant in the family Apiaceae. It is a perennial plant that grows in wet places such as marshes, stream banks, slough margins, ditches, meadows, and wet pastures^[1][2]. The roots of this plant are thick and tuberous, with many smaller tubers coming from the main tuber^[3]. This root structure allows the water hemlock to adapt and survive wet conditions. Water hemlock is most abundant in British Columbia^[1], and is indigenous to North America^[3]. In North America it primarily grows from the base of the Rocky Mountains to the Pacific coast, stretching all the way from Alaska down to California. Water necessities limit this plant from growing in open rangelands^[3].

The characteristics of water hemlock include its stem which is 0.5-2 meters tall with purplish spots, thick roots, and leaves that are compound pinnate and alternate^[2]. The leaflets are usually 5-8 cm long and 1-2 cm wide with jagged edges^[3]. The flowers on it are compound umbellate inflorescences with many small, white flowers^[3]. There are two seeds for each flower. Seed dispersal for water hemlock seeds comes from means of wind, water, machinery, on clothing, and through transported soil^[1]. The seeds germinate in spring, and flowers mature near the end of June and beginning of July^[3]. In addition to sprouting new plants from seeds, rootstocks can also product new plants. These are formed in the fall from the basal meristem, and when they detach the following spring, they may form a new plant.

[edit] Toxicity

The main distinguishable characteristic of western water hemlock is its toxicity. Cicutoxin is the toxin that is produced by the water hemlock, making it the most poisonous plant in North America.^{[citation needed]} Cicutoxin is a yellowish liquid that is prevalent in the roots. It is an unsaturated alcohol that 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 turn into tremors, muscular weakness, seizures and respiratory failure^[3]. Very small amounts of this poison, about .1% of a person’s body weight can even lead to death^[4]. In addition to being extremely dangerous to humans, this plant has an enormous impact on animals. It is one of the first plants to come out in springtime, and has a very appealing odor^[3]. 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 this toxin. These characteristics, along with the fact that it grows in moist areas make it a very desirable, yet deadly, plant for grazing animals.

Although this is a very lethal plant, there are a couple things that can be done to avoid the dangers of it. The only way to prevent animals from consuming the water hemlock is to prevent animals from grazing in areas where it is abundant, or to pull the plant from areas where livestock will be grazing. For humans, if this plant is consumed, there is very little time to react. However, if water hemlock is consumed, injections of pentobarbital, morphine, and potassium permanganate have shown some success^[3].

The plant also includes the toxin Coniine.

[edit] Similar species

These plants all have white flowers in large compound umbels. Therefore, these plants are confused with each other; the water parsnip, (swamp parsnip, sium suave) and the western water hemlock, (Cicuta douglasii, poison hemlock) or the spotted water hemlock (cicuta maculata, spotted water hemlock, spotted parsley, spotted cowbane). Water parsnip and water hemlock both have cluster of small white flowers shaped like umbrellas, and both have the same habitat near the shore line of lakes, and rivers. Water parsnip has leaves only once compound, and water hemlock has leaves which are three times compound. Water hemlock has a large swelling at the stem base. All water hemlock is highly poisonous.^[5] Water parsnip is not poisonous.^[6] The water hemlock has bracts at the base of each small flower cluster, not at the base of the main flower head.^[7] The Water parsnip has small bracts at the base of flowers and main flower head as well.^[8] The Yarrow, (Common Yarrow, Gordaldo, Nosebleed plant, Old Man's Pepper, Sanguinary, Milfoil, Soldier's Woundwort, Thousand-leaf (as its binomial name affirms), Thousand-seal or Achillea millefolium) also has many small white flowers in a cluster. However the yarrow has feathery looking leaves which are pinnately separated into small narrow segments.^[9] The cow parsnip (heracleum lanatum, Heracleum maxinium Indian Celery or Pushki, and Heracleum sphondylium, hogweed) is also confused in this group with similar flower groupings. However, the cow parsnip has large, broad leaves, and an unpleasant odour.^[10]

Hemlock's distinguishing characteristics are that it requires a more consistent supply of water than Lomatium or Osha, and Lomatium species tend to prefer dry rocky soils devoid of organic material. Lomatium roots have a delicate rice-like odor, unlike the musty odor of Hemlock, with finely divided, hairlike leaves in most Lomatium species. Lomatium species tend to produce yellow flowers, but some species are white flowered and closely resemble Poison Hemlock. If the plant is growing on a hillside in dry, mineral soil far away from a source of water and has umbells of yellow flowers, its likely a Lomatium. It the plant is growing in an area near water in consistently moist soil, is tall (0.75-2m), has purple splotches on the main stem, and is heavily branched with small umbels of white flowers, it is probably Hemlock and should be avoided.

Osha does not do well in overly moist soils since it is a species dependent on mycorrhizal fungi to survive, but there are areas where Osha and Poison Hemlock can be found only a few feet from each other. Poison Hemlock lacks the "spicy celery" odor of Osha, and is easily distinguished from it due to the absence of hairlike dead leaf material present on the root crown of Osha roots. Poison Hemlock roots in many cases have no discernible odor, and are typically heavily branched rather than carrot-like, but this is not always the case. The plants themselves smell musty or "mousy", and in most instances will have purple blotches or shading on the lower stem of the plant if the plant is fairly mature, but again, this is not always the case.

In the Mountain West of North America, poison hemlock has become well established and invasive, and can be found in remote mountain areas anywhere water is present or soils are persistently moist. It is often found growing in the same habitat and side by side with Osha and Lomatium species, useful medicinal relatives in the Parsley family which Hemlock closely resembles, and can be very difficult to distinguish from Lomatium (an important historical food plant of Native Americans known as Biscuit Root).

A useful trick to determine whether a plant is poison hemlock rather than fennel, which it resembles, is to crush some leaves and smell the result. Fennel smells like anise or liquorice, whereas the smell of poison hemlock is often described as mouse-like or musty. Considering the high toxicity of poison hemlock, if the plant cannot be identified it must be discarded. Coniine can be absorbed through the skin, and it is well advised to wash your hands immediately after handling this plant and avoid touching your eyes or mouth if you have recently handled or come into contact with Poison Hemlock, or if you have crushed the leaves of this plant in your hand to perform a "smell test".

Poison hemlock is sometimes confused with water hemlocks in the related genus Cicuta^[11], but are readily distinguished by the less finely divided leaves of the latter; the leaf veins of poison hemlock also run through the tips of the teeth, but those of the water hemlock run through the notches in between the teeth. The poison hemlock's root is long, white, and fleshy and is usually stringy and heavily branched, but can be carrot-like and unbranched in younger specimens of Conium. Water hemlock's roots are made up of several tubers, and are typically chambered, and exude a yellow, rank, highly toxic sap that contains cicutoxin^[12].

[edit] References

1. ^ ^{a b c} Weeds BC (2005-07-13). "Water hemlock, Cicuta douglasii". http://www.weedsbc.ca/weed_desc/water_hem.html. 
2. ^ ^{a b} Saskatchewan Agriculture and food (2005-07-13). "Western water hemlock". http://www.agr.gov.sk.ca/DOCS/crops/integrated_pest_management/weed_identification_broadleaf_weeds/whemlock.asp. 
3. ^ ^{a b c d e f g h i} Block, N. (n.d.). (2005-07-13). "Cicuta douglasii (DC.) Coult. & Rose". http://www.usask.ca/agriculture/plantsci/classes/range/cicuta.html. 
4. ^ Ministry of agriculture, food & fisheries (2005-07-13). Western water hemlock "Western water hemlock". http://www.agf.gov.bc.ca/cropprot/whemlock.htm Western water hemlock. 
5. ^ "Cicuta maculata.". http://www.em.ca/garden/native/nat_cicuta_maculata.html. Retrieved on 2008-08-03. 
6. ^ "Traditional Plant Foods of Canadian Indigenous Peoples By Harriet V Kuhnlein, Nancy J.". Google books. http://books.google.ca/books?id=fPDErXqH8YYC&pg=PA124&lpg=PA124&dq=hemlock++saskatchewan&source=web&ots=wEZs3Qy1Nb&sig=4XiR4NlX_41oreXB54L841HnbIs&hl=en&sa=X&oi=book_result&resnum=10&ct=result#PPA124,M1. Retrieved on 2008-08-03. 
7. ^ "Western Water Hemlock - Agriculture - Government of Saskatchewan". http://www.agriculture.gov.sk.ca/Default.aspx?DN=6896bcb3-d202-43e0-ace9-c4ec72d8835d. Retrieved on 2008-08-03. 
8. ^ "Water Parsnip - Agriculture - Government of Saskatchewan". http://www.agriculture.gov.sk.ca/Default.aspx?DN=e2b0945b-6609-4790-ae82-8fdd9135af26. Retrieved on 2008-08-03. 
9. ^ "Yarrow Achillea millefolium". http://www.em.ca/garden/native/nat_Achillea%20millefolium.html. Retrieved on 2008-08-03. 
10. ^ "Heracleum lanatum". University of Saskatchewan. http://www.usask.ca/agriculture/plantsci/classes/range/heracleum.html. Retrieved on 2008-08-03. 
11. ^ "Water hemlock (Cicuta spp.)". Natural Standard, The Authority on Integrative Medicine. http://www.naturalstandard.com/index-abstract.asp?create-abstract=/monographs/herbssupplements/patient-waterhemlock.asp. Retrieved on 2008-08-03. 
12. ^ "Water Hemlock (Cicuta douglasii)". Field Guide to Noxious and Other Selected Weeds of British Columbia. Ministry of Agriculture and Lands Government of British Columbia. http://www.agf.gov.bc.ca/cropprot/weedguid/waterhmlk.htm. Retrieved on 2008-08-03.