Hogweed

Taxobox
name = Hogweed

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image_width = 250px
image_caption = Flower and leaf of Cow Parsnip
regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Apiales
familia = Apiaceae
genus = "Heracleum"
subdivision_ranks = Species
subdivision = See text (about 60)

"Heracleum" (the hogweeds) is a genus of about 60 species (depending on taxonomic interpretation) of biennial and perennial herbs in the carrot family Apiaceae. They are found throughout the temperate northern hemisphere and in high mountains as far south as Ethiopia.

Major species include:
*Giant Hogweed "Heracleum mantegazzianum" A native of the Caucasus Mountains, grows to 4-5m tall, and can cause severe dermatitis if the sap gets on human skin. The main mechanism for this dermatitis is extreme photosensitivity, causing severe sunburn on exposure to relatively small amounts of sunlight, with rash and blistering appearing within a few minutes: accordingly immediately covering sap-affected skin can prevent the dermatitis in many cases. It has become a serious invasive weed in many areas of Europe and North America, after being introduced as a garden plant.
*Common Hogweed "Heracleum sphondylium "
*Cow Parsnip "Heracleum lanatum" (synonyms: "Heracleum sphondylium" subsp. "montanum", "Heracleum maximum").

Species

Note that this is a full list of the 187 names described in the genus; the majority of these names are treated as synonyms of earlier-described species by most botanists.

imilar 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.cite web
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title = Cicuta maculata.
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url = http://www.em.ca/garden/native/nat_cicuta_maculata.html
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accessdate =2008-08-03 ] Water parsnip is not poisonous.cite web
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title = Traditional Plant Foods of Canadian Indigenous Peoples By Harriet V Kuhnlein, Nancy J.
work = Google books
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url = 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
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accessdate =2008-08-03 ] The water hemlock has bracts at the base of each small flower cluster, not at the base of the main flower head.cite web
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title = Western Water Hemlock - Agriculture - Government of Saskatchewan
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url = http://www.agriculture.gov.sk.ca/Default.aspx?DN=6896bcb3-d202-43e0-ace9-c4ec72d8835d
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accessdate =2008-08-03 ] The Water parsnip has small bracts at the base of flowers and main flower head as well.cite web
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title = Water Parsnip - Agriculture - Government of Saskatchewan
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url = http://www.agriculture.gov.sk.ca/Default.aspx?DN=e2b0945b-6609-4790-ae82-8fdd9135af26
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accessdate =2008-08-03 ] 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.cite web
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title = Yarrow Achillea millefolium
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url = http://www.em.ca/garden/native/nat_Achillea%20millefolium.html
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accessdate =2008-08-03 ] 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.cite web
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title =Heracleum lanatum
work = University of Saskatchewan
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url =http://www.usask.ca/agriculture/plantsci/classes/range/heracleum.html
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accessdate =2008-08-03 ]

References

[http://www.ipni.org/index.html The International Plant Names Index]

External links

* [http://www.itis.usda.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=29669 ITIS 29669]

Footnotes