hogweed

Hogweed
Flower and leaf of Cow Parsnip
Scientific classification
Kingdom: Plantae (unranked): Angiosperms (unranked): Eudicots (unranked): Asterids Order: Apiales Family: Apiaceae Genus: Heracleum
Species
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.

Cow Parsnip (Heracleum lanatum)

Common Hogweed (Heracleum sphondylium)

Giant Hogweed (Heracleum mantegazzianum)

Siberian Hogweed (Heracleum sibiricum)

Major species include: Giant Hogweed Heracleum mantegazzianum A native of the Caucasus Mountains, grows to 4-5m tall, and can cause severe phytophotodermatitis 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.

Similar species

Many plants in the parsley family look similar to hogweeds, with white flowers in compound umbels. Plants confused with Heracleum include swamp parsnip (Sium suave), western water hemlock (Cicuta douglasii), and spotted hemlock (Cicuta maculata). All water hemlock is highly poisonous,^[1] while water parsnip is not poisonous.^[2] The water hemlock has bracts at the base of each small flower cluster, not at the base of the main flower head.^[3] The water parsnip has small bracts at the base of flowers and main flower head as well.^[4] Yarrow (Achillea millefolium) also has many small white flowers in its inflorescence, but the leaves are pinnately separated into small narrow segments.^[5]

References

The International Plant Names Index

External links

• ITIS 29669

Footnotes

1. ^ "Cicuta maculata.". http://www.em.ca/garden/native/nat_cicuta_maculata.html. Retrieved on 2008-08-03. 
2. ^ "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. 
3. ^ "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. 
4. ^ "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. 
5. ^ "Yarrow Achillea millefolium". http://www.em.ca/garden/native/nat_Achillea%20millefolium.html. Retrieved on 2008-08-03. 

Wikimedia Commons has media related to: Heracleum

Coordinates: 51°55′59″N 14°34′01″E / 51.933°N 14.567°E / 51.933; 14.567