hogweed n : tall coarse plant having thick stems and cluster of white to purple flowers [syn: cow parsnip, Heracleum sphondylium]

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.

References

The International Plant Names Index

External links

• ITIS 29669