Heracleum (plant)

Heracleum
Flower and leaf of Cow Parsnip
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Asterids
Order:	Apiales
Family:	Apiaceae
Genus:	Heracleum L.
Species
See text (about 60)

Heracleum 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. Common names for the genus or its species include hogweed^[1] and cow parsnip.^[2][3]

The genus name Heracleum was described by Carl Linnaeus in 1753.^[3] The word "heracleum" derives from the Greek "herákleion" and refers to the mythologic hero Heracles.

Major species

Major species include:

• Heracleum mantegazzianum, giant hogweed, is native to the western Caucasus region of Eurasia. Giant hogweed has become a serious invasive weed in many areas of Europe and North America.
• Heracleum sosnowskyi, Sosnowsky's hogweed, has a native range that includes the central and eastern Caucasus regions of Eurasia, extending into the southern Caucasus region called Transcaucasia. Sosnowsky's hogweed is now a common weed throughout Europe and Asia.
• Heracleum persicum, Persian hogweed, is native to Iran, Iraq and Turkey. In northern Norway, the Persian hogweed is known as the Tromsø palm.
• Heracleum sphondylium, common hogweed, is native to Europe and Asia.
• Heracleum maximum, cow parsnip, is native and common in North America.

The various species of the Heracleum genus are similar in appearance with only minor differences.^[4] An outlier is H. mantegazzianum, the size of which is exceptional.

Classification and naming

Other than size, the related species H. mantegazzianum, H. sosnowskyi, and H. persicum have very similar characteristics. The common name giant hogweed usually refers to H. mantegazzianum alone but in some locales that common name refers to all three species as a group.^[5][4]

The morphological similarity of species within the Heracleum genus and the difficulty of botanical identification has led to numerous synonyms and naming issues. For example, the classification of the species now widely known as H. maximum has been inconsistent. In the literature, the scientific names H. lanatum, H. maximum, and others are used interchangeably. Prior to 2000, the former name was most popular, but today the latter name is in vogue.

To make matters worse, the common names "hogweed" and "cow parsnip" are overused. In particular, both H. maximum and H. sphondylium are often referred to as cow parsnip. To avoid confusion, these species are sometimes referred to as American cow parsnip and European cow parsnip, respectively.^[6][7]

Photoxic effects

Most species of the Heracleum genus are known to cause phytophotodermatitis.^[8] In particular, the public health risks of giant hogweed (H. mantegazzianum) are well known.^[9][10][11]

At least 36 species of the Heracleum genus have been reported to contain furanocoumarin,^[12] a chemical compound that sensitizes human skin to sunlight.^[13] Of those, at least 25 species contained a psoralen derivative, either bergapten (5-methoxypsoralen) or methoxsalen (8-methoxypsoralen). Three of those species (H. mantegazzianum, H. sosnowskyi, and H. sphondylium) were found to contain both psoralen derivatives.

Gallery

• 
  Giant hogweed (Heracleum mantegazzianum)
• 
  Sosnowsky's hogweed (Heracleum sosnowskyi)
• 
  Cow Parsnip (Heracleum maximum) (Synonym: Heracleum lanatum)
• 
  Common hogweed (Heracleum sphondylium)
• 
  (Heracleum austriacum)

Species

The following species names are known. Boldfaced scientific names have been accepted by The Plant List.^[14]

See also

• wikispecies:Heracleum

References

External links

Wikimedia Commons has media related to Heracleum.

Wikispecies has information related to Heracleum

• The Plant List
• Integrated Taxonomic Information System
  • ITIS 29669
• The International Plant Names Index