Heracleum is a genus 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[2] and cow parsnip.[3][4]
Many species of the genus Heracleum are similar in appearance.[5] An outlier is H. mantegazzianum, the large size of which is exceptional. Common species include:
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.[6][5] 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.[7][8]
The morphological similarity of species within the genus Heracleum 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.
At least 36 species of the genus Heracleum have been reported to contain furanocoumarin,[13] a chemical compound that sensitizes human skin to sunlight.[citation needed] 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.
Logacheva, Maria; Valiejo-Roman, C. M.; Pimenov, Michael (February 2007). "ITS phylogeny of West Asian Heracleum species and related taxa of Umbelliferae–Tordylieae W.D.J.Koch, with notes on evolution of their psbA-trnH sequences". Plant Systematics and Evolution. 270 (3): 139–157. doi:10.1007/s00606-007-0619-x.