Eupatorium
Eupatorium is a genus of flowering plants in the family Asteraceae, containing from 36 to 60 species depending on the classification system. Most are herbaceous perennials growing to tall. A few are shrubs. The genus is native to temperate regions of the Northern Hemisphere. The type species of the genus Eupatorium cannabinum, which is also the sole European species, is known as hemp-agrimony. Most in North America are commonly called boneset, thoroughwort or snakeroot. The genus is named after Mithridates VI Eupator, king of Pontus.
Systematics and taxonomy
Eupatorium has at times been held to contain as many as 800 species, but many of these have been moved to other genera, including Ageratina, Chromolaena,
Condylidium, Conoclinium, Critonia, Cronquistianthus, Eutrochium, Fleischmannia, Flyriella, Hebeclinium, Koanophyllon, Mikania, and Tamaulipa.
The classification of the tribe Eupatorieae, including species placed in Eupatorium in the present or past, is an area of ongoing research, so further changes are likely. What seems fairly certain by now is that there is a monophyletic group containing Eupatorium and the Joe-pye weeds, and possibly others.
Uses
Eupatorium are grown as ornamental plants, particularly in Asia. A number of popular ornamental plants formerly included in Eupatorium have been moved to other genera, such as Bartlettina and Conoclinium.
Tobacco leaf curl virus is a pathogen occasionally affecting plants of this genus. The foliage is eaten by some Lepidoptera larvae, including those of Orthonama obstipata.
Medical use
The common names for the plants are all based on the previous usage of one species, Eupatorium perfoliatum, as an herbal medicine. Despite its name, boneset is not used to treat broken bones, instead the common name apparently derives from the herb's use to treat dengue fever, which was also called breakbone fever because of the pain that it caused. The name thoroughwort also comes from Eupatorium perfoliatum, and refers to the perfoliate leaves, in which the stem appears to pierce the leaf.
Boneset, although poisonous to humans and grazing livestock, has been used in folk medicine, for instance to excrete excess uric acid which causes gout.
Caution is advised when using boneset, since it contains toxic compounds that can cause liver damage. Side effects include muscular tremors, weakness, and constipation; overdoses may be deadly.
Selected species
North America
Eupatorium album L.- white thoroughwortEupatorium altissimum L. - tall thoroughwortEupatorium anomalum Nash – Florida thoroughwort an apomictic hybrid derivative of Eupatorium mohrii and Eupatorium rotundifoliumEupatorium capillifolium Small - dog-fennelEupatorium compositifolium Walter - YankeeweedEupatorium godfreyanum Cronquist, an apomictic hybrid derivative of Eupatorium rotundifolium and Eupatorium sessilifoliumEupatorium hyssopifolium L. - hyssop-leaved thoroughwortEupatorium lancifolium Small - lance-leaved thoroughwortEupatorium leptophyllum DC. - false fennelEupatorium leucolepis Torrey & A.Gray - justiceweedEupatorium linearifolium Walter - Eupatorium maritimum E.E.Schill. - an apomictic hybrid derivative of Eupatorium mohrii and Eupatorium serotinumEupatorium mikanioides Chapman - semaphore thoroughwortEupatorium mohrii Greene - Mohr's thoroughwortEupatorium novae-angliae V.I.Sullivan ex A.Haines & Sorrie an apomictic hybrid derivative of Eupatorium paludicola and Eupatorium perfoliatumEupatorium paludicola E.E.Schill. & LeBlond - swamp thoroughwort, until 2007 classified as part of Eupatorium leucolepisEupatorium perfoliatum L. - common bonesetEupatorium petaloideum Britton - showy white thoroughwort, often considered to be part of Eupatorium albumEupatorium pilosum Walter - rough boneset, often considered to be part of Eupatorium rotundifoliumEupatorium resinosum Torrey ex DC. - pine barren bonesetEupatorium rotundifolium L. - round-leaved thoroughwortEupatorium semiserratum DC. - smallflower thoroughwortEupatorium serotinum L. - late boneset, late thoroughwortEupatorium sessilifolium L. - upland bonesetEupatorium sullivaniae E.E.Schill. - an apomictic hybrid derivative of Eupatorium album and ''Eupatorium lancifolium''
Europe
Eupatorium cannabinum L. - hemp-agrimony
Asia
Eupatorium amabile Kitam.Eupatorium benguetense C.RobinsonEupatorium camiguinense Merr.Eupatorium chinense L.Eupatorium formosanum HayataEupatorium fortunei Turcz. - fujibakama, pei lanEupatorium japonicum Thunb. Eupatorium leonardii Ferreras & E.E.Lamont| Eupatorium lindleyanum DC.Eupatorium luchuense NakaiEupatorium makinoi T.Kawahara & T.Yahara Eupatorium nodiflorum DC.Eupatorium quaternum DC.Eupatorium sambucifolium ElmerEupatorium shimadai Kitam.Eupatorium squamosum D.DonEupatorium tashiroi HayataEupatorium toppingianum ElmerEupatorium variabile MakinoEupatorium yakushimaense Masam. & Kitam
Moved to other genera
Eupatorium adamantium Gardner Eupatorium amygdalinum Eupatorium ayapana - aya-pana, water hemp Eupatorium bracteatum Gardn. Eupatorium coelestinum - mistflower Eupatorium collinum Eupatorium itatiayense Hieron. Eupatorium gayanum Eupatorium laevigatum DC. Eupatorium ligustrinum Eupatorium maculatum Joe-Pye weedEupatorium maximiliani Schrad. ex DC. Eupatorium megalophyllum Eupatorium officinale Eupatorium pacificum Eupatorium purpureum Eupatorium pyrifolium DC. Eupatorium rufescens P.W.Lund. ex DC. Eupatorium rugosum Eupatorium sordidum Eupatorium squalidum DC. Eupatorium urticaefolium Eupatorium vauthierianum DC.