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 thoroughwort
  • Eupatorium altissimum L. - tall thoroughwort
  • Eupatorium anomalum Nash – Florida thoroughwort an apomictic hybrid derivative of Eupatorium mohrii and Eupatorium rotundifolium
  • Eupatorium capillifolium Small - dog-fennel
  • Eupatorium compositifolium Walter - Yankeeweed
  • Eupatorium godfreyanum Cronquist, an apomictic hybrid derivative of Eupatorium rotundifolium and Eupatorium sessilifolium
  • Eupatorium hyssopifolium L. - hyssop-leaved thoroughwort
  • Eupatorium lancifolium Small - lance-leaved thoroughwort
  • Eupatorium leptophyllum DC. - false fennel
  • Eupatorium leucolepis Torrey & A.Gray - justiceweed
  • Eupatorium linearifolium Walter -
  • Eupatorium maritimum E.E.Schill. - an apomictic hybrid derivative of Eupatorium mohrii and Eupatorium serotinum
  • Eupatorium mikanioides Chapman - semaphore thoroughwort
  • Eupatorium mohrii Greene - Mohr's thoroughwort
  • Eupatorium novae-angliae V.I.Sullivan ex A.Haines & Sorrie an apomictic hybrid derivative of Eupatorium paludicola and Eupatorium perfoliatum
  • Eupatorium paludicola E.E.Schill. & LeBlond - swamp thoroughwort, until 2007 classified as part of Eupatorium leucolepis
  • Eupatorium perfoliatum L. - common boneset
  • Eupatorium petaloideum Britton - showy white thoroughwort, often considered to be part of Eupatorium album
  • Eupatorium pilosum Walter - rough boneset, often considered to be part of Eupatorium rotundifolium
  • Eupatorium resinosum Torrey ex DC. - pine barren boneset
  • Eupatorium rotundifolium L. - round-leaved thoroughwort
  • Eupatorium semiserratum DC. - smallflower thoroughwort
  • Eupatorium serotinum L. - late boneset, late thoroughwort
  • Eupatorium sessilifolium L. - upland boneset
  • Eupatorium 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.Robinson
  • Eupatorium camiguinense Merr.
  • Eupatorium chinense L.
  • Eupatorium formosanum Hayata
  • Eupatorium fortunei Turcz. - fujibakama, pei lan
  • Eupatorium japonicum Thunb.
  • Eupatorium leonardii Ferreras & E.E.Lamont|
  • Eupatorium lindleyanum DC.
  • Eupatorium luchuense Nakai
  • Eupatorium makinoi T.Kawahara & T.Yahara
  • Eupatorium nodiflorum DC.
  • Eupatorium quaternum DC.
  • Eupatorium sambucifolium Elmer
  • Eupatorium shimadai Kitam.
  • Eupatorium squamosum D.Don
  • Eupatorium tashiroi Hayata
  • Eupatorium toppingianum Elmer
  • Eupatorium variabile Makino
  • Eupatorium 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 weed
  • Eupatorium 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.