Eupatorium
Eupatorium (syn. Ayapana Spach) is a genus of flowering plants, containing from 36 to 60 species (depending on the classification system), most of which are herbaceous perennial plants growing to 0.5-3 m tall. A few are shrubs. The genus is native to temperate regions of the Northern Hemisphere.
Species of Eupatorium, although poisonous (to humans and grazing livestock), have been used in folk medicine, for instance to excrete excess uric acid which causes gout. However, Eupatorium has many beneficial uses, including treatment of dengue fever, arthritis, infectious diseases, migraines, worms, malaria, and diarrhea. Boneset infusions are also considered an excellent remedy for influenza.
Use caution when consuming boneset, since it contains toxic compounds that can cause liver damage. Side effects include muscular tremors, weakness, and constipation leading to death.
Eupatorium species are used as food plants by the larvae of some Lepidoptera species including Bucculatrix eupatoriella (which feeds exclusively on Eupatorium perfoliatum), The V-pug, Wormwood Pug, Schinia bifascia, Schinia trifascia and the Coleophora case-bearers C. follicularis, C. trochilella and C. troglodytella.
A few species or cultivars, such as E. sordidum and E. coelestinum 'Album', are sometimes used as ornamental plants.  In particular, they are used for structural or background plantings or to attract butterflies.

# Selected species
- Eupatorium album (White Thoroughwort)
- Eupatorium altissimum (Tall Boneset, White Snakeroot)
- Eupatorium aromaticum (scented Hemp Agrimony, Lesser Snakeroot)
- Eupatorium  ayapana (Eupatorium aya-pana)
- Eupatorium cannabinum (Hemp Agrimony)
- Eupatorium capillifolium (Dog-fennel)
- Eupatorium coelestinum   (bluish flowered Hemp Agrimony, Blue Thoroughwort)
- Eupatorium  collinum
- Eupatorium dubium
- Eupatorium fistulosum (Hollow Joe-Pye Weed)
- Eupatorium  foeniculum
- Eupatorium gayanum (Asmachilca)
- Eupatorium glandulosum Kunth, non Michx. (sticky snakeroot, crofton weed, Maui pamakani, Mexican devil) An antibacterial perennial shrub. Current Name: Ageratina adenophora.
- Eupatorium  hyssopifolium  (Hyssop-leaved Thoroughwort)
- Eupatorium  leucolepsis
- Eupatorium lingustrinum
- Eupatorium megalophyllum
- Eupatorium maculatum  (Spotted Joe-Pye Weed)
- Eupatorium  officinalis
- Eupatorium perfoliatum (Common Boneset)
- Eupatorium purpureum (Sweet Joe-Pye Weed, green-stemmed Joe-pye Weed, Queen of the Meadow, Gravel root, Kidney root, Purple boneset)
- Eupatorium rugosum (White Snakeroot)
- Eupatorium  rotundifolium (Round-leaved Thoroughwort)
- Eupatorium serotinum  {Late Boneset, Thoroughwort)
- Eupatorium sessilifolium (Upland Boneset)
- Eupatorium  urticaefolium

# Other genera
Eupatorium has at times been held to contain as many as 800 species, but many of these have been moved (at least by some authors) to other genera, including Ageratina, Chromolaena, 
Condylidium, Conoclinium, Critonia, Eutrochium (syn. Eupatoriadelphus), 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.

# Cited references
-  Om P. Sharma, Rajinder K. Dawra, Nitin P. Kurade, Pritam D. Sharma (26 May 1999). "A review of the toxicosis and biological properties of the genus Eupatorium". Natural Toxins. 6 (1): 114. doi:10.1002/(SICI)1522-7189(199802)6:1%3C1::AID-NT3%3E3.0.CO;2-E.CS1 maint: Multiple names: authors list (link) .mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"\"""\"""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{display:none;font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
-  Ageratina adenophora (Spreng.) R.M. King & H. Rob.
-  Alan Whittemore (August 1987). "The Sectional Nomenclature of Eupatorium (Asteraceae)". Taxon. 36 (3): 618620. doi:10.2307/1221856.
-  "393. Eutrochium Rafinesque". Flora of North America. Vol. 21 Page 461, 462, 474, 475.
-  Motomi Ito, Kuniaki Watanabe, Yoko Kita, Takayuki Kawahara, DJ Crawford and Tetsukazu Yahara (March, 2000). "Phylogeny and Phytogeography of Eupatorium (Eupatorieae, Asteraceae): Insights from Sequence Data of the nrDNA ITS Regions and cpDNA RFLP". Journal of Plant Research. 113 (1): 7989. doi:10.1007/PL00013913. ISSN 1618-0860. Check date values in: |date= (help)CS1 maint: Multiple names: authors list (link)
-  Gregory J. Schmidt and Edward E. Schilling (2000). "Phylogeny and biogeography of Eupatorium (Asteraceae: Eupatorieae) based on nuclear ITS sequence data". American Journal of Botany. 87: 716726. PMID 10811796.

# Other references
- Lamont E.E. - Taxonomy of Eupatorium Section Verticillata (Asteraceae); New York Botanical Garden Press, 1995, ISBN 0-89327-391-0
- Encyclopedia of Folk Medicine: Old World and New World Traditions.  Santa Barbara: ABC-CLIO, Inc., 2004.
- The Gale Encyclopedia of Alternative Medicine.  Volume 1.  New York: Gale Group, 2001.
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