"Eupatorium is a genus of flowering plants in the aster family, Asteraceae, containing from 36 to 60 species depending on the classification system. Most 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. Most are commonly called bonesets, thoroughworts or snakeroots. The genus is named for Mithridates Eupator, king of Pontus.
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 (about 42 species of white flowered plants in North America, Europe and Asia, but not South America) and the Joe-pye weeds (Eutrochium), and possibly others.
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 (The Gem)."
Taken from wikipedia's page at:
http://en.wikipedia.org/wiki/E...