Ageratina Spach

Ageratina is a segregate of Eupatorium. It is best distinguished in having glabrous style bases (pubescent in Eupatorium s.str.), usually hairy achenes, an inflorescence with individual heads more compact and cylindrical in outline and with many more florets per head (usually more than 20) (Hind 2006, Whitehouse 2007). Ageratina comprises ca. 250 New World species mostly in subtropical and warm-temperate South and Central America (Mabberley 2008). A few species are cultivated as ornamentals (Galloway 2000) and some are reputed environmental weeds (for instance Ageratina adenophora (Spreng.) King et Robinson).

Ageratina altissima



Clewell A.F. & Wooten J.W. (1971) A revision of Ageratina (Compositae: Eupatorieae) from eastern North America. Brittonia 23: 123-143.

Galloway A.A. (2000) Eupatorium. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 6. Cambridge University Press, Cambridge: 663-666.

Hind N. (2006) Splitting Eupatorium. The Plantsman N.S. 5(3): 185-189.

Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.

Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.

Nesom G.L. (2006) Ageratina. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 21. Oxford University Press, New York-Oxford: 547-553.

Whitehouse C. (2007) Eupatorium: Joe Pye weeds and their ornamental relatives. The Plantsman N.S. 6(4): 242-247.

Taxonomic name: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith