ABSTRACT
The genus Eupatorium consists of about 40 species native to North America, with a few species from South America and Asia. Closely related to Eupatorium is the genus Ageratina, some taxonomists considering them the same genus. Only two species of Eupatorium and Ageratina are known to be toxic and these are: Eupatorium rugosum (Ageratina altissima) – white snakeroot Ageratina adenophora (E. adenophora) – Crofton weed. Another genus belonging to the tribe Eupatorieae, and very similar to the above genera is the genus Ageratum. It is commonly represented in cultivation by A. houstonianum, and is reported to be toxic.
