Rhaponticum repens, synonyms including Acroptilon repens and Leuzea repens, Augustin Pyramus de Candolle separated it from the genus Centaurea in 1838, placing it in the genus Acroptilon. A 1995 molecular phylogenetic study, the structure of the flower, and the chromosome number support separating it from the genus Centaurea. Some sources then continue to place it as the sole member of the monotypic genus Acroptilon.
Distribution
A native to Eurasia, Russian knapweed was introduced into North America in the late 19th century. Absent only from southeastern U.S., it has become widespread in other regions, especially in the western United States.
Toxicity
Nigropallidal encephalomalacia, also called chewing disease, a movement disorder similar to Parkinson's disease, is caused in horses ingesting Russian knapweed for prolonged periods. A sesquiterpene lactone, repin, in the plant is likely responsible for this toxicity.
thumb|Russian knapweed in Mashhad-Iran
References
External links
- Jepson Manual Treatment
- Species Profile- Russian Knapweed (Rhaponticum repens), National Invasive Species Information Center, United States National Agricultural Library. Lists general information and resources for Russian Knapweed.