Alternanthera philoxeroides reaches the Tarn-et-Garonne Department in France
Alternanthera philoxeroides (Amaranthaceae) originating from South America has been observed in 2002 and 2003 on the banks of the river Garonne at la Magistère (Tarn-et-Garonne, South-West of France). The plant seems only present in the Gironde estuary and on the river Garonne. It is thought that the possible origin or pathway of entry of the plant may be an accidental introduction related to portuary activities, or a voluntary introduction as an ornamental plant for ponds and aquaria. A. philoxeroides does not seem to show in France the same invasiveness as in California.
More information on this plant at:
http://www.hear.org/pier/species/alternanthera_philoxeroides.htm, http://www.invasivespecies.net/database/species/ecology.asp?si=763&fr=1&sts=, http://www.deh.gov.au/biodiversity/invasive/publications/a-philoxeroides.html,
Sources
Georges N (2004) L’herbe à l’alligator (Alternanthera philoxeroides (Martius) Grisebach) atteint le département du Tarn-et-Garonne. Le monde des plantes 484, 1-3.