Plants newly naturalized in North-Western France (Maine-et-Loire)
In France, the following plants have been observed in the department of Maine-et-Loire (North-West):
- Cortaderia selloana (Poaceae) is naturalizing in the area, and is already recorded as invasive in the South of France. In Maine-et-Loire, it escaped from cultivation and creates dense monospecific and impenetrable stands.
- Eichhornia crassipes (Pontederiaceae) is a tropical species originating from South America. It appeared in the Maine river but is not thought to have the potential to overwinter at these latitudes.
- Lagarosiphon major (Hydrocharitaceae, EPPO list of IAS) and Lemna minuta (Lemnaceae) have been observed.
- Pistia stratiotes (Araceae) was observed once.
- Saururus cernuus (Saururaceae) originates from North America. The species is recorded as naturalized in Italy (lake Comabbia near Varese), in Belgium (Flandres), and in the United Kingdom (Hampshire). In Maine-et-Loire it was first observed in 2002 in the Souzay river in Souzay-Champigny in association with Bidens tripartita, Bidens frondosa (Asteraceae), Ludwigia uruguayensis (= L. grandiflora) (Onagraceae, EPPO List of IAS) and Paspalum distichum (Poaceae). The species is considered invasive there and has been mechanically removed (hand pulling of rhizomes present in the sediments up to 1 m deep).
- Senecio inaequidens (Asteraceae, EPPO list of IAS) originates from South Africa and is invasive in the South of France. It arrived in Maine-et-Loire in 2001 and spreads along railways.
- Solanum sarrachoides (Solanaceae) originates from Brazil and is now very frequently found in the Loire department.
- Sporobolus indicus (Poaceae) is a pantropical species colonizing roadsides densely and rapidly. It competes with other plants and modifies floristic associations significantly and establishes very late in the season (August-November). This annual plant is also recorded as invasive in Lazio (Italy, Laura Celesti Grapow, pers. comm.) and in Serbia (Danijela Stesevic et al. pers. comm.)
Other species are newly recorded but are not considered invasive: Bocconia cordata (Papaveraceae), Chenopodium pumilio (Chenopodiaceae), Dryopteris erythrosora (Dryopteridaceae), Lagurus ovatus (Poaceae), Plantago major subsp. intermedia (Plantaginaceae), Populus jackii cv. “Gileadensis” (Salicaceae), Portulaca grandiflora (Portulacaceae), Mirabilis jalapa (Nyctoginaceae), Rostraria cristata (Poaceae), Sedum kamtschaticum subsp. ellacombinum (Crassulaceae), Setaria viridis (Poaceae), Tellima grandiflora (Saxifragaceae).
Delaunay G (2004) Contributions à l’étude de la flore du Maine-et-Loire: quelques observations récentes dans la dition et ses proches environs. Le Monde des Plantes. 483, 29-31.