Salvia reflexa, a new record for France
Salvia reflexa (Lamiaceae) originates from Southern USA. It is an annual, densely pubescent, greyish plant which smells strongly of mint. Flowers are pale blue. The species is not quoted in any European guides to flora, although it was mentioned in the EPPO region in 1884 in Germany, it has also been previously reported in Austria, Hungary, Romania, Slovakia, Switzerland, Ukraine, and is known in Belgium and United Kingdom. It has recently been recorded as naturalized in Serbia. Outside the EPPO region, it is naturalized in California (US), Eastern and Southern Africa, as well as in Australia where it is considered a major weed. In the Global Compendium of Weeds, this species is quoted as a ‘Noxious Weed’, an ‘Environmental Weed’, and an ‘Agricultural Weed’ (e.g. it is a weed in cotton fields). S. reflexa is toxic to weak cattle, most probably due to nitrate accumulation in the leaves. It is also thought to be able to release allelopathic substances during rainy periods, inhibiting the germination and growth of plantlets of other species.
In France, the species has been found in Côte-d’Or (Bourgogne region), on a North oriented and stony calcareous plateau with low water reserves. S. reflexa was very abundant (several hundred plants) on this site, the most important populations being found in two maize fields (separated by 100 m), and on fallow land. This area showed exceptional plant diversity since very rare messicole plants were present: Thymelea passerine, Nigella arvensis, Polycnemum majus, Adonis flammea, etc.). This species might have been introduced as a contaminant of seeds. Indeed, seeds of S. reflexa have already been found in Leguminosae seeds coming from North America according to the Canadian Food Inspection Agency (2001). In France, it is considered that this species could represent a risk and therefore should be monitored.
Sources
Girod C, Cadet E, Fried G (2007) Salvia reflexa Hornem. (Lamiaceae) a new weed for France discovered in Côte d’Or. Le Monde des Plantes 493, 24-26.
Agence canadienne d’Inspection des Aliments (2001) Essai de germination et de pureté des semences: rapport quinquennal 1er juillet 1996 – 30 juin 2001.