Rotala ramosior

Verloove, Filip & Ardenghi, Nicola M. G., 2015, New distributional records of non-native vascular plants in northern Italy, Natural History Sciences 2 (1), pp. 5-14 : 11

Rotala ramosior ( L.) Koehne, Fl. Bras. (Martius), 13 (2): 194. 1877.

( Lythraceae )

Naturalized neophyte new to the flora of the prov- ince of Alessandria (Piemonte) (Celesti Grapow et al., 2009a).

ITALY. Piemonte. Prov. Alessandria: Villanova Mon- ferrato, rice fields, 12.09.2014, F. Verloove 11079 ( BR) .

Rotala ramosior originally is an American species but it occurs in the Old World as a weed of rice fields, for in- stance in Italy and the Philippines ( Cook, 1979). In Italy it was first discovered in Piemonte in 1972 ( Cook, 1973), subsequently also in Lombardia ( Banfi & Galasso, 2010). In the past decades it has repeatedly been confirmed from Piemonte (e.g. Soldano, 1977; Abbà, 1980; Varalda et al., 1984; Desfayes, 2005) but it seemed to be confined to the province of Vercelli, from where it was originally re- ported by Cook (1973). In September 2014 it was found, apparently for the first time, in the province of Alessan- dria. It was found growing in quantity, with Ammannia coccinea Rottb. and other weeds, in a rice field near Vil- lanova Monferrato.