Salvinia natans (4811' N 1626' E)

Description:

2010.07.28 Vienna II. district (bayou in Vienna Prater - Mauthnerwasser 156 m).Put on a twig to shoot leaves and roots: note that not two leaves are paired on stems (as it seems) but three: two ordinary ones (swimming leaves), and a third one which remains submersed and looks like it were a root.German name: Gewhnlich-SchwimmfarmID: Fischer & al., Exkursionsflora A/FL/SdT (2008 3rd); see also comments here