In the 6th contribution, species are presented which are new to the flora of South Tyrol and such the occurrence of which is either reconfirmed or denied. Among the new species are the allochthonous Cardamine bulbifera, Erodium moschatum, Euphorbia davidii, Pennisetum alopecuroides, Spartium junceum, classified as casuals, and Eragrostis barrelieri, Vallisneria spiralis, and Viburnum tinus, considered as locally established. With regard to Festuca arundinacea subsp. uechtriziana and Pennisetum flaccidum, no statement can yet be made on the status. Recent records allowed to reconfirm the presence of Bifora radians, Samolus valerandi, and Vicia pannonica subsp. pannonica. However, in all cases there is no evidence of an established population. Festuca nitida, reported in the catalogue as a native species, and Sagittaria sagittifolia, reported as a locally occurring casual, have to be discarded.