Contribution to the floristic knowledge of the head of the Po Valley (Piedmont, north Italy)

In 2014, the annual field trip of the working group for Floristics, Systematics, and Evolution of the Italian Botanical Society was held in Piemonte (northern Italy), at the head of the Po Valley. This valley, at whose extremity is located the Monviso (3,841 m a.s.l.), belongs to the Cottian Alps about which very little is known from a floristic point of view. An inventory of the taxa of vascular plants collected during the field trip is reported here. The research led to the identification of 3,546 exsiccata, kept in nine public and nine private collections. A total of 669 taxa belonging to 79 plant families were recorded. Six taxa resulted endemic to Italy and three exclusive to Piemonte, while only nine alien species were detected; six taxa are new and five confirmed for the regional flora.