Iter trans Pyrenaeum

The Iter trans Pyrenaeum organized from 8 to 11 June 2014 allowed the achievement of a phytogeographic transect going from the south of Aquitaine in the north, to the region of Soria in the south, crossing the south of the Landes and Béarn in France, the Western Pyrenees and Ara-gon, the Province of Soria, La Rioja and Navarra in Spain. The report of this excursion is published in tribute to the memory of Professor Salva-dor Rivas-Martínez, an eminent scientist and specialist in the vegetation of the visited regions, who kindly supervised this excursion by sharing his experience and his immense knowledge. The itinerary, which straddles the Euro-siberian and Mediterranean biogeographical regions, offered the opportunity to study around thirty different vegetation series spreading from the mesomediterranean to the subalpine belt. A final syntaxi-nomical diagram recapitulates the syntaxa and a new alliance is described.