[The herbariums from Spanish scientific expeditions in the New World].

The herbaria compounded by the botanical Spanish expeditions to the New world during the XVIIIth century constitutes one of the most important treasures of the Royal Botanical Garden from Madrid. These collections of dry plants document the existence of the species in time and in space, and they are essential resources for the botanical investigation. The specimens type and of reference of these collections are fundamental for the correct identification of each species and their varieties. They are used to give validity to the botanical investigation securing that one could repeat or compare with future investigations.