Unio Itineraria was a German scientific society which was based at Esslingen am Neckar in Baden-Württemberg, Germany. The organisation paid botanists to travel and collect plants, and sold the collections in large sets which often resemble exsiccatae.[1] The fourteen series with the title Unio itineraria are listed and described with bibliographic data in IndExs – Index of Exsiccatae. Rising costs associated with the Wilhelm Schimper expeditions led to the collapse of Unio Itineraria in 1842. Significant portions of the Unio Itineraria collections were directed to Herbarium Tubingense at the University of Tübingen in Baden-Württemberg[2]