Unio Itineraria was a German Scientific Society.
Supported by William I of Württemberg, Unio Itineraria was established to promote scientific investigation through the collection and distribution of determined (identified) plant specimens. The directors of Unio Itineraria which was based in Esslingen am Neckar raised funds through subscribers to the project to pay for expeditions and sold specimens as a dealership. The organization also sold birds, insects and libraries often as intermediaries and maintained agents.
Several collectors are associated with the Unio Itineraria notably the organizers Ernst Gottlieb von Steudel Christian Ferdinand Friedrich Hochstetter and the explorer collectors:-
The rising costs of the Schimper expedition led to the collapse of Unio Itineraria in 1842.