An organisation based at Esslingen, Germany, established to promote scientific investigation through the collection and distribution of exsiccatae and they also determined material of other collectors. Supported by the liberal patronage of William I, King of Württemberg (1781-1864), the directors of Unio Itineraria also raised funds through subscribers to the project. Several collectors are associated with the Unio Itineraria but the last major project was an expedition to Egypt and Ethiopia for which the collectors A. Wiest and G.W. Schimper were employed. Wiest fell ill with the plague and died in the winter of 1834-1835 at Cairo. Schimper, who had earlier collected for the organisation in Algeria (1831-1832), continued alone but requested additional funds. In 1835 the directors asked their subscribers to double their contributions in order to cover rising costs. Final dissolution of the enterprise occurred around 1842.