TOUSSAINT, Dieudonne Gabriel (too-sang), Austrian naturalist, born in Vienna in 1717; died in Schoenbrunn in 1799. He was the son of a chancellor of the French legation, studied in Vienna and Prague, and, devoting himself afterward to botany, was made in 1759 imperial botanist by the Empress Maria Theresa, and shortly afterward appointed professor in the University of Prague. After the general peace of 1763 he was sent on a scientific mission to South America, and from 1764 till 1771 visited several of the West Indies. By special permission of Charles III. of Spain, he also went to Mexico and both Upper and Lower California, being detained a prisoner for several weeks by Indians in the neighborhood of the present city of Los Angeles. The valuable collections that he formed are preserved in the museum at Vienna. Toussaint's works include "Sertum Mexicanum " (Vienna, 1773);"Prodomus florae Mexicanae, exhibens characteres plant arum, nova genera, et species novas vel minus cognitas" (4 vols., 1773-'7) ; and "Bibliotheca botanica, continens genera plantarum in America Meridionali crescentium "(1779). His name has been given to a Brazilian plant of the family Polygalw.