Nicolas Joseph Von Jacquin, baron, an Austrian botanist, born in Leyden, Feb. 16, 1727, died in Vienna, Oct. 24, 1817. He was descended from a French family who had emigrated to Holland, was a friend of Gronovius, and completed his studies in Paris under Jus-sieu, and in Vienna, where he settled. In 1753 the emperor Francis I. commissioned him to lay out the garden at Schonbrunn; and from 1754 to 1759 he travelled in the West Indies and South America to collect new plants for it and for the imperial garden at Vienna. After his return he became professor in a provincial town, and subsequently he was professor of botany and chemistry at the university of Vienna, and was raised to the nobility in 1806. He discovered about 50 new genera of plants, some of which bear his name. His principal works are: Selectarum Stirpium Americana-rum Historia (fol., with 183 colored plates, Vienna, 1763 and 1781, and Mannheim, 1788); Hortus Botanicus Vindobonensis (fol., 1771, with 300 plates); Florae Austriacae (fol., 1773-'7, with 500 plates); Plantarum rariorum Horti Coesarei Schoenbrunnensis Descriptiones et Icones (9 vols, fol., 1797-1804); and Genitalia Asclepiadearum Controversa, published in 1811 in his 84th year. - His son Joseph Franz (1767-1839) was professor of botany and chemistry, and director of the botanical garden at Vienna, and the author of a manual of medical chemistry which had several editions.