French botanist and physician, a pioneer in systematic botany, whose system of plant classification represented a major advance in his day and remains, in some respects, valid to the present time.

Tournefort's interest in botany began early, but only after the death of his father, who was forcing him toward the priesthood, was he able to drop theology and study botany. He became a physician to support himself but continued his botanical studies. In 1688 he received an appointment as professor at the Jardin des Plantes in Paris, a position he held until his death. He collected many plant species on scientific expeditions to the Pyrenees, Asia Minor, and Greece and acquired a wide reputation for his botanical works, particularly the beautifully illustrated Éléments de botanique (1694).

Tournefort placed primary emphasis on the classification of genera, basing his classification entirely upon the structure of the flower and fruit. He excelled in observation and description, and some of his generic descriptions are still acceptable. He was less innovative in theory, however, for he denied the sexuality of plants, and the classifications that he put forward above the level of the genus were often artificial. By his use of a single Latin name for the genus, followed by a few descriptive words for the species, he provided a major step in the development of the binomial nomenclature—that is, the use of a two-word Latin name to denote each species.