Ernest Saint-Charles Cosson (July 22, 1819 – December 31, 1889) was a French botanist born in Paris
Cosson is known for his botanical research in North Africa, and during his career he participated in eight trips to Algeria.
In several of these he was accompanied by Henri-René Le Tourneux de la Perraudière (1831-1861), whom he honoured in the naming of several species and genera (e.g., Perralderia, Galium perralderii).
In 1863 he was elected president of the Société botanique de France, and from 1873 to 1889, he was a member of the Académie des sciences.In 1882 Jules Ferry, as Minister of Public Instruction, decided to create a mission to explore the Regency of Tunisia.
The expedition was headed by Cosson and included the botanist Napoléon Doumet-Adanson and other naturalists.
In 1884 a geological section under Georges Rolland was added to the Tunisian Scientific Exploration Mission.
Rolland was assisted by Philippe Thomas from 1885 and by Georges Le Mesle in 1887.With Jacques Nicolas Ernest Germain de Saint-Pierre (1815–1882), Cosson published the influential Atlas de la Flore des Environs de Paris.