French physician and botanist from Calais who was professor of medical natural history and director of the botanic garden at the Medical School (Faculté de Médecine) in Paris (1863-1895). His prolific work included the extensive Histoire des Plantes (1866-1895) and Dictionnaire de Botanique (1876-1892), both illustrated using woodcuts by Auguste Faguet (1841-1886). He was also Editor of the botanical journal Adansonia (1860-1870) and a founder of the Société Linnéenne de Paris (1866). His herbarium is maintained separately at P as one of the herbiers historiques. Genera named in his honour include Baillonacanthus Kuntze in the Acanthaceae, Baillonella Pierre in the Sapotaceae and Baillonia Bocq. in the Verbenaceae.