Adolphe-Théodore Brongniart was a French botanist who lived form 1801 to 1876.Brongniart's pioneering work on the relationships between extinct and existing plants has earned him the title of father of paleobotany. His major work on plant fossils was his Histoire des végétaux fossiles (1828–37). He wrote his dissertation on the Buckthorn family (
Rhamnaceae), an extant family of flowering plants, and worked at the Muséum national d'Histoire naturelle in Paris until his death. In 1851, he was elected a foreign member of the Royal Swedish Academy of Sciences. This botanist is denoted by the author abbreviation Brongn. when citing a botanical name.
In 1822 he published a paper on the classification and distribution of fossil plants.
It is of especial botanical interest, because, in accordance with Robert Brown's discoveries of the fundamental difference between Gymnosperms and Angiosperms, the Cycadeae and Coniferae were placed in the new group the gymnosperms. In Brongniart's Histoire des végétaux fossiles attention was also directed to the succession of forms in the various geological periods, with the important result that in the Palaeozoic period the
Pteridophyta are found to predominate; in the Mesozoic, the Gymnosperms; in the Cenozoic, the Angiosperms, a result subsequently more fully stated in his Tableau des genres de végétaux fossiles. But the Histoire itself was not completed; the publication of successive parts proceeded regularly from 1828 to 1837, when the first volume was completed, but after that only three parts of the second volume appeared. Apart from his more comprehensive works, his most important palaeontological contributions are perhaps his observations on the structure of the treelike lycopod, Sigillaria, an extinct plant related to the living club mosses, and his researches (almost the last he undertook) on fossil seeds, of which a full account was published posthumously in 1880.