French botanist. Growing up in Orléans, August de Saint Hilaire showed an early interest in natural history, especially entomology, but against his own inclinations was required to pursue a career in commerce alongside his maternal uncle who had fled to Hamburg during the Revolution. After a few years, he returned to France, where he applied himself to the study of botany, following the courses of Claude Richard, Antoine Laurent de Jussieu, and René Desfontaines. He moved to Paris to become an auditor of the council of state, but renounced the post after a visit to the Jardin des Plantes.
In 1816 the Duke of Luxembourg, who had been named French Ambassador in Rio de Janeiro, invited Saint Hilaire to join him on the voyage out and use the occasion to explore Brazil and Paraguay. During six years of exploration, Saint-Hilaire travelled approximately ten thousand kilometres around Rio de Janeiro, Espiritu-Santo, Minas-Gerais, Mato Grosso, Saint Paul, Saint Catherine, Rio Grande and the old missions in Paraguay and into Uruguay. He brought back to France an enormous collection of natural history specimens, which included approximately 7000 species of plants, 2000 birds, 1600 insects, 130 quadripeds, 55 fish, 35 reptiles, and diverse other animals. He also recorded the ethnobotany, customs, languages, commerce, industry, and habits of the people. The last two decades of his life were devoted to preparing his notes and collections for publication.
While working on the first volume of Flora Brasiliae Meridionalis, his exhaustion provoked a nervous breakdown, depriving him of speech and almost of sight, and obliged him to find refuge at Montpellier with his friends, the doctors Dunal and Lallemand. His health restored, he received help from de Jussieu and Jacques Cambassédes to complete his flora, the last volume of which appeared in 1825. This masterwork was followed by a number of important publications based on his travels and observations. In 1830 he was appointed Professor of Botany at the Sorbonne and, succeeding Lamarck, was elected to the Académie des Sciences. He described more than a thousand of the new species collected on his travels. Kunth named the genus Hilaria (Poaceae) in his honour. He died at Turpinière.
