Augustin Augier's “Arbre botanique” (“botanical tree”) (1801), a diagram representing the natural order of plants in the shape of a family tree, is today a standard reference in histories of systematics and phylogenetic trees. The previously unidentified author was a nobleman from Saint-Tropez, a schoolteacher and a priest in the Société de l'Oratoire de Jésus et de Marie immaculée. His biography and two previously unnoticed publications, as well as his correspondence with the Institut national in Paris, are discussed. Knowledge of Augier's identity, his life and works sheds new light upon his taxonomic theories, and helps us to understand his “Arbre botanique”. Long before the tree was made into an icon of evolutionism, Augier used it to demonstrate the beauty and perfect order of divine creation.