Augustin Pyramus de Candolle

Augustin Pyramus (or Pyrame) de Candolle (UK: /kænˈdɒl/, US: /kɒ̃ˈdɔːl/, French: [kɑ̃dɔl]; 4 February 1778 – 9 September 1841) was a Swiss botanist. René Louiche Desfontaines launched de Candolle's botanical career by recommending him at a herbarium. Within a couple of years de Candolle had established a new genus, and he went on to document hundreds of plant families and create a new natural plant classification system. Although de Candolle's main focus was botany, he also contributed to related fields such as phytogeography, agronomy, paleontology, medical botany, and economic botany.

De Candolle originated the idea of "Nature's war", which influenced Charles Darwin and the principle of natural selection. De Candolle recognized that multiple species may develop similar characteristics that did not appear in a common evolutionary ancestor; a phenomenon now known as convergent evolution. During his work with plants, de Candolle noticed that plant leaf movements follow a near-24-hour cycle in constant light, suggesting that an internal biological clock exists. Though many scientists doubted de Candolle's findings, experiments over a century later demonstrated that "the internal biological clock" indeed exists.

De Candolle's descendants continued his work on plant classification; son Alphonse and grandson Casimir de Candolle contributed to the Prodromus Systematis Naturalis Regni Vegetabilis, a catalog of plants begun by Augustin Pyramus de Candolle.

Augustin Pyramus de Candolle was born on 4 February 1778 in Geneva, Republic of Geneva, to Augustin de Candolle, a former official, and his wife, Louise Eléonore Brière. His family descended from one of the ancient families of Provence in France, but relocated to Geneva at the end of the 16th century to escape religious persecution.

At age seven de Candolle contracted a severe case of hydrocephalus, which significantly affected his childhood. Nevertheless, he is said to have had great aptitude for learning, distinguishing himself in school with his rapid acquisition of knowledge in classical and general literature and his ability to write fine poetry. In 1794, he began his scientific studies at the Collège de Genève, where he studied under Jean Pierre Étienne Vaucher, who later inspired de Candolle to make botanical science the chief pursuit of his life.

He spent four years at the Geneva Academy, studying science and law according to his father's wishes. In 1798, he moved to Paris after Geneva had been annexed to the French Republic. His botanical career formally began with the help of René Louiche Desfontaines, who recommended de Candolle for work in the herbarium of Charles Louis L'Héritier de Brutelle during the summer of 1798. The position elevated de Candolle's reputation and also led to valuable instruction from Desfontaines himself. de Candolle established his first genus, Senebiera, in 1799.

De Candolle's first books, Plantarum historia succulentarum (4 vols., 1799) and Astragalogia (1802), brought him to the notice of Georges Cuvier and Jean-Baptiste Lamarck. de Candolle, with Cuvier's approval, acted as deputy at the Collège de France in 1802. Lamarck entrusted him with the publication of the third edition of the Flore française (1805–1815), and in the introduction entitled Principes élémentaires de botanique, de Candolle proposed a natural method of plant classification as opposed to the artificial Linnaean method. The premise of de Candolle's method is that taxa do not fall along a linear scale; they are discrete, not continuous. Lamarck had originally published this work in 1778, with a second edition in 1795. The third edition, which bears the name of both Lamarck and de Candolle, was in reality the work of the latter, the former having only lent his name and access to his collection.

In 1804, de Candolle published his Essai sur les propriétés médicales des plantes and was granted a doctor of medicine degree by the medical faculty of Paris. Two years later, he published Synopsis plantarum in flora Gallica descriptarum. de Candolle then spent the next six summers making a botanical and agricultural survey of France at the request of the French government, which was published in 1813. In 1807, he was appointed professor of botany in the medical faculty of the University of Montpellier, where he would later become the first chair of botany in 1810. His teaching at the University of Montpellier consisted of field classes attended by 200–300 students, starting at 5:00 am and finishing at 7:00 pm.