Gaspard Bauhin or Caspar Bauhin (; 17 January 1560 – 5 December 1624), was a Swiss botanist whose Pinax theatri botanici (1623) described thousands of plants and classified them in a manner that draws comparisons to the later binomial nomenclature of Linnaeus. He was a disciple of the famous Italian physician Girolamo Mercuriale and he also worked on human anatomical nomenclature.
Bauhin described the ileocecal valve in 1588—hence the name Bauhin's Valve or Valve of Bauhin—in the preface of his first writing, De corporis humani partibus externis tractatus, hactenus non editus. Linnaeus honored the Bauhin brothers Gaspard and Jean in the genus name Bauhinia.
Biography
thumb|right|Caspar Bauhin (1623), Pinax Theatri Botanici, page 291. On this page, a number of Tithymalus species (now [[Euphorbia) is listed, described and provided with synonyms and references. Bauhin already used binomial names but did not consistently give all species throughout the work binomials.]]
Jean and Gaspard were the sons of Jean Bauhin (1511–1582), a French surgeon to the King who had to leave his native country on becoming a convert to Protestantism. Gaspard was born in Basel. From 1572 he studied in his hometown, Padua, Bologna, Montpellier, Paris and Tübingen. He was awarded his medical doctorate at the University of Basel in 1581 and started giving private lectures in botany and anatomy. In 1582 he was appointed to the Greek professorship at the same university, as well as in 1589 to the new established chair of anatomy and botany. After the death of Felix Platter in 1614, Bauhin was made professor of the practice of medicine and city physician (). He was rector of the University of Basel in 1592, then again in 1611 and 1619; during the second rectorate the university tried in vain to win back from the city council the freedoms of 1460, which were lost in 1532.
As a impressive example of how independent scientific disciplines as botany were established at early modern universities, Bauhin systematically trained a whole generation of scholars to become qualified botanists, while the University of Basel became the undisputed center of the science in the German-speaking world around 1600. With regard to empirical research, Bauhin’s herbarium was with more than 4,000 species one of the most extensive of its time. Its scientific layout and design corresponded to Bauhin's plan of a 'general history' (or catalogue) of all existing plants. To further his career, young Bauhin built up a large network of correspondents. These connections also allowed him to collect foreign and exotic botanical samples. With more than 2,500 letters preserved, his correspondence is a larger source corpus than even that of famous contemporary botanist Carolus Clusius.
Following the Phytopinax (Basel, 1596), Bauhin’s earliest botanical publication, the Pinax theatri botanici (Basel, 1623, English: Illustrated exposition of plants) was a landmark of botanical history, describing some 6,000 species and classifying them.