Ono Ranzan

 was a Japanese botanist and herbalist, known as the "Japanese Linnaeus".
Ono was born in Kyoto to a courtly family, and studied in his youth under Matsuoka Shoan. In 1754, he opened a school of botanical pharmacology (pharmacognosy) which enjoyed considerable success, with over a thousand pupils enrolling. One student who studied under Ono at this time was Kimura Kenkadō. In 1799, he was given a post at the Seijūkan, the country's major government medical school in Edo. Here he worked extensively on a translation into Japanese of Rembert Dodoens' herbal guide, the "Cruydeboeck". Ono was familiar with Western herbalism (making use of the work of Johann Wilhelm Weinmann in his translation) and had studied both traditional Chinese medicine and Western medicine as well. Some of Ono's own works on Japanese botany were translated by the French botanist Ludovic Savatier.
In the early years of the nineteenth century, Ono travelled around Japan gathering information on botanical remedies, which culminated in his most important literary work, the , which was published in 1803. Despite Ono's knowledge of Western and Chinese botany, this was one of the first books in the Japanese natural sciences to advocate experimentation and research rather than reliance on the Chinese Classics.
Ono never married, but fathered a son with one of his household servants. His botanical work was continued by his grandson, Ono Motoyoshi. After his death in 1810 he was interred at Asakusa; however his remains were moved to Nerima in 1927 after the graveyard was damaged in the Great Kantō earthquake. The barberry species "Ranzania japonica" was named in his honour.