Auxins—Charles Darwin (1809–1882) and his son, Francis (1845–1925), performed some of the first experiments on growth-regulating substances. They published their results in 1881 in The Power of Movement in Plants. In 1926 Frits W. Went (1903–1990) isolated the chemical substance responsible for elongating cells in the tips of oat (genus Avena) seedlings. He named this substance auxin, from the Greek term auxein, meaning “to increase.”