Rolf Nordhagen (21 October 1894 – 8 March 1979) is a Norwegian botanist.
He was born in Kristiania as a son of artist Johan Nordhagen (1856–1956) and Christine Magdalene Johansen (1858–1933). He was a brother of Olaf Nordhagen. In August 1925 in Oslo he married Elisabeth Marie Myhre (1900–1979). Their son Per Jonas Nordhagen was a notable art historian.[1]
He finished his secondary education at Kristiania Cathedral School in 1912 and took the cand.real. degree in 1918. He worked as an assistant in the Botanical Garden in Kristiania from 1915 to 1920, was a research fellow at the Royal Frederick University from 1920 to 1925 and took the dr.philos. degree in 1922 on the thesis Kalktufstudier i Gudbrandsdalen, about limestone tuff. He was a teacher at the Norwegian College of Agriculture from 1924 to 1925, professor at Bergen Museum from 1925 to 1945 and professor at the University of Oslo from 1946 to 1964. He was the manager of the Botanical Garden in Bergen, and the Botanical Garden and Museum in Oslo.[1]
His fields were phytomorphology, phytosociology and phytogeography. He was also known to draw from humanist subjects such as philology, ethnology and history. His first magnificent work was Die Vegetation und Flora des Sylenegebietes, about the flora of Sylane, released by the Norwegian Academy of Science and Letters in 1927–1928. Versuch einer neuen Einteilung der subalpinen-alpinen Vegetation Norwegens came in 1936. His main work was Sikkilsdalen og Norges fjellbeiter. En plantesosiologisk monografi, released in 1943. More popular releases were the text volume of Norsk flora in 1940 and Våre ville planter. The latter book was released in eight volumes between 1950 and 1958, and he contributed with four authors: Lagerberg, Holmboe, Du Rietz and Nannfeldt.[1]
Nordhagen was a member of the Norwegian Academy of Science and Letters from 1923, of the Royal Norwegian Society of Sciences and Letters from 1952, and of academies in København, Helsinki, Uppsala, Stockholm, Göteborg and Lund. He received an honorary degree at Lund University in 1957, and was decorated as a Knight, First Class of the Royal Norwegian Order of St. Olav in 1957. He died in March 1979 in Oslo.[1]