Johan Fredrik Wallenius

Johan Fredrik Wallenius (14 August 1765 – 12 January 1836) was a Finnish physician and botanist.

Wallenius was born in Åbo to mathematics professor Martin Johan and Renata Frosterus. He graduated from the Åbo secondary school. He studied medicine at Stockholm and received a medical license in 1785 under Johan  Johansson  Haartman  (1725–1787). He wrote a thesis under by Professor Carl Niclas Hellenius on supplementary plant foods for use during years when crops failed in 1782. He practiced medicine at Häme (1786–94) and then at Uusimaa (1794–1800). He became a demonstrator of botany at the Åbo Akademi 1800–05 after  Ander Dahl  (1751–1789) where he was to instruct students of medicine on medicinal plants. He later became a secretary of the Finnish Economy Society from 1800 to 1805 and its chairman from 1812 to 1813. He supervised 50 doctoral students including P.U.F. Sadelin. Wallenius died in Turku from dropsy.