Jean Louis (1903 - 1947) was an agronomic engineer (Gembloux 1925) with a doctorate in natural sciences (Louvain 1954). After a first position (1929-1931) in agronomy in the Congo, he held a botanical position in the Yangambi Station of the INEAC, on the equator (1935-1939).
Here he made the finest and most important botanical collections ever made in the Congo Basin. His 17,000 specimens were collected with numerous duplicates and are thus present in many institutes with a tropical African interest; two sheets of every number are present at BR. His labels were made with utmost care and contain very detailed field observations. Many specimens were made from numbered trees in observation, so allowed him to collect flowers and fruits from the same individual.
His publications are mainly devoted to vegetation studies. In 1939 Louis became professor at the agronomical institute in Gembloux, a chair that he held until his premature death in 1947.