Alexandre Louis Simon Lejeune

In 1801 he entered the school of medicine in Paris, but was subsequently forced to abandon his studies due to military conscription.

After finishing his military duties in late 1804, he relocated to Ensival as a physician.

[1] With Richard Courtois (1806–1835), he was co-author of "Compendium florae belgicae".

[2] He was a mentor to Marie-Anne Libert, who he introduced to Augustin Pyramis de Candolle.

[3] Libert named the genus Lejeunea (family Lejeuneaceae) in Lejeune's honor in 1820.