Sébastien René Lenormand (2 April 1796, in Condé-sur-Noireau – 10 December 1871) was a French lawyer and botanist who specialized in the field of phycology.
In 1835 he quit the legal profession, moved to an estate called "Lénaudières", from where he focused his energies towards botany.
Although he never left France, he collected a large number of botanical specimens from naturalists who travelled to all parts of the globe.
[3][4] The algae genus Lenormandia (family Rhodomelaceae) was named in his honor by Otto Wilhelm Sonder in 1845.
[5][6] Specimens collected by Lenormand are cared for in herbaria worldwide, including the National Museum of Brazil herbarium (MN), the National Museum of Natural History, France (MNHN), the Harvard University herbarium, and the National Herbarium of Victoria (MEL), Royal Botanic Gardens Victoria.