Maurice Léopold Joseph Bouly de Lesdain (20 September 1869–3 January 1965) was a French botanist and lichenologist.
In 1910, Bouly de Lesdain defended his research thesis for a doctorate in Natural Sciences, which was about the lichens near Dunkirk.
In the following decades, he went on many excursions to collect samples for his personal herbarium, and maintained correspondence with several leading French and foreign lichenologists, with whom he exchanged publications and specimens.
He took refuge in Paris, where he joined the team of the cryptogam laboratory of the French National Museum of Natural History.
His main work in lichenology was the systematic study of lichens, determination and description of their rare and exotic forms, in particular those of Cuba, Guadeloupe, New Mexico, and the Kerguelen Archipelago.
[3] The genus Lesdainea (in the Lichens family) was named in his honour in 1910 by French explorer and diplomat François Jules Harmand.