Martín Sessé y Lacasta (December 11, 1751 – October 4, 1808) was a Spanish botanist, who relocated to New Spain (now Mexico) during the 18th century to study and classify the flora of the territory.
He visited Santo Domingo, Puerto Rico, and Cuba, where similar (though smaller) studies had already been undertaken, to collaborate and learn.
Back in New Spain, he was joined by a group of Spanish botanists selected by Casimiro Gómez Ortega, director of the Royal Botanical Garden of Madrid.
These included Vicente Cervantes, the first professor of botany in New Spain, who continued to live in the country until his death in 1829; José Longinos Martínez, who organized the Gabinete de Historia Natural, the precursor of the Museum of Natural History; Juan Diego del Castillo, pharmacist and botanist; and José Maldonado.
Various companies of scientists were sent to such widely separated destinations as the Pacific coast of Canada, the Greater Antilles, Yucatán, Nicaragua, and San Francisco.
Alexander von Humboldt and his botanist travelling companion Aimé Bonpland were able to examine some of Sessé's and Mociño's results in Mexico in the Museum of Natural History in Madrid before their 1799 departure on their five-year sojourn in Spanish America.
"[3] After the end of the expedition Sessé returned to Spain with his scientific collections to work on Flora Mexicana, but he died in Madrid in 1808 before publishing it.