living plants prepared in the field by accompanying artists. In 1793 Castillo died in Mexico, after he had written Plantas descritas en el viaje de Acapulco. The genus Castilla was named for him by Vicente Cervantes. Although the works of these botanists ended in 1803, it was not until the 1880s that their work was published. 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. However, they did not actually meet Sessé and Mociñno; Humboldt said, "circumstances prevented me from benefiting from the advice of these distinguished scientists, whose insights could have been very useful to me." Afterwards 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. The scientific collections are held by the Royal Botanical Garden of Madrid (about 7100 herbarium sheets with 200 genera and 3500 new species of plants). The great impact that the results of the expedition had on the botanical community has been documented by the botanical scholar Rogers McVaugh, an expert on the flora of Mexico. The paintings remained in the possession of Mociño, who accompanied Sessé to Spain after the expedition, but they appeared lost after his death in 1820 in Barcelona, where he settled after living in France and Switzerland during periods of political upheaval in Spain. They had become part of a private library, where they remained unrecognized for their significance until 1980. The Hunt Institute for Botanical Documentation purchased the set, comprising ca. 1800 botanical and ca. 200 zoological subjects, in 1981 from the Torner family. The illustrations are now accessible for study at the Hunt Institute and are available online. The plant genera Sessea, Sesseopsis, Mocinna, Mozinna, and Mocinnodaphne are named in honor of the expedition leaders. Other expeditions The four expeditions authorized by King Charles III to the Spanish colonies were those of Hipólito Ruiz López and José Antonio Pavón to Peru and Chile (1777–88); José Celestino Mutis to New Granada (1783–1808); Juan de Cuéllar to the Philippines (1786–97); and Sessé y Lacasta to New Spain (1787–1803). See also Jean-Louis Berlandier. Publications Sessé, M. y J.M. Mociño, "Flora Mexicana", in La Naturaleza (2nd series, 1891; 2nd