Orchidaceae, typification, synonymization, systematics, taxonomy, volatile compounds.

Notylia Lindlley is a Neotropical genus with 45 accepted species. The small size of its flowers resulted in a large number of identification errors in herbaria and the incorrect description of numerous taxa. In addition, it was found that some names lacked synonymization and nomenclatural type designation, since some holotypes were destroyed at the Botanical Museum Berlin-Dahlem (herbarium B) during World War II, are lost or were not designated by the authors in the protologue. Furthermore, although it is known that Notylia is a genus with fragrant flowers that attract male Euglossini, little is known about the chemical composition of the floral perfumes of its species, since there was not even a complete record of the volatile compounds present in the perfume of a species of the genus, therefore, an in-depth phytochemical study was necessary. Therefore, the objective of this research was to carry out a taxonomic, nomenclatural and phytochemical study for the species of the genus Notylia. (Chapter I) A nomenclator with all published names for Notylia is presented. All 109 names were reviewed, for which it was necessary to designate 31 lectotypes and 20 neotypes. (Chapter II). The complex of N. platyglossa and related species was elucidated. The synonymization of N. peruviana, N. morenoi under N. platyglossa was proposed. Lectotypes were also designated for N. peruviana and N. morenoi, as well as neotypes for N. platyglossa and N. boliviensis. Additionally, N. boliviensis was distinguished from N. platyglossa and we validated the first record of this species for Brazil. (Chapter III). The first complete analysis of the chemical composition of the species N. fragrans and N. microchila was presented. A total of 82 compounds were identified and the results reveal significant differences in the abundance of compounds between the species. While N. fragrans has eugenol as its major compound, N. microchila exhibits high concentrations of (E)-β-Farnesene. (Chapter IV). A taxonomic review of the genus Notylia for Brazil was carried out. Thirty-three binomes were evaluated, of which 13 are recognized as species, two of which are endemic to the country. Notylia tenuis is reestablished at the species level and Notylia fragrans is confirmed as the accepted name. Additionally, the conservation status of the endemic species was presented. The present study with the genus Notylia led to a better understanding of the circumscriptions of the species, presented the real number of taxa, their delimitations and updated distributions. Therefore, it is extremely useful for future cytogenetic, biogeographic and phylogenetic works.