The use of medicinal plants for the treatment of diseases that attackhuman beings has been a practice for centuries and it is seen as one of themain therapeutic resource in many communities and ethnical groups,especially in developing countries. In Brazil, the economic potential of thegermoplasm of medicinal plants is a wealth to be used and preserved. Nativeand exotic species are used medicinally in Brazil. Among them, Aloysiagratissima (Gill et Hook) Tronc. (native) and Aloysia triphylla (L’Her.)Britton (exotic) both from Verbenaceae Family are highlighted. In this studythe meiotic behavior and pollen viability in populations of these species ofthe genus Aloysia from Rio Grande do Sul State were analyzed.Inflorescences of three populations of A. gratissima and one of A. triphyllawere collected in their native local, fixed in absolute ethanol glacial aceticacid (3:1) for 24 hours at room temperature, and after that maintained inethanol 70% until use. The chromosomal meiotic behavior and pollenviability analysis was performed with anthers by using the squashingtechnique, and staining in orcein acetic 2%. Our results show that occurreda good meiotic stability and a high viability of the pollen grains in the studiedpopulations of A. gratissima and A. triphylla. And more, that both speciespresent the gametic number n=18, allowing us to suggest the somaticnumber of 2n=36 chromosomes.
