Complex morphological variation among Oenothera L. species from Brazil: A comprehensive analysis of genus diversity and new taxonomic circumscriptions

Abstract This study aimed to organize the Oenothera specimens found in Brazil through multivariate statistical analyses of morphological and environmental characteristics. Morphological analysis identified four distinct groups, while environmental analysis did not confirm this separation, suggesting that these groups are not limited to specific climate or altitude conditions. Although the environmental analyses were insufficient to delimit the species, the morphological analysis was essential in defining new circumscriptions. Each of the four identified morphological groups includes more than one currently accepted species, indicating the need to revise these delimitations. As a result, four species were recognized in Brazil: O. affinis, O. mollissima, O. indecora, and O. longiflora. Additionally, a new identification key was developed to identify Oenothera species in Brazil.