Anatomical and phylogenetic studies of Bactris and Bactridinae (Palmae: Cocoeae)

Anatomical study of leaves of representative species of Bactris and five other palm genera in the subtribe Bactridinae was carried out. Anatomical descriptions and additional morphological information were used in a phylogenetic analysis intended to provide new insights into the generic relationships within Bactridinae, specific relationships within Bactris, and the origin of B. gasipaes var. gasipaes, the only neotropical domesticated palm. The results of the anatomical descriptions showed that Bactris is more diverse than previously thought and five major leaf anatomical types can be identified. The phylogenetic analysis of anatomical and morphological data sets performed independently supports the monophyletic status of Bactridinae but failed to resolve relationships within Bactridinae and Bactris. Relationships are resolved only when the data sets are analyzed in a combined analysis. In this, all Bactridinae genera are monophyletic and new relationships are found among them. Bactris is monophyletic and its internal structure is composed of several clades. Only one of these groups correspond to formally segregated genera and the fragmentation of Bactris into several smaller genera is not supported. The place of origin, number of domestication events, and ancestors of the domesticated B. gasipaes var. gasipaes is not completely explained because the phylogenetic analysis was hampered by computational limitations.