Chromosome Studies in Bignonieae (Bignoniaceae): The First Record of Polyploidy in Anemopaegma

Anemopaegma (Bignonieae, Bignoniaceae) includes 45 species distributed from Mexico to Northeastern Argentina. The genus is monophyletic and well supported by morphological and molecular characters. However, the delimitation of species within Anemopaegma is complex. In this study, we determined chromosome numbers and interphase nuclei structure for 5 shrubby species of Anemopaegma, 3 of which belong to the Anemopaegma arvense species complex. While most shrubby species analyzed were polyploids (2n=4x=80), polyploidy was not encountered among the climbing members of the genus. Furthermore, interphase nuclei was shown to vary among species. In particular, A. album was the only species that presented semi-reticulate interphase nuclei, while A. glaucum and A. scabriusculum presented areticulate nuclei. Anemopaegma acutifolium and A. arvense, on the other hand, presented an interphase nuclei structure that was intermediate between the areticulate and semi-reticulate types. Overall, our findings suggest that ploidy level may have had an important role in the diversification of the Neotropical genus Anemopaegma.