A Comparative study of two endemic limestone begonia species of Northern Palawan.

Abstract

Begonia of the family Begoniaceae is widely used for ornamentation because of its distinctly patterned leaves and flowers. Currently, there are 104 known Philippine species, 14 of which are located in Palawan thriving on limestone topographies. In this study, we reported a Begonia species in El Nido, Palawan which is observed to be very similar to Begonia wadei in Coron Island, Palawan. Both species were found to be different from the other members of the Begonia section Baryandra because of their suffrutescent stem and found in limestone crevices splashed with seawater compared with the other members, which prefer shaded, moist primary forest. Based on comparison of morphological, anatomical and molecular data, Begonia sp. of El Nido, Palawan was found to be a different species from Begonia wadei. The two species were morphologically different due to the asymmetric, clasping leaves and undulate leaf margin of B. sp. as compared to the subsymmetric, non-clasping leaves and denticulate leaf margin of B. wadei. Anatomical analysis also showed significant differences in terms of thickness of protective covering, width of interfascicular parenchyma between vascular bundles, length of vascular bundles and length of xylem tissues. Lastly, cladogram showed that B. sp. and B. wadei belong to two separate clades. This set of evidence may eventually lead to the identification of Begonia sp. as a novel species.