Systematic studies on Philippine Alocasia (Schott) G. Don (Araceae)

The genus Alocasia in the Philippines was studied morphologically and anatomically (leaf). The pollen characters as well as the ecology, distribution and conservation were investigated. Phenetic and phylogenetic relationships were analyzed to derive the infrageneric classification of the taxa. Results showed that gross morphological characters can be used in delimiting taxa while leaf anatomy showed continuous variation. Pollen grains are inaperturate, bilateral and of echinate type. The combined morphology, anatomy and pollen characters showed a clear distinction on the ‘macrorrhizos’, ‘coriaceae’, ‘macrorrhizos’, odora’ and ‘longiloba’ group which correspond to the proposed classification of Hay (1991, 1998, 1999). Phylogenetic reconstruction showed that the Philippine Alocasia assemblage is not monophyletic, whereas A. zebrina appeared to be paraphyletic. The center of diversity of Alocasia is Mindanao and Luzon. The analyses suggest that A. zebrina is deeply rooted in New Guinea while all the remaining species are of West Malesian, Bornean, and Asian origin. A total of seventeen (17) species was recognized for the Philippines, one (1) of which was published already while two species were proposed as new to science, namely: A. calochora M.P. Medecilo & Madulid, sp. nov. prop. and A. marginatusa Medecilo, sp. nov. prop