A new record of Begonia aptera in Southern Mindanao: the second species of Begonia sect. Platycentrum recorded from the Philippines

Begonia aptera was recently found during expeditions in the Matutum and Melibengoy mountains in South Cotabato province, southern Mindanao island, Philippines. The identification of the species was affirmed by the morphological similarities of the samples to specimens from the neighbouring island of Sulawesi in Indonesia. Begonia aptera is a member of the Begonia longifolia complex by having berry-like dull green, rhomboidal to spherical fruits with three locules, axillary, dichasial inflorescense, 4-tepaled male and 6-tepaled female flowers. Begonia aptera is distinct by having broadly elliptic leaves with bi-tooothed, serrate margins. This is just the second member of Begonia sect. Platycentrum in the Philippines, the only member of this section being B. halconensis endemic to Mindoro Island, with all other Philippine Begonia falling into sections Petermannia and Baryandra. It is proposed that the species be declared as vulnerable in the Philippines due to the fragmented population observed and potential threats to the observed populations.