A new Begonia species (sect. Baryandra, Begoniaceae) from Batangas Province, Luzon Island, Philippines

Begonia tanauanensis is a newly described endemic species in B. sect. Baryandra from Tanauan City, Batangas, southern Luzon, Philippines. Morphological data shows this species resembles B. chingipengii, a species from eastern Luzon as both species have light pink flowers, fleshy green lamina, and boat-shaped bracts. However, B. tanauanensis does not have the prominent white midrib and veins in the adaxial leaf surface, ciliate hairs on leaf margin, strongly keeled stipules and tomentose hairs on the abaxial leaf surface and petioles of B. chingipengii. The plants were observed to have a restricted and severely fragmented distribution. Unfortunately, these observed populations are also affected by human activities and threat of volcanic activity of the nearby Taal Volcano. Because of these threats, we provisionally assess the species as “Critically Endangered” (CR) following the IUCN Red List Categories and Criteria.