New tuberous Araceae from Binh Thuan Province (South Vietnam)

Two species of the Araceae family, Typhonium praelongum (having tuber of blunt cone shape, very long (about 30 cm) sterile appendix of the spadix, horizontal yellow-orange staminodes with tops turning upwards and a glossy entirely papillate upper surface of the simple leaf blade) and Amorphophallus opalinus (having narrow rhizome-like tuber with enlarged basal part, staminodes at the base of male zone of the spadix, narrow spathe, large, broadly-conical with rounded apex, opalescent stigmas and white, one-seeded berries), are described as species new to science from South Vietnam. Detailed morphological descriptions, colour plates of the species and their habitats, phenology, distribution map, provisional conservation status, taxonomic comments and overview of the genera Typhonium and Amorphophallus in the Flora of Vietnam are provided.