Two new species of Typhonium (Araceae) with bicolored staminodes from Central Vietnam

Typhonium bicolor and T. culaochamense are described as new species endemic to Central Vietnam. They have bicolored staminodes (apex and base of different colors) which are formerly reported for six species, namely T. bachmaense, T. blumei, T. filiforme, T. flagelliforme, T. kbangense and T. ramosum. The first species is characterized by its oblong -elliptic and thick leaflets, yellowish and elliptic flattened anthers with lateral dehiscence, pink 6-7 mm long staminodes with a pale purple verrucose surface and a bright yellow and obtuse or truncate apex, oblanceolate ovaries and stipitate spadix appendix, and the second by its elongate and cylindrical tuber, variable leaf blades, longer spathe tube, basically externally green -brownish spathe limb, 3-5 rows of pistils, apically brownish dotted ovaries, disciform stigmas and recurved staminodes with a yellow apex. The ecology, distribution and assessment of conservation status of the two new taxa as well as a key to all known Typhonium species in Vietnam are provided.