B. alta

terrestrial; Terrestrial herb to 2 m tall on very steep shady rocky slope. Locally common”). Terrestrial evergreen, regularly dioecious herb 1.5–2 m tall with hardly developed rhizome. Described plant belongs to group of south-east Asian species with tall, erect, stout, leafy, weakly branching stems. Among them, the new species has closest relation to Taiwanese B. chuyunshanensis C.-I Peng et Y.K. Chen and B. lukuana Y.C. Liu et C.H. Ou. Vietnamese plant differs from both these species in pistillate flowers having 2 sepals and 1 petal, in tall habit and glabrous leaves velvety green to grey-green above, often iridescent with green-blue. Like mentioned species, the new plant belongs to Sect. Diploclinium. Described plant may be easily recognized as tallest among Indochinese begonias, hence its species epithet.

• Classification: Species
• Plant Type: Rhizomatous
• Botanical Section: Diploclinium
• Origin: Asia, Vietnam
• Originator: Leonid V. Averyanov, H Q Nguyen
• Date of Origin: 2009