Additions to Podostemaceae Subfamily Podostemoideae of Laos

Abstract

Based on recent collections, Hydrobryum luangnamtaense (sp. nov.) and Thawatchaia laotica (sp. nov.) endemic to Laos, and H. japonicum, Polypleurum longistylosum and Paracladopus chanthaburiensis, all subfamily Podostemoideae, are reported as new to the flora of Laos. As a result, 20 species in six genera of Podostemoideae are known to occur in Laos. In total, Laos harbors 35 species in nine genera of the family Podostemaceae and is the second most species-rich country in Southeast Asia. A key to the genera and a key to the species of Podostemoideae in Laos is updated.