Abstract
Two new species of Diplobryum are described from Laos, bringing the number of species in the genus to four. Diplobryum vientianense (n. sp.) resembles D. minutale in the foliose root and longitudinally split spathella. Diplobryum koyamae (n. sp.) is similar to D. ramosum in the long, ramified, flower-bearing, floating root. In root features D. koyamae is also similar to some species of Polypleurum. The phylogeny of the diversified genus Diplobryum remains uncertain. Recent collections and a comparison of Podostmaceae in Thailand and Laos indicate the necessity of further field research to better understand the flora and taxonomy of the family of Laos. A list of the species of Laos Podostemaceae is provided.
