Taxonomic notes on Drepanolejeunea pleiodictya (Marchantiophyta, Lejeuneaceae), a little-known Asiatic species

Drepanolejeunea pleiodictya Herzog (Lejeuneaceae), a rare and poorly known species from Java and Malaysia, was newly discovered in tropical montane forest in southern Thailand. It is distinguished by the ventral margin of the leaf lobe being usually irregularly dentate with one large tooth, the apex of the lobule having a straight or slightly curved tooth, ocelli 3−4(−5) seriate in the leaf lobe separated by 2−5 ordinary leaf cells, and gynoecia usually with a single pycnolejeuneoid innovation. This species is described and illustrated in detail, and its diagnostic characters and geographical distribution are briefly discussed.