Abstract
We address phylogenetic relationships of Acrolejeunea and Trocholejeunea, two putatively related members of Lejeuneaceae subfam. Ptychanthoideae, by using nuclear (ITS) and chloroplast (rbcL, trnL-F) DNA regions. Bayesian, likelihood and parsimony phylogenetic analyses of a broad sampling of the two genera resolved Acrolejeunea as monophyletic. The species of Acrolejeunea were resolved in five clades, which partly correspond to previously described sections. Trocholejeunea was nested in Acrolejeunea as a sixth, monophyletic lineage. Based on our molecular-phylogenetic results, the species of Acrolejeunea are arranged in six sections including two new ones, sect. Recurvatae sect. nov. for A. recurvata from subtropical Asia and sect. Trocholejeunea (Schiffn.) stat. nov. The five species of Trocholejeunea are transferred to Acrolejeunea, which becomes a pantropical genus of 21 species (including a fossil one). New lectotypes are designated for A. infuscata and A. sandvicensis.