Preliminary phylogenetic analysis of Pylaisia (Hypnaceae, Musci) and its relatives based on rbcL gene sequences

Phylogenetic relationships among the species of Pylaisia and its relatives are investigated using nucleotide sequences of the chloroplast gene, rbcL. Nucleotide sequences of rbcL were determined in fourteen samples (six species) of the genus Pylaisia, one sample of Giraldiella levieri, one sample of Platygyrium repens, and two samples of the Hookeriales as out groups. Phylogenetic trees were constructed by the maximum-parsimony (MP) method, neighbor-joining (NJ) method, and maximum-likelihood (ML) method; and these topologies were compared with each other depending on the ML criteria. The sequence comparison reveals that the sequence reported as Pylaisia polyantha in our previous study is not that of P. polyantha, but that of Platygyrium repens. The result of the present study indicates the following: (1) the genus Pylaisia looks homogeneous including Giraldiella levieri, although it could not be concluded whether the genus Pylaisia is monophyletic because of insufficient information, (2) Platygyrium is placed in the Sematophyllaceae, and then the subfamily Pylaisioideae M.Fleisch. is polyphyletic, (3) P. selwynii is phylogenetically distinguished from P. brotheri, and (4) the populations of P. polyantha from the Russian Far East are phylogenetically distinguished from North European ones.