Molecular phylogeography of the moss Tortula muralis Hedw (Pottiaceae) based on chloroplast rps4 gene sequence data.

Tortula muralis is a moss species of cosmopolitan distribution, for which we present chloroplast rps4 sequence data. The sequences provided a sufficiently high degree of divergence ( h = 0.878, theta = 0.00989 +/- 0.0000106, a total of 18 haplotypes for 49 accessions) for the degree of differentiation between regions from different continents to be investigated. In fact, 18.53 % of the variation found corresponded to differences between these regions, while 81.43 % was attributed to intra-region differences. Only the Japanese area differed significantly from other regions. Some haplotypes are found on several continents, while others are restricted to certain areas. Six of the seven sequenced plants from Japan belong to a haplotype only found there. The phylogenetic analysis suggests that Tortula muralis might be paraphyletic, with Tortula vahliana nested within the Tortula muralis clade. At present, it is not clear whether gene flow between the different clades of Tortula muralis is a continuing process or whether Tortula muralis is an example of cryptic speciation.