Phylogenetic biogeography of the leafy liverwort <i>Herbertus</i> (Jungermanniales, Herbertaceae) based on nuclear and chloroplast DNA sequence data: correlation between genetic variation and geographical distribution

&lt;b&gt;Aim&lt;/b&gt; The cosmopolitan genus &lt;i&gt;Herbertus&lt;/i&gt; is notorious for having a difficult taxonomy and for the fact that there is limited knowledge of species ranges and relationships. Topologies generated from variable molecular markers are used to discuss biogeographical patterns in &lt;i&gt;Herbertus&lt;/i&gt; and to compare them with the geological history of continents and outcomes reported for other land plants. &lt;b&gt;Location&lt;/b&gt; Africa, Asia, Azores, Europe, southern South America, northern South America, North America, New Zealand. &lt;b&gt;Methods&lt;/b&gt; Phylogenetic analyses of nuclear ribosomal internal transcribed spacer and chloroplast (cp) &lt;i&gt;trn&lt;/i&gt;L–&lt;i&gt;trn&lt;/i&gt;F sequences of 66 accessions of &lt;i&gt;Herbertus&lt;/i&gt; and the outgroup species &lt;i&gt;Triandrophyllum subtrifidum&lt;/i&gt; and &lt;i&gt;Mastigophora diclados&lt;/i&gt; were used to investigate biogeographical patterns in &lt;i&gt;Herbertus&lt;/i&gt;. Areas of putative endemism were defined based on the distribution of species included in the analyses. Maximum parsimony analyses were undertaken to reconstruct ancestral areas and intraspecies migration routes. &lt;b&gt;Results&lt;/b&gt; The analyses reveal species-level cladograms with a correlation between genetic variation and the geographical distribution of the related accessions. The southern South American &lt;i&gt;Herbertus runcinatus&lt;/i&gt; is sister to the remainder of the genus, which is split into two main clades. One contains the Neotropical–African &lt;i&gt;Herbertus juniperoideus&lt;/i&gt; and the New Zealand/Tasmanian &lt;i&gt;Herbertus oldfieldianus&lt;/i&gt;. An African accession of &lt;i&gt;H. juniperoideus&lt;/i&gt; is nested within Neotropical accessions. The second main clade includes species that inhabit Asia, the Holarctic, Africa, and northern South America. Maximum parsimony analyses indicate that this clade arose in Asia. &lt;i&gt;Herbertus sendtneri&lt;/i&gt; originated in Asia and subsequently colonized the Holarctic and northern South America. An Asian origin and colonization into Africa is indicated for &lt;i&gt;H. dicranus&lt;/i&gt;. &lt;b&gt;Main conclusions&lt;/b&gt; The current distribution of &lt;i&gt;Herbertus&lt;/i&gt; cannot be explained by Gondwanan vicariance. A more feasible explanation of the range is a combination of short-distance dispersal, rare long-distance dispersal events (especially into regions that faced floral displacements as a result of climatic changes) extinction, recolonization, and diversification. The African &lt;i&gt;Herbertus&lt;/i&gt; flora is a mixture of Asian and Neotropical elements. Southern South America harbours an isolated species. The molecular data indicate partial decoupling of molecular and morphological variation in &lt;i&gt;Herbertus&lt;/i&gt;. Biogeographical patterns in &lt;i&gt;Herbertus&lt;/i&gt; are not dissimilar to those of other groups of bryophytes, but elucidation of the geographical ranges requires a molecular approach. Some patterns could be the result of maintenance of &lt;i&gt;Herbertus&lt;/i&gt; in the inner Tropics during glacial maxima, and dispersal into temperate regions in warm phases