Re-evaluating the Systematics of Using Restriction-Site Associated DNA-Sequencing.

The genus (Lycopodiaceae) includes four to five species across North America and East Asia. Species identification in is difficult due to limited or inconsistent characters. In addition, plants with intermediate morphologies regularly occur, potentially indicative of interspecific hybridization. To determine the species relationships in and investigate the existence of hybrids, we generated a draft genome assembly for and carried out double-digest restriction-site associated DNA sequencing (RADSeq) on 86 specimens. Our sampling includes all the described species and 11 individuals with intermediate morphology. We find that the genus can be divided into four clades that largely correspond to the described taxa, as well as evidence of interspecific hybridization. Within these clades, our STRUCTURE analysis suggests that there are multiple finer subgroups, with evidence of hybridization and introgression between these subgroups. Given the limited availability of specimens collected from Asia, the status of the various Asian species remains uncertain and will require further study. In summary, our study confirms several hybrid relationships in and provides a clear phylogenetic framework for future taxonomic revision.