Parablechnum is a fern genus with 68 species, the most speciose of the Blechnaceae (the youngest fern family, together with the Onocleaceae). It is widely distributed in Central and South America and the Austropacific, with some representatives in southern Africa, Madagascar, and the Mascarenes. The interpretation of this distribution proved to be challenging, with conflicting evidence supporting Gondwanan vicariance and long-distance dispersal (LDD). To contribute to its resolution, we performed a molecular phylogeny based on 5 plastid markers of 127 accessions from over 60 taxa, the largest molecular sampling of the genus to date, and a molecular dating analysis. Our results support the monophyly of the genus and show a complex evolutionary history, probably due to events of hybridization, cryptic diversification, and rapid radiations. The origin of Parablechnum occurred around 38 million years BP, and probably reached its distribution by several LDD events. A high diversification is seen in America with active cladogenesis in the Late Miocene, coinciding with the Andes uplift, which could have triggered the American radiations. Very likely, a substantial cryptic diversity within the genus remains unaccounted. Further research including nuclear genes will be needed to fully resolve the phylogeny of this genus. To achieve this, we will perform a new reconstruction based on Hyb-Seq of the GoFlag 408 nuclear loci set. We will also carry out gametophyte cultures to describe their morphology, mostly unknown in this genus, and as a source of tissue with simplified genomes to investigate ancestry of allopolyploid hybrids.