Molecular phylogeny of the fern family Dryopteridaceae inferred from chloroplast rbcL and atpB genes

Dryopteridaceae are a large family of leptosporangiate ferns exhibiting a rich diversity of morphological characteristics and generating many taxonomical controversies. Previous efforts to systematize this large group without a cladistic phylogenetic framework have not reached a consensus on circumscription of the family. In order to circumscribe the family and identify major groups within it, a broadscale phylogenetic analysis was conducted on these ferns plus representatives of putatively related families within the Eupolypods I clade. Two chloroplast loci, rbcL and atpB, were used in this study. A combined analysis of the two genes generated a well-resolved and strongly supported overall phylogeny of the Dryopteridaceae. The results indicate that the Dryopteridaceae form a monophyletic group with the exception of Didymochlaena, Hypodematium, and Leucostegia and are sister to a large clade comprising Lomariopsidaceae, Tectariaceae, Polypodiaceae, Davalliaceae, and Oleandraceae. Of the three previously unincorporated genera, Leptorumohra and Phanerophlebiopsis are nested within the genus Arachniodes, and Diacalpe is closely related to Acrophorus. The genus Pleocnemia, previously classified in Tectariaceae, clearly belongs in Dryopteridaceae and shows a close affinity to Lastreopsis. This study identifies four major lineages within the family, each strongly supported as a monophyletic group. Two large genera, Dryopteris and Polystichum, as traditionally defined, are shown to be polyphyletic and need to be revised in the future.