Paraphyly of Cyrtomium (Dryopteridaceae): evidence from rbcL and trnL-F sequence data.

Cyrtomium is an Asiatic genus characterized by anastomosing veins with included veinlets, and comprises about 40 species. We sequenced rbcL and trnL-F sequences of 19 species of Cyrtomium and eight species from related genera in order to elucidate a molecular phylogeny of the genus using maximum-parsimony methods. The phylogenetic trees did not agree with traditional classifications. Cyrtomium was resolved as paraphyletic, and a clade including subseries Balansana of Cyrtomium, Cyrtogonellum, Polystichum subacutidens and Cyrtomidictyum (the BCPC clade) and a second one containing Cyrtomium sensu stricto were monophyletic. The results also implied that: (1) C. uniseriale was synonymous with C. balansae; (2) C. falcatum was likely the female parent of C. devexiscapulae; and (3) based on the rbcL and trnL-F sequence data, C. nephrolepioides and C. grossum were the female parents of C. shingianum and C. chingianum, respectively, although other evidence is needed for the confirmation of this hypothesis.