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Adiantum consists of about 150-200 species mostly with a pantropical distribution, yet the classifications of Adiantum have been based primarily on regional studies. Confounding the clarity of reconstructing the evolutionary history of Adiantum is that previous molecular phylogenetic studies suggest that a separate and distinctive clade, the vittarioids, may be derived from within Adiantum. Five plastid markers (atpA, atpB, rbcL, trnL-F and rps4-trnS) are employed to assess the monophyly of Adiantum, and construct the molecular phylogeny of Chinese Adiantum. Our analyses support the monophyly of Adiantum. All temperate Adiantum species form a clade nested within the pantropical grade, suggesting a tropical origin of Adiantum. Six main clades are supported within Chinese Adiantum, which are only partially consistent with Lin's classification of the genus. Series Caudata is polyphyletic with series Gravesiana nested within one subgroup of series Caudata. The prolonged whip-like stolon at the apex of the fronds is the defining character for series Caudata, but it may have evolved multiple times. Adiantum reniforme with the simple fronds is sister to series Venusta, which has a decompound lamina with many flabellate to cuneate segments. Series Veneri-capilliformia is not monophyletic, with A. capillus-veneris sister to series Flabellulata except for A. diaphanum, and A. edentulum sister to series Pedata. Series Flabellulata is biphyletic with A. diaphanum nested within the pantropical grade. The phylogeny suggests that convergent evolution in frond architecture has occurred in Adiantum.

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.