Phylogenetic relationships among Pteridaceae, including Brazilian species, inferred from rbcL sequences

Phylogenetic relationships among Pteridaceae were established using rhcL sequences, parsimony and posterior probabilities. The analyses involved 38 Pteridaceae species native in Brazil (12 of them endemic) and 81 species of Dennstaedtiaceae, Lindsaeaceae, Saccolomataceae (outgroups) and Pteridaceae. The resultant phylogeny comprehends five main clades: Platyzomatoideae-Pteridoideae-Taenitoideae; Ceratopteris-Acrostichum; Adiantoideae-vittarioids; Cheilanthoideae; Coniogramme-Cryptogramma-Llavea. The cladograms support the most recent classification of Pteridaceae and demonstrate the paraphyly of Cheilanthoideae and the unnaturalness of Ceratopteridoideae, Platyzomatoideae, Pteridoideae, and Taenitidoideae as traditionally defined. Adiantoideae can only be recognized if combined with the vittarioids. Several genera of Pteridaceae appear to be paraphyletic (e.g., as Cheilanthes, Doryopteris, Pellaea, Pteris), and new generic affinities suggested by consistent internal clades are proposed.