Recent molecular investigations have elucidated the generic and subgeneric relationships of most vittarioid genera (Pteridaceae sensu lato pro parte). However, the phylogenetic placement of Monogramma and Rheopteris remains to be examined. The inclusion of the monotypic Rheopteris in the vittarioids has been questioned since its description half a century ago, and although the placement of Monogramma within the vittarioids is well supported with nonmolecular characters, its relationship to other members of the vittarioid clade is unknown. We present new phylogenetic evidence from plastid rbcL sequence data indicating that Rheopteris cheesmaniae is well supported as a member of the vittarioid clade, and that Monogramma is polyphyletic. Data from molecular and nonmolecular characters suggest that a clade containing Rheopteris and part of Monogramma (i.e. those species sometimes recognized in the genus Vaginularia) represents the earliest diverging lineage within the vittarioids, and that remaining members of Monogramma are derived from within Haplopteris. Our study supports the separation of Vaginularia from Monogramma sensu stricto.