Systematics of Grammitid Ferns (Polypodiaceae): Using Morphology and Plastid Sequence Data to Resolve the Circumscriptions of Melpomene and the Polyphyletic Genera Lellingeria and Terpsichore

Recent phylogenetic analyses of grammitid ferns (Polypodiaceae) have demonstrated that some genera recognized within this clade are not monophyletic. We focus on resolving the circumscriptions of some large Neotropical genera by focusing on a clade, identified in previous analyses, that includes the monophyletic genus Melpomene, plus portions of two polyphyletic genera, Lellingeria and Terpsichore. Phylogenetic analyses using chloroplast markers atpB, rbcL, and trnL-F, along with 109 morphological characters, resolve this ingroup as monophyletic and sister to a clade that includes Cerademia, Enterosora, and Zygophlebia. We use morphological characters included in the analysis to circumscribe clades. Melpomene is clearly monophyletic, but forms a polytomy with Lellingeria s. l. in a strict consensus of MP trees. Ingroup species of Terpsichore form three well supported monophyletic groups that together are paraphyletic with respect to Melpomene plus Lellingeria. Two clades corresponding to species groups of Terpsichore will be recognized as new genera.