A Revised Circumscription of the Genera of the Fern Family Vittariaceae

Abstract

Based on phylogenetic analysis of rbcL gene sequences from species of Vittariaceae, Vittaria and Antrophyum are, respectively, polyphyletic and paraphyletic. New circumscriptions are developed with the goal of organizing the species into genera that are strictly monophyletic. Species of Vittaria are placed in three genera, Vittaria, Haplopteris, and Radiovittaria, reflecting new hypotheses of their phylogenetic relation- ships. Species with leaves 4 mm wide and paraphyses bearing narrow apical cells are retained in Vittaria. Old World species with funnelform terminal cells on paraphyses and distichous phyllotaxy are placed in Haplopteris, whereas those with funnelform terminal cells on paraphyses and spiral phyllotaxy are placed in the new genus Radiovittaria. Species of Antrophyum are divided between the monophyletic genera Antrophyumn and Scoliosorus. Antrophyum is restricted to paleotropical species with pluriseriate venation and globose- tetrahedral spores. Those species with pluriseriate venation (neotropical and African) and bilateral spores are assigned to Scoliosorus. The genera Ananthacorus, Anetium, Hecistopteris, Monogramma, and Polytaenium are retained and given clarified circumscriptions. A description of the Vittariaceae and a key to the genera of the family are presented; all genera are described and new combinations are made for a number of species.