Phylogeny of the Vittariaceae: Convergent Simplification Leads to a Polyphyletic Vittaria

The fern family Vittariaceae contains nearly 100 species of tropical epiphytes with simple leaf morphology. Different interpretations of the limited number of morphological characters has led to controversy in the generic and subgeneric taxonomy of the family. A 1380 bp fragment of the chloroplast-encoded rbcL gene was amplified and sequenced from species representing the genera and subgenera of the family. Parsimony analysis of the sequence data resulted in two most parsimonious trees which differ only in the position of the monotypic Ananthacorus. Each tree has two main clades which separate in a basal dichotomy. In the first principal clade, Ananthacorus appears either as sister to a clade containing Antrophyum ensiforme and A. boryanum or sister to a clade containing Vittaria lineata, V. graminifolia, V. dimorpha, and V. isoetifolia. The other principal clade is made up primarily of species divided into two sister groups. One of these groups contains only Old-World species of Vittaria while the other contains New-World species of Vittaria corresponding to Benedict's subgenus Radiovittaria with Hecistopteris sister to the latter clade. The rbcL topology is congruent with the character-state distributions for several morphological characters: Spore shape, paraphysis terminal cell shape, gametophyte gemma development, and leaf arrangement on the rhizome.