Dissertation Research: Phylogeny of the Vittariaceae Ferns

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Graduate student Edmund Crane, under the supervision of advisers Jonathan Wendel and Donald Farrar at Iowa State University, seeks to clarify the taxonomic delimitation of species and genera in the tropical fern family Vittariaceae and to infer a phylogenetic framework for the relationships among these taxa. The phylogenetic study will focus both on morphological features of these ferns and on DNA sequence data from chloroplast genes. The ferns are mostly tropical epiphytes, a group little studied with respect to DNA variation within and among species. Geographic outliers include the strange "Appalachian gametophyte," Vittaria appalachiana, which is widespread in the eastern U.S. but found solely as the asexual, clonal haploid stage or gametophyte and not known in the wild in the sexual, diploid spore-forming stage. Gene sequence data from samples representing a wide range of fern families will be analyzed to determine the likely genealogical position of the Vittariaceae among the leptosporangiate ferns. The results of the interfamily analysis will then be used to assess the likely derivation of morphological traits within the Vittariaceae. Both morphological and molecular datasets will be integrated in the interpretation of evolutionary pathways in these plants.