Collaborative Research: Morphological and Molecular Systematics of the Polypodiaceae and Grammitidaceae

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9807053 Smith This study is a three-way collaboration between Dr. Alan R. Smith at the University of California, Berkeley, and colleagues, Dr. Thomas Ranker at the University of Colorado and Dr. Christopher H. Haufler at the University of Kansas, that builds upon the previous successful collaborative efforts of fern researchers. This major research initiative will increase our understanding of the evolution and diversification of seedless vascular land plants. The goals of the proposed research are to explore groupings of related species of two advanced fern families (Polypodiaceae and Grammitidaceae), their evolutionary relationships and geographical histories, and morphological changes through time. The 1000 species of ferns are well represented in the tropical regions around the world and have relatively few temperate members, except for the genus Polypodium itself. Although ferns in general are ancient plants, recent analyses of the relationships of fern families suggest that species in these two families originated more recently than any other ferns. Such a recent origin suggests that a greater proportion of species in these two families should be extant than in other more ancient groups where extinction may have eliminated some groups; efforts to reconstruct the genealogical history of this group may be more successful than those of more ancient, derived groups. This research will consider a large number of species, and will attempt to sample all of about 50 recognized genera and subgenera from both the New World and Old World. Morphological characters and DNA sequences from at least three chloroplast genes will be used in analyses designed to construct hypotheses of the evolutionary history of these families. Quantitative techniques will be used for inferring the historical biogeography of the ferns.