Murdock, Andrew G. , Smith, Alan R. , Mishler, Brent D. , Renzaglia, Karen S. .
Evolutionary origin of the leptosporangiate ferns: sorting through conflicting evidence.
THE structure of the leptosporangium is so distinctive that a shared evolutionary history of the leptosporangiate ferns has never been doubted. One of the major unsolved mysteries in land plant systematics concerns the origin of this recognizable and highly successful group of plants. Molecular phylogenetic studies have generally supported the often-held hypothesis that Osmundaceae is sister to the rest of leptosporangiate ferns. However, the relationship of the leptosporangiate ferns to the eusporangiate families Marattiaceae and Ophioglossaceae, as well as to the enigmatically related Psilotaceae and Equisetaceae, remains frustratingly unresolved. Gene sequences from all compartments of the genome resolve conflicting topologies but are generally poorly supported; morphological investigations of living and fossil taxa have also been inconclusive to date, and homologies of characters are difficult to assess. In this study we incorporate data from multiple sources, including a multigene phylogenetic analysis, ultrastructure and morphology, the fossil record, and genomic-level data. We attempt to isolate sources of conflict and develop a robust hypothesis for the evolutionary origin of the leptosporangiate ferns and relationships amongst the early-branching fern lineages.
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1 - University of California, Berkeley, Department of Integrative Biology, 1001 Valley Life Sciences Bldg. #2465, Berkeley, California, 94720-2465, USA
2 - University of California, University Herbarium, Valley Life Science Bldg. 2465, Berkeley, California, 94720, USA
3 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, Illinois, 62901-6509, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, August 1st, 2006
Time: 8:30 AM