Ranunculales - a Basal Eudicot Perspective of Angiosperm Evolution
Hoot, Sara B. .
Evolution of Nonfloral Characters in Ranunculales.
In spite of the large amount of diversity present in Ranunculales, characters related to fruit, seed, and vegetative morphology, cytology, and biochemistry provide significant information about phylogenetic patterns in this important early-diverging eudicot order. The addition of morphological data to our DNA sequence data (atpB, rbcL to date) substantially reduces the number of trees recovered (>5000 to 74), improves resolution and, in some cases, branch support. When superimposed on the molecular tree, the CI (0.52) for the morphological characters is reasonable for this taxonomic level. Characters that are especially useful are: habit, breeding system (hermaphrodite, monoecy, dioecy), number and fusion of carpels, placentation type, fruit type, and endosperm development (nuclear or cellular). While many morphological characters exhibit substantial homoplasy at the ordinal level, they still improve resolution at the family level. For example, characters related to trichome type, micromorphology of leaf surfaces, chromosome size and number are especially useful within Ranunculaceae. The direction of evolution for a few key characters will be traced on the molecular phylogeny. There is a great deal of missing or unreliable data in our Ranunculales database to date; ongoing work in my lab to develop a reliable morphological (and molecular) database for the order will be briefly discussed.
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1 - University of Wisconsin-Milwaukee, Department of Biological Sciences, P.O. Box 413, Milwaukee, Wisconsin, 53201, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Stevens 2/Hilton
Date: Wednesday, July 11th, 2007
Time: 4:30 PM