The Evolution of Ericales: Recent Insights using both Morphology and Molecules
Schönenberger, Jürg .
Comparative floral structure of Polemoniaceae and Fouquieriaceae in light of their phylogenetic position in the Ericales.
IN recent phylogenetic analyses based on molecular data, Polemoniaceae and Fouquieriaceae form a strongly supported clade within the asterid order Ericales. Although a possible closer relationship between the two families was suggested by several earlier authors, the two families were generally placed far from each other in pre-molecular times: Fouquieriaceae mostly in the dilleniid order Violales and Polemoniaceae in the asterid order Solanales. Arguments for such a disparate position of the two families were mainly based on differences in floral structure and embryology including the number of stamens, integument number, and endosperm formation. In this study, floral morphology, anatomy, and histology of selected representatives of the two families are compared and earlier work of the two families is reviewed and discussed in the current phylogenetic framework. The flowers of both families are characterized by a persistent calyx, a strongly sympetalous corolla, stamens attached to the corolla tube, and a tri-carpellate gynoecium. Some special floral features occurring in both families include free or almost free sepals, the presence of stomata on the calyx, anthers with a sterile connective tip, unicellular or uniseriate hairs on the filaments, a symplicate upper- and a synascidiate lower zone in the ovary, a stylar canal, and winged seeds. While the results of this investigation further support the close relationship of Polemoniaceae and Fouquieriaceae, they also emphasize that it is necessary to abandon preconceptions about the “importance” of certain characters, which turn out to be more homoplasious than previously thought. This study is part of a broader comparative investigation of floral morphology in the Ericales.[c.e.:srb]
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1 - Stockholm University, Department of Botany, Lilla Frescativägen 5, Stockholm, SE-10691, Sweden
Presentation Type: Symposium or Colloquium Presentation
Date: Monday, July 31st, 2006
Time: 11:45 AM