Developmental and Structural Section
Schoenenberger, Juerg , Von Balthazar, Maria .
Comparative floral structure and systematics in the balsaminoid clade (Ericales).
The balsaminoid clade (Balsaminaceae, Marcgraviaceae, Tetrameristaceae) has been identified as the first-diverging lineage of the asterid order Ericales and the monophyly of the clade is strongly supported in molecular phylogenetic studies. Interfamilial relationships, however, are still problematic, apparently due to conflicting phylogenetic signals from chloroplast and mitochondrial sequence data. While a closer relationship of Marcgraviaceae and Tetrameristaceae had been recognized for a long time, the systematic position of Balsaminaceae was much debated in pre-molecular times. It is therefore not surprising that non-molecular synapomorphies for the balsaminoids have largely been lacking in the past. In order to test conflicting hypotheses about interfamilial relationships and in order to search for potential synapomorphies for the clade as a whole, we have comparatively studied floral morphology, anatomy and histology in representatives of all three families. We find that the entire clade is strongly supported by the shared presence of series of characters including thread-like structures on anthers, punctiform stigmas, mucilage in the ovary, as well as several histological features. In addition, a sister-group relationship between Tetrameristaceae and Balsaminaceae is supported by the partial postgenital fusion of filaments and ovary and a distinctly star-shaped stylar canal.
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1 - University of Vienna, Department of Structural and Functional Botany, Rennweg 14, Vienna, 1030, Austria
2 - University of Vienna, Department of Systematic and Evolutionary Botany, Rennweg 14, Vienna, 1030, Austria
Presentation Type: Oral Paper:Papers for Sections
Location: 551A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 11:45 AM