Developmental and Structural Section
Matthews, Merran L. , Endress, Peter K. .
Malpighiales: comparative floral structure and systematics in Rhizophoraceae s.l (Rhizophoraceae, Erythroxylaceae) and potentially associated families.
Malpighiales (rosids) represent the largest angiosperm order in terms of number of families. However poor molecular resolution plus limited structural knowledge of many of the families currently limit our ability to characterize the order. In an attempt to partially rectify this problem we have begun comparative floral structural studies which focus upon well supported clades within the order with the overall aim of compiling a list of floral features which characterize individual clades, and eventually the entire order. Rhizophoraceae s.l. represent one such clade and include Rhizophoraceae (‘mangrove’ family) and Erythroxylaceae (‘coca’ family). Additionally, recent molecular studies have weakly suggested the association of this clade with several other families. Using both serial microtome sections and SEM studies of flowers we aim to determine whether shared, special floral features exist which support the current relationships suggested by molecular studies. To our knowledge this is the first detailed floral comparative study combining these families. Preliminary results support Rhizophoraceae s.l., including some quite special floral features such as exceedingly elaborate conduplicate petals enwrapping a single stamen or groups of stamens, and crassinucellar ovules (and not incompletely tenuinucellar or weakly crassinucellar) with an endothelium, which is a rare combination of features in ovules of Malpighiales. Additional shared features that are also found elsewhere within Malpighiales include gynoecia with free styles and a dorsally bulged-up ovary, epitropous ovules with an obturator and a micropyle formed by the inner integument. Additionally, as this work is part of a larger project on rosids, floral features from this clade that appear to be more widespread will also be addressed.
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1 - University of Zurich, Institute of Systematic Botany, Zollikerstrasse 107, Zurich, ZH, 8008, Switzerland
Presentation Type: Oral Paper:Papers for Sections
Location: Boulevard C/Hilton
Date: Tuesday, July 10th, 2007
Time: 11:00 AM