DENGLER, NANCY1*, DENIS BARABE2, and JUDY CANNE-HILLIKER3. 1Department of Botany, University of Toronto, Toronto, Ontario, Canada, M5S 1A1; 2Montreal Botanical Garden, 4101 Sherbrooke E. Montreal, Quebec, Canada H1X 2B2; 3Department of Botany, University of Guelph, Guelph, Ontario, Canada N1G 2W1. - Generating diversity: The link between developmental morphology and phylogeny.
This symposium explores the developmental basis of evolutionary
diversification in plant morphology. Recent advances in moleculaar
systematics have provided a new perspective for understanding the
evolution of whole plant architecture, as well as the morphology of
individual organs. Phylogenies based on molecular and morphological
data sets constitute an evolutionary framework for the interpretation
of developmental observations on both vegetative and reproductive
features. This symposium presents six case studies that link
comparative developmental morphology and phylogeny. The striking
diversity of leaf form is one of the hallmarks of the flowering
plants. Two speakers will address the broad phylogenetic patterns of
this variation and its developmental basis. Plant architectural
features such as inflorescence morphlogy have diversified during the
evolution of the grasses. An understanding of the developmental basis
of these seemingly diverse patterns illuminates how this
diversification has occurred. Analyses of early floral ontogeny can
reveal how relative positions of floral parts and distinctive features
of gynoecia and ovules can be altered in derived groups in comparison
to ancestral ones at the level of genus and family. Characterization
of later stages of ontogeny, particularly the allometric expansion of
floral parts, demonstrates how diversification of features of floral
form related to pollinator visitation arises at the population and
species level.
Key words: Development, floral ontogeny, inflorescence architecture, leaf morphology, phylogeny