Developmental and Structural Section
Little, Damon .
Transfusion tracheid pitting in Cupressoideae with particular attention to Callitropsis and Cupressus (Cupressaceae).
THE degree of elaboration around leaf transfusion tracheid pits has been used as a taxonomic character within Cupressaceae particularly in Cupressoideae. Within Cupressoideae, the presence or absence of vermiform thickenings around the leaf transfusion tracheid pits has been used as part of an ensemble of characteristics to distinguish between several prominent genera (e.g., Cupressus versus Chamaecyparis). A survey of pit structure in Cupressoideae resulted in several possible cladistic codings. A series of phylogenetic analyses of morphological, anatomical, and DNA sequence data along with different codings of transfusion pit structure indicate that pitting characteristics are consistent with the inferred phylogeny to some degree, but these characteristics vary such that they cannot be used exclusively to delimit genera. Correlations among the size of vermiform thickenings, the occurrence of anastomosis between intracellular pits, and environmental factors (i.e., the amount of precipitation, seasonality of rainfall, and edaphic factors) are discussed.
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1 - The New York Botanical Garden, Lewis B. and Dorothy Cullman Program for Molecular Systematic Studies, 200th St. & Southern Blvd., Bronx, New York, 10458-5126, USA
leaf transfusion tracheid pitting
Presentation Type: Oral Paper:Papers for Sections
Location: 312/Bell Memorial Union
Date: Monday, July 31st, 2006
Time: 2:30 PM