XVI International Botanical Congess

We have undertaken a developmental study of endosperm in basal angiosperms. We focus on five taxa: Acorus calamus, Cabomba caroliniana, Ceratophyllum demersum, Illicium sp., and Platanus racemosa. Phylogenetically based analysis confirms that ab initio cellular endosperm is plesiomorphic for angiosperms. Aspects of this plesiomorphic pattern are maintained in the basal monocot, Acorus. Developmental transformations also occurred among magnoliids through modification of the basic ab initio cellular pattern. Free nuclear endosperm in Platanus may represent one of many separate origins of this character during early eudicot evolution. Our analysis provides critical insights into key ontogenetic transformations of endosperm associated with the early diversification of flowering plants.