Cytologie et histologie de la reproduction chez le <i>Nymphaea heudelotii</i>

The ontogenesis of reproductive cells has been cytologically analysed in Nymphaea heudelotii Planch.. family Nymphaeaceae, subclass Magnoliidae. Our observations of embryo sac development on sections differ from those made by Cook in 1906. Embryo sacs derive from a single functional megaspore and are four nucleate. After fertilization. the polar nucleus divides and successively generates two Storage tissues that are located in two separate chambers. Nucellar tissue, which is filling up with starch inclusions, then insures a storage function. This species possesses 14 bivalents at meiosis and 14 somatic chromosomes at the first mitosis of the pollen grain. A reorganization of amyliferous organelle aggregates has also been observed in microsporocytes.