Flower morphogenesis and embriogeny in a bisexualPOPULUS DELTOIDES. —Flower organogeny and embryogeny in a bisexualP. deltoidesis studied. The most interesting stages of its sexual cycle: microsporogenesis, megasporogenesis, evolution of the female gametophyte, fertilization, endosperm and embryo development, are described. From the research appears that the flower is protrandrous and embryogeny is of the normal type as described by Nagaraj (1952) for the dioeciousP. deltoides.It is also pointed out that in the poplar studied the self-fertilization with production of high percentage (more than 65%) of fertile seeds is possible.