Embryological researches of an invasive plant Rudbeckia laciniata focused on the process of megasporogenesis, female gametophyte formation, and fertilization. A disturbed first meiotic division results in the formation of restitution nucleus. In some megaspore mother cells micronuclei or vacuoles were observed near the restitution nucleus. Different course of megasporogenesis led to the development of unreduced embryo sacs with various organization which is reflected in the embryo formation and capacity of seed germination. Our research confirmed the occurrence of hemigamy in the Polish representatives of R . laciniata. In spite of a reduced germination capacity of R . laciniata seeds, their production allows a long-distance dispersal and expansion of the species.