Abstract
In the course of this study no significant differences in the length of pollen-tubes of ecological types collected from natural stations (Trifolium pratense L. var. spontaneum Willk., T. hybridum L. and T. repens L,) were found as compared with their polyploid forms obtained in the experimental way. Disorders in fertilization, decay of unfertilized embryo sacs, and degeneration of embroys were observed more frequently on a percentage basis in the polyploid forms. Embryo and endosperm development were similar in the initial species and in the experimentally obtained polyploids.