In a self-pollinated bisexual flower of a plant, the probability of fruit set is far greater than a dioecious plant. The transfer of pollen to stigma of flowers is easier in self pollinated bisexual plants, than the dioecious plants. It is so because the anther and stigma lie close to each other and pollination is not effected even in the absence of pollinator. But in dioecious plants as the anther and stigma lie away from each other pollinator is necessary to bring about effective pollinator.