In dioecious plants, male and female flowers are present on entirely different plants (dioecy), meaning each individual plant is either male or female . This condition successfully prevents both autogamy (pollination within the same flower) and geitonogamy (pollen transfer between different flowers on the same plant) . In contrast, monoecious plants like castor and maize only prevent autogamy, as geitonogamy can still occur between male and female flowers on the same plant .