Dichogamy is a cross-pollination promoting device. In this, the bisexual flower promotes cross-pollination by maturing the carpel and stamen at different times. It is of two types:
1. Protandry: when the stamens mature earlier than the carpels. It occurs in sunflower, jasmine, etc.
2. Protogyny: when the carpel mature earlier than the stamens. It occurs in rose, Ashoka, etc.