Devices which prevent both autogamy and Geitonogamy in flowering plant are:
1. In some species, pollen reiease and stigma receptivity are not synchronized. Either the pollen is released before the stigma becomes receptive or stigma becomes receptive before the release of pollen. It prevents autogamy.
2. Different positioning of the anther and the stigma. As a result, the pollen does not come in contact with the stigma of the same flower.
