Protandry is a condition in which male reproductive organ mature before the maturation of female reproductive organ. In plants, anther mature before the maturation of ovary in a bisexual flower. It is an adaptation to encourage cross-pollination in plants. Example: carrot.

Protogyny is an adaptation to encourage cross-pollination in a bisexual plant. It is the condition in which the female reproductive organ mature before the maturation of the male reproductive organ. Here, the ovary matures before the maturation of anther. Examples: apple, pear, etc.

Staminodes are sterile, non-functional and abortive stamen of a flower that does not produce pollen. These are located at the inner whorl of the flower. In some flowers, these are modified to produce nectar. Staminodes are present in the members of the family Caesalpiniaceae.

The pistil is the female reproductive structure in a flower that has different parts such as style, stigma and ovary. The sterile, nonfunctional and abortive pistil present in staminate flower is called pistillode. It has a simple, reduced structure and function.

Herkogamy is an outbreeding device of a bisexual flower that prevent self-pollination. In this condition, the pollen grains are unable to reach the stigma of the same flower because of spatial separation of the anthers and stigma. The anthers and stigma are arranged in different height or position is an example of herkogamy. It encourages cross-pollination. Example: Gloriosa superba.