Syngeny is a type of cohesion of stamens in which the members of the same floral sets are fused. In this case, the stamens remain united by their anthers and filaments are free. These stamens are called syngenesious stamen. Example: Sunflower.

In some flowers, the accessory organs such as calyx and corolla are not differentiable. This undifferentiated organ is called the perianth. The unit of perianth is called tepals. The term perianth comes in an appropriate manner wherein flowers either calyx or corolla is present and the term petaloid perianth or sepaloid perianth respectively applied. Example: tuberose.

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.