The term adhesion is used to mean the union of members of different floral sets, i.e., stamens with petals, stamens with carpels, stamen to perianth, etc. When the stamens attached to the petals are called epipetalous condition. Examples: Datura, Tobacco , etc.

Adelphy is a type of cohesion of stamens in which the stamens remain united by their filaments. Based on the number of bundles of stamens, it is classified into monadelphous, diadelphous and polyadelphous conditions. In monadelphous condition, all stamens are united together into a single bundle by their filaments. Anthers are free. In diadelphous condition, two bundles of stamens are seen and more than two bundles of stamens are found in the polyadelphous condition.

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.