Relative Position of floral parts on the thalamus:

The arrangement of floral leayes on the thalamus varies and is of the following types:

1. Hypogyny: When the various whorls of flower are arranged below the ovary, the carpel occupies the central position and other floral parts are borne below it in their respective whorls. Such flowers are called hypogynous e.g. China rose. In such a case ovary is called superior and other parts are inferior.
2. Perigyny: If the thalamus is flattened out to form a disc or a cup or flask shaped top, the gynoecium will be placed not on the top of the flower are usually inserted on the rim of the disc like thalamus. The gynoecium lies at the centre or tip of the thalamus and therefore considered as superior and remaining parts inserted on the rim  of the thalamus are described inferior.
3. Epigyny: In this type of thalamus is also a hollow cup or flask-like structure but the ovary is completely fused with the inner wall of the thalamus or hollow receptacle. The gynoecium is described as inferior while other floral parts are superior e.g. Sunflower. Coriander and Apple.