Based on the position of calyx, corolla and the androecium in respect of ovary on the thalamus, flowers may be of three kinds :
(a) Hypogynous flower: Gynoecium located at highest position and rest whorls of flower lies below it e.g., Mustard.
(b) Perigynous flower : The gynoecium is situated in centre and other parts of flower lie on the rim of thalamus almost at same level. Ovary is half inferior e.g., Rose.
(c) Epigynous flower: The margins of thalamus grows
upwards enclosing the ovary fully and getting united to it, the rest parts of the flower arise above the ovary e.g., Guava.