Based on the position of calyx, corolla and androecium in respect of the ovary on thalamus, the flowers are described as HYPOGYNOUS, perigynous and epigynous.
The flower is described as hypogynous if the gynoecium occupies the highest position while the other parts are situated below it.
Let's understand it differently.
When thalamus is curved outwards or elongated, the carpel occupies the top most position on it and the other floral members (sepals, petals, and stamens) are placed below them. This type of arrangement is termed as hypogyny.
The ovary is known as superior (having flower parts attached below the ovary).
Examples: Malvaceae, Annonaceae, mustard, china rose and brinjal.