(a) The small green leaves at the base of flower are known as sepals.

The sepals protect the flower when it is in the form of a bud in the initial stage.

(b) The swollen basal part of the pistil is the ovary which bears the ovules .

The ovary contains tiny egg-like structures called ovules. The ovary may contain one or more several ovules. The ovules contain female sex cell of a plant.

(c) Stamen has two parts called anther and filament .

Stamen is the male part of a flower. It is made up of two parts: a filament and an anther. The stalk of stamen is called filament and the swollen top of stamen is called anther.

(d) The young unopened flower is termed as bud .

Bud is a knob-like structure that grows on a plant which later develops into a leaf, flower, or a shoot.