Class 11 Biology chapter 5 notes describe flower and its parts as follows.

In angiosperms, the flower is the reproductive unit. It's designed to be used for sexual reproduction.

Calyx:

Sepals are the members of the calyx, which is the flower's outermost whorl. Sepals are green, leaf-like structures that protect the flower when it is in the bud stage. The calyx can be either gamosepalous (all sepals are together) or polysepalous (all sepals are apart).

Corolla:

Petals make up the corolla. Petals are often vividly coloured to attract pollinating insects. The corolla, like the calyx, can be gamopetalous (petals joined) or polypetalous (petals separated).

Androecium:

Stamens make up the androecium. A stalk or filament and an anther make up each stamen, which represents the male reproductive organ. Each anther is normally bilobed, with two pollen-sac chambers in each lobe.

Gynoecium:

The female reproductive organ of the flower, made up of one or more carpels, is known as the gynoecium. The stigma, style, and ovary are the three sections of a carpel. The expanded basal portion of the ovary is where the elongated tube, the style, is located