Sunflower is not a flower.

Sunflower is not a flower but a type of inflorescence called capitulum in which the receptacle is flattened. The whole cluster of florets gets surrounded by bracts, known as an involucre. Two kinds of florets are recognised in sunflower:

(i) Ray Florets – Arranged on the rim of a receptacle having distinct yellow and strap-shaped petals. These florets are female, sterile and are always zygomorphic and may be arranged in one or more whorls.

(ii) Disc florets – Grouped in the centre, bisexual and actinomorphic.