Ans. Sunflower is actually not a flower, but a bunch of flowers, altogether. Inflorescence is the term used for a bunch of exceedingly small flowers, for what it appears to be a single flower. These flowers are put on a receptacle in a special arrangement. This type of inflorescence of flowers is called capitulum.
These are some characteristics of capitulum: -
There are many tiny, sessile florets present on the receptacle.
The youngest florets are present at the center, while the oldest florets are at the periphery.
The receptacle is flattened.
There are two kinds of florets in a sunflower, viz. ray florets and disc florets.
Ray florets are present on the rim of the receptacle. These are of yellow colour.
Disc florets are present in the center. They are bisexual in nature and are actinomorphic.