Question

Flowers do not produce fruit then why they comes in angiosperms?

Answer 1

All angiosperms produce flowers. Flowers do not produce fruits if fertilisation does not occur.
Different plants adapt different techniques for propagation.A plant like Hibiscus does not produce fruits or seeds.That is because it propagates by producing roots on its stems.
The purpose of the fruit is for protecting the seed.If the seeds are not formed , fruits also cant be formed.
But all other charecetrs are same as the angiosperms.That is why plants like hibiscus, rose etc also come under angiosperms.