Here's why:

* Actinomorphic flowers have radial symmetry. This means they can be divided into two equal halves by any plane passing through the center.

* Zygomorphic flowers have bilateral symmetry. They can only be divided into two equal halves by a single plane.

Hibiscus flowers have multiple petals that are arranged symmetrically around the center. You can cut them through the center in multiple ways and get two identical halves.