This flower contains numerous stamen. The stamen is monadelphous meaning that the filaments fused up to form a single tube, supporting many separated anthers.
The flower petals are usually crushed and being used as a black hair dye and shoe polish.
It has a colourful appearance which seems to be attractive to animals like birds. Yet, it also has an exposed anther seems to be specialised for wind pollination. Is it wind-pollinated or animal-pollinated or adopting both pollination methods?

A single flower of Hibiscus rosa-sinensis. It has an inflorescence of a ssingle flower. The leaves are alternate and simple. Instead of two layers of sepals, the outer layer actually is the epicalyx, which is the bract. Information on the internet has shown that this plant species has insect pollinators, such that they have adopted animal pollination. It could be used as a cooling herb which checks bleeding and soothes irritated tissues.