Nymphae caerulea

Description:  It is an aquatic plant of freshwater lakes, pools and rivers, naturally found throughout most of the eastern half of Africa, as well as parts of southern Arabia, but has also been spread to other regions as an ornamental plant. It was grown by the Ancient Egyptian civilization, and had significance in their religion. It can tolerate the roots being in anoxic mud in nutritionally poor conditions, and can become a dominant plant in deeper water in such habitats.

Flowering and Fruiting:  May to October.

Economic Importance:  Used as sleep aid and anxiety relievers.

Reference: https://en.wikipedia.org/wiki/Nymphaea_nouchali_var._caerulea