Nymphaea is a genus of hardy and tender aquatic plants in the family Nymphaeaceae. There are about 50 species in the genus, which has a cosmopolitan distribution.
The name Nymphaea comes from the Greek term "Νυμφαία", meaning "nymph". The nymphs in Greek mythology were supernatural feminine beings associated with springs, so the application of the name to delicately flowered aquatic plants is understandable. Despite its common name "water lily" (water-lily, waterlily), Nymphaea is not related to the true lily, Lilium.
The main plant is submerged, with large floating, plate-like leaves and showy flowers in many different colours produced in spring. Blue flowers are only produced by the tender species, e.g. N. caerulea. The fruits, containing many seeds, are produced in the autumn, and are also submerged. The leaves have a radial notch from the circumference to the petiole (leaf stem) in the center.