A water lily is a plant with large flat leaves and colourful flowers which floats on the surface of lakes and rivers. Any of various cosmopolitan aquatic herbs of the genus Nymphaea, having floating leaves and showy, variously colored flowers, especially N. odorata, with fragrant many-petaled white or pinkish flowers. Also called pond lily. water lilies a plant that grows in water, with large white or pink flowers. Any of the freshwater plants in eight genera that make up the family Nymphaeaceae, native to temperate and tropical regions. All are perennial except those in the genus Euryale. Most have rounded, floating, waxy-coated leaves growing atop long stalks that contain many air spaces. Thick, fleshy, creeping underwater stems are buried in the mud. In some species the leaves are also submerged. Showy, solitary, cuplike flowers with numerous spirally arranged petals are borne at or above the water surface on the long stalks. The genus Nymphaea includes the water lilies proper (or water nymphs). The common North American white water lily, pond lily, or toad lily is N. odorata. The lotus of ancient Egyptian art was usually the blue lotus (N. caerulea). The largest water lilies are two species that make up the tropical South American genus Victoria; the Santa Cruz water lily (V. cruziana) has leaves 2-6 ft (60-180 cm) in diameter. Water lilies provide food for fish and wildlife but sometimes cause drainage problems because of their rapid growth. Many varieties have been developed for ornamental use in garden pools and conservatories