Each of the four stamps depicts a close-up of the flower of one of four classic garden water lilies. Water lilies are aquatic herbs that live in both temperate and tropical climates around the world; they are found in still freshwater habitats. There are more than 50 species in the water lily family (Nymphaeaceae) and hundreds of hybrids.

The flowers of the hardy water lily sit at or slightly above the water’s surface; the flowers of tropical water lilies, which produce more blossoms each season than the hardy variety, are held aloft on stems several inches from the surface.

Although delicate looking, the flowers are tough, and in the United States., hardy water lilies grow well in most of the USDA hardiness zones. Tropical water lilies, which require water temperatures above 70 degrees, have a more limited range, but the flowers are larger and more vibrantly colored. Water lilies bloom in the U.S. from spring to fall. Many water lilies bloom only during the day, but there are several night bloomers whose flowers open in the late afternoon and close at morning’s light.

The appreciation for the beauty of water lilies has a long history. The plants take their botanical name, Nymphaea, from the nymphs, nature deities from Greek mythology. Water lilies are featured often in the art of the Maya, an ancient Mesoamerican culture. Some of the most well-known paintings of French impressionist Claude Monet were of water lilies; the artist dedicated the last decades of his life to capturing the beauty of the lily pond on his estate in Giverny, France.