The large white shield-like structure is called a spathe. The cylindric structure is called the spadix, the small "bumps" on it are the actual (very tiny!) flowers.
Indoors peace lilies are non-stop bloomers when provided adequate water and fertilizer and bright indirect light.
The genus Spathiphyllum includes some three dozen species of evergreen tropical perennials that spread on short rhizomes. All have glossy dark green, lance shaped leaves around 8-12 in (20-30 cm) long. The pointy tipped leaves are carried on short erect stems. The fragrant inflorescence consists of a pure white shield-like spathe to 8 in (20 cm) tall, backing up a central spike-like white to yellowish spadix to 3 in (8 cm) tall. The spadix is densely covered with many tiny bisexual flowers, each with 4-6 perianth segments The whole shebang stands gracefully above the shiny leaves.
Peace lilies have been hybridized and back-hybridized until it is no longer known for certain which species are parents of which cultivars. Probably most cultivars have Spathiphyllum wallisii somewhere in their parentage. Some cultivars are tiny little things with 2 in (5 cm) leaves; others more robust with leaves up to 18 in (45 cm) long. Among the most common cultivars are Spathiphyllum ‘Mauna Loa’ which is larger and bushier than most, to 24 in (60 cm) in height; ‘Sensation’, which is even larger, to 5 ft (1.5 m) tall with 18 in (45 cm) leaves; ‘Golden Delicious’, which has yellow new growth; ‘Petite’ which stands only 6 in (18 cm) tall with 2 in (5 cm) leaves; ‘Domino’, with leaves splashed with white spots; and ‘Clevlandii’ (perhaps the most familiar), which has narrow, drooping leaves with wavy margins, to 12 in (18 cm) long.
The several species of Spathiphyllum occur naturally in the Philippines, Indonesia, and in tropical Central and South America. They grow in damp soils in shady, humid jungles. S. wallisii, a likely parent of most commonly available cultivars, is native to Panama and Costa Rica.
Peace lilies do best in a moist, humus-rich potting medium with plenty of organic matter. Light: In the wild, peace lilies grow in humid tropical jungles, in deep to moderate shade. They make ideal house plants if kept in bright indirect light. Never let your lily bathe in direct sunlight. Peace lilies will survive in a shady living room setting, but may not bloom unless they get bright (but indirect) light, such as near a north facing window. Moisture: Peace lilies like a humid environment and thrive with frequent watering and misting. As long as the soil drains, it is almost impossible to over-water a peace lily. Reduce watering in winter, but still don’t let the soil dry out completely. In winter, in a heated home, humidity may become quite low, and your peace lily will surely appreciate the occasional misting. Peace lilies don’t like cold feet, so bring the water to room temperature, and they prefer rain water. Hardiness: USDA Zones 10-11. : Peace lilies like it warm. Try not to let the temperature fall below around 55 °F (13 °C), and avoid drafts. Propagation: Peace lilies produce short rhizomes, pieces of which can be used to start new plants.
In the tropics or near-frostfree climates the peace lily is used outdoors much like a small shrub - in beds, borders and in large scale ground covers in shaded areas.
NASA research indicates that container grown peace lilies can elimate volatile organic chemicals from indoor environments - and look beautiful while doing it!
Peace lilies are very easy to maintain and even a gardener with a black thumb can grow this interesting and beautiful house plant. Often seen in waiting rooms and public lobbies, peace lilies will usually thrive if the light is bright and indirect and they get watered at least occasionally. This is the perfect indoor foliage plant, and often used by interior decorators. Even when not in bloom, the shiny dark green leaves are very attractive, and a nice alternative to plastic plants.
Planted in masses in a large container, peace lilies make a striking display of tropical character. The graceful flowers last for several weeks, floating on thin stalks above the shiny dark green foliage. Sometimes they bloom twice a year, providing flowers for several months.
The cut inflorescences are used in arrangements, and even live flowering plants are sometimes available from florists.
Easy to maintain, peace lilies should be among the first indoor plants for young budding gardeners to grow up with.
WARNING Spathiphyllum leaves and flowers are poisonous if ingested. They have been known to poison cats and dogs. The sap may irritate sensitive skin.