The peace lily is a tropical species that is a favorite flowering houseplant. A striking plant when used in mass display, the peace lily blooms in spring with long-lasting flower stalks that hover gracefully over the foliage. A well-grown peace lily may bloom twice a year, resulting in several months of flowers. The plant has glossy oval leaves with points that emerge from the soil.Peace lilies are indisputably terrific as houseplants. Small varieties look attractive on a tabletop and bigger ones can occupy a nice-sized spot on the floor. They filter more indoor pollutants than most other plants, so are great for bedrooms or other frequented rooms. Inside the tropical plant's pores, toxic gases like carbon monoxide and formaldehyde are broken down and neutralized. Peace lily can also be grown outdoors in warm climates, where it can tower as much as 6 feet high.Despite their name, peace lilies are not members of the lily family. The peace lily is a member of the Araceae family of plants, known collectively as aroids. It is related to the philodendron, anthurium, and alocasia—also very popular as houseplants.