Both prayer plants (marantas) and heliconias (parrot-flowers) are tropical understory herbs with very large leaves, related to bananas, gingers, bird-of-paradise, and cannas.
Heliconias are prized for their spectacular inflorescences, whose large colorful bracts serve to attract hummingbirds to the flowers. Prayer plants have special joints in their leaves that allow the leaves to change position. Their leaves open up during the day and close (like hands folded in prayer) when it gets dark, or when it is very hot and dry.