Pitcher plant pitchers. View of pitchers of the insectivorous pitcher plant (Sarracenia flava). These modified leaves have red veins, and produce a sweet smelling nectar to attract insects. When an insect alights on the rim, it loses its grip on the waxy, downward-facing detachable scales which line the inside of the pitcher. It then falls into a liquid at the bottom of the pitcher which contains digestive juices. The insects provide the plant with nitrogen, which the poor soils it grows in lacks. The flap above the pitcher is to prevent rain entering the pitcher and diluting the juices.