DK Science: Parasitic Plants
Most plants make all the food they need by photosynthesis, but some species are parasites. They steal food from other plants, known as host plants. Parasitic plants have special suckers that may invade the host plant’s food channels and draw off sugars and minerals. Many parasitic plants are totally dependent on their host for food and no longer need green leaves. Others still have green leaves and make some of their own food through photosynthesis.
Dodder is a parasitic plant that cannot photosynthesize at all. Its leaves are reduced to tiny brown scales. Since it has no green chlorophyll, it must obtain all its food from the host plant. Dodder is a climber related to bindweed. Its stems twine around the host, producing suckers, called haustoria, that invade the host and steal its food.
Mistletoe is a parasite that steals water and minerals from its host tree. However, mistletoe also has green leaves. It produces its own food through photosynthesis, using water stolen from the host tree.
Rafflesia arnoldii is a parasitic plant that produces the world’s largest flower. It grows in the rainforests of Southeast Asia. The plant invades the underground roots of vines to take food. Sometimes the Rafflesia puts out a shoot from one of these roots. This develops into a giant, stinking flower that may be 1 m (3 ft) across. The flower’s powerful smell of rotting flesh attracts pollinating flies.