Parasitic plants, which feed only on living organisms, obtain all or most of the nutrients and water they need from green plants. And make the host plant gradually wither and die.

Southern China has a widely distributed, harmful vine parasitic weed called rootless vine, and dodder "look" similar, often parasitic in trees, shrubs and herbaceous plants.

The locking sun is also a perennial herb. It has no chlorophyll all over the body, the stem is fat and fleshy, black-purple cylindrical, the base is more

, buried in the sand. The leaves are reduced to scales and scattered on the flowering stem. The stem is topped by a rounded rod-shaped spike. The flowering and fruiting period is very short, and seed development requires a lot of nutrients and water, the thick juicy fleshy stems are just right for this "role". Fruit spherical, each lock yang can bear two or three million fruits, can be said to be "full of children and grandchildren". The fruit is tiny, but it has a long life. Put it indoors to save 12 years later, still have the ability to parasitize. Originally, its fruit skin is very strong, the harsh environment has amazing adaptability. In the gravelly Gobi of the Tarim Basin, where the sunlight is strong and the daytime surface temperature is as high as 70℃ or more, the seeds of Liao Yang and Cistanchis can still grow and reproduce there tenaciously.