Tu Si Zi

Cuscuta chinensis is a leafless, rootless, annual parasitic vine in the Convolvulaceae, distributed across eastern and southern Asia, including China, Korea, Japan, Vietnam and adjacent regions, where it parasitises a wide range of herbaceous and shrubby hosts, particularly leguminous and composite plants. After germination the slender seedling withers at its base and the wiry, twining, pale yellow to orange thread-like stems, 0.5-1 mm thick, climb and coil tightly around host stems. Functional roots and chlorophyll are absent; instead, small haustoria penetrate host tissues to extract water and nutrients. The leaves are reduced to minute, scale-like vestiges along the stems. In summer the species produces dense, sessile clusters of small, bell-shaped, creamy-white flowers about 3 mm long, with five short corolla lobes. The fruits are small, depressed-globose capsules opening by a transverse split to release several minute, hard, brownish seeds.