Chinese wedelia

Chinese wedelia (Sphagneticola calendulacea), also called cúc nhám or ngổ núi in Vietnamese, is a perennial herb of the daisy family (Asteraceae). It has stems that creep along the ground and then rise, 20–40 cm tall, branched and covered with hairs. The opposite, lanceolate leaves are 2–7 cm long with serrated margins and rough hairs on both surfaces. The solitary flower heads are bright yellow, 2–2.5 cm across, with ray florets around disc florets. The fruit is a small hairy achene. The species likes moist, shaded places such as field edges, streamsides and waste ground, spreads quickly by runners and may flower year-round. It ranges from India and South Asia through China and Japan to Southeast Asia, including Vietnam.

Chinese wedelia is a familiar folk remedy: the whole plant is decocted to cool the body, clear toxins, support the liver and treat measles, fever and boils, or pounded and applied externally. In some places the young leaves are cooked in soup or eaten raw. Because its runners spread quickly it is also grown as a ground cover, green carpet and ornamental for its bright yellow flowers. Modern pharmacological studies show that extracts of the plant have antibacterial, antioxidant and liver-protective effects. The plant prefers a tropical or subtropical climate and is easily grown in moist spots; it is propagated from stem cuttings or seed. In Vietnam it grows widely as a wild plant and is also cultivated as a medicine.