Description:
This annual or biennial herbaceous plant typically reaches a height of approximately 1 meter. It has small, twisted roots that taper from the root collar to the tip, measuring 10-15 cm in length and 2-5 mm in diameter. The leaves are arranged oppositely and have wavy margins. Numerous flowers develop in spikes, 20-30 cm long, at the top of the plant. The fruit is a capsule, with persistent bracts forming sharp spines. The seeds are elongated and ovate in shape.
Distribution:
This species is found in intertropical regions, including India, China, Japan, Thailand, Laos, Cambodia, and Vietnam. It is also relatively common in Vietnam.
Ecology:
The plant grows in grasslands, old fields, around villages, along roadsides, and in brushy areas with adequate sunlight and fertile soil, up to an altitude of 1500 meters. It flowers during the summer and autumn.
Uses:
The young shoots and leaves are harvested before flowering. They are thoroughly crushed, chopped, washed, and blanched in boiling water for use in stir-fries or soups. Nutritional analysis of this vegetable reveals the following composition (per 100g): water 81.9g, protein 3.7g, carbohydrates 9.2g, fiber 2.9g, ash 2.3g, carotene 2.6 mg, and vitamin C 2.0 mg.
The roots and other parts of the plant are used to treat: fever associated with the common cold and nasal congestion; malaria and dysentery; otitis media and mumps; rheumatic arthritis; nephritis with edema; urinary retention, frequent urination, and dysuria; menstrual cramps, amenorrhea, and irregular menstruation; and traumatic injuries. Dosage: 15-30g, administered as a decoction. For external use, fresh plants are crushed and applied as a poultice.
In India, the whole plant is used to treat edema, hemorrhoids, boils, skin rashes, abdominal pain, and snake bites. The roots are used as an astringent decoction. The seeds are used to treat hydrophobia.