What kind of grass is Tongcao?

Akebia manshuriensis is the stem pith of Araliaceae plants, also known as Cotuo, Linan, Huolu, relying on Shang, Tongtuo, onion grass, Baitong grass, etc., distributed in Jiangsu, Hubei, Sichuan, Guizhou, Yunnan and other places. At present, the Chinese market is mainly replaced by Akebia manshuriensis, Akebia trifoliata and Akebia trifoliata, while Akebia manshuriensis and Akebia trifoliata are used in Japan, and Akebia manshuriensis and Aristolochia manshuriensis were used in Taiwan market, and Akebia manshuriensis was once used in the mainland. But it is forbidden because it is toxic.

Tongcao stem slender, cylindrical, winding, stem bark grayish brown, with round, small and protruding lenticels, bud scales imbricate arrangement, light reddish brown. Palmately compound leaves alternate or clustered on short branches, usually 5-foliolate, petiole slender. Leaflets papery, Obovate or Obovate-elliptic, apex rounded or concave, apiculate, base rounded or broadly cuneate, dark green above, bluish white below. Midrib sunken above and raised below. Petiolule slender, 8 × 10 mm long, the middle one up to 18 mm long.

The corymbose raceme of Tongcao is axillary, with 1-2 female flowers at the base and 10 male flowers above. The total pedicel is 2-5 cm long, inserted on shortened lateral branches, the base is covered by bud scales, and the flowers are slightly fragrant. Male pedicel slender, female pedicel slender, staminodes 6-9. Fruit twin or solitary, oblong or elliptic, purple at maturity, ventral suture dehiscent. Seeds numerous, ovate-oblong, seed coat brown or black, glossy. The flowering period is from April to May and the fruiting period is from June to August.

Tongcao likes light and warmth, grows well in moist and fertile soil, has strong lateral growth ability of roots, and can form a large number of root tillers, not very cold-resistant, and the overwintering temperature is above 5 ℃. It is suitable for cultivation in fertile sandy loam, often growing in grass under low-altitude hillside forests, growing well in slightly acidic and humus yellow soil, and adapting to neutral soil. Stems often grow on creeping ground. Produced in Jiangsu, Hubei, Sichuan, Guizhou, Yunnan and other places.

Tongcao uses sowing, cutting or root cutting in early spring, seedlings are raised with seeds in early spring, and the underground stem has strong germination ability. Part of the underground stem is injured in winter to stimulate the emergence of new seedlings in the second year, and these new seedlings are transplanted before sprouting in the early spring of the third year, and planted according to the row spacing of 1.3 meters. Cut the base in autumn and winter, remove the head, tail and young branches, scrape off the rough skin of the wooden column and dry it. In the process of drying, straighten the rattan stem, tie it up according to the diameter at ordinary times, and then continue to dry.

Tongcao is divided into Tongcao and cinnabar according to different processing methods. After processing, Tongcao is stored in a drying container and placed in a ventilated and dry place to prevent moisture. Tongcao taste sweet, light, slightly cold, return to the lung and stomach meridian, clear heat and diuresis, ventilated under the effect of milk, the main treatment of damp-heat syndrome, edema, less urine, milk and other diseases, but qi and yin deficiency, middle cold, no damp-heat and pregnant women take carefully.