Source1.Datong grass: it is the stem pith of Tetrapanax papyrifera (hook.) K. Koch, a plant of Araliaceae.
2. Akebia Akebia: the pith of Akebia japonica (also known as Akebia Akebia), Stachyurus hi-malaicus h cook. F.et Thorns, China Akebia japonica (also known as liang zi), Stachyurus chinensisFranch．, or Helvetia japonica (Thunb.) Dietr. of Cornaceae.
Origin and distribution1.Datong grass: mainly produced in Guizhou, Sichuan, Hunan, Yunnan, Guangxi and other places. Sell nationwide.
2. Xiaotongcao: mainly produced in Sichuan, Hunan, Hubei, Shaanxi, Henan and other places. Sell nationwide.
Identification points: The main characteristics of medulla tetrapanacis are white and cylindrical, with a diameter of 3cm, light, soft and elastic body, vertical section, trapezoidal diaphragm and light taste. On the other hand, the stem pith of the tree with continuous flowers is thin and cylindrical, solid, white in section, shiny and elastic, and can be crushed by hand; Except for the green pod leaves, it feels sticky and slippery when soaked in water.
However, several kinds of counterfeit products are hard, not flat, and have no sticky feeling when soaked in water; There are fine holes and concentric rings in the cross section of Hemei, which can be distinguished.
Classic identification 1 Tang? Chen Zangqi said, "Tongtuomu grows on the side of the mountain. Leaves are like castor beans. Its stem is hollow, with a pulp in it, which is light, white and lovely. Women take ornaments, and the common name is Tong Cao. "2 Song? Su Song said: "... born in the south of the Yangtze River, with high praise, big leaves are like lotus and fat, middle pulp is just white, and there are also plants in the garden today ..." Ming? Chen Jiamo said, "The white pulp hides in the middle, and the wood is removed to get it, hence the name Tongtuo. Li Shizhen said, "In a sprawling mountain, those with big stems are surrounded by several inches. "5 Qing? "Materia Medica from the New": "Tong Cao. The ancient name is Tombstone. The color is white and cold, and the body is light and tasteless. "6" Compilation of Medicinal Materials ":"Tetramedulla Tetrapanacis (Tombs) is mainly produced in Guizhou, Sichuan, Hubei and Hunan. Commodities are divided into Chuanfangtong, Jianfangtong, Chuansitong and Xiaotongcao (commonly known as Tongcao), which are shaped like pens and about two or three feet long, and are sold in bundles with original strips. Sales habits are: Fangtong's high-end multi-selling handicrafts are used to tie paper flowers, and also for pharmacies in big cities; Tongcao silk is sold nationwide; Phoenix tail silk is mostly sold in the north, and trimming silk is mostly sold in Jiangsu and Zhejiang. Xiaotongcao sells mainly in the north. "
Rapid identification1.Datong grass: the stem pith is round (not processed into "Fangtongcao"), with a length of 30 ~ 60 cm and a diameter of1.3 ~ 3 cm. The surface is white or yellowish white with shallow longitudinal stripes. The body is light and soft, elastic, easy to break, with a flat section and a hollow or white translucent film in the middle; Longitudinal section shows the ladder arrangement of films. Odorless, tasteless.
2. Tetramedulla Tetrapanacis: The pith of the stem is thin and cylindrical, with different lengths and a diameter of 4 ~ 7 mm.. The surface is white or yellow-white, and the longitudinal texture is fine and solid. Soft, slightly elastic, flat by hand, white cross section, showing white flash. No breath, light taste.