1, Tongcao is what family plant
Tongcao is the stem pith of the family of plants Tongtuomu, white color, with transverse and longitudinal grooves. Light, soft, flexible, easy to break, flat section, the middle has a diameter of 0.5 ~ 1.5 centimeters of hollow or white translucent film. The outer ring of silver-white, longitudinal dissection of the see layers of septum, odorless and tasteless. To color white, hollow heart, elastic is better.
2, the characteristic form of Tongzhao
Tongzhao, deciduous woody vine. Stem slender, cylindrical, twining, stem bark gray-brown, with round, small and raised lenticels; bud scales imbricate arrangement, light reddish brown. Leaves palmately compound alternate or in clusters on short branches, usually with 5 leaflets, occasionally 3-4 or 6-7; petiole slender, 4.5-10 cm long; leaflets papery, obovate or obovate-elliptic, 2-5 cm long, 1.5-2.5 cm wide, apex rounded or concave, with a small convex apiculus, base rounded or broadly cuneate, dark green above, glaucous-white below; midrib concave above, raised below. Lateral veins 5-7 per side, with reticulate veins raised on both sides; petiolules slender, 8-10 mm long, the middle one up to 18 mm long.
Two, what are the species of Tongzhi
What are the species of Tongzhi? Solid Tongzhi and hollow Tongzhi are the most common.
1, solid Tongzhi
Source: the dried stem pith of the small tree plant Tongzhi tree and its cognate plants of the family of sparkle flower. All wild.
Origin: Sichuan, Hubei, Jiangxi, Guangxi, Shanxi, Gansu and other places.
Trait identification: stem pith is thin cylindrical, length varies, diameter 0.4--1 cm. Surface white or slightly yellow, platform, no longitudinal texture, soft, bendable, hand pinch can make it deformed. Section white color, no hollow. After immersed in water, the appearance and cross-section have a sticky and slippery feeling. No gas, light flavor. To strip uniform, white color, no mildew spot is good.
2, hollow Tongzhi
Alias: Tongzhi, Tongtuo wood.
Source: the dried stem pith of Tongtuomu, a shrub or small tree plant in the family of Wugacaceae. Mostly wild.
Origin: Mainly produced in Guizhou, Yunnan, Sichuan, Guangxi and Taiwan.
Trait Identification: The stem pith is cylindrical, about 30--50 centimeters long, 1.5--2 centimeters in diameter. Surface white color, with longitudinal texture. The center has a translucent circular film of about 0.5--1 cm in diameter, and neatly arranged intervals can be seen after longitudinal dissection. The body is extremely light and loose, floating in water, and hygroscopic. Easily broken, the fracture surface is flat, showing silver-white flash. Gas is absent, taste is light. To strip stout, white color, the center of the film is good.