Huang Yao Zi (Densely distributed circular root scars)
Huang Yao Zi Slice (Granular unevenness)
【Naming】
【Source】
Kai Bao Ben Cao (Materia Medica of the Kai Bao Era)
【Common Usage Level】
E
【Botanical Origin】
The tuber of Dioscorea bulbifera L. (Air Potato Yam), family Dioscoreaceae.
【Appearance】
The dried tuber is a circular or nearly circular slice, with a transverse diameter of 2.5-6cm, a longitudinal diameter of 4-7cm, and a thickness of 0.5-1.5cm. The surface is brownish-black, wrinkled, densely covered with short, small branch roots and yellowish-white circular branch root scars, slightly raised, about 2mm in diameter. Some of the cork layer peels off, revealing a light yellow and smooth center underneath. The cut surface is light yellow to yellowish-brown, smooth or granularly uneven. It is hard and brittle, easily broken, and the fracture surface is flat or granular. Historical Materia Medica records regarding the original plant of Huang Yao Zi are inconsistent and often confused with Hong Yao Zi (Red Medicine Yam). Currently, commercial Huang Yao Zi is mainly the above-mentioned species. Although it does not resemble most records in the Materia Medica, it is completely consistent with the shape and morphological description of Huang Yao Zi recorded in the Ming Dynasty’s “Ben Cao Yuan Shi” (Original Materia Medica).
【Identification】
The ones with a gray-black peel and a yellowish-white fracture surface are considered the best.
【Category】
Roots