Microscopic examination of rhubarb powder:
1. There are many clusters of calcium oxalate crystals, and the corners are mostly short and blunt
2. The ducts are mostly reticulate
3. The starch is mostly single grain, and the umbilical point is mostly star-shaped
Microscopic examination of Coptis chinensis powder:
1. Stone cells are square, round, and rectangular, yellow, with thick walls and obvious wall holes.
2. Spindle sheath fiber spindle shape or diamond shape
3. With wood fiber and wood parenchyma cells
4. Scaly leaf epidermal cells greenish yellow or yellowish brown, rectangular or long polygonal cells, the wall is curved like a microwave, or thickened with beads .
5. Conduit is mesh or hole pattern, short section shape