Table 2 Summary of the macroscopic and microscopic features of ATR, AGR, ACR and AAR

Morphology

 Shape

Flattish-cylindrical

Cylindrical

Fusiform

 Length (cm)

3–15

1–4

5–20

1–4

 Diameter (mm)

3–10

2–7

10–15

3–5

 Fracture

Fibrous, numerous dotted vascular bundles and brown oil spots visible

Fibrous, numerous dotted vascular bundles visible

Granular protuberances, starchy

 Odor

Aromatic; taste bitter and slightly pungent

Strong aromatic and taste pungent

Slight; taste slightly sour and numbness

Transverse section

 1. Epidermis

Sub-square brown cells

Flat square cells

 2. Cortex

3. Fiber bundles, 4. Secretory cells and 5. Leaf-trace vascular bundle are scattered

3. Fiber bundles arrange in ring, 8. Stone cells, suborbicular, scattered

Small intercellular spaces

Large intercellular spaces

 7. Stele vascular bundle

Amphivasal or collateral, densely lined up near the 6. Endodermis

N/A

 9. Pith

N/A

Large

Powder

 1. Crystal fibers

Fiber bundles surrounded by cells containing prisms of calcium oxalate, forming crystal fibers

6. Fibers, not crystal fiber

 2. Starch granules

Ellipsoid, spheroidal or long-ovoid, black and cruciate-shaped under the polarized microscope

 3. Secretory cells

Abundant, sub-rounded or elongated-rounded

N/A

 4. Vessels

Mainly reticulate

 5. Epidermal cells of leaf sheath

Greyish-green or pale yellowish-brown, rectangular

N/A

 7. Stone cells

N/A

Abundant

 8. Parenchymatous cells

Less

Abundant