Page 238 - Pharmacognosy 2 PG303

Pharmacognosy-2 (PG303) Level 2 Clinical Pharmacy-Pharm D

Diagram in a star spot; a, medullary ray; d, cambium, e, xylem vessel.

Part of T.S. in Rhubarb; a, xylem vessel; b, cluster; c, starch granules.

Powder
Powdered rhubarb is reddish-brown to yellowish-brown, characterized by:
1- Abundant fragment of thin-walled parenchyma, containing numerous starch
granules, brownish masses of amorphous cell contents giving reddish pink
color with solutions of caustic alkali.
2- Fragments of non-lignified reticulate, spiral or annular vessels.
3- Numerous cluster crystals of calcium oxalate, 20-200, mostly 60-120 µ in
diameter, numerous starch granules, simple, 4-25 mostly 20 µ in diameter, or

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