Page 130 - Pharmacognosy-I (02-06-06-102)

turns red when treated with dilute alkali (Bornträger’s test).
- Fracture: short and granular in outer part and somewhat fibrous in the
inner part.

Microscopic characters:

- Cork formed of several layers of small, flattened, thin-walled cells with

yellowish-brown content.

- Cortex is narrow, yellowish grey, composed of few layers of

collenchyma and parenchyma. Some of the parenchymatous cell contain
starch granules and cluster crystals of calcium oxalate and showing
numerous scattered, bright ovoid groups of sclereids, usually encircled by
crystal sheath of prisms of calcium oxalate.

- Phloem is wide, brownish-yellow, traversed by numerous slightly

wavy medullary rays, 1-5 cells mostly 2-4 cells wide, and consists of
alternating bands of lignified fibres, surrounded by crystal sheath, with
prisms of calcium oxalate, and parenchyma with scattered cluster crystals
of calcium oxalate and starch granules.

T.S. of Cascara bark

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