Page 129 - Pharmacognosy 2 PG303

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

Microscopical Characters
The leaves and bracts show dorsiventral structure in T.S., where the mesophyll contains
numerous small clusters of calcium oxalate. The midrib has a central large vascular bundle with
unbranched laticeferous vessels in the phloem. The upper epidermis consists of polygonal cells
with straight anticlinal walls, faint striated cuticle and shows short non glandular trichomes which
are unicellular, sharply pointed, curved, conical (120- 220 µm L.) with enlarged bases containing
cystoliths of calcium carbonate. The glandular trichomes have a globular glandular multicellular
head of 8- 16 radiating club- shaped cells which secrete the oleo resin beneath the cuticle which
raised as a delicate envelope. Some of the glands are sessile and the others have a cylindrical
multicellular stalk. The lower epidermis consists of smaller wavy walled cells, numerous
anomocytic stomata and trichomes but the non- glandular trichomes are longer 340- 500 µm L.
and without cystolith. The bracteoles have undifferentiated mesophyll of 4 layers of cells, each
cell of the hypodermal layer contains cluster crystals of calcium oxalate, and the outer surface
shows numerous trichomes. The stem has epidermal cells similar to those of the leaves, cortex
formed of collenchyma, endodermis, parenchymatous pericycle showing well developed bundles
of pericyclic fibers behind the phloem bundles which encloses unbranched brownish laticiferous
vessels and cluster crystals of calcium oxalate, xylem and pith. Pericarp shows palisade layer
formed of brown thick- walled, pitted, non- lignified cells. Stigmas have epidermis, each cell of
which is extended as a unicellular papilla 90- 180 µm L. with rounded apex.

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