Page 129 - Pharmacognosy 2 PG303 (1)
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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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