Page 89 - Pharmacognosy 02-06203
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SUBTERRANEAN ORGANS
Introduction
The underground organs of the plant are either of stem origin or of
root origin. Many drugs of this class consist of both roots and rhizomes.
Medicinal Roots
The root is the plant axis which grows vertically downwards into the
soil away from light. It never develops leaves. It usually bears no buds. It
doesn’t show nodes and internodes. It is characterized by the absence of
chlorophyll.
Medicinal roots usually occur in the dried condition, being entire as
Senega or sliced as Calumba. They may be peeled as Liquorice.
Types of root:
1- Primary roots as Senega
2- Secondary roots as Krameria
3- Adventitious roots as Ipecacunha
4- Fibrous root as Grass
5- Root tubers as Aconite
Medicinal Underground Stems
The underground stem is fundamentally a mean of perennation of
the plant as well as a storage organ. It is characterized from root by bearing
scale leaves, axillary buds, adventitious roots and the growing point
protected by a bud.
Types of subterranean stems:
1- Rhizomes as Ginger
2- Stem tuber as Potato
3- Corm as Colchicum
4- Bulb as Squill
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