Page 157 - Pharmacognosy 2 PG303

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

This group includes the following members:
1- Rhizome: It is the most important and predominating member of this

group as regards the medicinal value, A rhizome is an underground stem with
nodes and internodes, terminal buds and aerial shoots. The internodes are either
long as in, American Podophyllum or short as in Indian Podophyllum. Rhizomes
usually, grow horizontally with the roots on the lower side and the scale leave and
buds of aerial shoots on the upper side, as in podophyllum, couch grass etc, but
sometimes they grow vertically, with the roots and scale leaves all over the surface,
a large bud at apex, and with the surface usually annulate as in valerian etc.; and
occasionally they grow obliquely as in fillix mas. Rhizomes may be branched, but
mostly they branch sympodially as in Ginger and occasionally they branch
monopodially as in Filix mas. Sometimes, the rhizome starts its elongation
monopodially but, later on, it continues its growth sympodially as in Iris. Sobole
is a kind of rhizome which is long, thin, tough, rapid in growth and with long
internodes as in couch grass, Dog Grass etc. Sucker is also a kind of rhizome.
It is a branch growing under the ground, arising from the stem as in Mentha or
from the top of the root as in Rose and giving off roots and aerial shoots at the nodes.
Stolon: is an underground stem which travels near or below the surface of the soil
and gives roots at its extremity, it is similar in function to a runner, but it is much
thicker.

2. Corm: It is a shortened swollen erect underground stem, covered with

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