Page 101 - Pharmacognosy 2 PG303

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

5- Surface: it may be smooth, rough, hairy, spiny, striated, wrinkled…………etc.

6- Fracture: it depends mainly upon the nature and arregements of the tissues constituting the

organs. It may be:
Complete: when the part breaks clean across.
Incomplete: when it breaks part way across.
Short: when it brakes quickly and straight across, and the fractured surface is almost smooth.
Flexible: when breaking only by tearing or twisting.
Tough: when breaking with difficulty.
Weak: breaking quickly with little effort.
Hard: when not easily broken.
Splintery: when breaking irregularly across withjagged projecting points in broken surface.
Fibrous: when resisting during breaking and fibrous projections protruding from the broken

surface.
Brittle: when easily broken into fragments.
Even (smooth): when breaking with smooth surface.
Uneven: when breaking with irregular surface.
Mealy (starchy): when breaking readily across and exhibiting whitish powdery broken

surfaces due to starch.
Resinous: when exhibiting smooth glossy broken surfaces.

7- Insertion of leaves:

1- Cauline: arise from the aerial stem.
2- Radical: arise from the crown of the root.

8- Phyllotaxis: is the mode of arrangement of cauline leaves on the stem.

1- Alternate or spiral: leaves occur singly at a node e.g. Lobelia.
2- Opposite: leaves occur as pair at a node and opposite decussate: opposite but each pair

alternated at right angles to one another e.g. Mentha.
3- Whorled or verticillate: when several leaves occur at a node e.g. Nerium.

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