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PHARMACEUTICAL BOTANY 
rounded cells having delicate cell walls of cellulose which enclose 
protoplasm and nucleus and wherever found in living embryos are in 
a rapid state of division. 
The generative tissues are found in the growing apices of plant 
organs such as root, stem and leaf apex. By the division and redivi- 
sions of their cells they give rise to the mature or adult tissues of 
plants. 
1. Dermatogen originates epidermal tissue and derivative struc- 
tures such as stomata, non-glandular and glandular hairs, glands, 
and cork cambium. 
2. Periblem originates cortex tissue, chlorophylloid cells (chlor- 
enchyma) colloid cells (collenchyma), strengthening cells (scleren- 
chyma), crystal cells (raphiderchyma) latex cells (lacterchyma), 
endodermis and cork cambium. 
3. Plerome originates fibro-vascular bundles, fundamental tissue, 
pericambium and cambium. 
According to structure the following tissues are found in various 
forms of 
higher plants: 
1. 
Meristem 
7. Cork 
2. 
Parenchyma 
8. Laticiferous tissue 
3- 
Collenchyma 
9. Cribiform or sieve tissue 
4- 
Sclerenchyma 
10. Tracheary tissue 
5- 
Epidermis 
n. Medullary rays 
6. 
Endodermis 
MERISTEM 
Meristem, frequently called embryonic tissue, is undifferentiated 
tissue composed of cells in the state of rapid division. It is found 
in the growing apices of roots, stems and leaves and is in these 
regions called primary meristem, since it is the first meristem to 
appear. Such meristem gives rise to the permanent or mature 
tissues of plants and retains the power of independent growth and 
capacity for division as long as the plant part survives which con- 
tains it. Meristem is also found in other regions of plant organs 
such as the cambium, cork cambium and pericambium and is there 
called secondary meristem. Secondary meristem loses with its de- 
velopment the power of division and independent growth. 
