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A Handbook of Biology

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Pith is large and well developed.

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Monocot roots do not undergo any secondary growth.

DÏÇØTÝLËDØÑØÜS (DÏÇØT) STËM

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Epidermis: Outermost protective layer. Covered with a thin layer of

cuticle, it may bear trichomes & few stomata.

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Cortex: Multiple layers of the cells arranged in between epidermis and

pericycle. (NEET-II 2016)

Epidermis

Collenchyma

Parenchyma

Phloem

Cambium

Endodermis

Pericycle

Metaxylem

Protoxylem

Epidermis

Hypodermis

Endodermis

Pith

Parenchyma

Vascular

bundle

Pericycle

Epidermal

hair

Medullary

rays

Pith

Consists of 3 sub-zones:

Endodermis:

Innermost layer of the

cortex. The cells are

rich in starch grains.

So the layer is also

called as the starch

sheath.

Cortical layers:

Below hypodermis.

They consist of

rounded thin walled

parenchymatous

cells with

conspicuous

intercellular spaces.

Hypodermis: Outer

zone. It consists

of a few layers of

collenchymatous

cells just below the

epidermis. It provides

mechanical strength

to the young stem.

1

2

3

Pericycle is present on the inner side of the endodermis and above the

phloem in the form of semi-lunar patches of sclerenchyma.

Stele: Consists of pericycle, vascular bundles, medullary rays & pith.