(a) Monocot Root and Dicot Root:

The transverse section of a dicot root shows the outermost layer called epiblema, with cells protruding as unicellular root hairs. The cortex consists of thin-walled parenchyma cells. The dicot root has fewer xylem bundles (usually 2 to 4, called diarch to tetrarch). It undergoes secondary growth.

In contrast, the monocot root has a similar organisation with epidermis, cortex, endodermis, pericycle, vascular bundles and pith. However, there are usually more than six xylem bundles (polyarch condition). The pith is large and well developed. Monocot roots do not undergo secondary growth.

(b) Monocot Stem and Dicot Stem:

The dicot stem has an outermost protective layer called epidermis. The vascular bundles are arranged in a ring and are fewer in number. They are conjoint, collateral and open, allowing for secondary growth.

The monocot stem has a sclerenchymatous hypodermis. The vascular bundles are scattered throughout a large, conspicuous parenchymatous ground tissue. Each bundle is surrounded by a sclerenchymatous bundle sheath. The vascular bundles are conjoint and closed. Peripheral bundles are smaller than centrally located ones. Phloem parenchyma is absent, and water-containing cavities are present within the vascular bundles. No secondary growth occurs.