Describe the internal structure of a monocot (Maize) stem.

(N/A) $\rightarrow$ Maize is a monocot plant. When a thin section of its stem is observed under a microscope,the following parts are seen: $(1)$ Epidermis,$(2)$ Ground tissue,$(3)$ Vascular bundles.
$(1)$ Epidermis: It is the outermost layer,consisting of a single layer of parenchymatous cells. The outer walls of these cells are cuticularized.
$\rightarrow$ No stem appendages are produced from this layer,so its surface is soft. Stomata can be seen in this layer. This layer functions in protection and gas exchange.
$(2)$ Ground Tissue: Unlike a dicot stem,distinct regions like cortex,endodermis,and pericycle are not found in the ground tissue.
$\rightarrow$ At the outermost side of the ground tissue,the hypodermis is located. It is made up of two or three layers of sclerenchyma tissue. These cells are non-living and lignified,providing mechanical support to the stem.
$\rightarrow$ Inside the hypodermis,thin-walled parenchyma is located,where vascular bundles are embedded. The ground tissue cells towards the center are comparatively larger and have intercellular spaces.
$(3)$ Vascular Bundles: In a maize stem,numerous vascular bundles are scattered throughout the ground tissue. Peripheral vascular bundles are generally smaller,more numerous,and arranged closer to each other. They are surrounded by a sclerenchymatous bundle sheath.
$\rightarrow$ Centrally located vascular bundles are fewer in number and spaced further apart. Each vascular bundle is surrounded by a sclerenchymatous bundle sheath,making them fibro-vascular bundles.
$\rightarrow$ Each vascular bundle is conjoint,collateral,and closed (lacking cambium).
$\rightarrow$ In the vascular bundles,phloem tissue lies outside and xylem tissue lies inside,arranged in a '$V$' shape.
$\rightarrow$ Phloem tissue: Located outside in a '$V$' shape. Phloem parenchyma is absent.
$\rightarrow$ Xylem tissue: Arranged in the shape of the English alphabet '$V$'. It typically contains three to four vessels. Two large vessels are known as metaxylem,located at the two upper ends of the '$V$',while the protoxylem is located at the base of the '$V$'.