It is anatomical abnormality. It is an abnormal type of secondary growth, where a regular vascular cambium or cork cambium is not formed in its normal position. In case of old tree trunks, anomalous secondary growth produces cortical and medullary vascular bundles. Thus, the additional or accessory vascular bundles given appearance of several fused trunks.

Difference between lenticels and stomata is as follows

Lenticels	Stomata
Lenticels are formed due to loosening of the epidermal and cortical tissues.	Stomata are specialised epidermal structure.
These are mostly found on the stem region. Lenticels does not have guard cells.	Mostly found on lower surface of leaves. Stoma has guard cells.
These openings are not regulated. They are used for removal of waste.	Opening and closing is regulated mechanism. They are involved in gaseous exchange, removal of extra water and waste.

Sieve tube

It is present in the phloem tissue. It's function is the transportation of synthesised food through out the plant.

Interfascicular Cambium

It's function is to bring about secondary growth in the dicot stem and root. It is a kind of secondary meristematic tissue present in between two vascular bundles.

Collenchyma

It's function is to provide mechanical support to young growing herbaceous stem. It's cells have angular thickening at corners.

Aerenchyma

It provides buyoncy to the hydrophytic plants. It is a specialised parenchyma having large air spaces.

The epidermal cells surrounding the guard cells of stomata are called subsidiary cells. Differences between guard cells and epidermal calls are

Guard cells	Epidermal cells
They are bean or kidney shaped.	They are barrel shaped.
They possess chloroplasts.	They ladk chloroplasts.
They are smaller.	They are bigger.
Cell walls of guard cells are not uniform and thicker.	Epidermal cells are uniformly thin.

Difference between Ficus leaf and maize leaf is as follows

Character	Ficus leaf (Dicot Leaf)	Maize leaf (Monocot leaf)
Type of leaf	Dorsiventral.	Isobilateral.
Stomata	Usually more on lower epidermis	Equal on both, lower and upper epidermis.
Mesophyll	Made up of two types of tissues (a) Lower spongy parenchyma with large intercellular spaces. (b) Upper palisade parenchyma.	Only spongy parenchyma is present which has very small intercellular spaces.
Bundle sheath	Made up of parenchyma. Just above and below the vascular bundle some parenchymatous cells or collenchymatous cells are present (up to epidermis).	Made of parenchyma, but just above and below, the vascular bundles are found sclerenchymatous cells (up to epidermis).
Bulliform cells	Absent in dicot leaves.	Present, particularly in grasses (monocot leaves).