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).

Palms, despite being monocotylednous plant show secondary growth, i.e., increase in girth. This is due to the division and enlargement of parenchymatous cells in the ground tissue. Thus, repeated divisions cause increase in girth of stem and this type of growth is referred to as diffused secondary growth.

Placenta are soft cushion like tissues with which the ovules are attached to the inner surface of ovary wall.

The arrangement of ovules within the ovary is known as placentation. The placentations are of different types, i.e., marginal, axile, parietal, basal and free central.

Marginal Placentation In this placentation, the placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge forming two rows, as in pea.

Axile Placentation In this placentation, the ovules are borne on central axis and the marginal of placenta grow in word and fuse, thus making a multilocular ovary, as in China rose, tomato, etc.

Parietal Placentation In this placentation, the ovules develop on the inner wall of the ovary or on peripheral part. Ovary is one chambered but it becomes two chambered due to the formation of a false septum known as replam, e.g., mustard.

Free Central Placentation In this type of placentation, the ovules are present on the central axis of ovary and septa is absent so ovary is unilocular, as in Dianthus and Primose.

Basal Placentation In this placentation, the placenta develops at the base of ovary and a single ovule is attached to it, as in sunflower.

The process of shedding of leaves during hot summer or in autumn by deciduous plants is known as abscission. Anatomically, the cells of abscission zone are thin-walled and without deposition of lignin or suberin. At the time of abscission, the middle lamella may dissolve between the cells of two middle layers but the primary wall remain intact. The middle lamella as well as the primary walls of the adjacent cells is dissolved. Ultimately the whole cells of middle layer found in the abscission layer gets dissolve completely. Thus, there is separation of plant organ, i.e., leaf from the plant, wherever there is rainfall or wind.