The stomatal pore is guarded by two kidney shaped guard cells. Name the epidermal cells surrounding the guard cells. How does a guard cell differ from an epidermal cell ? Use a diagram to illustrate your answer.

The stomatal pore is guarded by two kidney shaped guard cells. These guard cells are surround by the epidermal cells known as subsidiary cells or accessory cells.
The guard cell differ from an epidermal cell in showing the following characters:
i) They are smaller in size.
ii) They are bean shaped in dicots and dumb-bell shaped in monocots.
iii) Their cell wall is differentially thickened to help in turgor movements. In bean shaped guard cells the outer walls are thin and inner walls are highly thick. In dumb bell shaped guard cells middle walls are thick and end walls are thin.
iv) Guard cells contain chloroplasts. However, the chloroplasts are absent in other epidermal cells.
v) Guard cells regulate process of transpiration.