Stomata is the tiny pore present in almost all the leaves of land plants. The main function of the stomata is the gaseous exchange. This process is completed by the opening and closing of guard cells of stomata. The guard cells of most of the plants are bean-shaped, but the guard cells of stomata of grasses and monocots are dumbbell-shaped or bone-shaped. The nucleus in these guard cells is also dumbbell-shaped. This shape of stomata is the characteristic of grasses and monocot leaves.
