(i) The stomata occur either on lower or both the surfaces of leaves.
(ii) They regulate transpiration in plants and help in exchange of gases.
(iii) Each stoma is made of two bean-shaped cells called the guard cells.
(iv) These are dumb-bell shaped in monocots like grasses.
(v) The guard cells possess chloroplast.
(vi) Guard cells regulate opening and closing of stomata.
(vii) Some epidermal cells in the vicinity of guard cells become specialized in shape and size and they are termed as the subsidiary cells.
(viii)The stomatal aperture (pore), the guard cells, and the surrounding subsidiary cells make the stomatal apparatus.