In xerophytes (plants which grow in dry conditions), stomata are located on the lower (abaxial) surface of the leaves which is a cooler side compared to the upper (adaxial) surface which faces the sun. Stomata in such plants are further protected from the desiccating outer air by their location being present in stomatal crypts. In day time their stomata is closed. In hydrophytes (plants which live in moist environments and partially/fully submerged in water) stomata are mostly open as they do not have the requirement for saving water in comparison to terrestrial plants.