Xerophytes are plants that are adapted in such a way that they are able to tolerate extended periods of dry conditions. Most water lost from plants is in the form of water vapour that diffuses out of the leaves through the stomata during the process of transpiration. Transpiration may also take place through the cuticle. The plant cannot stop all loss of water vapour as this would prevent diffusion of oxygen & carbon dioxide during respiration and photosynthesis.
The following characteristics are typical of xerophytic plants and help to prevent moisture loss and to store available water:
Roots:
The roots have large capacity for storing water along with deep taproots. This allows them to take up as much as water as possible and store it for a long time. They also have wide-spreading roots near the soil surface which means they are able to spread widely in search of sources of fresh water.
Leaves
The leaf is the part of the plant where the greatest amount of transpiration takes place. A xerophytic plant may have any of the following leaf characteristics to help reduce transpiration while still being able to photosynthesise:
They might have shiny white leaves with thick, waxy cuticle which is reflective and reduces evaporation and therefore limits transpiration. Additionally, certain plants have fewer leaves with smaller surface area which limits area of transpiration and also less leaves to transpire. Leaves of certain xerophytes stop growing during the dry season therefore greater moisture conservation. Rolled leaves can also be found in xerophytes to reduce leaf area exposure. Their leaves may be covered with a layer of light-coloured hairs or thorns which acts as a wind break, produce small shadows on the surface of the plant which cools it, trap humid air and are a light reflecting surface.
Furthermore, the plants might also have succulent stems which mean the stems are more fleshy and spongy to help store water.
Stomata
The stomata might be located in different places for different plants depending on their habitat.
Some plants might have stomata in pits and grooves which helps increase humidity in the air currents around the stomata. In order to create humidity and reduce exposure to air currents, some plants might also have stomata inside of a rolled leaves. The rolled leaf also exposes less surface area. In some plants, the stomata might also be located on the underside of the leaf to limit exposure to heat which means less transpiration takes place. As more stomata mean more transpiration, the amount of stomata also seem reduced in certain plants.
Additionally, the stomata are normally closed during the day. This reduces the amount of water being lost due to the temperature, air currents, etc. They open at night and photosynthesis can still take place as a result of the change in a chemical process within the plant (Crassulacean Acid Metabolism).
Certain plants also have more supporting tissues (fibres) which strengthen the plant so that if it begins to wilt through lack of water it won’t completely collapse. The movement of xerophytes are normally away from the light to avoid surface exposure to the sun and therefore reduce the amount of transpiration that takes place.
Reproduction
The plants can be dormant for years until the right moisture conditions occur and then they can complete their whole reproductive cycle in a few days. Some sand dune plants also have the ability to adapt to fast changing levels of sand.

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Information from:
http://www.conservancy.co.uk/learn/downloads/fieldtrips/xerophytes.pdf