Desert plants deal with water shortages in two main ways:
ò One way is to grow, flower and fruit only when water is available, even if that's only once every few years. The plants that do this live all the rest of the time as seeds, and only come to life when it rains. If the winter rains are good, springtime flowering in the desert will be good too; but if the rains are poor, the flowering will be disappointing. Species that survive this way are called 'ephemerals'.
ò The other way of dealing with severe drought is to store up water internally during the rainy season. Cacti do this, which means they can keep growing year on year, and don't have to shrivel back to nothing each summer. Some of these 'permanent' plants, as they're called - the saguaro, for example - can store tonnes of water in their tissues. That's why they're called 'succulents'.
