Plants adapt to the harsh climate of the desert in many ways, but most find some way to conserve water as much as possible. Some plants do this by storing water internally, while other plants have evolved waxy cuticles that cover their leaves, thereby limiting losses through transpiration. Additionally, a number of desert plants have evolved the ability to lie dormant until rains arrive.
Cacti are a group of plants that are supremely adapted to living in the desert. Cacti store water deep within the outer walls of the plant to help them survive during extended droughts. Further, cacti often have few, if any, leaves, which limits the amount of water that exists in the leaves. However, because cacti hold such resources, they must defend themselves from animals that would eat them for their water. Cacti have accomplished this by evolving sharp spines that cover their bodies.
Other plants produce seeds that last long periods of time, waiting underground for the rains to provide them with enough water to germinate. This allows the species to survive, even if individual plants die. Plants such as aloe, sedum and agave protect themselves from desiccation by having thick, waxy cuticles on their leaves.