Plants and animals make special adaptations to the desert environment. Some plants are annuals. They race the sun to make seeds before the water evaporates and the heat dries them up. Some of these plants are so tiny that the whole plant could be hidden under a dime. Others spread colorful blossoms over the sand and rocks for a few brief days.
Some plants develop water-storing strategies.
Cacti have chlorophyll in their fleshy stems, and they store the water that they gather in those stems. They defend themselves with sharp spines. They have large networks of roots that lie under the ground near the surface of the soil. If it does happen to rain, these roots can soak up the water quickly. Many cacti have corrugated stems which can expand quickly if water becomes available.