Study Fig. 2, a description of the effect of rain in a desert area. It's amazing the difference a drop of rain can make. Millions of seeds have been lying dormant waiting for water. Overnight dew has kept the Desert Thorn alive but now it has sprouted new growth. Land that had been parched and barren now supports a wide variety of vegetation. Depressions in the landscape have retained moisture and now have a thick carpet of bright yellow Pulicaria flowers. Ground-hugging plants are spreading rapidly. Even wheel ruts criss-crossing the landscape now contain long lines of pale, silvery-green tasselled grasses. Bushes are blooming. Arabian Tamarisk, with spikes of pale pink, is interspersed with the yellows, greens and purples of the Zygophyllum plants, while the Caper plant, with its large white blossoms, is looking spectacular. [Figure 2]