Sparse, not empty

Life in deserts

Most desert plants are drought- or salt-tolerant. USGS Some desert plants store water in their leaves, roots, and stems. Others have long tap roots that penetrate the water table. USGS Deserts typically have a plant cover that is sparse but enormously diverse. USGS The Sonoran Desert of the American Southwest has the most complex desert vegetation on Earth. USGS

Saguaro grow slowly but may live 200 years. USGS When 9 years old, they are about 15 centimeters high. USGS After about 75 years, the cacti are tall and develop their first branches. USGS When fully grown, saguaro are 15 metres tall and weigh as much as 10 tons. USGS

Cold deserts have grasses and shrubs as dominant vegetation. USGS Whether hot or cold, deserts pose great challenges for the plants and animals that live there, which must adapt to extreme, prolonged water deficits. Met Office

Deserts of the United States

In the United States, three "hot deserts" receive precipitation in the summer months: the Mojave, Sonoran and Chihuahuan. USGS One "cold desert" receives precipitation in the winter: the Great Basin. USGS These US desert ecosystems receive less than 10 inches (250 mm) of annual precipitation. USGS Far from desolate, the deserts support high levels of biodiversity, including iconic species such as Joshua trees. USGS The Mojave Desert is among the hottest and driest of the North American drylands. USGS

Water, when it does arrive, is on the next page.