The Sahara Desert covers approximately one-third of the African continent and encompasses regions with a wide range of annual rainfall amounts and temperatures. Although plants are sparse throughout much of the desert, it is home to an estimated 1,200 species of vegetation, including halphytes, which grow in salt-rich soil. Scrub grass and shrubs grow in low-lying areas. Trees such as cypress, olive, acacia, date and doum palm grow in higher regions.
The Kalahari Desert is located in southwestern Africa and stretches across South Africa, Botswana and Namibia. The landscape is characterized by sand ridges and dunes, anchored by drought-resistant vegetation in some areas and seasonal grass plains in others. The camelthorn, a type of acacia, is unique to the Kalahari and one of the few trees to grow in the desert. It provides shelter, nutrients and food for other plants as well as animals. Another unique species is the Hoodia cactus, a slow-growing plant that stores water extremely well and flourishes in hot climates.
The Namib Desert, located in Namibia, has little vegetation except in dry riverbeds, where hardy plants tap into water below the surface and also store runoff from erratic, heavy rainfalls. One of these plants, the Welwitschia mirabilis, grows only in the Namib and the neighboring Kaokoveld Desert. A gymnosperm, the plant can grow to nearly five feet tall and has only two leaves. These plants have extremely long lives, with some estimated at 2,500 years old.
