Geoscience Reference
In-Depth Information
Figure 4.3. Saguaro desert cactus (
Carnegiea gigantea
), near Tucson, Arizona.
but was probably imported originally from Mexico. The mountain summits of the
Red Sea Hills are scattered with spectacular
Euphorbia candelabra
trees and derive
some of their water from the mists that sweep up in winter from the Red Sea, just as
the succulents of the Namib Desert benefit from more than 200 days of coastal fogs
a year.
One group of succulents able to store water and tolerate high soil salinities is the
desert saltbush (
Atriplex
) of the Australian outback. In fact, during a time of successive
droughts that had driven many South Australian wheat farmers in the semi-arid zone
bankrupt during the 1860s, the surveyor-general of South Australia, George Goyder,
covered 30,000 km (approximately 20,000 miles) on horseback and in 1866 used the
southern limit of saltbush and what he had observed about the soils to define what
