Xerophytes

Posted by Robert Dailey Jan 26, 2008

Xerophytes (from the Greek xeros meaning dry and phytos, meaning plant) are plants that have adapted to deserts and extremely arid conditions by actually changing their physical structure. They are by far the largest group of plants living in the southwestern deserts of North America.

Additionally, different xerophytic species have colonized different deserts. Mesquite (Prosopis var.), yucca (Yucca var.) and prickly pear cactus (Opuntia var.) are the dominate plant species in the Chihuahuan Desert. In the Mojave, Joshua Trees (Yucca brevifolia) and creosote bush (Larrea tridendate) thrive. The Sonoran Desert is noted for the giant saguaro cactus (Cereus giganteus), Paloverde (Cercideum microphyllum) and ironwood (Olneya tesota) . Vast fields of sagebrush (Artemesia tridentata) and saltbush (Atriplex canescens) are the primary vegetation in the Great Basin Desert.

Cacti are actually members of the rose family which have become xerophytic. They are among the most drought-resistant plants on Earth, mainly because they have no leaves, have shallow root systems and can store water n their stems. They have spines for shade and protection and have a waxy skin to keep them rom losing moisture.

Many other xerophytic plants have adapted to desert conditions by losing their leaves as well, replacing them with thorns (not the same thing as spines). Some instead have drastically reduced the size of their leaves.