Encyclopedia Article


A plant common to the U.S. Southwest, cactus grows in habitats that regularly experience drought. Most cacti are considered succulents, meaning that they store water above ground in their flesh, water they scavenge from their harsh climate with their extensive, wide-spreading root systems. As a result, many cacti grow spines, which are modified leaves, which can prick to the touch. These spines protect the plant against herbivorous predators on the hunt for water during the brutal dry spells that help to characterize their desert environs.

Photo Credit: 

"Rooftop cactus garden on old University of New Mexico Bookstore, currently CERIA, 1997," photograph by Kate Nash, (acc 028 017 017), Center for Southwest Research, University of New Mexico