Cacti / Desert Succulents
Hot temperatures pose special problems for cacti. Most leafy plants cool themselves during the day by opening their pores. The movement of water from stem to leaf to air keeps leaf temperatures from rising too high. Because their pores open only at night, cacti cannot take advantage of such transpirational cooling. They adapt to desert heat by internal mechanisms. Teddybear cholla, for instance, can withstand an air temperature of 138 degrees F. Most other plants would literally cook at this temperature, but teddybear cholla often rises 59 degrees F or more above the air temperature!
Cacti of Joshua Tree National Park
Coryphantha alversonii (cushion foxtail cactus)
Did You Know?
Joshua Tree is crisscrossed with hundreds of faults, and is a great place to see raw rocks and the effects of earthquakes. The famous San Andreas Fault bounds the south side of the park and can be observed from Keys View. More...