Cacti / Desert Succulents

Silver Cholla Bloom

National Park Service

 

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)
Cylindropuntia bigelovii (teddybear cholla)
Cylindropuntia chuckwallensis (chuckwalla cholla)
Cylindropuntia echinocarpa (silver cholla)
Cylindropuntia ramosissima (pencil cholla)
Echinocactus polycephalus (cottontop cactus)
Echinocereus engelmannii (hedgehog cactus)
Echinocereus mojavensis (Mojave mound cactus)
Ferocactus cylindraceus (California barrel cactus)
Grusonia parishii (matted cholla)
Mammillaria tetrancistra (common fishhook cactus)
Opuntia basilaris var. basilaris (beavertail pricklypear)
Opuntia chlorotica (dollarjoint pricklypear)
Opuntia phaeacantha (tulip pricklypear)
Opuntia polyacantha var. erinacea (grizzlybear pricklypear)