From a CNN story by Macie Goldfarb headlined “Phoenix’s record heat is killing off cactuses”:

At a botanical garden in Phoenix some cactuses can’t take the heat.

Record-high temperatures in Arizona, combined with a lack of seasonal monsoons, have caused saguaro cactuses at the Desert Botanical Garden to become “highly stressed,” according to Chief Science Officer Kimberlie McCue. She said a saguaro can appear “fairly normal” or feel somewhat squishy before it suddenly collapses and reveals it has been rotting from the inside out due to heat-related stress.