Parkinsonia florida, the blue palo verde, is a species of palo verde native to the Sonoran Deserts in the Southwestern United States and Northwestern Mexico. Its name means "green pole or stick" in Spanish, referring to the green trunk and branches, that perform photosynthesis.
This cache is on Arizona State Trust land so a ASTL recreation permit is required to search for this cache. Per their webpage, all geocachers must have a recreation permit which is available on the Arizona State Land Department's website in order to geocache there. I keep one in my geomobile and a copy in my cache pack.