The tall, skinny cactus that has "arms", and is always associated with Arizona (because the Sonoran desert is the only place in the world where they are naturally occuring). I've seen many a prospective University of Arizona student's family all gather around a saguaro cactus to take pictures of it to show their friends back home. "Hey, look, Bob, there's me and the kids standing next to a real cactus!" Sadly, most non-desert dwellers aren't even familiar with the term "saguaro", and think that this is the only kind of cactus that exists; quite the contrary, there are many varieties, from the barrel cactus, to the cholla cactus, and the always exciting prickly pear.

Saguaros live for hundreds of years, and are sometimes homes to small birds that make their nests inside of them. They also have sharp spines sticking out of them, which not only provide the cacti with shade, but also have provided humorous sight gags for almost every cartoon I've ever seen.