Tucson Mountain Park

Tucson Mountain Park is found on the west side of Tucson, just outside of Saguaro National Park. This picture shows a wash (dry river bed). These areas flood and become very dangerous following a rain (even a small rain of 1 cm!)
There is a lot of plant diversity in this area of the Sonoran Desert. Some of the plants you can see in this picture are cholla, palo verde, mesquite, prickley pear cactus, creosote, and saguaros.

Hiking trails run throughout Tucson Mountain Park.
Watch out for the Teddy Bear Cholla. It isn't as cute and fuzzy as it looks.
It is full of very spiny sections that attach to you or other animals like giant burrs. I found this out the hard way when I first moved to Arizona. I took my dog out hiking, and within 5 minutes of hitting the tail, he bumped into one of these chollas. Several 5-inch-long segments stuck into his flank. He tried to pull it off with his mouth, but instead ended up with the spines on his face and in his mouth. As I tried to help him, he panicked and transfered the remaining pieces of cactus to my arm.

Neither of us enjoyed the subsequent removing of the spines. The tip is slightly barbed, so even when you pull the main spine out, a tiny bit is left behind.
To this day, I still have scars on my arm from that incident - and it's been 17 years!
As you drive northwest through the park, you enter Saguaro National Park.