This is a Jumping Cholla cactus.  The yellow ends of each branch can jump off the cactus and onto a passerby.  Apparently the cactus doesn't really "jump".  Instead, the wind will blow the yellow part off of the cactus and if you happen to be passing by, it will stick to you. There were many of these on the trail.

I took lots of pictures of the desert landscape and various cacti.  For some reason I really like Saguaro cacti (the tall skinny ones like in this picture).  By the time you look through all these pictures for this trip you'll be sick of seeing them.

Another view of the same cactus.  The little light green cactus in the front is a Pear Cactus -- but you probably already knew that.

Saguaro cacti need to be around 50 years old before they get any arms.  I'm not sure how many they get after that.  But some, like this one, end up with a lot of arms.  You see more arms on the cacti out in the desert than in the city because most of the cacti in the city are transplants.  It's a lot easier to transplant a cactus without arms that one with arms.

This picture is looking back towards where the car is parked. It's not very exciting.  I don't know why I took it.