Thanks for the comments, everyone. With a couple of kids extremely allergic to poison ivy, and with it very abundant in this area, I long ago learned to spot it at a glance. It's deceptive, it can grow as ground cover, a climbing vine, as a small bush, or can even appear to refoliate a dead tree and droop over a trail in the woods. Leaves always grow in clusters of three, usually 2-3 inches in size, but can vary from an inch to the size of a dinner plate. The leaves are pointed, usually irregularily lobed (one side different from the other). Dark green and dull in summer, red and shiny when emerging in the spring, red or yellow in the fall. Mature climbing vines are usually hairy-looking. In the northeast US at least, the only thing resembling it is box elder tree leaves, and box elder seedlings (harmless) look very similar to PI plants. Contact with PI leaves or sap can cause a reaction in any season, and the active component can stay on boots, clothing and dog fur, and affect people later.

Great photo of the pretty red leaves. :) This desert lizard would be in big trouble around there...

Prettiest Poison Ivy I have seen

Beautiful image, I am pleased we dont have poison ivy over here, I understand it can effect some really quite bad.