Richard Kuehn noticed the little green frog posing on a Calla Lily. It's a Sierran Treefrog, also called a Chorus Treefrog.

They have the ability to change their color to match certain environments. They seem to enjoy being close to hot tubs. Here's a photo by Rich of one changing to match the wood.

I love these little frogs. At the first hint of moisture they begin to vocalize.
Thanks to Rich for allowing me to share these photos with you here.