Tonight I learned that cat nip is in the mint family. I let the boys run around out back this evening, and found Lemur very joyfully rolling around and rubbing his face in a patch of leaves. He seemed utterly content. At one point Wiley walked over to him and started licking his face and chewing on the leaves.
When I picked Lemur up to go inside, I noticed he smelled minty fresh. And he was purring his head off, not something he usually does when forced back into the house. I quickly looked up "cats and mint" and learned my 'something new for the day.'
Apparently in many parts of the world, cat nip is called 'cat mint.' All plants in this family produce a group of chemicals that cats apparently enjoy. Based on Lemur's response, I'd add "...quite a bit." Twenty-five years of cat companions and I never knew this. Fun little discovery, I'm going to plant more.