First Signs of Fall: Sour Grass in my Knish?

My new friend Marcia, from piano class, says she uses sour-grass to flavor her homemade knish recipe. Hummmm... check with somebody who knows more than me first, ok? Your local medical provider, maybe. If you've got one.

And don't use this much-altered picture of sour-grass to identify oxalis. I've altered it to make it arty. While you're looking, why don't you click on the picture to see the lovely details?