Janet

Rhubarb photo. (Thank you Cornell, I borrowed your pix.)
Rhubarb leaves are poisonous but the stalks are good for pies and sauces. As a kid, we just ate them fresh in the garden. Sour.

Burdock (photo VA Tech) burdock leaves aren't as smooth and are lighter in color. I know, if you don't have both, how can you compare?

I copied this off the Sacred Earth site: The leave stems can be peeled and cut and either added raw to salads, or added to various soups, stews or bakes, or even made into a candied sweet. Leaves are rarely used for food as they soon become too bitter and tough to be enjoyable. The roots however, are delectable, although they require some determined effort to collect, as they are long and deeply anchored. They usually need to be dug out. Once brought to the surface they must be thoroughly cleaned and peeled to cut away the tough outer rind. What remains can be prepared as a delicious root vegetable, with a slightly sweet, nutty flavour that some have likened to Jerusalem Artichokes. The roots are excellent when pureed or added to stews and soups. As a healing food, the root is particularly recommended for diabetes sufferers, as it is rich in inulin and helps to even out blood sugar levels.

There's a picture of it on my blog if you're interested.