poppysue maybe this will help
It almost looks too shiny to be the Jerusalem Artichoke. Maybe you can tell from this picture http://communities.msn.com/PoppysuesGarden/pernnialshi.msnw?action=ShowPhoto&PhotoID=307 The roots have a tuber that's eaten like a potato. I've got them all over here. They spread like a weed.
I believe this might be it. I'll go as soon as I can and check it again.