My coworker found this plant growing outside near our recycle bins and immediately came to me for identification. I had no idea what it was (I really only know about local, native forest plants). I believe it might be a weed of some kind. Location: Willamette Valley region (Polk County), Oregon, USA. Recently disturbed site. Time: Spring, 2012. Thank you for any help in identifying this plant! It has our little group of kitchen workers completely puzzled.