wild radish, Raphanus raphanistrum
Wild radish plants are edible, but hopefully you're not often that hungry. When did you last save and eat the leaves from a bunch of radishes? That's pretty much what you would have with this. These wild roots are theoretically edible too, but they're really just too tough. Cultivated radishes are generally considered a separate species, perhaps originally derived from this one. Wild radishes can now be found in weedy situations in every state and province except NT, NU, and YT, and they're on GL and SPM. Beal Gardens, MSU, 7/27/11. Mustard family, Brassicaceae.