prickly sowthistle, Sonchus asper

Our sowthistles are weedy plants, often in planted fields or flower beds.  Hence their name, which has much more to do with planting than with pigs.  Wiki says the spiny leaves are not only edible, but "palatable".  Never realized what a distance there is from palatable to good!  Prickly sowthistle could be gathered in every state and province except NT and NU, and from GL and SPM.  Lenawee Co MI, 6/19/11.  Aster family, Asteraceae.