It is legal to possess opium poppy seeds because otherwise, no one would ever be able to have a lemon-poppy seed muffin again and McCormick and other spice companies really don't want that to happen.

It is illegal to possess any other part of the opium poppy, but because it's the opium poppy seed that provides the "poppy seed" used in baking and the flowers themselves are so beautiful, many seed companies fudge the scientific name -- there's the "real" scientific name and there's the "fudge" name that refers to the flowers in Latin, but it's the same flower.

Opium poppies reseed very easily -- they have naturalized in Canada from the Chinese immigrants in the 19th century, so Canada doesn't even bother to ban them at all.

The Seed Savers Exchange Yearbook usually contains 3 pages of heirloom opium poppies -- mostly from the plains of Eastern Europe where they were used as a walnut subsitute. SSE's attitude has been "ya want to arrest a bunch of 80 year old Hungarian women or are we all going to pretend these pages aren't here?" So far, DEA has decided it isn't worth it.

Don't overpay for poppy seeds -- the ones from McCormick are probably irradiated, but you can buy them the same as any other flower from the major flower seed companies.