I'm guessing that you mean Meconopsis cambrica (the Welsh Poppy) in which case the seeds do contain potentially hallucinogenic alkaloids....but that's obviously also the case for the Opium Poppy which we all eat quite merrily.....I can't find any reference to anyone eating M. cambrica seeds however, though the flowers and foliage are all non-toxic.

The edible poppy seeds are from the oriental poppy or papaver somniferum, I wouldn't like to try eating any other sort just in case.

If they are the California poppy or the Mexican Tulip poppy (Hunnemannia), both of which are yellow, I wouldn't eat those, either.

Thanks...guess I won't be baking lemon and poppy seed muffins then!

You could bake the muffins and try them out at the next 'Rural' coffee morning, Gaia, Please let me know the results as we have a lot od Welsh Poppies in the garden :-).