This is going to be slightly contraversial. There are two very similar species. Meconopsis baileyii and M. betonicifolia. Dr Chris Grey-Wilson, who has written the latest monograph on the Genus Meconopsis  recognises these as two separate species based, as I remember, on nine distinct characteristics. There are also sub species, one of which - M. baileyii ssp. pratensis - is very distinct and breeds true. M. baileyii occurs in S.E. Tibet and across to NE India. M. betonicifolia occurs in S.W. China - down in NW Yunnan. My theory, and I doubt anyone has taken any notice of of it (!), is that we know both these species were very valuable for obtaining oil for cooking and other purposes. The site in NW Yunnan where it now grows was on the trade route out of the Himalayas into China and I do seriously wonder if it was not introduced there and cultivated as a farm crop some thousands of years ago. Having got that off my chest we can return to cultivation problems!

               Plants grown from recently collected seed from the defined areas can be grown under the correct names. For us gardeners they are very difficult to tell apart and many of the characteristics do have overlap or need a taxonomists eye. They are not difficult and seed which is readily available from some commercial sources but also plentifully  from all three seeds exchanges mentioned above. If you really do want to grow the two species and make your own comparisons then you must be certain of your seed sources since they can be  very muddled in cultivation. The seed  is sown in the standard way. They germinate well and usually prick on and grow on without trouble. It is better, with a successful germination and lots of plants to put out, to dis-bud a small number and these  will go on and form nice large perennial clumps for further years which can be divided when dormant as they die back to resting buds. As almost always with Meconopsis you need at least two plants to cross pollinate for a seed set. The Yunnan plants are reportedly stoloniferous. This character when they are happy would allow the easy propagation of plants.