Your porcelain cider pot was originally produced as a blank in Limoges, France. The plain green mark is indicative a 'white ware; producer that would sell for export or to a decorator studio. If this was decorated in a professional studio it would have a second stamped mark on the underside for the painting studio. If it does not have a 2nd mark, then the piece was purchased by a hobbyist decorator who added the poppies on their own. These cider jugs originally would come in a set with 5-6 matching porcelain tumblers. On today's market, expect to garner a high of $100 - $200 for the jug on its own. The suggested insurance or replacement value is $250.