This genus is similar to that of the common poppy except that the stems of the individual flowers (peduncles) are less than 2 inches long and the capsules are linear. According to the Flora of the Great Plains, this species was first reported for the U.S. in Clark County Kansas in 1979. It has since been reported for California, Oregon, Oklahoma, Texas, Montana, Nevada, Pennsylvania and 8 other states. Any new sightings should be reported to your state Department of Agriculture.