Can you see how different this looks from the Rocky Mountain image? Some do, some don't. Most botanists would agree that this is a pond-lily, although this particular one is in my files as bullhead-lily. That's only the beginning of the confusion. The genus has sustained botanical debate for centuries. At one extreme, there are many different species. At the other, they are all one pan-global species, N. lutea. Volume three (1997) of Flora of North America notes that molecular studies were ongoing, and could settle the debate. Good luck with that! Here in 2020 some current sources still divide the species while others do not. FNA notes that those studies have clearly shown that our plants are distinct from the Old World N. lutea. USDA still lists them all as subspecies under that taxon. So lets just go our own way, and consider them separate. That way we can look at more pictures.