Yes, we of course know there are a lot of other reasons for variation in flowers within species. Heck, too often we don't even know the species! For years, botanists have debated the question. The plants that include Oakes' and the other closely related Oenothera have been lumped together as O. biennis, common evening-primroses. At the other extreme they can be split into a bewildering array of species. Some authors have even got into comparing the relative size of the pistil lobes. Here, we will side with the splitters, because it gives us more pictures to look at. And like the butterfly, we will keep looking for the biggest and brightest.