If one adopts the most common opinion, Pallas' wallflower becomes sanddune wallflower, Erysimum capitatum, and looks a lot more like this. Or even clear yellow. And it grows all over the west, in almost any habitat that's not inundated. It produces many forms with all its adaptation to habitats, and that variation underlies the confusion in nomenclature. It commonly reproduces asexually, continuing lines that prove successful even in microhabitats. So, many species, or all one?