According to the USDA Plants Database there are 25 species of Viola in Indiana. So, if you don’t identify every one, don’t feel bad. I doubt that I’ll find them all. I’m pretty sure that the number of species in any particular genus is exactly proportional to the time that taxonomists spend looking at them. Some of the slight nuances that distinguish the different species are difficult to determine, and oftentimes they will say something like “often hybridizes”, meaning that there may be more of a continuum of genetic traits rather than distinct species. I’ve got nothing against taxonomists. It’s just that they can get a little OCD. On the other hand, here’s what some people think about them – Taxonomist Rant.
That said, the Canadian White Violet isn’t too hard to figure out. It’s a white flower with a yellow throat and the plant, leaves and flower have stems.