I do find ccassional self-sown F2 seedlings that are rather variable and I hope to eventually select some forms for better foliage color.
Here's the not-so-cold-hardy but beautiful Viola walteri. The foliage reminds me of hardy cyclamens. Note also the tiny light purple flower.
Here's a picture of the seed parent - Viola striata. It's more upright growing, vigorous and has loads of (a little bit bigger) cream-colored flowers.
Below's an old picture of the F1, when it was only a year I think. The color of the flowers is washed out and should look a little more purple than it does. And also a foliage detail shot that shows undersides (top row) and upper leave surfaces (bottom row) for the two parents and the F1. Viola walteri is on the left, Viola striata on the right, with the F1 between them (eatly intermediate in appearance). The last picture (sorry it's so blurry) shows striata blooms (top row) compared to the F1 hybrid's blooms (bottom row). I never could keep walteri happy enough (or even alive) to have blooms of it to do a comparison picture.