While violas will readily reseed in the garden I wanted to collect seeds from my Viola 'BlackJack' blooms as a backup because I was growing them in a small terracotta pot on my porch garden. Before I could collect seeds I had to make sure the blooms were pollinated. The tiny blooms on these plants made finding the right tool difficult, artist brushes were too large so I ended up using a hair from my beard. Yes, you read that right. It seems like a lot of trouble to go through for a garden annual but the seeds for these violas were kind of expensive.
The almost black flowers of Viola 'BlackJack' before being hand pollinated by me since small pollinators in the garden weren't paying them any attention. Inserting a hair into each of the opening and ensuring there was a coating of pollen on it was like threading a needle. I found that in my quest to collect viola seeds this was the hardest part of the process.
After a few days the violas began to form seed pods. If you're trying to figure out where the seeds are on viola plants just look for the sepals or spent blooms. When the pod is brown and crispy you can safely remove it from the stem and break it open to release the seeds, then set the seeds out to dry.
Here is another photo of a viola seed pod that I collected seeds from. As you can see the seed pod has split open.
Another photo showing two viola seed pods I collected from my container garden. Both of the seed pods are ripe and reveal a cluster of small, tan-colored seeds inside of each pod. Unlike other seed pods I don't find that I had to keep a constant eye on the developing seed pods to catch them when they were just ripen enough. The seed pods pictured here had been open for a few days and even managed to hold onto their seeds during a rainy spell. Collecting viola seeds isn't hard once you know where to look for the developing seeds on your plants. If you combine the seeds you collect every year with the seed you purchase every spring you'll have plenty of edible flowers in the garden. Or you could share the seeds with gardening friends, swap the seeds you save for seeds you don't already have with other gardeners.
See my post on How to Save Seeds. In it you'll find tips for the beginner gardener who would like to save seeds.