I have a volunteer Viola in one of the boxes on my porch. It is 10 to 12 inches tall, no stem, and blooms look like spouted beans rather than like conventional bloom, and seed is set soon after the "blooms" appear. This is its second year in the box and it is now sucumbing to the cold as it did last fall.
What in the world do I have and how did I get it?
Mystery bloom on hardy Viola
Sounds like some variation on cleistogamous flowering... ?
I agree. Violas can have two types of blooms, the "regular" kind and the cleistogamous type. It's completely normal.