An important feature for distinguishing this species from other blue and violet-flowered Violets are the club-tipped hairs inside the two lateral petals.
Here is a close-up photo of these hairs.
Another photo of the club-tipped hairs.
Typical Marsh Blue Violet leaf.
Marsh Blue Violet grow in really wet areas. They grow in or almost in the water, usually in clumps, or there's water very close by.
Another view of a flower.
Here is a photo of a less typical flower. This may in fact even be a hybrid. It has club-shaped hairs inside, but the flower colour is not typical of this species.
This photo is included here to show the difficulties that one encounters with Violets!