Flower:

Single flower at the end of a smooth to densely hairy but otherwise naked stem. Flowers are ¾ to 1 inch across, slightly irregular with 5 broadly spreading petals, the 2 side petals with thick tufts of white hairs (bearded) at the base. Petal color is typically a deep blue-violet, fading to white then pale yellow at the base, but this is a variable species that may have white or white and blue petals, all typically fading to pale yellowish at the base. The lower petal is heavily veined dark blue-violet, and forms a short rounded spur at the back that barely projects past the sepals. A plant has a few to several flowering stems arising directly from the rootstock.

Leaves and stems:

Leaves are all basal, to 2 inches long and wide, generally heart shaped with rounded lobes at base, rounded teeth all around the edges, on a stem up to 6 inches long. Lower leaves have more rounded tips, upper leaves more tapering to a blunt tip.

The upper surface is smooth, the undersided hairy especially along veins. Rootstock is thick and multi branched, often forming colonies. Leaf and flower stems are typically hairy, but may be smooth.

Notes:

This is a common urban violet, most likely in every county in Minnesota but with a few gaps in the herbarium collection. It is often weedy in gardens and lawns—my own yard is thick with it. I found it difficult to get rid of so caved in and now just let it grow where it will. Who wants a monoculture bluegrass lawn anyway, eh? Violets can be difficult to distinguish and Common Blue Violet's variability does not help with an ID. Typically it has bearded blue-violet flowers with a short spur, broad, heart-shaped basal leaves rounded or blunt at the tip, and is hairy to varying degrees. The white-petaled flowers may be confused for Canada White Violet (Viola canadensis), but it has stem leaves as well as basal leaves, and a much brighter yellow at the base of the petals. There are differences of opinion whether the different colored flowers are different species, or different varieties of V. sororia. Ditto those with hairy or smooth stems. At this time the DNR does not make any distinctions, so we won't either.