Flower:

Irregular 5-petaled blue to purple flower less than ¾ inch (to 18 mm) long at the end of a long naked stalk usually held above the leaves at peak bloom. The 2 lateral petals have tufts of long, fine, white hairs at the base (bearded), the hairs typically more than 1 mm long. The lower petal is white at the base with dark purple veins radiating from the center, forms a slightly elongated spur at the back, and is also bearded but the hairs are hidden within the throat.

Sepals are lance-oblong to narrowly egg-shaped, blunt to rounded at the tip, and hairless.

Leaves and stems:

Leaves are all basal; color is medium green. Mature leaves are up to 2¾ inches (to 7 cm) long and nearly as wide, kidney to heart-shaped with a blunt or rounded tip; at flowering time, younger leaves are more typically longer than wide, rarely more than 1½ inches (~4 cm) long. Leaf edges are scalloped or have blunt serrations; surfaces are hairless, sometimes sparsely hairy on the upper surface, the lower surface sometimes purplish. Leaf stalks are hairless.

Fruit:

Both petalled (chasmogamous) and petal-less, self-pollinating (cleistogamous) flowers produce fruit, in an ovoid capsule up to about 3/8 inch (7 to 10 mm) long, initially green, erect when mature and drying tan.

Seeds are medium brown to dark olive-brown, 1.3 to 1.9 mm long.

Notes:

Northern Bog Violet has the widest distribution of the North American blue violets, covering all of Canada and most of the US except Alaska and the southeast and mid-Atlantic states. Several references note it having a preference for cold wet habitats such as bogs or in calcareous fens, but Minnesota herbarium collections are from all manner of moist to wet places including tamarack swamps, prairies, along river and stream banks, in rock crevices at the edge of a waterfall, and in wet woods. Most similar is Marsh Blue Violet (V. cucullata), which is distinguished from all other violets by its short (less than 1 mm long) club-shaped hairs on the lateral petals.