Marsh Violet, Viola cucullata, is a perennial wildflower is consists of a low rosette of basal leaves spanning about 6 inches across, from which one or more flowering stalks develop. The basal leaves are up to 3½ inches long and 3½ inches across; they are ovate-cordate, cordate, to nearly orbicular in shape and their margins are crenate-serrate. Leaf bases are indented, while leaf tips are rounded to bluntly pointed. The root system consists of a crown with fibrous roots and rhizomes.
Solitary flowers are produced at the tips of pedicels up to 7 inches long. The erect to ascending pedicels are light green to light purplish green and glabrous. Each flower is about ¾" across, consisting of 5 medium to dark blue-violet petals (rarely white), 5 light green sepals, and the reproductive organs. The petals are elliptic-obovate in shape and about twice the length of the sepals. The 2 lateral petals have short white hairs with swollen tips near the throat of the flower. The lowermost petal has a patch of white with radiating purple veins in the front, while in the back it has a short stout nectar spur. The sepals are linear-lanceolate and glabrous; they usually have pointed auricles (eared basal lobes) up to 4 mm. long. The blooming period occurs from mid- to late spring for about 1 month. Afterwards, successfully fertilized flowers are replaced by seed capsules about ½-inch long that are light green and ovoid-oblongoid in shape. In addition to these flowers, cleistogamous (self-fertile) flowers are produced that lack showy petals. The cleistogamous flowers are produced on ascending pedicels during the summer. At maturity, the capsules of both types of flowers split open into 3 sections, to eject their seeds. Individual seeds are about 2.5 mm. in length, globoid in shape, and dark-colored.
Habitats include marshes, bogs, swamps, seeps, and borders of rocky streams. This violet is found in both sandy and non-sandy wetlands in both shaded and unshaded areas.