Violet family (Violaceae)
Description: This herbaceous perennial plant consists of a rosette of leaves about 6" across, from which flowering stalks develop directly from the rootstock. Each blade of a basal leaf is up to 3½" long and 2½" across, while its petiole is about as long as the blade. The leaf blades are deltoid-cordate to oval-cordate, glabrous or nearly so, palmately veined, and crenate along their margins. The petioles are rather stout, pale green, hairless or nearly so, and widely spreading to ascending. The ascending flowering stalks are about as tall as the leaves; the stalks are pale green to pale reddish green and hairless.
Each stalk nods downward at its apex and terminates in a single flower. Each flower is about ½–¾" across, consisting of 5 pale blue-violet petals and 5 pale green sepals. The lower lateral petals are bearded with white hairs near the throat of the flower; the lowest petal and upper lateral petals are beardless. The throat of the flower is white, and there are dark blue-violet veins on the lowest petal and lower lateral petals that function as nectar guides to flower-visiting insects. Sometimes the white throat of the flower is surrounded by a band of blue-violet that is slightly darker than the outer regions of the petals. At the back of each flower, there is a short blunt nectar spur. The blooming period occurs during mid- to late spring and lasts about 1½ months. Somewhat later, cleistogamous flowers are produced that are self-fertile; they lack showy petals. Each fertilized flower is replaced by a tripartite seed capsule. The small seeds in each capsule are dull light brown with oily elaisomes; they are ejected mechanically from the capsule. The root system consists of a short crown with thick rhizomes and fibrous roots. Reproduction occurs through the seeds and rhizomes.
Cultivation: The preference is light shade to partial sun, moist to mesic conditions, and a fertile loamy soil with abundant organic material.
Range & Habitat: The native Missouri Violet occurs occasionally throughout Illinois; it is more common in the southern half of the state than the northern half (see Distribution Map). Habitats include deciduous woodlands (bottomland or floodplain), woodland openings, areas along woodland paths, and rocky bluffs. The Missouri Violet doesn't occur in sunny areas to the same extent as Viola sororia sororia (Common Blue Violet) and its various color forms.
Faunal Associations: The flowers occasionally attract bees and other insects, including the oligolectic Andrena viola (Violet Andrenid Bee). These insects suck nectar from the flowers, although some of the bees collect pollen. The caterpillars of several Fritillary butterflies (Speyeria spp., Boloria spp., & Eupoieta claudia) eat the foliage of Viola spp. (Violets). Because of their oily elaisomes, the seeds are distributed in part by ants. The seeds of Violets are eaten to a limited extent by various birds and small rodents, including the Wild Turkey, Bobwhite, Mourning Dove, and White-Footed Mouse. The Wild Turkey also eats the foliage and fleshy rhizomes. Mammalian herbivores eat the foliage to a limited extent.
Photographic Location: Along a woodland path at Busey Woods in Urbana, Illinois.
Comments: The Missouri Violet is very similar to Viola sororia sororia (Common Blue Violet). It differs from the latter species in the following ways: 1) the Missouri Violet has leaf blades that are more deltoid (triangular-shaped) and less rounded than the blades of the Common Blue Violet, 2) the flowers of Missouri Violet are a lighter shade of blue-violet and slightly smaller in size than the flowers of the Common Blue Violet, and 3) the seeds of Missouri Violet are a lighter shade of brown. The Missouri Violet is even more similar to Viola sororia priceana (Confederate Violet) because their flowers are about the same shade of blue-violet. However, the Confederate Violet has more rounded leaf blades, seeds that are a darker shade of brown, and it is often found in close proximity to the Common Blue Violet, with which it freely interbreeds. The Missouri Violet is classified as a variety of Viola sororia by some authorities, in which case its scientific name is Viola sororia missouriensis.