Violet family (Violaceae)
Description: This native perennial plant consists of a rosette of basal leaves about 5" across. The blade of each basal leaf is about 2" long and ¾" across; it is oval to ovate-oblong, crenate and ciliate along the margins, and more or less hairy, especially along the lower surface. The bottom of each leaf blade has small basal lobes that are rather pointed, while the tip of the leaf blade is rather blunt and obtuse. The leaf blade may fold upward along its central vein. The stout petiole of each leaf is green to reddish brown and hairy; it is as long as the leaf blade or a little shorter.
From the center of the rosette, there develops one or stalks of flowers up to 6" long. Each stalk develops directly from the rootstock and is rather hairy; it is naked, except for a pair of tiny leaf-like bracts near the middle. At the apex of each stalk, there is a single flower about ¾" across. It consists of 5 green sepals and 5 blue-violet petals consisting of 2 upper lateral petals, 2 lower lateral petals, and a bottom petal. The sepals are lanceolate and glabrous or hairy. The lower lateral petals have conspicuous white hairs near the throat of the flower. The bottom petal is white at the base and it has dark blue-violet lines that function as nectar guides for visiting insects. The blooming period occurs from mid- to late spring and lasts about a month. There is no noticeable floral scent. Flowers that are successfully cross-pollinated will develop oblongoid capsules that contain many seeds. Later, self-fertile cleistogamous flowers will develop from erect or ascending stalks; they lack petals and are inconspicuous. The cleistogamous flowers produce seeds that are mechanically ejected. At maturity, the seeds of both types of flowers are small, globoid, and brown. The root system consists of a stout scaly rhizome with fibrous roots.
Cultivation: The preference is full sun to light shade, moist to slightly dry conditions, and sandy soil.
Range & Habitat: The Sand Violet is occasional in sandy areas of central and northern Illinois, otherwise it is rare or absent. Habitats include sandy woodlands, thinly wooded slopes, sandy savannas, sand prairies, semi-shaded areas along sandy paths, and abandoned sandy fields. Usually, this species is found in mesic to slightly dry areas of these habitats. It benefits from occasional wildfires, as this reduces the competition from taller vegetation.
Faunal Associations: The flowers of Violets are pollinated by bees, especially Mason and Andrenid bees. Butterflies and skippers may suck nectar from the flowers, but they are less effective at cross-pollination. The foliage of Violets is eaten by the caterpillars of Fritillary butterflies and several species of moths (see Butterfly & Moth Table). The seeds are eaten to a limited extent by upland gamebirds, including the Mourning Dove, Ruffed Grouse, Bobwhite, and Wild Turkey. The Wild Turkey also digs up and eats the rhizomes. The White-Footed Mouse also eats the seeds of Violets, while the White-Tailed Deer and Cottontail Rabbit browse on the foliage only very sparingly.
Photographic Location: Along a path through a sandy savanna that had been subjected to a recent wildfire in Kankakee County, Illinois.
Comments: The Sand Violet is closely related to Viola sagitatta (Arrow-Leaved Violet), and it is classified as a variety of the latter species, Viola sagitatta ovata, by some authorities. The Sand Violet is usually hairier and its leaves are more broad with blunt tips. The Arrow-Leaved Violet has leaves that are more lanceolate with spreading basal lobes (i.e., they are hastate in shape). It occurs throughout Illinois in both sandy and non-sandy habitats.