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Wild pansy's flower stalks are long, hairless, and bend like a shepherd's crook just below the base of the flower so the flower axis is approximately horizontal. Individual flowers have five 7-15 mm long, lance-shaped sepals that are longer than the petals and are sharply pointed at their tips; a 4-12 mm long corolla with five white or pale cream-colored petals, a yellow throat with a few dark purple lines, the lateral petals bearded on their upper surface, and a 1-1.5 mm long spur; two stamens not visible externally; and a single style enlarged into a hollow, globose stigma. The fruit is a spherical or ellipsoidal three-valved capsule, 5-10 mm long containing 6-75, 1.5 mm long, brown seeds.

Viola

Viola arvensis

wild pansy [Blooms: Jun-?]

Birdfoot violet (Viola pedata) is a native perennial widely distributed in the eastern half of the U.S. and Canada. The flower stalks (peduncles) arise from the rootstock, reaching heights of only 3-6" tall. The leaves also arise directly from the rootstock, making them formally basal leaves. The flower stalks are green or purple, up to 4" long, each bearing a single flower at its apex. Each flower is 3/4-1.5" across. Visible components include five green sepals; five pale blue-violet to dark purple-violet petals; a tight grouping of orange stamens that pokes out of the throat of the flower; and a short (2 mm long) green style with an oblique, concave area near its tip that is hidden inside the flower. Most violets show some degree of self-fertilization within unopened flowers (cleistogamy) but birdfoot violet does not. Pollination is usually mediated by long-tongued bees and skippers and other small butterflies. Birdfoot violet uses two steps to disperse its seeds. First, the drying 3/8" long seed capsule exerts increasing force on the tiny (~2 mm), copper-colored seeds; at some point, the three segments of the seed capsule split apart and the seeds are explosively ejected (an average of 4.5 feet, but up to 15 feet) "much like a marble squeezed between the fingers" (Beattie and Lyons. 1975. Am. J. Bot. 62:714-722). A stalk-like structure on the seeds (the elaiosome) that is made of a sugary gel encourages ants to pick up the seed (or a clump of seeds) and carry them back to the ants' nests where they germinate. All petals in a flower may be the same color, or the upper two petals may be dark purple-violet while the lower three petals are pale blue-violet. Near the throat of the flower, the base of the lowest petal is white with fine violet nectar guides; this petal extends to form a short spur at the back of the flower. Unlike common violets, there are no white hairs on the lateral petals that occlude the throat of the flower. Birdfoot violet is easily distinguished from the other violets in Jackson Park by the large size of their flowers, the absence of white hairs occluding the throat of the flower, and the deeply lobed leaves.

Viola

Viola pedata

birdfoot violet [Blooms: May]

Yellow violet is a native perennial, the only yellow violet species in Jackson Park (indeed, in all of Illinois). One or more stems arise from an axil of a stem leaf; they are up to 6" tall with a single 3/4" long flower at their tips. Each flower consists of five light green sepals, five yellow petals, five stamens, and a single style; the stamens and style cannot be seen from the exterior. On the lower petal, the flowers have purple lines (nectar guides) and a spur reduced to a small pouch. The two lower, lateral petals have small tufts of hair that obscure the throat of the flower and hide the stamens and style; the two upper, lateral petals are beardless and have only faint lines (nectar guides), if any. The fruit of this species is a bullet-shaped (hairless in the Jackson Park forms) capsule nestled in the calyx with the remnant of the style at its tip, initially green but turning brown as it matures; it ultimately splits along three suture lines to fling the seeds away from the plant.

Viola

Viola pubescens

yellow violet [Blooms: Apr-May]

Common blue violet flowers are 3/4-1" across with the calyx formed from five elongate oval, dark green sepals with a pointed tip, five petals (two upper, two lateral petals with white hairs ("beards") that occlude the throat of the flower, and one lower petal with a white patch and superimposed dark blue lines near the throat). The lower petal has a pouch (the "spur") that extends backwards past the base of the sepals; the spur houses the ovary, single style, and stigma (positioned just behind the petal beards) and, more posteriorly, the nectary. The two stamens surround the ovary and can't be seen without dissecting the flower. Flower color may range from deep violet to white with a purple center, all fading to pale yellow in the center. The fruit is a bullet-shaped capsule 1/4-1/2" long that is nestled in the calyx with the remnant of the style at its tip, initially green but turning brown as it matures; it ultimately splits along three suture lines to fling the approximately 75 seeds, beige or bronze in color, 1.5-2.5 mm long, away from the plant. Much of the reproduction occurs from vegetative clones produced from the rhizomes. Common blue violet prefers light sun or partial shade and a rich soil.

Viola

Viola sororia

common blue violet [Blooms: Apr-May]