3. Viola bicolor Pursh (Johnny-jump-up, field pansy, wild pansy)

V. kitaibeliana Roem. & Schult. var. rafinesquei (Greene) Fernald

V. rafinesquei Greene

Pl. 575 d–g; Map 2694

Plants annual, with a slender, vertical taproot 1–2 mm thick. Stems 4–25 cm long, erect or ascending. Leaves alternate and basal, subsessile to long-petiolate, the petiole glabrous. Stipules relatively large and leaflike, free from the petiole, deeply lobed with a fringe of several, long, linear or oblong-lanceolate segments on each side, the terminal segment similar to the lateral ones, entire or with 1(2) pair(s) of blunt or rounded teeth along the margins. Leaf blades 0.7–3.0 cm long, unlobed, obspatulate to nearly circular, rounded or angled to a bluntly or sharply pointed tip, truncate to rounded at the base, the margins otherwise entire or with 1(2) pair(s) of blunt or rounded teeth, the surfaces glabrous. Cleistogamous flowers rarely produced (not observed in Missouri specimens). Flower stalks not or only slightly overtopping the leaves (those of the cleistogamous flowers erect or ascending). Sepals 3–5 mm long, lanceolate, angled to a sharply pointed tip, the margins glabrous, the basal auricles well-developed. Corollas 4–12 mm long, appearing strongly frontally flattened in life, the petals longer than the sepals, pale blue to occasionally light blue or nearly white (the upper petals lacking dark blue tips), often with darker veins or dark purple lines, with a yellow throat (this usually best-developed on the lower petal), the lateral petals bearded on the upper surface with mostly knob-shaped hairs, the lowermost petal glabrous on the upper surface, the spur 1.0–1.5 mm long, well-exserted beyond the sepal auricles, relatively stout. Stamens not exserted, typically not visible without dissection of the flower. Style enlarged into a globose, hollow stigmatic tip. Fruits 4–6 mm long, broadly ellipsoid, green, drying to tan, the surface glabrous. Seeds 1.3–1.5 mm long, tan. 2n=34. March–May.

Common south of the Missouri River, scattered farther north (eastern U.S. west to South Dakota, Arizona, and Idaho, Canada). Glades, disturbed margins of loess hill prairies, ledges and tops of bluffs, savannas, openings of bottomland and upland forest, and banks of streams, rivers, and spring branches; also old fields, pastures, fallow fields, margins of crop fields, gardens, railroads, roadsides, and open disturbed areas.

Steyermark (1963) reviewed the long-standing controversy on whether this taxon is native in North America, but did not express an opinion. Russell (1965) also discussed the topic, concluding that Shinners (1961) had provided a convincing case for its nativity (albeit with weedy tendencies) in eastern temperate North America. It is also accepted as a member of the native flora in the present treatment. Although some botanists have treated the taxon as a variety of the European V. kitaibeliana, its morphology and chromosome number differ from that species.

As in some other members of the Violaceae, V. bicolor contains quantities of methyl salicylate (oil of wintergreen) in its taproot. It is a well-known winter annual with a complex seed dormancy. Unlike other pansies in Europe (or introduced as weeds here in North America), it apparently rarely produces cleistogamous flowers.