2. Viola arvensis Murray (wild pansy, European field pansy)

Pl. 575 a; Map 2693

Plants annual, with a slender, vertical taproot 1–2 mm thick. Stems 8–35 cm long, erect or ascending. Leaves alternate and basal, subsessile to long-petiolate, the petiole glabrous or minutely and inconspicuously hairy. 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 much longer and broader than lateral ones, usually entire. Leaf blades 0.5–2.5 cm long, unlobed, obspatulate to obovate, broadly to narrowly angled to a bluntly or sharply pointed tip, broadly angled to rounded at the base, the margins otherwise bluntly toothed, the surfaces glabrous or minutely and inconspicuously hairy. Cleistogamous flowers not produced. Flower stalks not or only slightly overtopping the leaves. Sepals 7–15 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 shorter than the sepals, white or pale cream-colored with a yellow throat (this usually best developed on the lower petal and there usually also with a few, dark purple lines), 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 5–10 mm long, broadly ellipsoid, green, drying to tan, the surface glabrous. Seeds 1.5–1.7 mm long, tan. 2n=34. April–June.

Introduced, uncommon in the eastern half of the state (native of Europe, introduced nearly throughout the U.S. [except in some portions of the Great Plains], Canada, Greenland). Edges of forests; also old fields and railroads.

Steyermark (1963) excluded this species from the Missouri flora, having concluded that a historical specimen from Johnson County that was reported as this species by Palmer and Steyermark (1935) had been misdetermined. The specimens currently accepted as escapes of V. arvensis in Missouri were all collected after 1970.