Viola arvensis
Viola vallicola
European field violet, European field-pansy, field pansy, field violet, pansy, violette des champs, wild pansy
sagebrush violet, valley violet, valley yellow violet, yellow prairie violet, yellow sagebrush violet
1–5, usually erect, sometimes prostrate or decumbent, branched, subglabrous or puberulent, clustered on taproot.
1–5, decumbent or ascending to erect, leafy proximally and distally, ca. 1/2 subterranean, glabrate to puberulent, on caudex from usually vertical, subligneous rhizome.
cauline;
stipules palmately lobed, middle lobe oblanceolate, obovate, elliptic, or lanceolate, ± equaling leaf blade, proximal lobes dissected, shorter, margins ciliate, apex acute to obtuse;
petiole 0.5–2.3 cm, glabrous or puberulent;
blade: proximal ovate to ± oblong, distal narrowly or broadly lanceolate, 0.8–3.4 × 0.3–1.9 cm, base attenuate to ± truncate, margins coarsely crenate-serrate, ciliate or eciliate, apex acute to obtuse, surfaces pubescent abaxially, at least on major veins, glabrous adaxially.
basal and cauline;
basal: 1–6;
stipules adnate to petiole, forming 2 linear-lanceolate wings, margins entire, apex of each wing free, sometimes divided into filiform processes;
petiole 3–10 cm, glabrous or puberulent;
blade ovate to oblong-ovate, 1.5–4.3 × 0.9–1.1 cm, base usually truncate, sometimes attenuate, margins entire or serrulate, sometimes sinuate, ciliate (sometimes only on proximal 1/2 of leaf), apex acute to obtuse, surfaces glabrous or puberulent;
cauline similar to basal except: stipules linear to linear-lanceolate, margins ± entire, apex acute;
petiole 1.5–9.2 cm;
blade ovate or lanceolate to elliptic, 2.3–4 × 1–2 cm, length ca. 2.2 times width, base usually ± truncate to subcordate, sometimes attenuate on new leaves, margins sinuate, apex acute.
2–8 cm, glabrous or pubescent.
3–11.5 cm, glabrous or puberulent.
sepals lanceolate, margins ciliate or eciliate, auricles 2–4 mm;
petals white to pale yellow on both surfaces, upper 2 ± violet, lower 3 with yellow basal area, often violet-veined, lateral 2 bearded, ± equaling or shorter than sepals, lowest with dark yellow area basally, 7–15 mm, spur blue-violet to purple, elongated, 3–5 mm;
style head bearded; cleistogamous flowers absent.
sepals lanceolate, margins eciliate, auricles 0.5–1 mm;
petals deep lemon-yellow adaxially or on both surfaces, upper 2 often brownish purple abaxially, lower 3 dark brown- to brownish purple-veined, lateral 2 sparsely bearded, lowest 9–14 mm, spur yellow, gibbous, 0.8–1.2 mm;
style head bearded; cleistogamous flowers axillary.
± spherical, 5–9 mm, glabrous.
spherical, ca. 5 mm, glabrous or finely puberulent.
brown, 1.5–1.9 mm.
tan, 2.1–2.2 mm, elaiosome extending beyond and covering funiculus.
= 34.
= 12.
Viola arvensis
Viola vallicola
A. R. Clapham et al. (1987) noted that Viola arvensis is pollinated by insects and is often selfed; T. Marcussen and T. Karlsson (2010) stated that V. arvensis regularly self-pollinates. Roots of V. arvensis have the odor of wintergreen when crushed (A. E. Radford et al. 1968; W. J. Hayden and J. Clough 1990). Viola arvensis is not vegetatively distinguishable from V. tricolor var. tricolor.
G. Halliday (pers. comm.) reported that Viola arvensis occurs in southwestern Greenland, where it is introduced, and is ephemeral on St. Pierre and Miquelon.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
D. M. Fabijan et al. (1987) distinguished two varieties of Viola vallicola based on geographic location and type of leaf flavonoids: 1) var. major (Hooker) Fabijan, occurring west of the Continental Divide with leaf flavonoids primarily kaempferol derivatives; and 2) var. vallicola occurring east of the Continental Divide with leaf flavonoids all apigenin derivatives. Fabijan et al. reported that var. major (valley violet) occurs in sagebrush flats, prairie grasslands, open forests, juniper woodlands, 400–2800 m, in Alberta, Colorado, Idaho, Montana, Nevada, Oregon, Utah, and Washington.
M. S. Baker (1957) noted that there is only a tendency for leaves of Viola vallicola to be wide with truncate bases; on some plants only a few leaves are truncate. Images of type specimens at NY show truncate leaf bases for most basal and cauline leaves, with only some cauline leaves being attenuate. The key to V. vallicola in D. M. Fabijan et al. (1987) described the cauline leaf bases as truncate with some later cauline leaves becoming cuneate. G. Davidse (1976) stated that the V. vallicola plants he studied had cordate to truncate leaf bases; he made no distinction between basal and cauline leaves. Baker stated that V. vallicola may have given rise to V. nuttallii through a doubling of its chromosomes.
Because intermediate leaf forms are found in areas where Viola vallicola and V. nuttallii are sympatric, some question the specific status of V. vallicola. No hybrids involving V. nuttallii and V. vallicola are known (D. M. Fabijan et al. 1987).
V. Harms (pers. comm.) reported that Viola vallicola is frequent in southern Saskatchewan grasslands, usually occurring with V. nuttallii and appearing the more frequent of the two.
Observed pollinators of Viola vallicola in the intermountain region include flies in the genera Bombylius Linnaeus and Eristalis Latreille (G. Davidse 1976).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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