Viola arvensis
Viola clauseniana
European field violet, European field-pansy, field pansy, field violet, pansy, violette des champs, wild pansy
Clausen's violet
1–5, usually erect, sometimes prostrate or decumbent, branched, subglabrous or puberulent, clustered on taproot.
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, 2–10, often prostrate, sometimes ascending;
stipules narrowly lanceolate, margins faintly glandular-toothed, apex acute or obtuse;
petiole 5–11 cm, glabrous;
blade unlobed, ± deltate, 3–5 × 4–5 cm, base ± truncate, margins serrate, ciliate or eciliate, apex obtuse, surfaces usually glabrous, sometimes sparsely pubescent abaxially.
2–8 cm, glabrous or pubescent.
8–14 cm, glabrous.
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 to ovate, margins eciliate or ciliate around auricles, auricles 1–2 mm;
petals light violet on both surfaces, lower 3 purple-veined, all beardless, lowest petal 8–20 mm, spur white, gibbous, 2–3 mm;
style head beardless; cleistogamous flowers on prostrate to ascending peduncles.
± spherical, 5–9 mm, glabrous.
oblong, 8–10 mm, glabrous.
brown, 1.5–1.9 mm.
dark brown to black, 1.2–2 mm.
= 34.
= 44.
Viola arvensis
Viola clauseniana
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.)
Of conservation concern.
Viola clauseniana is endemic to Zion National Park, Washington County. M. S. Baker reported that its seeds were minutely roughed, a characteristic not recorded for other Viola species. Viola clauseniana was originally thought to be closely related to the acaulescent blue violets, most notably V. nephrophylla (S. L. Welsh et al. 1987; L. E. McKinney 1992). After contemplating the 2n = 44 chromosome count obtained by J. Clausen (1964), H. E. Ballard (pers. comm.) suggested that V. clauseniana might be more closely related with the stemless white violets (for example, V. blanda) than with V. nephrophylla. Viola clauseniana was considered a distinct species by N. H. Holmgren (2005d) and T. Marcussen and T. Karlsson (2010).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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