Viola howellii
Viola vallicola
Howell's violet, violette de Howell
sagebrush violet, valley violet, valley yellow violet, yellow prairie violet, yellow sagebrush violet
1–4, ascending to erect (sometimes later reclining to nearly prostrate), glabrous or sparsely pubescent, on caudex from subligneous rhizome.
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.
basal and cauline;
basal: 1–6;
stipules linear-lanceolate to oblong, margins mostly entire or laciniate with gland-tipped projections, apex acute to acuminate;
petiole 4–15 cm, glabrous or sparsely puberulent;
blade ovate to reniform, 1.9–6.8 × 2.1–6.4 cm, thin, base cordate, margins crenate, ciliate, apex acute to usually obtuse, surfaces glabrous or sparsely puberulent;
cauline similar to basal except: stipules linear-lanceolate or deltate to oblong, apex acute or long-acuminate;
petiole 1–4.5 cm;
blade 2–5.1 × 1.2–5.8 cm.
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.
2.8–17.8 cm, glabrous or sparsely pubescent.
3–11.5 cm, glabrous or puberulent.
sepals lanceolate, margins ciliate or eciliate, auricles 1–2 mm;
petals violet to soft blue-violet on both surfaces, whitish basally, lower 3 dark violet-veined, lateral 2 densely bearded, lowest 14–23 mm, spur blue-violet to whitish, gibbous to elongated, 2.4–5 mm, usually less than 1/2 lowest petal, tip straight;
style head bearded; cleistogamous flowers axillary.
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.
ellipsoid, 7–11 mm, glabrous.
spherical, ca. 5 mm, glabrous or finely puberulent.
light brown, 2.1–2.8 mm.
tan, 2.1–2.2 mm, elaiosome extending beyond and covering funiculus.
= 40, 80.
= 12.
Viola howellii
Viola vallicola
Viola howellii is similar to V. adunca and usually occupies moister habitats along the western side of the Cascade Mountains (H. E. Ballard 1992). The first documented record of this species in California was recently reported from Siskiyou County (R. J. Little 2010).
(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.)
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
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- Wikipedia
- Google Image Search
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