The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Howell's violet, violette de Howell

Cascades early blue violet, common periwinkle, early blue violet, hook-spur violet, hookedspur violet, large periwinkle, sand violet, western dog violet, wild dog violet

Habit Plants perennial, caulescent, not stoloniferous, 2–44 cm. Plants perennial, caulescent, not stoloniferous, 1.8–30(–35) cm.
Stems

1–4, ascending to erect (sometimes later reclining to nearly prostrate), glabrous or sparsely pubescent, on caudex from subligneous rhizome.

1–5, erect, ascending, or decumbent, sometimes later reclining to nearly prostrate, glabrous or puberulent, on caudex from subligneous rhizome.

Leaves

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: 1–4;

stipules linear to linear-lanceolate, margins entire or laciniate with gland-tipped projections, apex acute to acuminate;

petiole 0.5–13.5 cm, glabrous or puberulent;

blade usually ovate or ovate-deltate to ovate-orbiculate, sometimes ± reniform or oblong, 0.5–6.9 × 0.4–5 cm, base cordate, subcordate, truncate, or attenuate, usually decurrent on petiole, margins crenate to crenulate or entire, ciliate or eciliate, apex acute to obtuse, surfaces glabrous or sparsely to densely puberulent;

cauline similar to basal except: stipule margins lacerate to laciniate;

petiole 0.5–6.5 cm;

blade 0.6–5.5 × 0.4–4.7 cm.

Peduncles

2.8–17.8 cm, glabrous or sparsely pubescent.

1.7–13.8 cm, glabrous or puberulent.

Flowers

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 ciliate or eciliate, auricles not enlarged in fruit, 0.5–2 mm;

petals light- to deep- to lavender-violet on both surfaces, rarely white, lower 3 usually white basally, dark violet-veined, lateral 2 (and sometimes upper 2) bearded, lowest 7–17(–23) mm, spur purple to violet or white, elongated, 5–7 mm, tip straight or pointed, curved up or lateral;

style head sparsely to densely bearded, sometimes beardless; cleistogamous flowers axillary.

Capsules

ellipsoid, 7–11 mm, glabrous.

short-ovoid, 6–11 mm, glabrous.

Seeds

light brown, 2.1–2.8 mm.

dark brown to olive-black, 1.5–2 mm.

2n

= 40, 80.

Viola howellii

Viola adunca

Phenology Flowering Apr–Jul.
Habitat Moist, shady areas, coniferous forests, prairies, along streams
Elevation 50–1500 m (200–4900 ft)
Distribution
from FNA
CA; OR; WA; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AZ; CA; CO; IA; ID; MA; ME; MI; MN; MT; ND; NE; NH; NM; NV; NY; OR; SD; UT; VT; WA; WI; WY; AB; BC; MB; NB; NS; NT; NU; ON; QC; SK; YT
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Varieties 2 (2 in the flora).

Viola adunca is polymorphic with over 50 named taxa. G. D. McPherson and J. G. Packer (1974) reported that diploid, triploid, and tetraploid races of V. adunca occur in Canada and northwestern United States. They found that diploid and tetraploid chromosome races can be distinguished morphologically based on style beards and on the size of guard cells and pollen grains and recommended taxonomic recognition of both races. In diploid races, the style projections are more or less cylindrical and about one-sixth the width of the style; in tetraploid races they are short-conical or globular, and about one-tenth or less than the width of the style beard.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Plants (4–)4.5–30(–35) cm; basal blades 1.3–6.9 × 1.2–5 cm; peduncles 3–13.8 cm; 0–3600 m; widespread in North America.
var. adunca
1. Plants 1.8–4.5(–6.5) cm; basal blades 0.5–1.7 × 0.4–1.4 cm; peduncles 1.7–5 cm; 2500–3800 m; restricted to Rocky Mountains (Colorado, Montana, Wyoming, British Columbia).
var. bellidifolia
Source FNA vol. 6, p. 134. FNA vol. 6, p. 119.
Parent taxa Violaceae > Viola Violaceae > Viola
Sibling taxa
V. adunca, V. affinis, V. arvensis, V. bakeri, V. beckwithii, V. bicolor, V. biflora, V. blanda, V. brittoniana, V. canadensis, V. canina, V. charlestonensis, V. clauseniana, V. cucullata, V. cuneata, V. douglasii, V. egglestonii, V. epipsila, V. flettii, V. frank-smithii, V. glabella, V. guadalupensis, V. hallii, V. hastata, V. hirsutula, V. japonica, V. labradorica, V. lanceolata, V. langsdorffii, V. lithion, V. lobata, V. macloskeyi, V. missouriensis, V. nephrophylla, V. novae-angliae, V. nuttallii, V. ocellata, V. odorata, V. orbiculata, V. palmata, V. palustris, V. pedata, V. pedatifida, V. pedunculata, V. pinetorum, V. praemorsa, V. primulifolia, V. prionantha, V. pubescens, V. purpurea, V. quercetorum, V. renifolia, V. riviniana, V. rostrata, V. rotundifolia, V. sagittata, V. selkirkii, V. sempervirens, V. septemloba, V. sheltonii, V. sororia, V. striata, V. subsinuata, V. tomentosa, V. tricolor, V. trinervata, V. tripartita, V. umbraticola, V. utahensis, V. vallicola, V. villosa, V. walteri
V. affinis, V. arvensis, V. bakeri, V. beckwithii, V. bicolor, V. biflora, V. blanda, V. brittoniana, V. canadensis, V. canina, V. charlestonensis, V. clauseniana, V. cucullata, V. cuneata, V. douglasii, V. egglestonii, V. epipsila, V. flettii, V. frank-smithii, V. glabella, V. guadalupensis, V. hallii, V. hastata, V. hirsutula, V. howellii, V. japonica, V. labradorica, V. lanceolata, V. langsdorffii, V. lithion, V. lobata, V. macloskeyi, V. missouriensis, V. nephrophylla, V. novae-angliae, V. nuttallii, V. ocellata, V. odorata, V. orbiculata, V. palmata, V. palustris, V. pedata, V. pedatifida, V. pedunculata, V. pinetorum, V. praemorsa, V. primulifolia, V. prionantha, V. pubescens, V. purpurea, V. quercetorum, V. renifolia, V. riviniana, V. rostrata, V. rotundifolia, V. sagittata, V. selkirkii, V. sempervirens, V. septemloba, V. sheltonii, V. sororia, V. striata, V. subsinuata, V. tomentosa, V. tricolor, V. trinervata, V. tripartita, V. umbraticola, V. utahensis, V. vallicola, V. villosa, V. walteri
Subordinate taxa
V. adunca var. adunca, V. adunca var. bellidifolia
Synonyms Lophion aduncum, V. canina var. adunca
Name authority A. Gray: Proc. Amer. Acad. Arts 22: 308. (1887) Smith: in A. Rees, Cycl. 37: Viola no. 63
Web links