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early yellow or roundleaf yellow violet, round-leaf violet, roundleaf yellow violet, violette à feuilles rondes

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, acaulescent, not stoloniferous, 1–20 cm; rhizome thick, fleshy. Plants perennial, caulescent, not stoloniferous, 1.8–30(–35) cm.
Stems

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

Leaves

basal, 2–5, prostrate to ascending, often overlapping basally;

stipules linear-lanceolate, margins entire, apex acute;

petiole 2–8 cm, pubescent;

blade unlobed, orbiculate, reniform, or ovate, 2–12 × 1.5–9 cm, base cordate, margins crenate to serrate, sometimes glandular, ciliate or eciliate, apex rounded to acute, surfaces usually pubescent throughout or concentrated proximally on both surfaces.

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

1.5–7 cm, usually pubescent.

1.7–13.8 cm, glabrous or puberulent.

Flowers

sepals lanceolate to ovate, margins ciliate or eciliate, auricles 0.5–1 mm;

petals deep lemon-yellow on both surfaces, lower 3 brownish purple-veined, lateral 2 bearded, lowest 8–11 mm, spur yellow, gibbous, 1–2 mm;

style head beardless; cleistogamous flowers on prostrate or partially subterranean rhizomes or on racemelike, nonrooting, and usually leafless branches growing from rhizome apex.

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, 5–10 mm, glabrous.

short-ovoid, 6–11 mm, glabrous.

Seeds

beige, 1–2 mm.

dark brown to olive-black, 1.5–2 mm.

2n

= 12.

Viola rotundifolia

Viola adunca

Phenology Flowering Mar–May.
Habitat Rich montane forests and other mesic woodlands
Elevation 200–2000 m (700–6600 ft)
Distribution
from FNA
CT; DE; GA; KY; MA; MD; ME; NC; NH; NY; OH; PA; RI; SC; TN; VA; VT; WV; ON; QC
[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

N. H. Russell (1955b) stated that Viola rotundifolia is a primitive member of Viola and probably one of the ancestral species of stemmed yellow violets of North America. Russell (1965) stated that morphologically, V. rotundifolia is one of the most invariable violets and suggested that its nearest relative is V. orbiculata.

(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. 155. 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. 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. 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 Michaux: Fl. Bor.-Amer. 2: 150. (1803) Smith: in A. Rees, Cycl. 37: Viola no. 63
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