Viola labradorica
Viola biflora
alpine violet, American dog or Labrador or alpine violet, American dog violet, dog violet, Labrador violet, violette du Labrador
arctic yellow violet, European field pansy, northern violet, queen Charlotte twinflower violet, twinflower violet
1–5, erect (later reclining), glabrous, on caudex from subligneous rhizome.
1–3+, ascending or erect, leafy proximally and distally, glabrous, on caudex from fleshy rhizome.
basal and cauline;
basal: 1–5;
stipules mostly lanceolate-linear, margins usually laciniate with gland-tipped projections, apex acute;
petiole 1–9.5 cm, glabrous or puberulent;
blade reniform or ovate to deltate, 1.4–5.5 × 1.8–5.3 cm, base cordate, not decurrent on petiole, margins crenate or serrate, mostly eciliate, apex acute to obtuse, surfaces usually glabrous, sometimes pubescent adaxially near margin;
cauline similar to basal except: stipules lanceolate to ovate, margins ± entire or laciniate, projections often gland-tipped, apex acuminate;
petiole 0.5–3.6 cm, glabrous;
blade narrowly ovate to orbiculate, 1.8–2.9 × 1.5–3.1 cm, base deeply cordate to truncate, margins regularly crenate, apex obtuse to broadly rounded or apiculate.
basal and cauline;
basal: 2–3(–4);
stipules ovate-lanceolate, ovate, or oblong, margins entire, apex ± acute;
petiole 1.5–15 cm, glabrous;
blade broadly reniform to orbiculate, 0.5–4.6 × 0.9–6.4 cm, base cordate, margins crenate to crenate-serrate, ciliate, apex obtuse, rounded, or truncate, rarely with terminal point, abaxial surface sparsely puberulent on veins, adaxial surface glabrate to ± densely puberulent;
cauline similar to basal except: stipules lanceolate, ovate, or oblong, margins entire to erose, apex acute to obtuse;
petiole 0.3–7(–10) cm;
blade sometimes ovate, 0.8–3.7 × 1–4.8 cm.
5–9 cm, glabrous or pubescent.
2–9 cm, usually glabrous.
sepals lanceolate, margins ciliate or eciliate, auricles not enlarged in fruit, 1–1.5 mm;
petals usually lavender-violet to violet on both surfaces, rarely white, lower 3 white basally, darker violet-veined, lateral 2 sparsely bearded, lowest 9–16 mm, spur white to pinkish violet, elongated, 4–8 mm, tip usually straight, sometimes curved up;
style head beardless; cleistogamous flowers unknown.
sepals with or without purple stripe on both sides of midvein, narrowly lanceolate to oblong, margins ciliate or eciliate, auricles 0.5–1 mm;
petals deep lemon-yellow on both surfaces, lower 3 and often upper 2 brownish purple-veined, lateral 2 beardless, lowest 6–15 mm, spur yellow to yellowish green, gibbous, 2–2.5 mm;
style head beardless; cleistogamous flowers axillary.
ovoid to ellipsoid, 5–7 mm, glabrous.
oblong-ovoid, 3–6 mm, glabrous or sparsely pubescent.
beige to bronze, 1.5–2 mm.
purple, sometimes streaked with light and dark brown, 1.5–2.5 mm.
= 20.
Viola labradorica
Viola biflora
H. E. Ballard (1994) made a compelling case for including Viola conspersa within V. labradorica, which is followed here. Ballard (1992) did not recognize V. labradorica as occurring in Colorado. Several western herbaria have collections identified as V. labradorica (ASC, CS, KHD, RM, RMBL; http://swbiodiversity.org/seinet/index.pho). Labels on some collections at KHD imply that V. labradorica is considered synonymous with V. adunca var. bellidifolia.
Viola labradorica reportedly hybridizes with V. adunca, V. rostrata (= V. ×malteana House), and V. striata (= V. ×eclipes H. E. Ballard), and less frequently with V. walteri var. appalachiensis and var. walteri.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 5 (2 in the flora).
Viola biflora may be the most widely distributed species of the genus in the Northern Hemisphere. Although occurring most often in mountainous areas at high elevations, it is known from Alaska near the coast at elevations of ca. 45 m (PNW Herbaria Portal 2010) and has been reported from lowland meadows in Kamchatka (V. B. Baird 1942), and is occasionally found near sea level in exposed rocky habitats on the west coast of the Queen Charlotte Islands (R. A. Calder and R. L. Taylor 1968).
Sometimes described as high latitude, circumpolar, Viola biflora also occurs in mid latitudes north of the equator. It is not truly circumpolar; it does not occur in eastern Canada or in Greenland. The deeply cleft style head sets V. biflora apart from all other species in North America. V. B. Baird (1942) suggested that the occasional presence of two cleistogamous flowers in the axil of the same leaf may account for the name “biflora.”
H. N. Ridley (1930) said that in Europe, deer (Cervus dama Linnaeus and Rangifer tarandus Linnaeus) may play a role in the dispersal of Viola biflora; seeds have been recovered from their droppings.
Nonflowering Viola biflora can be confused with V. renifolia where their ranges overlap in Yukon, Alaska, and Colorado.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Lowest petal 6–10 mm; seeds 1.5–2 mm; sepals usually without purple stripe; Yukon, Alaska, Colorado. | var. biflora |
1. Lowest petal 11–15 mm; seeds 2.5 mm; sepals usually with purple stripe; Queen Charlotte Islands, Vancouver Island, British Columbia. | var. carlottae |
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