Viola hirsutula
Viola biflora
southern woodland violet
arctic yellow violet, European field pansy, northern violet, queen Charlotte twinflower violet, twinflower violet
1–3+, ascending or erect, leafy proximally and distally, glabrous, on caudex from fleshy rhizome.
basal, 2–4, prostrate or nearly so;
stipules linear-lanceolate, margins entire, apex acute;
petiole 1–10 cm, usually glabrous;
blade unlobed, reniform to ovate, 1–6 × 1–5 cm, base cordate, margins serrate, ciliate or eciliate, apex rounded, adaxial leaf surface with silvery strigose patches.
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.
2–12 cm, glabrous.
2–9 cm, usually glabrous.
sepals lanceolate to ovate, margins ciliate or eciliate, auricles 1–2 mm;
petals light to deep reddish violet to blue-violet on both surfaces, 3 lower whitish basally, dark violet-veined, lateral 2 densely bearded, lowest 11–17 mm, spur violet, gibbous, 2–3 mm;
style head beardless; cleistogamous flowers on prostrate to ascending peduncles.
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.
ellipsoid, 8–12 mm, glabrous.
oblong-ovoid, 3–6 mm, glabrous or sparsely pubescent.
beige, mottled to bronze, 1–1.5 mm.
purple, sometimes streaked with light and dark brown, 1.5–2.5 mm.
= 54.
Viola hirsutula
Viola biflora
Viola hirsutula exhibits little phenotypic plasticity. Although considered by N. L. Gil-Ad (1997) to be a putative hybrid, he did not identify the potential parents and chose not to recognize it. A. Cronquist in H. A. Gleason and Cronquist (1991) considered V. hirsutula a form of V. villosa. Viola hirsutula is considered one of the more distinct species throughout its range by McKinney because of the pattern of silvery strigose patches on adaxial leaf surfaces and a more prostrate growth habit than similar species. He believes V. hirsutula is one of the least variable species in the flora. Viola hirsutula appears to occur much less frequently than herbarium collections suggest. Some herbarium specimens are misidentified and represent depauperate plants, usually of V. sororia. These specimens are often hairy on the adaxial leaf surfaces but lack the silvery patches.
Viola hirsutula reportedly hybridizes with V. sororia var. sororia (= V. ×cordifolia [Nuttall] Schweinitz) and V. sagittata var. sagittata (= V. ×redacta House).
(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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