kingdom Plantae - plants »  divisio Magnoliophyta - flowering plants »  class Rosopsida - eudicots » order Malpighiales »  family Violaceae »  tribus Violeae > genus Viola > Viola sect. Viola  L. > Viola subsect. Rostratae Kupffer    

Viola stagnina Kit. ex Schult. - Fen Viole

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Synon.: Viola canina subsp. stagnina (Kit ex Schult.) Rouy & Fouc.; Viola persicifolia  auct. non Schreber

Common names: Фиалка прудовая 

Description: Hemicryptophyte. Rhizomatous, caulescent perennial. Rhizome vertical, branching below or at the soil surface, covered with numerous brown stipules; terminal leaf rosette absent. Aerial stems erect, normally to 25 cm, glabrous or with few, scattered, small hairs. Stem leaves up to 10; stipules narrowly lanceolate, 5–22 mm, usually not longer than the petiole, green, hairy, with few coarse teeth; petiole to 2 cm, glabrous except for hyaline hairs at the base; blade narrowly ovate to lanceolate, 20–40 × 5–20 mm, 2–4 times as long as wide, light green, with scattered, hyaline hairs on the upper surface, glabrous on the lower surface; margin crenate with 10–15 obtuse teeth or near the base with forwards-pointing teeth; base truncate or slightly cordate, markedly decurrent onto the petiole; apex acute.

Chasmogamous flowers scentless, from the middle or upper part of the aerial stems. Pedicels glabrous, to 3 cm, shorter than the subtending leaves; bracteoles subulate, in the upper half of the pedicel. Sepals lanceolate, acute, 4.5–10 × 1.3–2.5 mm (excluding the appendage); appendage suborbicular to truncate, 0.6–2.5 × 1.3–2.5 mm, 0.1–0.3 times as long as the rest of the sepal. Corolla 20 × 15 mm, 1.3 times as high as wide, flat in front view. Petals white with light violet veins; upper petals recurved, obovate, obtuse, 6–13 × 3.5–8 mm, 1.8–2 times as long as wide; lateral petals narrowly obovate, obtuse, 10–13 × 4–6 mm, 1.8–2.2 times as long as wide, with hyaline hairs at the throat; spurred petal slightly concave, 8–16 × 4–8 mm excluding the spur, 1.9–2.1 times as long as wide; spur light green to yellow-green, sac-like, 2–4 × 2–3.5 mm, 0.9–1.1 times as long as wide, 2.5–3.5 times as long as the sepal appendages. Style papillose at the tip. Cleistogamous flowers 4–5 mm. Capsule ovoid, trigonous, acute, 6–8 mm, glabrous, explosive. Seeds ovoid, 1.4–1.6 × 0.65–0.8 mm, pale to light brown; elaiosome small. – Late spring to early summer (chasmogamous flowers), mid-summer (cleistogamous flowers). 2n=20 (N Ak 4, Bu 10). – [2n=20]

Distributional Range:  Native [From the British Isles and northern Spain east to W Siberia, although most Siberian records are based on misidentified V. pumila]

• Asia-Temperate 

  • CAUCASUS: Russian Federation [Krasnodar]

  • SIBERIA: Russian Federation [Altay, Evenk, Irkutsk, Khanty-Mansi, Tomsk, Tuva]

• Europe 

  • NORTHERN EUROPE: Denmark, Finland, Ireland, Norway, United Kingdom

  • MIDDLE EUROPE: Austria, Belgium, Czechoslovakia, Germany, Hungary, Luxembourg, Netherlands, Poland, Switzerland

  • EASTERN EUROPE: Belarus, Estonia, Latvia, Lithuania, Moldova, Russian Federation-European part, [European part] Ukraine

  • SOUTHEASTERN EUROPE: Former Yugoslavia, Italy, Romania

  • SOUTHWESTERN EUROPE: France, Spain

Habitat:  Temporarily flooded shores of lakes, streams and fens usually on base-rich but nutrient-poor substrate. Thermophilous and light-demanding. – Gravelly to stony bare shores, rock fissures close to the water, wet and moist meadows on rather rich humus soils, low grassland, temporarily dried-out pools in forest, sometimes in swamps. Sensitive to competition and in grassland localities dependent on mowing or grazing. Declining all over Norden due to eutrophication, overgrowth, water regulation and ditching.

References:

1. Applequist, W. L. 2012. Report of the Committee for Spermatophyta: 64. Taxon 61:1110. Note: proposal recommended

2. Danihelka, J. et al. 2010. (1983–1984) Proposals to reject the names Viola montana and V. persicifolia (Violaceae). Taxon 59:1900-1902.

3. Danihelka, J. et al. 2010. Viola montana and V. persicifolia (Violaceae): two names to be rejected. Taxon 59:1869-1878.