kingdom Plantae - plants »  divisio Magnoliophyta - flowering plants »  class Rosopsida - eudicots » order Malpighiales »  family Violaceae »  tribus Violeae > genus Viola > Viola sect. Melanium  Ging. 

Viola maritima (Schweigg.) Tzvel.

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Synon. :  Viola tricolor ssp. maritima Schweigg. ex Clausen; Viola tricolor ssp. subsp. curtisii (E. Forst.) Syme

Description: Hemicryptophyte. Short-lived perennial; fairly sparsely hairy or sometimes glabrous. Stems usually richly branched below the soil surface; subterranean parts whitish, covered with scale-like, fleshy leaves; aerial stems often purplish at the base, to 30 cm; central stems erect, peripheral ones ascending to procumbent. Leaves slightly fleshy. Stipules of middle and upper leaves 9–18(–21) mm, shorter than the petiole; lateral lobes (on the outer edge) 3–5(–6), almost lingulate; terminal lobe ensiform, falcate or spathulate. Blade of lower leaves ovate to lanceolate with broadly cuneate base and obtuse apex, 5–10 × 3–7 mm, 1.25–2 times as long as wide; blade of middle and upper ones ovate to narrowly elliptic with cuneate base and fairly acute apex, 9–16 × 3–7 mm, 1.5–5 times as long as wide. Sepals 5–7 × 1–2 mm (excluding the appendage); appendages 1–1.8 × 0.9–1.7 mm, 0.2–0.3 times as long as the sepals. Corolla violet, rose, yellowish white, bright yellow or occasionally white, with dark lilac veins; upper petals recurved, 7.5–13.5 × 4–8.5 mm, 1.5–2.2 times as long as wide, lateral petals 6–11 × 3–7 mm, 1.5–2 times as long as wide, spurred petal 8–14 × 4–10 mm, 1.2–2 times as long as wide; spur violet or occasionally white, straight, 3–5 × 0.9–1.5 mm, 1.6–3 times as long as the sepal appendages. Capsule triangular in cross-section, acute, 4–7.5 × 2–3 mm. Seeds 1.5–2.5 × 0.8–1.5 mm.

Distributional Range: Coasts of Europe from France and the British Isles to southernmost N; in the Baltic to Russia (St. Petersburg and Kaliningrad). NORTHERN EUROPE: Fennoscandia  [Finland,  Norway, Sweden, Russia [Murmansk Oblast, Karelia, Leningrad Oblast]

Habitat: Shifting sand, mainly on seashores; more rarely grassland on sand.

Note: The Nordic sand ecotypes are possibly more closely related to subsp. tricolor than to subsp. curtisii in its narrowest sense (Nauenburg 1986); they have sometimes been referred to a separate taxon, var. or subsp. maritima. It is clear that the variation pattern needs to be studied more closely.

References:

1. Tutin, T. G. et al., eds. 1964-1980. Flora europaea.