Viola palustris L.

Plants perennial, acaulescent, stoloniferous, 3–21.5 cm; stolons pale, often rooting and leafy at nodes; rhizome slender, fleshy. Leaves basal, 2–4, ascending to erect; stipules linear-lanceolate, margins entire, apex acute; petiole 1–17 cm, glabrous; blade unlobed, reniform or ovate to orbiculate, 0.5–6.4 × 0.5–5.5 cm, ± as long as wide, base cordate, margins crenulate, eciliate, apex obtuse to acuminate, surfaces glabrous. Peduncles 2–20.7 cm, glabrous, bracteoles usually below middle in chasmogamous flowers. Flowers: sepals ovate or lanceolate, margins eciliate, auricles 1–2 mm; petals lilac, pale blue, or pale violet on both surfaces, sometimes nearly white and tinged with lilac, lowest and sometimes lateral 2 dark violet-veined, lateral 2 bearded or beardless, lowest 8–16 mm, spur usually same color as petals, gibbous, 1–3 mm; style head beardless cleistogamous flowers on ascending peduncles. Capsules ellipsoid, 6–10 mm, glabrous. Seeds dark brown, 1–2 mm. 2n = 48.

It is a temperate plant. It grows in moist and wet sites.