Common Dog Violet
- Name also: Common Violet, Wood Violet, Common Dog-violet
- Family: Violet Family – Violaceae
- Growing form: Perennial herb. Rootstock vertical, dark.
- Height: 5–20 cm (2–8 in.). Stem leafy, branched, usually glabrous (sometimes sparsely hairy).
- Flower: Corolla zygomorphic, blue–purple, inner parts white (sometimes completely white), 1.4–2.5 cm (0.55-1 in.) wide; petals 5, overlapping, covering one another, lowest with short, thick, usually upwardly-curved pale spur. Sepals 5. Stamens 5. Gynoecium fused, single-styled. Flowers solitary, nodding.
- Leaves: In basal rosette and alternate on stem, stalked, stipulate; stalk wingless. Blade widely cordate–almost kidney-shaped, with rounded teeth (crenate), bright green. Stipules linearly elliptic, long-tipped, usually densely slender-toothed, teeth spreading, narrow.
- Fruit: Glabrous, 3-valved capsule.
- Habitat: Young forests, broad-leaved forests, forest margins, coppices, grazing land, young meadows.
- Flowering time: May–June.
Common dog violet’s beautiful flowers adorn fertile forests in southern and central Finland from the end of spring and the beginning of summer. A chilly early spring can mean that pollinators do not visit during the flowering time, so to be on the safe side the species grows self-pollinating flowers at the end of the summer that remain unopened. Violet capsules open up into three separate gutters, which are almost at the same level. Each gutter has seeds in two rows, and when the gutter’s sides begin to curl together the seeds are catapulted out one by one. Their journey might not end there as ants drag the seeds further as they eat their fatty elaiosomes (oily appendage on seed).
Common dog violet’s virtually unbroken habitat reaches as far north in Finland as Vaasa and Joensuu. North of here it quickly becomes much rarer and its stands are far apart towards the mouth of the River Tornio, around Kemi and in Kuusamo. Common dog violet grows in forests and meadows, and can show where forests and forest margins used to be.
Common dog violet is often confused with its close relative heath dog violet (V. canina) even though there are clear differences between the two with regards to their leaves and ways of growing. Common dog violet has a vertical root and a basal rosette, while heath dog violet’s creeping rootstock doesn’t develop one. The species’ leaves are similar but common dog violet’s are much wider and its stipules are narrower and densely slender-toothed (heath dog violet’s are serrated). Heath dog violet is at home in open environments, from meadows to coppices. It also grows in the forest, usually close to human activity, as a consequence of e.g. grazing, slash-and-burn agriculture and logging. Sometimes common dog violet shares its habitat with its larger relative wonder violet (V. mirabilis), but common dog violet’s leaves are much smaller, under 4 cm (1.6 in.) wide.