Northern Ontario Plant Database

General: A low, perennial forb, stemless, with shoots originating from a thick rhizome. Violet species often hybridize, so plants that do not clearly fit the keys or descriptions may be hybrids.

Nomenclatural Note: Viola septentrionalis Greene and V. latiuscula Greene are now considered to be synonyms of Viola sororia. See also the discussion below on synonymy, under the heading "Similar Species".

Leaves: Basal, simple, palmately-veined, petiolate. Leaf blades ovate to cordate, dark green, 6–10+ cm wide at maturity; leaves hairy; basal lobes cordate; apices of early leaves nearly rounded to blunt (obtuse), to somewhat pointed (acute) in mature leaves; margins crenate, with rounded teeth.

Flowers: Bisexual; petaliferous flowers not fragrant; solitary on a slender, hairy flower stalk (peduncle), about equal in length to the leaves. Sepals 5, oblong to ovate, with blunt (obtuse) tips, margins of the sepals and the short auricles are ciliate –edged with stiff, straight hairs; petals 5, deep purple, the upper 2 glabrous; lateral 2 petals bearded with slender, straight hairs; the lower, short-spurred petal is generally beardless, though some flowers may have a few hairs on the spurred petal. Fertile cleistogamous flowers are produced on fleshy, underground peduncles that become prostrate to arching in fruit. Petaliferous flowers bloom in mid to late May.

Fruit: An ovoid, purplish or purple-mottled, 3-valved capsule, glabrous, about 6 mm long. Capsules from cleistogamous flowers are borne on prostrate to arching peduncles. Seeds are buff to brown. Fruits mature in summer.

Habitat and Range: Viola sororia is typically found in moist, sugar maple forests as well as other hardwood or mixedwood forest stands. It often grows in moist meadows and slopes, in lawns, and along skidder trails. Viola sororia is native to temperate to southern boreal eastern North America. In northern Ontario, it has been reported from as far north as Timmins and Kapuskasing (as V. septentrionalis) (Scoggan 1978).

Internet Images: The Viola sororia webpage from the Missouriplants.com website.

The Viola sororia webpage from the Gallery of Connecticut Wildflowers, a website of the Connecticut Botanical Society.

In addition to the typical purple corolla, two other forms of Viola sororia are encountered occasionally, these are sold through nurseries under the names forma albiflora (white wood violet), a solid white-flowered form, and forma priceana (Confederate violet), a white-flowered version with heavy blue veining. Both of these webpages are from the website Wildflowers of Illinois in Savannas & Thickets.

Similar Species: There are several blue- or purple-flowered violets in northern Ontario. Some authors (McKinney & Russell 2002) reduce Viola novae-angliae House (New England violet) and V. missouriensis Greene (Missouri violet) to varietal status under V. sororia Willd., with V. nephrophylla Greene and V. papilionacea Pursh placed in synonymy under V. sororia Willd. var. sororia, and Viola affinis LeConte (LeConte's violet, sand violet) placed under V. sororia var. missouriensis (Greene) L.E. McKinney.

We have chosen to follow H.E. Ballard's classification, as described in his paper "Violets of Michigan" (Ballard 1994), which treats Viola sororia, V. affinis, V. novae-angliae, and V. nephrophylla as distinct species. Certainly, Viola nephrophylla, with its glabrous foliage, blunt, eciliate sepals, and preference for calcareous habitats, deserves recognition as a distinct species on both morphological and ecological grounds. I have not yet seen V. affinis or V. novae-angliae in the field, but Ballard (1994) also recognized these as distinct. Viola affinis can be differentiated from V. sororia by its smooth, more triangular-ovate leaf blades, its acuminate, eciliate sepals, and its preference for muck soils of hardwood floodplains and swamps. V. novae-angliae is restricted in Ontario to the western portion of the province. Like V. affinis, it has narrower leaf blades that are longer than broad, but it prefers the drier habitats of mixedwood and coniferous forests and sandy or rocky soils along lake shores. Ballard (1994) includes Viola missouriensis as a synonym of V. affinis, but states that it may represent a hybrid between V. affinis and V. sororia, based on the smooth, narrower leaves and beardless spurred petal (like V. affinis), and the blunt, ciliate sepals (like V. sororia).

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