Viola communis Pollard. Section: Nosphinium. Subsection: Borealiamericanae. Phen: Chasmogamous flower Mar-Jun (-Oct); chasmogamous fruit Apr-Jul; cleistogamous fruit July-Oct. Hab: Widespread in moist loam and clay soils of floodplains, thickets, transitioning between forested slopes and swamp or wetland borders, as well as lawns, suburban woodlots, roadsides and other open sites. Dist: Se. PA west to MI and KY, south to VA and MO.
ID notes:The undivided deep green and essentially glabrous glossy orbiculate to broadly deltate-ovate or deltate-reniform leaf blades with margins closely and uniformly crenate, apex broadly obtuse to rounded, render this species unmistakable. It is most similar to Borealiamericanae taxa with glabrous foliage and leaf blades as broad as to broader than long, as well as species with leaf blades broadening substantially in fruit. Besides the vegetative features noted above, this species differs in chasmogamous flower from V. nephrophylla in its glabrous spurred petal, sepals with acute apices and prominent auricles; and from V. domestica, V. sororia var. 1, and V. sororia var. 2 in its shorter stature, ovate-triangular sepals acuminate from the middle, and prominent auricles. Viola communis f. communis differs from V. cucullata in the flowers held among the leaves, ovate-triangular sepals acuminate from the middle, blue to purple corolla lacking a conspicuously contrasting eyespot around the throat, and lateral petal beards with long filiform to slightly clavate hairs concealing the throat; f. priceana shares a conspicuously contrasting eyespot around the throat with V. cucullata but diverges in its usually white to very pale violet petals, as well as the other traits mentioned for f. communis. In cleistogamous fruit, it can be separated from V. affinis and V. missouriensis in its often unspotted cleistogamous capsule on gradually erect-sinuous peduncle, ovate-triangular acuminate eciliate sepals, weakly elongating auricles, and blackish unspotted or minutely spotted seeds. It is distinguished from V. langloisii, V. pratincola, and V. retusa in its its glossy orbiculate to deltate-reniform leaf blades with apex obtuse to rounded, margins closely and uniformly crenate, and shorter and broader ovate-triangular sepals acuminate from the middle rather than from the base.
Origin/Endemic status: Native
Taxonomy Comments: Recently resurrected from obscurity as the earliest valid name for a narrowly defined but distinctive and widespread violet. This was formerly included with other glabrous or glabrate taxa under the name V. papilionacea by Brainerd and others, but the latter name has been misapplied (type material of V. papilionacea Pursh has been discovered and is an exact match for V. affinis Leconte). Russell (1965) conversely treated V. pratincola Greene as a distinct species of the Great Plains and w. Midwest region but lumped all eastern glabrous or glabrate violets into a broadly defined V. sororia; using leaf traits alone, he inadvertently included V. retusa Greene in his concept of V. pratincola, in part. The geographic range of this taxon is being reinterpreted and may be broader than indicated here. The frequent and conspicuous “Confederate Violet”, V. priceana Pollard, bears somewhat larger, attractive white or very pale violet corollas with a conspicuous broad blue-gray or purple eyespot (consisting of a dense, coalescing set of nectar-guide lines) around the throat. It is otherwise very similar to typical V. communis and frequently grows near or intermingled with the latter.
Synonymy: = Ballard, Kartesz, & Nishino (2023); < Viola papilionacea Pursh – RAB; > Viola papilionacea Pursh var. priceana (Pollard) Alexander – G; > Viola pratincola Greene – Tx; > Viola priceana Pollard – S; < Viola sororia Willd. – FNA6, Il, Pa