62. Viola sororia Willdenow, Hort. Berol. 1: plate 72. 1806.
Common or downy or woolly blue violet, violette parente Common or downy or woolly blue violet, violette parente
Viola chalcosperma Brainerd; V. floridana Brainerd; V. latiuscula Greene; V. palmata Linnaeus var. sororia (Willdenow) Pollard; V. papilionaceae Pursh; V. priceana Pollard; V. rosacea Brainerd; V. septentrionalis Greene; V. wilmattiae Pollard & Cockerell
Flowering Mar–Jun. Dry to mesic habitats in woods, thickets, stream banks, moist prairies, pastures, disturbed ground, not in saturated soil; 0–3000 m; B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Sask.; Ala., Ark., Colo., Conn., Del., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., W.Va., Wis.
Viola sororia is similar to V. palmata in the high degree of phenotypic plasticity. The petal color is usually light to dark blue-violet. In V. sororia forma priceana (the Confederate violet) petals are grayish white with violet veins. Viola septentrionalis was recognized by N. L. Gil-Ad (1997) based on what he considered distinct capsule and seed morphology. His assumptions were based on one to four specimens. A. Haines (2011) alluded to the variability of V. sororia and indicated that a more northern form has often been called V. septentrionalis. He suggested that range-wide patterns of variation make it difficult or impractical to separate. We currently see no valid reason to recognize V. septentrionalis.
Viola floridana was recognized by D. B. Ward (2006) as distinct from V. sororia based on being glabrous except for scattered hairs on petioles.
Viola sororia reportedly hybridizes with V. cucullata (= V. ×bissellii House), V. hirsutula [= V. ×cordifolia (Nuttall) Schweinitz], V. pedatifida var. brittoniana (= V. ×insolita House), V. pedatifida var. pedatifida (= V. ×bernardii Greene), and V. sagittata var. sagittata (= V. ×conjugens Greene).