*Viola tricolor Linnaeus. Section: Melanium. Subsection: Bracteolatae. Phen: Chasmogamous flower Mar-Aug (-Oct); chasmogamous fruit Apr-Aug (-Sep). Hab: Lawns, garden borders, railroad rights-of-way, commonly cultivated. Dist: Native of Europe.
ID notes: This species is similar to the other two widely distributed pansies in our region, introduced V. arvensis and native V. rafinesquei. It differs from V. arvensis in the palmatifid stipules, petals well surpassing the sepals, and the upper petals commonly purple-black or occasionally the whole corolla purple. It differs further from V. rafinesquei in the common presence of basal leaves, stipules with the terminal leaf-like lobe much larger and with 4 or more crenations per side, leaf blade much longer than broad and with 4 or more teeth per side, and corolla commonly cream with upper petals purple-black or occasionally with all purple petals. It is most similar to the barely escaped garden pansy, V. ×wittrockiana, distinguished most obviously by its consistently smaller and usually less dramatically colorful flowers and narrower leaves.
Origin/Endemic status: Europe
Taxonomy Comments: Apparently hybridizes rarely with V. arvensis (Ballard, Kartesz, & Nishino 2023).
Synonymy: = Ar, C, F, Fl2, G, Il, K1, K3, K4, NE, Pa, RAB, WH3, Ballard, Kartesz, & Nishino (2023), Haines (2001); > Viola tricolor L. var. tricolor – FNA6