Viola sororia is a low, stemless, perennial herb, about 10 cm; colonial from a short knobby branching rhizome, roots associated with VA mycorrhizas (Brundrett and Kendrick 1988); life span about 10-14 years (Bierzychudek 1982; Solbrig et al. 1980).
Leaves basal, stalk to 20 cm long, blade to 7 cm long, 6 cm wide, heart-shaped, held at an angle to the erect stalk, summer leaves to 13 cm wide, emergence in Spring corresponds to soil temp above 10 ºC, an air temp above 0 ºC., well before canopy closure (Solbrig et al 1980; Collins et al. 1985).
Flowers purple, to white, to 3 cm wide, rather flat-faced 5-parted, bilaterally symmetrical, side petals bearded, blooms in April, later in season produces inconspicuous, closed flowers barely above soil.
Fruit a purplish-green capsule, elliptic, longer than persistent sepals, seed brown, to 0.25 cm long, 0.15 cm wide, several with a fatty appendage (elaiosome), initially dispersed by explosive dehiscence, secondarily dispersed by ants attracted to fleshy appendage, seeds eaten by birds,).
Wetland status: FAC-.
Frequency in NYC: Frequent.
Habitat: Disturbed woods, shady lawns, edges. Shade tolerant, appears to go dormant during dry summers, does not appear to compete well with taller vegetation in full sun. (Martin et al. 1951; Beattie and Culver 1981; Thompson 1981; Wein and Pickett 1989).
Notes: Probably the most common violet in the United States. Foliage eaten by small mammals (rabbits), and butterfly larvae of the great spangled fritillary, Speyeria cybele (Nymphalidae) (Klots 1951; Martin et al 1951; Solbrig et al 1980).