Triodanis perfoliata is an annual herb, 10-100 cm tall, hairy or rough, few-branched, often flowering to near base.
Leaves alternate, stalkless, clasping stem, blade heart-shaped 0.5-3 cm long and about as wide, rounded, veins palmate, margin usually toothed.
Flowers purple to lavender, radially symmetrical (regular), 5-parted, fused at base, 0.8-1.3 cm long, in axils along upper stem, lower flowers closed, inconspicuous.
Fruit capsule about 1 cm, opening by pores to release tiny seeds.
Wetland status: FAC.
Frequency in NYC: Very infrequent.
Habitat: Open habitats, disturbed, sterile soil.