Chelidonium majus is a biennial herb to 80 cm tall, branched, pale, somewhat blue-green, very hairy, sap bright orange, sticky, very toxic if ingested, contains a number of alkaloids common to Papaveraceae including chelidonine, sanguinarine, and berberine (Kingsbury 1964).
Leaves alternate, deeply pinnately lobed to compound, hairy below, blunt toothed, from an overwintering rosette, new leaves produced after leaf drop in autumn (Brundrett and Kendrick 1988).
Flowers yellow, ca. 2 cm wide, 4 petals.
Fruit green, thin, cylindrical pods to 5 cm long, seeds with arils (possibly ant dispersed).
Wetland status: UPL.
Frequency in NYC: Occasional.
Habitat: Escaped from cultivation along edges, in semi-shade.
Notes: A European garden and medicinal plant. Apparently brought to North America early in colonial times and therefore erroneously often thought to be native. May be toxic to liver (Therapeutic Goods Admin. 2003)