Plants to 10 dm. Stems branching, ribbed. Leaves to 35 cm; petiole 2-10 cm; blade deeply 5-9-lobed; margins irregularly dentate or crenate, rarely laciniate. Inflorescences: peduncle 2-10 cm. Flowers: pedicels 5-35 mm; sepals to 1 cm; petals bright-yellow, obovate to oblong, to 2 cm wide; style ca. 1 mm. Capsules linear to narrowly oblong, 2-5 cm, glabrous. Seeds black, reticulate-pitted.
Phenology: Flowering spring–summer.
Habitat: Moist to dry woods, thickets, fields, hedgerows and fences, roadsides, railroads, and waste ground
Elevation: 0-1000 m
Distribution
Introduced; B.C., N.B., N.S., Ont., P.E.I., Que., Conn., Del., Ill., Ind., Iowa, Maine, Md., Mass., Mich., Minn., Mo., Mont., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., Utah, Vt., Va., Wash., W.Va., Wis., Eurasia
Discussion
The irritating sap of Chelidonium has been used to treat warts. In the vegetative state, this weedy introduction from Eurasia is difficult to distinguish from the native Stylophorum diphyllum.
Selected References
None.