These are poppies of the woodlands, favoring moist and shaded areas. Their stems are bristly, and the leaves are lobed and/or divided. The flowers are yellow, with four petals, with the style unusually long, thus the name of the genus. Several may be found on each stem.
Stylophorum is closely related to Hylomecon vernalis, but the latter has only single flowers on each stem, and to the greater celandine Chelidonium majus, which has branched stems and no bracts or bracteoles.
Stylophorum diphyllum is native to eastern North America, where it is found in low-elevation deciduous forests from Ontario south to Kentucky. Stylophorum lasiocarpum is a poppy of central and eastern China, while the lesser-known Stylophorum sutchuenense, distinguished by the shaggy red hairs on stems and underneath leaves, comes from western China.