Stylophorum diphyllum (USA)

Stylophorum diphyllum (celandine-poppy, wood poppy, poppywort) is a herbaceous perennial native to moist woodland in eastern North America, valued for its yellow flowers.

Plants grow about 1.5 feet tall from rhizomes. Leaves are pinnately cut and lobed. They grow from the base and off the flowering stems. Apart from its normal sap, Stylophorum diphyllum produces a yellow-orange latex that stains.

In spring, the deep yellow flowers of the Wood Poppy appear as a brilliant display on the forest floor. It comes as no surprise that the other common names of this plant are “Yellow Poppy” and “Celandine Poppy”. Members of the Poppy Family are characterized by their production of latex, which in the case of the Wood Poppy is yellow. The flowers have 4 yellow petals, two soon falling sepals, many yellow-orange stamens, and a single knobby stigma. They appear in umbels of one or more flowers from early spring to early summer.

After fertilization, a bristly blue-green pod hangs below the leaves. Seeds with white elaiosomes ripen in midsummer and the pod opens by four flaps.

Plants are relatively long lived and readily self-seed under garden conditions, where they are grown under full to part shade.

References:

The Plant List  GRIN  Flora of North America (As in bold at top)  Wikipedia