This is the equivalent of the N. American wood poppy (S. diphyllum), with similar yellow flowers, which are followed by bristly, silvery-haired, elongated seed capsules. The leaves are slightly different though, with 4-7 lobes, pinnatifid. Also, the roots and stems when broken will exude an orange-red sap (instead of yellow as in S. diphyllum).
It will tolerate dry shade better than S. diphyllum.
Germination: sown after collecting or kept moist and sown in late fall or (after a cold stratification period) in early spring.