Stylophorum is a small genus of Papaveraceae found in North America and eastern Asia. In the eastern United States, there is only one species, S. diphyllum (Michx.) Nutt., the celandine poppy, which is a perennial herb found in rich woods. Standard floristic works (Fernald 1950, Gleason 1952, Ernst 1962) state that S. diphyllum occurs from western Pennsylvania to Michigan and Wisconsin and south to Tennessee and Arkansas. In a recent treatment for the southeastern United States (Ernst and Kiger, in press), the range for that region is given as Alabama, Arkansas, Kentucky, Illinois, Indiana, Maryland, Missouri, Ohio, Tennessee, and West Virginia with Pennsylvania listed as questionable.