Like a larger version of the Celandine, this bright yellow poppy blooms at the same time, but is easily distinguished by its larger flowers with overlapping petals and bright orange stamens. This plant was blooming in early May along the Trillium Trail in Fox Chapel.
Gray describes the genus and the species:
STYLOPHORUM Nutt. CELANDINE POPPY. Sepals 2, hairy. Petals 4. Style distinct, columnar; stigma 2-4-lobed. Pods bristly, 2-4-valved to the base. Seeds conspicuously crested. — Perennial low herbs, with stems naked below and oppositely 2-leaved, or sometimes 1-3-leaved, and umbellately 1-few-flowered at the summit; the flower-buds and the pods nodding. Leaves pinnately parted or divided. Juice yellow. (From stylos, style, and pherein, to bear, one of the distinctive characters.)
S. diphyllum (Michx.) Nutt. Leaves pale beneath, smoothish, deeply pinnatifid into бог 7 oblong sinuate-lobed divisions, and the root-leaves often with a pair of small distinct leaflets; peduncles equaling the petioles; flower deep yellow (5 cm. broad); stigmas 3 or 4; pod ovoid. —Damp woods, w. Pa. to Wisc., ” Mo.,” and Tenn. May. —Foliage and flower resembling Celandine.