Hypericum ellipticum is an aquatic perennial herb 20-50 cm, colonial from rhizomes, stems mostly unbranched below inflorescence.
Leaves opposite, elliptic, 1-3 cm long to ca 1.5 cm wide, blunt at both ends, speckled with minute, translucent glands (hold up to light).
Flowers bright yellow, 5-parted, petals 0.5-0.7 cm long, sepals to 0.6 cm long, stamens numerous, stigmas 3; inflorescence rather few-flowered, with a few linear bracts.
Fruit becoming dry, styles persistent as a beak, capsule egg-shaped, to 0.6 cm.
Wetland status: OBL.
Frequency in NYC: Very infrequent.
Habitat: Wet shores, marshes.