||Plant 1 to 6 feet tall. Leaves
lance-shaped, wavy-edged, slightly toothed, not opposite each
other. Flowers sulfur yellow, with four petals and four
sepals bent way back. Flowers are wide open at twilight
and during the night, but close up during the day. Fruit a
capsule, green at first (as in lower right), become dry and
brown, splitting open at the top to release the seeds.
Blooms in the summer, seed capsules persisting into the winter.
Weedy native of open spaces. In Wildwood, in the meadows
and along the bikeway.
Nothing else in the Park has 4-parted sulfur yellow flowers
opening at night. Buttercups are smaller, with 5-parted glossy