Brook Sunflower. Bidens laevis.
Composite Family. Aug. - Oct.
Plant 1 - 2 feet high, found in swamps, wet places. New England to Minnesota and southward.
Yellow, 1 - 2 1/2 inches across, rays 8 - 10. Seed vessels with 2 - 4 prongs.
Opposite, toothed, narrow lance-shaped, seated on stem.