Northeast Wetland Flora
Field Office Guide to Plant Species
Bidens tripartita L.
- Family: Composite (Compositae)
- Flowering: August-October
- Field Marks: This species of Bidens is characterized by its 3- to 5-lobed leaves with winged stalks, its flat achenes with 2-4 awns only about 1/8 inch long, and its rayless flower heads.
- Habitat: Swampy areas.
- Habit: Annual herb with fibrous roots.
- Stems: Upright, branched or unbranched, smooth, up to 3 feet tall.
- Leaves: Opposite, simple, usually 3- to 5-lobed, pointed at the tip, tapering to a winged stalk, toothed, smooth, up to 6 inches long.
- Flowers: Many flowers in heads, with several heads on smooth stalks up to 4 inches long, each head with 4-8 outer bracts, the bracts linear to lanceolate, densely ciliate, each head rayless, the disk flowers 1/6-1/4 inch long.
- Sepals: 0.
- Petals: 5, united to form tubular disk flowers.
- Stamens: 5.
- Pistils: Ovary inferior.
- Fruits: Achenes obovate, flat, with downward-pointing hairs along the edges, otherwise smooth, 1/4-1/3 inch long, with 2-4 awns only about 1/8 inch long.
- Notes: Although this family is called Asteraceae by Gleason and Cronquist, they do not recognize this species.
Previous Species -- Smooth Beggar-ticks (Bidens laevis)
Return to Species List -- Group 7
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